revert change in guider

* feat: implement three RAE encoders(dinov2, siglip2, mae)

* feat: finish first version of autoencoder_rae

* fix formatting

* make fix-copies

* initial doc

* fix latent_mean / latent_var init types to accept config-friendly inputs

* use mean and std convention

* cleanup

* add rae to diffusers script

* use imports

* use attention

* remove unneeded class

* example traiing script

* input and ground truth sizes have to be the same

* fix argument

* move loss to training script

* cleanup

* simplify mixins

* fix training script

* fix entrypoint for instantiating the AutoencoderRAE

* added encoder_image_size config

* undo last change

* fixes from pretrained weights

* cleanups

* address reviews

* fix train script to use pretrained

* fix conversion script review

* latebt normalization buffers are now always registered with no-op defaults

* Update examples/research_projects/autoencoder_rae/README.md

Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>

* Update src/diffusers/models/autoencoders/autoencoder_rae.py

Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>

* use image url

* Encoder is frozen

* fix slow test

* remove config

* use ModelTesterMixin and AutoencoderTesterMixin

* make quality

* strip final layernorm when converting

* _strip_final_layernorm_affine for training script

* fix test

* add dispatch forward and update conversion script

* update training script

* error out as soon as possible and add comments

* Update src/diffusers/models/autoencoders/autoencoder_rae.py

Co-authored-by: dg845 <58458699+dg845@users.noreply.github.com>

* use buffer

* inline

* Update src/diffusers/models/autoencoders/autoencoder_rae.py

Co-authored-by: dg845 <58458699+dg845@users.noreply.github.com>

* remove optional

* _noising takes a generator

* Update src/diffusers/models/autoencoders/autoencoder_rae.py

Co-authored-by: dg845 <58458699+dg845@users.noreply.github.com>

* fix api

* rename

* remove unittest

* use randn_tensor

* fix device map on multigpu

* check if the key is missing in the original state dict and only then add to the allow_missing set

* remove initialize_weights

---------

Co-authored-by: wangyuqi <wangyuqi@MBP-FJDQNJTWYN-0208.local>
Co-authored-by: Kashif Rasul <kashif.rasul@gmail.com>
Co-authored-by: Sayak Paul <spsayakpaul@gmail.com>
Co-authored-by: dg845 <58458699+dg845@users.noreply.github.com>

docs/source/en/api/models/helios_transformer3d.md

@@ -11,7 +11,7 @@ specific language governing permissions and limitations under the License. -->
 
 # HeliosTransformer3DModel
 
-A 14B Real-Time Autogressive Diffusion Transformer model (support T2V, I2V and V2V) for 3D video-like data from [Helios](https://github.com/PKU-YuanGroup/Helios) was introduced in [Helios: Real Real-Time Long Video Generation Model](https://huggingface.co/papers/) by Peking University & ByteDance & etc.
+A 14B Real-Time Autogressive Diffusion Transformer model (support T2V, I2V and V2V) for 3D video-like data from [Helios](https://github.com/PKU-YuanGroup/Helios) was introduced in [Helios: Real Real-Time Long Video Generation Model](https://huggingface.co/papers/2603.04379) by Peking University & ByteDance & etc.
 
 The model can be loaded with the following code snippet.
 

docs/source/en/api/pipelines/helios.md

@@ -22,7 +22,7 @@
 
 # Helios
 
-[Helios: Real Real-Time Long Video Generation Model](https://huggingface.co/papers/) from Peking University & ByteDance & etc, by Shenghai Yuan, Yuanyang Yin, Zongjian Li, Xinwei Huang, Xiao Yang, Li Yuan.
+[Helios: Real Real-Time Long Video Generation Model](https://huggingface.co/papers/2603.04379) from Peking University & ByteDance & etc, by Shenghai Yuan, Yuanyang Yin, Zongjian Li, Xinwei Huang, Xiao Yang, Li Yuan.
 
 *  <u>We introduce Helios, the first 14B video generation model that runs at 17 FPS on a single NVIDIA H100 GPU and supports minute-scale generation while matching a strong baseline in quality.</u> We make breakthroughs along three key dimensions: (1) robustness to long-video drifting without commonly used anti-drift heuristics such as self-forcing, error banks, or keyframe sampling; (2) real-time generation without standard acceleration techniques such as KV-cache, causal masking, or sparse attention; and (3) training without parallelism or sharding frameworks, enabling image-diffusion-scale batch sizes while fitting up to four 14B models within 80 GB of GPU memory. Specifically, Helios is a 14B autoregressive diffusion model with a unified input representation that natively supports T2V, I2V, and V2V tasks. To mitigate drifting in long-video generation, we characterize its typical failure modes and propose simple yet effective training strategies that explicitly simulate drifting during training, while eliminating repetitive motion at its source. For efficiency, we heavily compress the historical and noisy context and reduce the number of sampling steps, yielding computational costs comparable to—or lower than—those of 1.3B video generative models. Moreover, we introduce infrastructure-level optimizations that accelerate both inference and training while reducing memory consumption. Extensive experiments demonstrate that Helios consistently outperforms prior methods on both short- and long-video generation. All the code and models are available at [this https URL](https://pku-yuangroup.github.io/Helios-Page).
 

docs/source/en/api/pipelines/ltx2.md

@@ -193,6 +193,179 @@ encode_video(
 )
 ```
 
+## Condition Pipeline Generation
+
+You can use `LTX2ConditionPipeline` to specify image and/or video conditions at arbitrary latent indices. For example, we can specify both a first-frame and last-frame condition to perform first-last-frame-to-video (FLF2V) generation:
+
+```py
+import torch
+from diffusers import LTX2ConditionPipeline, LTX2LatentUpsamplePipeline
+from diffusers.pipelines.ltx2.latent_upsampler import LTX2LatentUpsamplerModel
+from diffusers.pipelines.ltx2.pipeline_ltx2_condition import LTX2VideoCondition
+from diffusers.pipelines.ltx2.utils import DISTILLED_SIGMA_VALUES, STAGE_2_DISTILLED_SIGMA_VALUES
+from diffusers.pipelines.ltx2.export_utils import encode_video
+from diffusers.utils import load_image
+
+device = "cuda"
+width = 768
+height = 512
+random_seed = 42
+generator = torch.Generator(device).manual_seed(random_seed)
+model_path = "rootonchair/LTX-2-19b-distilled"
+
+pipe = LTX2ConditionPipeline.from_pretrained(model_path, torch_dtype=torch.bfloat16)
+pipe.enable_sequential_cpu_offload(device=device)
+pipe.vae.enable_tiling()
+
+prompt = (
+    "CG animation style, a small blue bird takes off from the ground, flapping its wings. The bird's feathers are "
+    "delicate, with a unique pattern on its chest. The background shows a blue sky with white clouds under bright "
+    "sunshine. The camera follows the bird upward, capturing its flight and the vastness of the sky from a close-up, "
+    "low-angle perspective."
+)
+
+first_image = load_image(
+    "https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/diffusers/flf2v_input_first_frame.png",
+)
+last_image = load_image(
+    "https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/diffusers/flf2v_input_last_frame.png",
+)
+first_cond = LTX2VideoCondition(frames=first_image, index=0, strength=1.0)
+last_cond = LTX2VideoCondition(frames=last_image, index=-1, strength=1.0)
+conditions = [first_cond, last_cond]
+
+frame_rate = 24.0
+video_latent, audio_latent = pipe(
+    conditions=conditions,
+    prompt=prompt,
+    width=width,
+    height=height,
+    num_frames=121,
+    frame_rate=frame_rate,
+    num_inference_steps=8,
+    sigmas=DISTILLED_SIGMA_VALUES,
+    guidance_scale=1.0,
+    generator=generator,
+    output_type="latent",
+    return_dict=False,
+)
+
+latent_upsampler = LTX2LatentUpsamplerModel.from_pretrained(
+    model_path,
+    subfolder="latent_upsampler",
+    torch_dtype=torch.bfloat16,
+)
+upsample_pipe = LTX2LatentUpsamplePipeline(vae=pipe.vae, latent_upsampler=latent_upsampler)
+upsample_pipe.enable_model_cpu_offload(device=device)
+upscaled_video_latent = upsample_pipe(
+    latents=video_latent,
+    output_type="latent",
+    return_dict=False,
+)[0]
+
+video, audio = pipe(
+    latents=upscaled_video_latent,
+    audio_latents=audio_latent,
+    prompt=prompt,
+    width=width * 2,
+    height=height * 2,
+    num_inference_steps=3,
+    sigmas=STAGE_2_DISTILLED_SIGMA_VALUES,
+    generator=generator,
+    guidance_scale=1.0,
+    output_type="np",
+    return_dict=False,
+)
+
+encode_video(
+    video[0],
+    fps=frame_rate,
+    audio=audio[0].float().cpu(),
+    audio_sample_rate=pipe.vocoder.config.output_sampling_rate,
+    output_path="ltx2_distilled_flf2v.mp4",
+)
+```
+
+You can use both image and video conditions:
+
+```py
+import torch
+from diffusers import LTX2ConditionPipeline
+from diffusers.pipelines.ltx2.pipeline_ltx2_condition import LTX2VideoCondition
+from diffusers.pipelines.ltx2.export_utils import encode_video
+from diffusers.utils import load_image, load_video
+
+device = "cuda"
+width = 768
+height = 512
+random_seed = 42
+generator = torch.Generator(device).manual_seed(random_seed)
+model_path = "rootonchair/LTX-2-19b-distilled"
+
+pipe = LTX2ConditionPipeline.from_pretrained(model_path, torch_dtype=torch.bfloat16)
+pipe.enable_sequential_cpu_offload(device=device)
+pipe.vae.enable_tiling()
+
+prompt = (
+    "The video depicts a long, straight highway stretching into the distance, flanked by metal guardrails. The road is "
+    "divided into multiple lanes, with a few vehicles visible in the far distance. The surrounding landscape features "
+    "dry, grassy fields on one side and rolling hills on the other. The sky is mostly clear with a few scattered "
+    "clouds, suggesting a bright, sunny day. And then the camera switch to a winding mountain road covered in snow, "
+    "with a single vehicle traveling along it. The road is flanked by steep, rocky cliffs and sparse vegetation. The "
+    "landscape is characterized by rugged terrain and a river visible in the distance. The scene captures the "
+    "solitude and beauty of a winter drive through a mountainous region."
+)
+negative_prompt = (
+    "blurry, out of focus, overexposed, underexposed, low contrast, washed out colors, excessive noise, "
+    "grainy texture, poor lighting, flickering, motion blur, distorted proportions, unnatural skin tones, "
+    "deformed facial features, asymmetrical face, missing facial features, extra limbs, disfigured hands, "
+    "wrong hand count, artifacts around text, inconsistent perspective, camera shake, incorrect depth of "
+    "field, background too sharp, background clutter, distracting reflections, harsh shadows, inconsistent "
+    "lighting direction, color banding, cartoonish rendering, 3D CGI look, unrealistic materials, uncanny "
+    "valley effect, incorrect ethnicity, wrong gender, exaggerated expressions, wrong gaze direction, "
+    "mismatched lip sync, silent or muted audio, distorted voice, robotic voice, echo, background noise, "
+    "off-sync audio, incorrect dialogue, added dialogue, repetitive speech, jittery movement, awkward "
+    "pauses, incorrect timing, unnatural transitions, inconsistent framing, tilted camera, flat lighting, "
+    "inconsistent tone, cinematic oversaturation, stylized filters, or AI artifacts."
+)
+
+cond_video = load_video(
+    "https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/diffusers/cosmos/cosmos-video2world-input-vid.mp4"
+)
+cond_image = load_image(
+    "https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/diffusers/cosmos/cosmos-video2world-input.jpg"
+)
+video_cond = LTX2VideoCondition(frames=cond_video, index=0, strength=1.0)
+image_cond = LTX2VideoCondition(frames=cond_image, index=8, strength=1.0)
+conditions = [video_cond, image_cond]
+
+frame_rate = 24.0
+video, audio = pipe(
+    conditions=conditions,
+    prompt=prompt,
+    negative_prompt=negative_prompt,
+    width=width,
+    height=height,
+    num_frames=121,
+    frame_rate=frame_rate,
+    num_inference_steps=40,
+    guidance_scale=4.0,
+    generator=generator,
+    output_type="np",
+    return_dict=False,
+)
+
+encode_video(
+    video[0],
+    fps=frame_rate,
+    audio=audio[0].float().cpu(),
+    audio_sample_rate=pipe.vocoder.config.output_sampling_rate,
+    output_path="ltx2_cond_video.mp4",
+)
+```
+
+Because the conditioning is done via latent frames, the 8 data space frames corresponding to the specified latent frame for an image condition will tend to be static.
+
 ## LTX2Pipeline
 
 [[autodoc]] LTX2Pipeline
@@ -205,6 +378,12 @@ encode_video(
   - all
   - __call__
 
+## LTX2ConditionPipeline
+
+[[autodoc]] LTX2ConditionPipeline
+  - all
+  - __call__
+
 ## LTX2LatentUpsamplePipeline
 
 [[autodoc]] LTX2LatentUpsamplePipeline

docs/source/en/using-diffusers/helios.md

@@ -130,4 +130,4 @@ pipe.to("cuda")
 
 Learn more about Helios with the following resources.
 - Watch [video1](https://www.youtube.com/watch?v=vd_AgHtOUFQ) and [video2](https://www.youtube.com/watch?v=1GeIU2Dn7UY) for a demonstration of Helios's key features.
-- The research paper, [Helios: Real Real-Time Long Video Generation Model](https://huggingface.co/papers/) for more details.
+- The research paper, [Helios: Real Real-Time Long Video Generation Model](https://huggingface.co/papers/2603.04379) for more details.

docs/source/zh/using-diffusers/helios.md

@@ -131,4 +131,4 @@ pipe.to("cuda")
 通过以下资源了解有关 Helios 的更多信息：
 
 - [视频1](https://www.youtube.com/watch?v=vd_AgHtOUFQ)和[视频2](https://www.youtube.com/watch?v=1GeIU2Dn7UY)演示了 Helios 的主要功能;
-- 有关更多详细信息，请参阅研究论文 [Helios: Real Real-Time Long Video Generation Model](https://huggingface.co/papers/)。
+- 有关更多详细信息，请参阅研究论文 [Helios: Real Real-Time Long Video Generation Model](https://huggingface.co/papers/2603.04379)。

scripts/convert_rae_to_diffusers.py

@@ -335,8 +335,11 @@ def convert(args: argparse.Namespace) -> None:
     model_keys |= {name for name, _ in model.named_buffers()}
     loaded_keys = set(full_state_dict.keys())
     missing = model_keys - loaded_keys
-    # trainable_cls_token and decoder_pos_embed are initialized, not loaded from original checkpoint
-    allowed_missing = {"decoder.trainable_cls_token", "decoder.decoder_pos_embed"}
+    # decoder_pos_embed is initialized in-model. trainable_cls_token is only
+    # allowed to be missing if it was absent in the source decoder checkpoint.
+    allowed_missing = {"decoder.decoder_pos_embed"}
+    if "trainable_cls_token" not in decoder_state_dict:
+        allowed_missing.add("decoder.trainable_cls_token")
     if missing - allowed_missing:
         print(f"Warning: missing keys after conversion: {sorted(missing - allowed_missing)}")
 

src/diffusers/__init__.py

@@ -433,6 +433,12 @@ else:
             "FluxKontextAutoBlocks",
             "FluxKontextModularPipeline",
             "FluxModularPipeline",
+            "HeliosAutoBlocks",
+            "HeliosModularPipeline",
+            "HeliosPyramidAutoBlocks",
+            "HeliosPyramidDistilledAutoBlocks",
+            "HeliosPyramidDistilledModularPipeline",
+            "HeliosPyramidModularPipeline",
             "QwenImageAutoBlocks",
             "QwenImageEditAutoBlocks",
             "QwenImageEditModularPipeline",
@@ -572,6 +578,7 @@ else:
             "LEditsPPPipelineStableDiffusionXL",
             "LongCatImageEditPipeline",
             "LongCatImagePipeline",
+            "LTX2ConditionPipeline",
             "LTX2ImageToVideoPipeline",
             "LTX2LatentUpsamplePipeline",
             "LTX2Pipeline",
@@ -1185,6 +1192,12 @@ if TYPE_CHECKING or DIFFUSERS_SLOW_IMPORT:
             FluxKontextAutoBlocks,
             FluxKontextModularPipeline,
             FluxModularPipeline,
+            HeliosAutoBlocks,
+            HeliosModularPipeline,
+            HeliosPyramidAutoBlocks,
+            HeliosPyramidDistilledAutoBlocks,
+            HeliosPyramidDistilledModularPipeline,
+            HeliosPyramidModularPipeline,
             QwenImageAutoBlocks,
             QwenImageEditAutoBlocks,
             QwenImageEditModularPipeline,
@@ -1320,6 +1333,7 @@ if TYPE_CHECKING or DIFFUSERS_SLOW_IMPORT:
             LEditsPPPipelineStableDiffusionXL,
             LongCatImageEditPipeline,
             LongCatImagePipeline,
+            LTX2ConditionPipeline,
             LTX2ImageToVideoPipeline,
             LTX2LatentUpsamplePipeline,
             LTX2Pipeline,

src/diffusers/models/attention_dispatch.py

@@ -38,6 +38,7 @@ from ..utils import (
     is_flash_attn_available,
     is_flash_attn_version,
     is_kernels_available,
+    is_kernels_version,
     is_sageattention_available,
     is_sageattention_version,
     is_torch_npu_available,
@@ -318,6 +319,7 @@ class _HubKernelConfig:
     repo_id: str
     function_attr: str
     revision: str | None = None
+    version: int | None = None
     kernel_fn: Callable | None = None
     wrapped_forward_attr: str | None = None
     wrapped_backward_attr: str | None = None
@@ -327,31 +329,34 @@ class _HubKernelConfig:
 
 # Registry for hub-based attention kernels
 _HUB_KERNELS_REGISTRY: dict["AttentionBackendName", _HubKernelConfig] = {
-    # TODO: temporary revision for now. Remove when merged upstream into `main`.
     AttentionBackendName._FLASH_3_HUB: _HubKernelConfig(
         repo_id="kernels-community/flash-attn3",
         function_attr="flash_attn_func",
-        revision="fake-ops-return-probs",
         wrapped_forward_attr="flash_attn_interface._flash_attn_forward",
         wrapped_backward_attr="flash_attn_interface._flash_attn_backward",
+        version=1,
     ),
     AttentionBackendName._FLASH_3_VARLEN_HUB: _HubKernelConfig(
         repo_id="kernels-community/flash-attn3",
         function_attr="flash_attn_varlen_func",
-        # revision="fake-ops-return-probs",
+        version=1,
     ),
     AttentionBackendName.FLASH_HUB: _HubKernelConfig(
         repo_id="kernels-community/flash-attn2",
         function_attr="flash_attn_func",
-        revision=None,
         wrapped_forward_attr="flash_attn_interface._wrapped_flash_attn_forward",
         wrapped_backward_attr="flash_attn_interface._wrapped_flash_attn_backward",
+        version=1,
     ),
     AttentionBackendName.FLASH_VARLEN_HUB: _HubKernelConfig(
-        repo_id="kernels-community/flash-attn2", function_attr="flash_attn_varlen_func", revision=None
+        repo_id="kernels-community/flash-attn2",
+        function_attr="flash_attn_varlen_func",
+        version=1,
     ),
     AttentionBackendName.SAGE_HUB: _HubKernelConfig(
-        repo_id="kernels-community/sage_attention", function_attr="sageattn", revision=None
+        repo_id="kernels-community/sage-attention",
+        function_attr="sageattn",
+        version=1,
     ),
 }
 
@@ -521,6 +526,10 @@ def _check_attention_backend_requirements(backend: AttentionBackendName) -> None
             raise RuntimeError(
                 f"Backend '{backend.value}' is not usable because the `kernels` package isn't available. Please install it with `pip install kernels`."
             )
+        if not is_kernels_version(">=", "0.12"):
+            raise RuntimeError(
+                f"Backend '{backend.value}' needs to be used with a `kernels` version of at least 0.12. Please update with `pip install -U kernels`."
+            )
 
     elif backend == AttentionBackendName.AITER:
         if not _CAN_USE_AITER_ATTN:
@@ -694,7 +703,7 @@ def _maybe_download_kernel_for_backend(backend: AttentionBackendName) -> None:
     try:
         from kernels import get_kernel
 
-        kernel_module = get_kernel(config.repo_id, revision=config.revision)
+        kernel_module = get_kernel(config.repo_id, revision=config.revision, version=config.version)
         if needs_kernel:
             config.kernel_fn = _resolve_kernel_attr(kernel_module, config.function_attr)
 

src/diffusers/models/autoencoders/autoencoder_rae.py

@@ -226,7 +226,17 @@ class ViTMAELayer(nn.Module):
 
 
 class RAEDecoder(nn.Module):
-    """Lightweight RAE decoder."""
+    """
+    Decoder implementation ported from RAE-main to keep checkpoint compatibility.
+
+    Key attributes (must match checkpoint keys):
+    - decoder_embed
+    - decoder_pos_embed
+    - decoder_layers
+    - decoder_norm
+    - decoder_pred
+    - trainable_cls_token
+    """
 
     def __init__(
         self,
@@ -253,7 +263,11 @@ class RAEDecoder(nn.Module):
         self.num_patches = num_patches
 
         self.decoder_embed = nn.Linear(hidden_size, decoder_hidden_size, bias=True)
-        self.register_buffer("decoder_pos_embed", torch.zeros(1, num_patches + 1, decoder_hidden_size))
+        grid_size = int(num_patches**0.5)
+        pos_embed = get_2d_sincos_pos_embed(
+            decoder_hidden_size, grid_size, cls_token=True, extra_tokens=1, output_type="pt"
+        )
+        self.register_buffer("decoder_pos_embed", pos_embed.unsqueeze(0).float(), persistent=False)
 
         self.decoder_layers = nn.ModuleList(
             [
@@ -275,27 +289,8 @@ class RAEDecoder(nn.Module):
         self.decoder_pred = nn.Linear(decoder_hidden_size, patch_size**2 * num_channels, bias=True)
         self.gradient_checkpointing = False
 
-        self._initialize_weights(num_patches)
         self.trainable_cls_token = nn.Parameter(torch.zeros(1, 1, decoder_hidden_size))
 
-    def _initialize_weights(self, num_patches: int):
-        # Skip initialization when parameters are on meta device (e.g. during
-        # accelerate.init_empty_weights() used by low_cpu_mem_usage loading).
-        # The weights are initialized.
-        if self.decoder_pos_embed.device.type == "meta":
-            return
-
-        grid_size = int(num_patches**0.5)
-        pos_embed = get_2d_sincos_pos_embed(
-            self.decoder_pos_embed.shape[-1],
-            grid_size,
-            cls_token=True,
-            extra_tokens=1,
-            output_type="pt",
-            device=self.decoder_pos_embed.device,
-        )
-        self.decoder_pos_embed.data.copy_(pos_embed.unsqueeze(0).to(dtype=self.decoder_pos_embed.dtype))
-
     def interpolate_pos_encoding(self, embeddings: torch.Tensor) -> torch.Tensor:
         embeddings_positions = embeddings.shape[1] - 1
         num_positions = self.decoder_pos_embed.shape[1] - 1
@@ -445,6 +440,7 @@ class AutoencoderRAE(ModelMixin, AttentionMixin, AutoencoderMixin, ConfigMixin):
     # NOTE: gradient checkpointing is not wired up for this model yet.
     _supports_gradient_checkpointing = False
     _no_split_modules = ["ViTMAELayer"]
+    _keys_to_ignore_on_load_unexpected = ["decoder.decoder_pos_embed"]
 
     @register_to_config
     def __init__(
@@ -477,31 +473,6 @@ class AutoencoderRAE(ModelMixin, AttentionMixin, AutoencoderMixin, ConfigMixin):
                 f"Unknown encoder_type='{encoder_type}'. Available: {sorted(_ENCODER_FORWARD_FNS.keys())}"
             )
 
-        if encoder_input_size % encoder_patch_size != 0:
-            raise ValueError(
-                f"encoder_input_size={encoder_input_size} must be divisible by encoder_patch_size={encoder_patch_size}."
-            )
-
-        decoder_patch_size = patch_size
-        if decoder_patch_size <= 0:
-            raise ValueError("patch_size must be a positive integer (this is decoder_patch_size).")
-
-        num_patches = (encoder_input_size // encoder_patch_size) ** 2
-        grid = int(sqrt(num_patches))
-        if grid * grid != num_patches:
-            raise ValueError(f"Computed num_patches={num_patches} must be a perfect square.")
-
-        derived_image_size = decoder_patch_size * grid
-        if image_size is None:
-            image_size = derived_image_size
-        else:
-            image_size = int(image_size)
-            if image_size != derived_image_size:
-                raise ValueError(
-                    f"image_size={image_size} must equal decoder_patch_size*sqrt(num_patches)={derived_image_size} "
-                    f"for patch_size={decoder_patch_size} and computed num_patches={num_patches}."
-                )
-
         def _to_config_compatible(value: Any) -> Any:
             if isinstance(value, torch.Tensor):
                 return value.detach().cpu().tolist()
@@ -526,6 +497,21 @@ class AutoencoderRAE(ModelMixin, AttentionMixin, AutoencoderMixin, ConfigMixin):
             latents_std=_to_config_compatible(latents_std),
         )
 
+        self.encoder_input_size = encoder_input_size
+        self.noise_tau = float(noise_tau)
+        self.reshape_to_2d = bool(reshape_to_2d)
+        self.use_encoder_loss = bool(use_encoder_loss)
+
+        # Validate early, before building the (potentially large) encoder/decoder.
+        encoder_patch_size = int(encoder_patch_size)
+        if self.encoder_input_size % encoder_patch_size != 0:
+            raise ValueError(
+                f"encoder_input_size={self.encoder_input_size} must be divisible by encoder_patch_size={encoder_patch_size}."
+            )
+        decoder_patch_size = int(patch_size)
+        if decoder_patch_size <= 0:
+            raise ValueError("patch_size must be a positive integer (this is decoder_patch_size).")
+
         # Frozen representation encoder (built from config, no downloads)
         self.encoder: nn.Module = _build_encoder(
             encoder_type=encoder_type,
@@ -534,7 +520,22 @@ class AutoencoderRAE(ModelMixin, AttentionMixin, AutoencoderMixin, ConfigMixin):
             num_hidden_layers=encoder_num_hidden_layers,
         )
         self._encoder_forward_fn = _ENCODER_FORWARD_FNS[encoder_type]
-        num_patches = (encoder_input_size // encoder_patch_size) ** 2
+        num_patches = (self.encoder_input_size // encoder_patch_size) ** 2
+
+        grid = int(sqrt(num_patches))
+        if grid * grid != num_patches:
+            raise ValueError(f"Computed num_patches={num_patches} must be a perfect square.")
+
+        derived_image_size = decoder_patch_size * grid
+        if image_size is None:
+            image_size = derived_image_size
+        else:
+            image_size = int(image_size)
+            if image_size != derived_image_size:
+                raise ValueError(
+                    f"image_size={image_size} must equal decoder_patch_size*sqrt(num_patches)={derived_image_size} "
+                    f"for patch_size={decoder_patch_size} and computed num_patches={num_patches}."
+                )
 
         # Encoder input normalization stats (ImageNet defaults)
         if encoder_norm_mean is None:
@@ -569,7 +570,6 @@ class AutoencoderRAE(ModelMixin, AttentionMixin, AutoencoderMixin, ConfigMixin):
             num_channels=int(num_channels),
             image_size=int(image_size),
         )
-
         self.num_patches = int(num_patches)
         self.decoder_patch_size = int(decoder_patch_size)
         self.decoder_image_size = int(image_size)
@@ -579,19 +579,16 @@ class AutoencoderRAE(ModelMixin, AttentionMixin, AutoencoderMixin, ConfigMixin):
 
     def _noising(self, x: torch.Tensor, generator: torch.Generator | None = None) -> torch.Tensor:
         # Per-sample random sigma in [0, noise_tau]
-        noise_sigma = self.config.noise_tau * torch.rand(
+        noise_sigma = self.noise_tau * torch.rand(
             (x.size(0),) + (1,) * (x.ndim - 1), device=x.device, dtype=x.dtype, generator=generator
         )
         return x + noise_sigma * randn_tensor(x.shape, generator=generator, device=x.device, dtype=x.dtype)
 
     def _resize_and_normalize(self, x: torch.Tensor) -> torch.Tensor:
         _, _, h, w = x.shape
-        if h != self.config.encoder_input_size or w != self.config.encoder_input_size:
+        if h != self.encoder_input_size or w != self.encoder_input_size:
             x = F.interpolate(
-                x,
-                size=(self.config.encoder_input_size, self.config.encoder_input_size),
-                mode="bicubic",
-                align_corners=False,
+                x, size=(self.encoder_input_size, self.encoder_input_size), mode="bicubic", align_corners=False
             )
         mean = self.encoder_mean.to(device=x.device, dtype=x.dtype)
         std = self.encoder_std.to(device=x.device, dtype=x.dtype)
@@ -620,10 +617,10 @@ class AutoencoderRAE(ModelMixin, AttentionMixin, AutoencoderMixin, ConfigMixin):
         else:
             tokens = self._encoder_forward_fn(self.encoder, x)  # (B, N, C)
 
-        if self.training and self.config.noise_tau > 0:
+        if self.training and self.noise_tau > 0:
             tokens = self._noising(tokens, generator=generator)
 
-        if self.config.reshape_to_2d:
+        if self.reshape_to_2d:
             b, n, c = tokens.shape
             side = int(sqrt(n))
             if side * side != n:
@@ -660,7 +657,7 @@ class AutoencoderRAE(ModelMixin, AttentionMixin, AutoencoderMixin, ConfigMixin):
 
         z = self._denormalize_latents(z)
 
-        if self.config.reshape_to_2d:
+        if self.reshape_to_2d:
             b, c, h, w = z.shape
             tokens = z.view(b, c, h * w).transpose(1, 2).contiguous()  # (B, N, C)
         else:
@@ -669,7 +666,7 @@ class AutoencoderRAE(ModelMixin, AttentionMixin, AutoencoderMixin, ConfigMixin):
         logits = self.decoder(tokens, return_dict=True).logits
         x_rec = self.decoder.unpatchify(logits)
         x_rec = self._denormalize_image(x_rec)
-        return x_rec
+        return x_rec.to(device=z.device)
 
     @apply_forward_hook
     def decode(self, z: torch.Tensor, return_dict: bool = True) -> DecoderOutput | tuple[torch.Tensor]:

src/diffusers/modular_pipelines/__init__.py

@@ -56,6 +56,14 @@ else:
         "WanImage2VideoModularPipeline",
         "Wan22Image2VideoModularPipeline",
     ]
+    _import_structure["helios"] = [
+        "HeliosAutoBlocks",
+        "HeliosModularPipeline",
+        "HeliosPyramidAutoBlocks",
+        "HeliosPyramidDistilledAutoBlocks",
+        "HeliosPyramidDistilledModularPipeline",
+        "HeliosPyramidModularPipeline",
+    ]
     _import_structure["flux"] = [
         "FluxAutoBlocks",
         "FluxModularPipeline",
@@ -103,6 +111,14 @@ if TYPE_CHECKING or DIFFUSERS_SLOW_IMPORT:
             Flux2KleinModularPipeline,
             Flux2ModularPipeline,
         )
+        from .helios import (
+            HeliosAutoBlocks,
+            HeliosModularPipeline,
+            HeliosPyramidAutoBlocks,
+            HeliosPyramidDistilledAutoBlocks,
+            HeliosPyramidDistilledModularPipeline,
+            HeliosPyramidModularPipeline,
+        )
         from .modular_pipeline import (
             AutoPipelineBlocks,
             BlockState,

src/diffusers/modular_pipelines/helios/__init__.py

@@ -0,0 +1,59 @@
+from typing import TYPE_CHECKING
+
+from ...utils import (
+    DIFFUSERS_SLOW_IMPORT,
+    OptionalDependencyNotAvailable,
+    _LazyModule,
+    get_objects_from_module,
+    is_torch_available,
+    is_transformers_available,
+)
+
+
+_dummy_objects = {}
+_import_structure = {}
+
+try:
+    if not (is_transformers_available() and is_torch_available()):
+        raise OptionalDependencyNotAvailable()
+except OptionalDependencyNotAvailable:
+    from ...utils import dummy_torch_and_transformers_objects  # noqa F403
+
+    _dummy_objects.update(get_objects_from_module(dummy_torch_and_transformers_objects))
+else:
+    _import_structure["modular_blocks_helios"] = ["HeliosAutoBlocks"]
+    _import_structure["modular_blocks_helios_pyramid"] = ["HeliosPyramidAutoBlocks"]
+    _import_structure["modular_blocks_helios_pyramid_distilled"] = ["HeliosPyramidDistilledAutoBlocks"]
+    _import_structure["modular_pipeline"] = [
+        "HeliosModularPipeline",
+        "HeliosPyramidDistilledModularPipeline",
+        "HeliosPyramidModularPipeline",
+    ]
+
+if TYPE_CHECKING or DIFFUSERS_SLOW_IMPORT:
+    try:
+        if not (is_transformers_available() and is_torch_available()):
+            raise OptionalDependencyNotAvailable()
+    except OptionalDependencyNotAvailable:
+        from ...utils.dummy_torch_and_transformers_objects import *  # noqa F403
+    else:
+        from .modular_blocks_helios import HeliosAutoBlocks
+        from .modular_blocks_helios_pyramid import HeliosPyramidAutoBlocks
+        from .modular_blocks_helios_pyramid_distilled import HeliosPyramidDistilledAutoBlocks
+        from .modular_pipeline import (
+            HeliosModularPipeline,
+            HeliosPyramidDistilledModularPipeline,
+            HeliosPyramidModularPipeline,
+        )
+else:
+    import sys
+
+    sys.modules[__name__] = _LazyModule(
+        __name__,
+        globals()["__file__"],
+        _import_structure,
+        module_spec=__spec__,
+    )
+
+    for name, value in _dummy_objects.items():
+        setattr(sys.modules[__name__], name, value)

src/diffusers/modular_pipelines/helios/before_denoise.py

@@ -0,0 +1,836 @@
+# Copyright 2025 The HuggingFace Team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import numpy as np
+import torch
+
+from ...models import HeliosTransformer3DModel
+from ...schedulers import HeliosScheduler
+from ...utils import logging
+from ...utils.torch_utils import randn_tensor
+from ..modular_pipeline import ModularPipelineBlocks, PipelineState
+from ..modular_pipeline_utils import ComponentSpec, InputParam, OutputParam
+from .modular_pipeline import HeliosModularPipeline
+
+
+logger = logging.get_logger(__name__)  # pylint: disable=invalid-name
+
+
+# Copied from diffusers.pipelines.flux.pipeline_flux.calculate_shift
+def calculate_shift(
+    image_seq_len,
+    base_seq_len: int = 256,
+    max_seq_len: int = 4096,
+    base_shift: float = 0.5,
+    max_shift: float = 1.15,
+):
+    m = (max_shift - base_shift) / (max_seq_len - base_seq_len)
+    b = base_shift - m * base_seq_len
+    mu = image_seq_len * m + b
+    return mu
+
+
+class HeliosTextInputStep(ModularPipelineBlocks):
+    model_name = "helios"
+
+    @property
+    def description(self) -> str:
+        return (
+            "Input processing step that:\n"
+            "  1. Determines `batch_size` and `dtype` based on `prompt_embeds`\n"
+            "  2. Adjusts input tensor shapes based on `batch_size` (number of prompts) and `num_videos_per_prompt`\n\n"
+            "All input tensors are expected to have either batch_size=1 or match the batch_size\n"
+            "of prompt_embeds. The tensors will be duplicated across the batch dimension to\n"
+            "have a final batch_size of batch_size * num_videos_per_prompt."
+        )
+
+    @property
+    def inputs(self) -> list[InputParam]:
+        return [
+            InputParam(
+                "num_videos_per_prompt",
+                default=1,
+                type_hint=int,
+                description="Number of videos to generate per prompt.",
+            ),
+            InputParam.template("prompt_embeds"),
+            InputParam.template("negative_prompt_embeds"),
+        ]
+
+    @property
+    def intermediate_outputs(self) -> list[str]:
+        return [
+            OutputParam(
+                "batch_size",
+                type_hint=int,
+                description="Number of prompts, the final batch size of model inputs should be batch_size * num_videos_per_prompt",
+            ),
+            OutputParam(
+                "dtype",
+                type_hint=torch.dtype,
+                description="Data type of model tensor inputs (determined by `prompt_embeds.dtype`)",
+            ),
+        ]
+
+    def check_inputs(self, components, block_state):
+        if block_state.prompt_embeds is not None and block_state.negative_prompt_embeds is not None:
+            if block_state.prompt_embeds.shape != block_state.negative_prompt_embeds.shape:
+                raise ValueError(
+                    "`prompt_embeds` and `negative_prompt_embeds` must have the same shape when passed directly, but"
+                    f" got: `prompt_embeds` {block_state.prompt_embeds.shape} != `negative_prompt_embeds`"
+                    f" {block_state.negative_prompt_embeds.shape}."
+                )
+
+    @torch.no_grad()
+    def __call__(self, components: HeliosModularPipeline, state: PipelineState) -> PipelineState:
+        block_state = self.get_block_state(state)
+        self.check_inputs(components, block_state)
+
+        block_state.batch_size = block_state.prompt_embeds.shape[0]
+        block_state.dtype = block_state.prompt_embeds.dtype
+
+        _, seq_len, _ = block_state.prompt_embeds.shape
+        block_state.prompt_embeds = block_state.prompt_embeds.repeat(1, block_state.num_videos_per_prompt, 1)
+        block_state.prompt_embeds = block_state.prompt_embeds.view(
+            block_state.batch_size * block_state.num_videos_per_prompt, seq_len, -1
+        )
+
+        if block_state.negative_prompt_embeds is not None:
+            _, seq_len, _ = block_state.negative_prompt_embeds.shape
+            block_state.negative_prompt_embeds = block_state.negative_prompt_embeds.repeat(
+                1, block_state.num_videos_per_prompt, 1
+            )
+            block_state.negative_prompt_embeds = block_state.negative_prompt_embeds.view(
+                block_state.batch_size * block_state.num_videos_per_prompt, seq_len, -1
+            )
+
+        self.set_block_state(state, block_state)
+
+        return components, state
+
+
+# Copied from diffusers.modular_pipelines.wan.before_denoise.repeat_tensor_to_batch_size
+def repeat_tensor_to_batch_size(
+    input_name: str,
+    input_tensor: torch.Tensor,
+    batch_size: int,
+    num_videos_per_prompt: int = 1,
+) -> torch.Tensor:
+    """Repeat tensor elements to match the final batch size.
+
+    This function expands a tensor's batch dimension to match the final batch size (batch_size * num_videos_per_prompt)
+    by repeating each element along dimension 0.
+
+    The input tensor must have batch size 1 or batch_size. The function will:
+    - If batch size is 1: repeat each element (batch_size * num_videos_per_prompt) times
+    - If batch size equals batch_size: repeat each element num_videos_per_prompt times
+
+    Args:
+        input_name (str): Name of the input tensor (used for error messages)
+        input_tensor (torch.Tensor): The tensor to repeat. Must have batch size 1 or batch_size.
+        batch_size (int): The base batch size (number of prompts)
+        num_videos_per_prompt (int, optional): Number of videos to generate per prompt. Defaults to 1.
+
+    Returns:
+        torch.Tensor: The repeated tensor with final batch size (batch_size * num_videos_per_prompt)
+
+    Raises:
+        ValueError: If input_tensor is not a torch.Tensor or has invalid batch size
+
+    Examples:
+        tensor = torch.tensor([[1, 2, 3]]) # shape: [1, 3] repeated = repeat_tensor_to_batch_size("image", tensor,
+        batch_size=2, num_videos_per_prompt=2) repeated # tensor([[1, 2, 3], [1, 2, 3], [1, 2, 3], [1, 2, 3]]) - shape:
+        [4, 3]
+
+        tensor = torch.tensor([[1, 2, 3], [4, 5, 6]]) # shape: [2, 3] repeated = repeat_tensor_to_batch_size("image",
+        tensor, batch_size=2, num_videos_per_prompt=2) repeated # tensor([[1, 2, 3], [1, 2, 3], [4, 5, 6], [4, 5, 6]])
+        - shape: [4, 3]
+    """
+    # make sure input is a tensor
+    if not isinstance(input_tensor, torch.Tensor):
+        raise ValueError(f"`{input_name}` must be a tensor")
+
+    # make sure input tensor e.g. image_latents has batch size 1 or batch_size same as prompts
+    if input_tensor.shape[0] == 1:
+        repeat_by = batch_size * num_videos_per_prompt
+    elif input_tensor.shape[0] == batch_size:
+        repeat_by = num_videos_per_prompt
+    else:
+        raise ValueError(
+            f"`{input_name}` must have have batch size 1 or {batch_size}, but got {input_tensor.shape[0]}"
+        )
+
+    # expand the tensor to match the batch_size * num_videos_per_prompt
+    input_tensor = input_tensor.repeat_interleave(repeat_by, dim=0)
+
+    return input_tensor
+
+
+# Copied from diffusers.modular_pipelines.wan.before_denoise.calculate_dimension_from_latents
+def calculate_dimension_from_latents(
+    latents: torch.Tensor, vae_scale_factor_temporal: int, vae_scale_factor_spatial: int
+) -> tuple[int, int]:
+    """Calculate image dimensions from latent tensor dimensions.
+
+    This function converts latent temporal and spatial dimensions to image temporal and spatial dimensions by
+    multiplying the latent num_frames/height/width by the VAE scale factor.
+
+    Args:
+        latents (torch.Tensor): The latent tensor. Must have 4 or 5 dimensions.
+            Expected shapes: [batch, channels, height, width] or [batch, channels, frames, height, width]
+        vae_scale_factor_temporal (int): The scale factor used by the VAE to compress temporal dimension.
+            Typically 4 for most VAEs (video is 4x larger than latents in temporal dimension)
+        vae_scale_factor_spatial (int): The scale factor used by the VAE to compress spatial dimension.
+            Typically 8 for most VAEs (image is 8x larger than latents in each dimension)
+
+    Returns:
+        tuple[int, int]: The calculated image dimensions as (height, width)
+
+    Raises:
+        ValueError: If latents tensor doesn't have 4 or 5 dimensions
+
+    """
+    if latents.ndim != 5:
+        raise ValueError(f"latents must have 5 dimensions, but got {latents.ndim}")
+
+    _, _, num_latent_frames, latent_height, latent_width = latents.shape
+
+    num_frames = (num_latent_frames - 1) * vae_scale_factor_temporal + 1
+    height = latent_height * vae_scale_factor_spatial
+    width = latent_width * vae_scale_factor_spatial
+
+    return num_frames, height, width
+
+
+class HeliosAdditionalInputsStep(ModularPipelineBlocks):
+    """Configurable step that standardizes inputs for the denoising step.
+
+    This step handles:
+    1. For encoded image latents: Computes height/width from latents and expands batch size
+    2. For additional_batch_inputs: Expands batch dimensions to match final batch size
+    """
+
+    model_name = "helios"
+
+    def __init__(
+        self,
+        image_latent_inputs: list[InputParam] | None = None,
+        additional_batch_inputs: list[InputParam] | None = None,
+    ):
+        if image_latent_inputs is None:
+            image_latent_inputs = [InputParam.template("image_latents")]
+        if additional_batch_inputs is None:
+            additional_batch_inputs = []
+
+        if not isinstance(image_latent_inputs, list):
+            raise ValueError(f"image_latent_inputs must be a list, but got {type(image_latent_inputs)}")
+        else:
+            for input_param in image_latent_inputs:
+                if not isinstance(input_param, InputParam):
+                    raise ValueError(f"image_latent_inputs must be a list of InputParam, but got {type(input_param)}")
+
+        if not isinstance(additional_batch_inputs, list):
+            raise ValueError(f"additional_batch_inputs must be a list, but got {type(additional_batch_inputs)}")
+        else:
+            for input_param in additional_batch_inputs:
+                if not isinstance(input_param, InputParam):
+                    raise ValueError(
+                        f"additional_batch_inputs must be a list of InputParam, but got {type(input_param)}"
+                    )
+
+        self._image_latent_inputs = image_latent_inputs
+        self._additional_batch_inputs = additional_batch_inputs
+        super().__init__()
+
+    @property
+    def description(self) -> str:
+        summary_section = (
+            "Input processing step that:\n"
+            "  1. For image latent inputs: Computes height/width from latents and expands batch size\n"
+            "  2. For additional batch inputs: Expands batch dimensions to match final batch size"
+        )
+
+        inputs_info = ""
+        if self._image_latent_inputs or self._additional_batch_inputs:
+            inputs_info = "\n\nConfigured inputs:"
+            if self._image_latent_inputs:
+                inputs_info += f"\n  - Image latent inputs: {[p.name for p in self._image_latent_inputs]}"
+            if self._additional_batch_inputs:
+                inputs_info += f"\n  - Additional batch inputs: {[p.name for p in self._additional_batch_inputs]}"
+
+        placement_section = "\n\nThis block should be placed after the encoder steps and the text input step."
+
+        return summary_section + inputs_info + placement_section
+
+    @property
+    def inputs(self) -> list[InputParam]:
+        inputs = [
+            InputParam(name="num_videos_per_prompt", default=1),
+            InputParam(name="batch_size", required=True),
+        ]
+        inputs += self._image_latent_inputs + self._additional_batch_inputs
+
+        return inputs
+
+    @property
+    def intermediate_outputs(self) -> list[OutputParam]:
+        outputs = [
+            OutputParam("height", type_hint=int),
+            OutputParam("width", type_hint=int),
+        ]
+
+        for input_param in self._image_latent_inputs:
+            outputs.append(OutputParam(input_param.name, type_hint=torch.Tensor))
+
+        for input_param in self._additional_batch_inputs:
+            outputs.append(OutputParam(input_param.name, type_hint=torch.Tensor))
+
+        return outputs
+
+    def __call__(self, components: HeliosModularPipeline, state: PipelineState) -> PipelineState:
+        block_state = self.get_block_state(state)
+
+        for input_param in self._image_latent_inputs:
+            image_latent_tensor = getattr(block_state, input_param.name)
+            if image_latent_tensor is None:
+                continue
+
+            # Calculate height/width from latents
+            _, height, width = calculate_dimension_from_latents(
+                image_latent_tensor, components.vae_scale_factor_temporal, components.vae_scale_factor_spatial
+            )
+            block_state.height = height
+            block_state.width = width
+
+            # Expand batch size
+            image_latent_tensor = repeat_tensor_to_batch_size(
+                input_name=input_param.name,
+                input_tensor=image_latent_tensor,
+                num_videos_per_prompt=block_state.num_videos_per_prompt,
+                batch_size=block_state.batch_size,
+            )
+
+            setattr(block_state, input_param.name, image_latent_tensor)
+
+        for input_param in self._additional_batch_inputs:
+            input_tensor = getattr(block_state, input_param.name)
+            if input_tensor is None:
+                continue
+
+            input_tensor = repeat_tensor_to_batch_size(
+                input_name=input_param.name,
+                input_tensor=input_tensor,
+                num_videos_per_prompt=block_state.num_videos_per_prompt,
+                batch_size=block_state.batch_size,
+            )
+
+            setattr(block_state, input_param.name, input_tensor)
+
+        self.set_block_state(state, block_state)
+        return components, state
+
+
+class HeliosAddNoiseToImageLatentsStep(ModularPipelineBlocks):
+    """Adds noise to image_latents and fake_image_latents for I2V conditioning.
+
+    Applies single-sigma noise to image_latents (using image_noise_sigma range) and single-sigma noise to
+    fake_image_latents (using video_noise_sigma range).
+    """
+
+    model_name = "helios"
+
+    @property
+    def description(self) -> str:
+        return (
+            "Adds noise to image_latents and fake_image_latents for I2V conditioning. "
+            "Uses random sigma from configured ranges for each."
+        )
+
+    @property
+    def inputs(self) -> list[InputParam]:
+        return [
+            InputParam.template("image_latents"),
+            InputParam(
+                "fake_image_latents",
+                required=True,
+                type_hint=torch.Tensor,
+                description="Fake image latents used as history seed for I2V generation.",
+            ),
+            InputParam(
+                "image_noise_sigma_min",
+                default=0.111,
+                type_hint=float,
+                description="Minimum sigma for image latent noise.",
+            ),
+            InputParam(
+                "image_noise_sigma_max",
+                default=0.135,
+                type_hint=float,
+                description="Maximum sigma for image latent noise.",
+            ),
+            InputParam(
+                "video_noise_sigma_min",
+                default=0.111,
+                type_hint=float,
+                description="Minimum sigma for video/fake-image latent noise.",
+            ),
+            InputParam(
+                "video_noise_sigma_max",
+                default=0.135,
+                type_hint=float,
+                description="Maximum sigma for video/fake-image latent noise.",
+            ),
+            InputParam.template("generator"),
+        ]
+
+    @property
+    def intermediate_outputs(self) -> list[OutputParam]:
+        return [
+            OutputParam.template("image_latents"),
+            OutputParam("fake_image_latents", type_hint=torch.Tensor, description="Noisy fake image latents"),
+        ]
+
+    @torch.no_grad()
+    def __call__(self, components: HeliosModularPipeline, state: PipelineState) -> PipelineState:
+        block_state = self.get_block_state(state)
+
+        device = components._execution_device
+        image_latents = block_state.image_latents
+        fake_image_latents = block_state.fake_image_latents
+
+        # Add noise to image_latents
+        image_noise_sigma = (
+            torch.rand(1, device=device, generator=block_state.generator)
+            * (block_state.image_noise_sigma_max - block_state.image_noise_sigma_min)
+            + block_state.image_noise_sigma_min
+        )
+        image_latents = (
+            image_noise_sigma * randn_tensor(image_latents.shape, generator=block_state.generator, device=device)
+            + (1 - image_noise_sigma) * image_latents
+        )
+
+        # Add noise to fake_image_latents
+        fake_image_noise_sigma = (
+            torch.rand(1, device=device, generator=block_state.generator)
+            * (block_state.video_noise_sigma_max - block_state.video_noise_sigma_min)
+            + block_state.video_noise_sigma_min
+        )
+        fake_image_latents = (
+            fake_image_noise_sigma
+            * randn_tensor(fake_image_latents.shape, generator=block_state.generator, device=device)
+            + (1 - fake_image_noise_sigma) * fake_image_latents
+        )
+
+        block_state.image_latents = image_latents.to(device=device, dtype=torch.float32)
+        block_state.fake_image_latents = fake_image_latents.to(device=device, dtype=torch.float32)
+
+        self.set_block_state(state, block_state)
+        return components, state
+
+
+class HeliosAddNoiseToVideoLatentsStep(ModularPipelineBlocks):
+    """Adds noise to image_latents and video_latents for V2V conditioning.
+
+    Applies single-sigma noise to image_latents (using image_noise_sigma range) and per-frame noise to video_latents in
+    chunks (using video_noise_sigma range).
+    """
+
+    model_name = "helios"
+
+    @property
+    def description(self) -> str:
+        return (
+            "Adds noise to image_latents and video_latents for V2V conditioning. "
+            "Uses single-sigma noise for image_latents and per-frame noise for video chunks."
+        )
+
+    @property
+    def inputs(self) -> list[InputParam]:
+        return [
+            InputParam.template("image_latents"),
+            InputParam(
+                "video_latents",
+                required=True,
+                type_hint=torch.Tensor,
+                description="Encoded video latents for V2V generation.",
+            ),
+            InputParam(
+                "num_latent_frames_per_chunk",
+                default=9,
+                type_hint=int,
+                description="Number of latent frames per temporal chunk.",
+            ),
+            InputParam(
+                "image_noise_sigma_min",
+                default=0.111,
+                type_hint=float,
+                description="Minimum sigma for image latent noise.",
+            ),
+            InputParam(
+                "image_noise_sigma_max",
+                default=0.135,
+                type_hint=float,
+                description="Maximum sigma for image latent noise.",
+            ),
+            InputParam(
+                "video_noise_sigma_min",
+                default=0.111,
+                type_hint=float,
+                description="Minimum sigma for video latent noise.",
+            ),
+            InputParam(
+                "video_noise_sigma_max",
+                default=0.135,
+                type_hint=float,
+                description="Maximum sigma for video latent noise.",
+            ),
+            InputParam.template("generator"),
+        ]
+
+    @property
+    def intermediate_outputs(self) -> list[OutputParam]:
+        return [
+            OutputParam.template("image_latents"),
+            OutputParam("video_latents", type_hint=torch.Tensor, description="Noisy video latents"),
+        ]
+
+    @torch.no_grad()
+    def __call__(self, components: HeliosModularPipeline, state: PipelineState) -> PipelineState:
+        block_state = self.get_block_state(state)
+
+        device = components._execution_device
+        image_latents = block_state.image_latents
+        video_latents = block_state.video_latents
+        num_latent_frames_per_chunk = block_state.num_latent_frames_per_chunk
+
+        # Add noise to first frame (single sigma)
+        image_noise_sigma = (
+            torch.rand(1, device=device, generator=block_state.generator)
+            * (block_state.image_noise_sigma_max - block_state.image_noise_sigma_min)
+            + block_state.image_noise_sigma_min
+        )
+        image_latents = (
+            image_noise_sigma * randn_tensor(image_latents.shape, generator=block_state.generator, device=device)
+            + (1 - image_noise_sigma) * image_latents
+        )
+
+        # Add per-frame noise to video chunks
+        noisy_latents_chunks = []
+        num_latent_chunks = video_latents.shape[2] // num_latent_frames_per_chunk
+        for i in range(num_latent_chunks):
+            chunk_start = i * num_latent_frames_per_chunk
+            chunk_end = chunk_start + num_latent_frames_per_chunk
+            latent_chunk = video_latents[:, :, chunk_start:chunk_end, :, :]
+
+            chunk_frames = latent_chunk.shape[2]
+            frame_sigmas = (
+                torch.rand(chunk_frames, device=device, generator=block_state.generator)
+                * (block_state.video_noise_sigma_max - block_state.video_noise_sigma_min)
+                + block_state.video_noise_sigma_min
+            )
+            frame_sigmas = frame_sigmas.view(1, 1, chunk_frames, 1, 1)
+
+            noisy_chunk = (
+                frame_sigmas * randn_tensor(latent_chunk.shape, generator=block_state.generator, device=device)
+                + (1 - frame_sigmas) * latent_chunk
+            )
+            noisy_latents_chunks.append(noisy_chunk)
+        video_latents = torch.cat(noisy_latents_chunks, dim=2)
+
+        block_state.image_latents = image_latents.to(device=device, dtype=torch.float32)
+        block_state.video_latents = video_latents.to(device=device, dtype=torch.float32)
+
+        self.set_block_state(state, block_state)
+        return components, state
+
+
+class HeliosPrepareHistoryStep(ModularPipelineBlocks):
+    """Prepares chunk/history indices and initializes history state for the chunk loop."""
+
+    model_name = "helios"
+
+    @property
+    def description(self) -> str:
+        return (
+            "Prepares the chunk loop by computing latent dimensions, number of chunks, "
+            "history indices, and initializing history state (history_latents, image_latents, latent_chunks)."
+        )
+
+    @property
+    def expected_components(self) -> list[ComponentSpec]:
+        return [
+            ComponentSpec("transformer", HeliosTransformer3DModel),
+        ]
+
+    @property
+    def inputs(self) -> list[InputParam]:
+        return [
+            InputParam.template("height", default=384),
+            InputParam.template("width", default=640),
+            InputParam(
+                "num_frames", default=132, type_hint=int, description="Total number of video frames to generate."
+            ),
+            InputParam("batch_size", required=True, type_hint=int),
+            InputParam(
+                "num_latent_frames_per_chunk",
+                default=9,
+                type_hint=int,
+                description="Number of latent frames per temporal chunk.",
+            ),
+            InputParam(
+                "history_sizes",
+                default=[16, 2, 1],
+                type_hint=list,
+                description="Sizes of long/mid/short history buffers for temporal context.",
+            ),
+            InputParam(
+                "keep_first_frame",
+                default=True,
+                type_hint=bool,
+                description="Whether to keep the first frame as a prefix in history.",
+            ),
+        ]
+
+    @property
+    def intermediate_outputs(self) -> list[OutputParam]:
+        return [
+            OutputParam("num_latent_chunk", type_hint=int, description="Number of temporal chunks"),
+            OutputParam("latent_shape", type_hint=tuple, description="Shape of latent tensor per chunk"),
+            OutputParam("history_sizes", type_hint=list, description="Adjusted history sizes (sorted, descending)"),
+            OutputParam("indices_hidden_states", type_hint=torch.Tensor, kwargs_type="denoiser_input_fields"),
+            OutputParam("indices_latents_history_short", type_hint=torch.Tensor, kwargs_type="denoiser_input_fields"),
+            OutputParam("indices_latents_history_mid", type_hint=torch.Tensor, kwargs_type="denoiser_input_fields"),
+            OutputParam("indices_latents_history_long", type_hint=torch.Tensor, kwargs_type="denoiser_input_fields"),
+            OutputParam("history_latents", type_hint=torch.Tensor, description="Initialized zero history latents"),
+        ]
+
+    @torch.no_grad()
+    def __call__(self, components: HeliosModularPipeline, state: PipelineState) -> PipelineState:
+        block_state = self.get_block_state(state)
+
+        batch_size = block_state.batch_size
+        device = components._execution_device
+
+        block_state.num_frames = max(block_state.num_frames, 1)
+        history_sizes = sorted(block_state.history_sizes, reverse=True)
+
+        num_channels_latents = components.num_channels_latents
+        h_latent = block_state.height // components.vae_scale_factor_spatial
+        w_latent = block_state.width // components.vae_scale_factor_spatial
+
+        # Compute number of chunks
+        block_state.window_num_frames = (
+            block_state.num_latent_frames_per_chunk - 1
+        ) * components.vae_scale_factor_temporal + 1
+        block_state.num_latent_chunk = max(
+            1, (block_state.num_frames + block_state.window_num_frames - 1) // block_state.window_num_frames
+        )
+
+        # Modify history_sizes for non-keep_first_frame (matching pipeline behavior)
+        if not block_state.keep_first_frame:
+            history_sizes = history_sizes.copy()
+            history_sizes[-1] = history_sizes[-1] + 1
+
+        # Compute indices ONCE (same structure for all chunks)
+        if block_state.keep_first_frame:
+            indices = torch.arange(0, sum([1, *history_sizes, block_state.num_latent_frames_per_chunk]))
+            (
+                indices_prefix,
+                indices_latents_history_long,
+                indices_latents_history_mid,
+                indices_latents_history_1x,
+                indices_hidden_states,
+            ) = indices.split([1, *history_sizes, block_state.num_latent_frames_per_chunk], dim=0)
+            indices_latents_history_short = torch.cat([indices_prefix, indices_latents_history_1x], dim=0)
+        else:
+            indices = torch.arange(0, sum([*history_sizes, block_state.num_latent_frames_per_chunk]))
+            (
+                indices_latents_history_long,
+                indices_latents_history_mid,
+                indices_latents_history_short,
+                indices_hidden_states,
+            ) = indices.split([*history_sizes, block_state.num_latent_frames_per_chunk], dim=0)
+
+        # Latent shape per chunk
+        block_state.latent_shape = (
+            batch_size,
+            num_channels_latents,
+            block_state.num_latent_frames_per_chunk,
+            h_latent,
+            w_latent,
+        )
+
+        # Set outputs
+        block_state.history_sizes = history_sizes
+        block_state.indices_hidden_states = indices_hidden_states.unsqueeze(0)
+        block_state.indices_latents_history_short = indices_latents_history_short.unsqueeze(0)
+        block_state.indices_latents_history_mid = indices_latents_history_mid.unsqueeze(0)
+        block_state.indices_latents_history_long = indices_latents_history_long.unsqueeze(0)
+        block_state.history_latents = torch.zeros(
+            batch_size,
+            num_channels_latents,
+            sum(history_sizes),
+            h_latent,
+            w_latent,
+            device=device,
+            dtype=torch.float32,
+        )
+
+        self.set_block_state(state, block_state)
+
+        return components, state
+
+
+class HeliosI2VSeedHistoryStep(ModularPipelineBlocks):
+    """Seeds history_latents with fake_image_latents for I2V pipelines.
+
+    This small additive step runs after HeliosPrepareHistoryStep and appends fake_image_latents to the initialized
+    history_latents tensor.
+    """
+
+    model_name = "helios"
+
+    @property
+    def description(self) -> str:
+        return "I2V history seeding: appends fake_image_latents to history_latents."
+
+    @property
+    def inputs(self) -> list[InputParam]:
+        return [
+            InputParam("history_latents", required=True, type_hint=torch.Tensor),
+            InputParam("fake_image_latents", required=True, type_hint=torch.Tensor),
+        ]
+
+    @property
+    def intermediate_outputs(self) -> list[OutputParam]:
+        return [
+            OutputParam(
+                "history_latents", type_hint=torch.Tensor, description="History latents seeded with fake_image_latents"
+            ),
+        ]
+
+    @torch.no_grad()
+    def __call__(self, components: HeliosModularPipeline, state: PipelineState) -> PipelineState:
+        block_state = self.get_block_state(state)
+
+        block_state.history_latents = torch.cat([block_state.history_latents, block_state.fake_image_latents], dim=2)
+
+        self.set_block_state(state, block_state)
+        return components, state
+
+
+class HeliosV2VSeedHistoryStep(ModularPipelineBlocks):
+    """Seeds history_latents with video_latents for V2V pipelines.
+
+    This step runs after HeliosPrepareHistoryStep and replaces the tail of history_latents with video_latents. If the
+    video has fewer frames than the history, the beginning of history is preserved.
+    """
+
+    model_name = "helios"
+
+    @property
+    def description(self) -> str:
+        return "V2V history seeding: replaces the tail of history_latents with video_latents."
+
+    @property
+    def inputs(self) -> list[InputParam]:
+        return [
+            InputParam("history_latents", required=True, type_hint=torch.Tensor),
+            InputParam("video_latents", required=True, type_hint=torch.Tensor),
+        ]
+
+    @property
+    def intermediate_outputs(self) -> list[OutputParam]:
+        return [
+            OutputParam(
+                "history_latents", type_hint=torch.Tensor, description="History latents seeded with video_latents"
+            ),
+        ]
+
+    @torch.no_grad()
+    def __call__(self, components: HeliosModularPipeline, state: PipelineState) -> PipelineState:
+        block_state = self.get_block_state(state)
+
+        history_latents = block_state.history_latents
+        video_latents = block_state.video_latents
+
+        history_frames = history_latents.shape[2]
+        video_frames = video_latents.shape[2]
+        if video_frames < history_frames:
+            keep_frames = history_frames - video_frames
+            history_latents = torch.cat([history_latents[:, :, :keep_frames, :, :], video_latents], dim=2)
+        else:
+            history_latents = video_latents
+
+        block_state.history_latents = history_latents
+
+        self.set_block_state(state, block_state)
+        return components, state
+
+
+class HeliosSetTimestepsStep(ModularPipelineBlocks):
+    """Computes scheduler parameters (mu, sigmas) for the chunk loop."""
+
+    model_name = "helios"
+
+    @property
+    def description(self) -> str:
+        return "Computes scheduler shift parameter (mu) and default sigmas for the Helios chunk loop."
+
+    @property
+    def expected_components(self) -> list[ComponentSpec]:
+        return [
+            ComponentSpec("transformer", HeliosTransformer3DModel),
+            ComponentSpec("scheduler", HeliosScheduler),
+        ]
+
+    @property
+    def inputs(self) -> list[InputParam]:
+        return [
+            InputParam("latent_shape", required=True, type_hint=tuple),
+            InputParam.template("num_inference_steps"),
+            InputParam.template("sigmas"),
+        ]
+
+    @property
+    def intermediate_outputs(self) -> list[OutputParam]:
+        return [
+            OutputParam("mu", type_hint=float, description="Scheduler shift parameter"),
+            OutputParam("sigmas", type_hint=list, description="Sigma schedule for diffusion"),
+        ]
+
+    @torch.no_grad()
+    def __call__(self, components: HeliosModularPipeline, state: PipelineState) -> PipelineState:
+        block_state = self.get_block_state(state)
+
+        patch_size = components.transformer.config.patch_size
+        latent_shape = block_state.latent_shape
+        image_seq_len = (latent_shape[-1] * latent_shape[-2] * latent_shape[-3]) // (
+            patch_size[0] * patch_size[1] * patch_size[2]
+        )
+
+        if block_state.sigmas is None:
+            block_state.sigmas = np.linspace(0.999, 0.0, block_state.num_inference_steps + 1)[:-1]
+
+        block_state.mu = calculate_shift(
+            image_seq_len,
+            components.scheduler.config.get("base_image_seq_len", 256),
+            components.scheduler.config.get("max_image_seq_len", 4096),
+            components.scheduler.config.get("base_shift", 0.5),
+            components.scheduler.config.get("max_shift", 1.15),
+        )
+
+        self.set_block_state(state, block_state)
+
+        return components, state

src/diffusers/modular_pipelines/helios/decoders.py

@@ -0,0 +1,110 @@
+# Copyright 2025 The HuggingFace Team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import numpy as np
+import PIL
+import torch
+
+from ...configuration_utils import FrozenDict
+from ...models import AutoencoderKLWan
+from ...utils import logging
+from ...video_processor import VideoProcessor
+from ..modular_pipeline import ModularPipelineBlocks, PipelineState
+from ..modular_pipeline_utils import ComponentSpec, InputParam, OutputParam
+
+
+logger = logging.get_logger(__name__)  # pylint: disable=invalid-name
+
+
+class HeliosDecodeStep(ModularPipelineBlocks):
+    """Decode all chunk latents with VAE, trim frames, and postprocess into final video output."""
+
+    model_name = "helios"
+
+    @property
+    def description(self) -> str:
+        return (
+            "Decodes all chunk latents with the VAE, concatenates them, "
+            "trims to the target frame count, and postprocesses into the final video output."
+        )
+
+    @property
+    def expected_components(self) -> list[ComponentSpec]:
+        return [
+            ComponentSpec("vae", AutoencoderKLWan),
+            ComponentSpec(
+                "video_processor",
+                VideoProcessor,
+                config=FrozenDict({"vae_scale_factor": 8}),
+                default_creation_method="from_config",
+            ),
+        ]
+
+    @property
+    def inputs(self) -> list[InputParam]:
+        return [
+            InputParam(
+                "latent_chunks", required=True, type_hint=list, description="List of per-chunk denoised latent tensors"
+            ),
+            InputParam("num_frames", required=True, type_hint=int, description="The target number of output frames"),
+            InputParam.template("output_type", default="np"),
+        ]
+
+    @property
+    def intermediate_outputs(self) -> list[OutputParam]:
+        return [
+            OutputParam(
+                "videos",
+                type_hint=list[list[PIL.Image.Image]] | list[torch.Tensor] | list[np.ndarray],
+                description="The generated videos, can be a PIL.Image.Image, torch.Tensor or a numpy array",
+            ),
+        ]
+
+    @torch.no_grad()
+    def __call__(self, components, state: PipelineState) -> PipelineState:
+        block_state = self.get_block_state(state)
+
+        vae = components.vae
+
+        latents_mean = (
+            torch.tensor(vae.config.latents_mean).view(1, vae.config.z_dim, 1, 1, 1).to(vae.device, vae.dtype)
+        )
+        latents_std = 1.0 / torch.tensor(vae.config.latents_std).view(1, vae.config.z_dim, 1, 1, 1).to(
+            vae.device, vae.dtype
+        )
+
+        history_video = None
+        for chunk_latents in block_state.latent_chunks:
+            current_latents = chunk_latents.to(vae.dtype) / latents_std + latents_mean
+            current_video = vae.decode(current_latents, return_dict=False)[0]
+
+            if history_video is None:
+                history_video = current_video
+            else:
+                history_video = torch.cat([history_video, current_video], dim=2)
+
+        # Trim to proper frame count
+        generated_frames = history_video.size(2)
+        generated_frames = (
+            generated_frames - 1
+        ) // components.vae_scale_factor_temporal * components.vae_scale_factor_temporal + 1
+        history_video = history_video[:, :, :generated_frames]
+
+        block_state.videos = components.video_processor.postprocess_video(
+            history_video, output_type=block_state.output_type
+        )
+
+        self.set_block_state(state, block_state)
+
+        return components, state

src/diffusers/modular_pipelines/helios/encoders.py

@@ -0,0 +1,392 @@
+# Copyright 2025 The HuggingFace Team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import html
+
+import regex as re
+import torch
+from transformers import AutoTokenizer, UMT5EncoderModel
+
+from ...configuration_utils import FrozenDict
+from ...guiders import ClassifierFreeGuidance
+from ...models import AutoencoderKLWan
+from ...utils import is_ftfy_available, logging
+from ...video_processor import VideoProcessor
+from ..modular_pipeline import ModularPipelineBlocks, PipelineState
+from ..modular_pipeline_utils import ComponentSpec, InputParam, OutputParam
+from .modular_pipeline import HeliosModularPipeline
+
+
+if is_ftfy_available():
+    import ftfy
+
+
+logger = logging.get_logger(__name__)  # pylint: disable=invalid-name
+
+
+def basic_clean(text):
+    text = ftfy.fix_text(text)
+    text = html.unescape(html.unescape(text))
+    return text.strip()
+
+
+def whitespace_clean(text):
+    text = re.sub(r"\s+", " ", text)
+    text = text.strip()
+    return text
+
+
+def prompt_clean(text):
+    text = whitespace_clean(basic_clean(text))
+    return text
+
+
+def get_t5_prompt_embeds(
+    text_encoder: UMT5EncoderModel,
+    tokenizer: AutoTokenizer,
+    prompt: str | list[str],
+    max_sequence_length: int,
+    device: torch.device,
+    dtype: torch.dtype | None = None,
+):
+    """Encode text prompts into T5 embeddings for Helios.
+
+    Args:
+        text_encoder: The T5 text encoder model.
+        tokenizer: The tokenizer for the text encoder.
+        prompt: The prompt or prompts to encode.
+        max_sequence_length: Maximum sequence length for tokenization.
+        device: Device to place tensors on.
+        dtype: Optional dtype override. Defaults to `text_encoder.dtype`.
+
+    Returns:
+        A tuple of `(prompt_embeds, attention_mask)` where `prompt_embeds` is the encoded text embeddings and
+        `attention_mask` is a boolean mask.
+    """
+    dtype = dtype or text_encoder.dtype
+
+    prompt = [prompt] if isinstance(prompt, str) else prompt
+    prompt = [prompt_clean(u) for u in prompt]
+
+    text_inputs = tokenizer(
+        prompt,
+        padding="max_length",
+        max_length=max_sequence_length,
+        truncation=True,
+        add_special_tokens=True,
+        return_attention_mask=True,
+        return_tensors="pt",
+    )
+    text_input_ids, mask = text_inputs.input_ids, text_inputs.attention_mask
+    seq_lens = mask.gt(0).sum(dim=1).long()
+
+    prompt_embeds = text_encoder(text_input_ids.to(device), mask.to(device)).last_hidden_state
+    prompt_embeds = prompt_embeds.to(dtype=dtype, device=device)
+    prompt_embeds = [u[:v] for u, v in zip(prompt_embeds, seq_lens)]
+    prompt_embeds = torch.stack(
+        [torch.cat([u, u.new_zeros(max_sequence_length - u.size(0), u.size(1))]) for u in prompt_embeds], dim=0
+    )
+
+    return prompt_embeds, text_inputs.attention_mask.bool()
+
+
+class HeliosTextEncoderStep(ModularPipelineBlocks):
+    model_name = "helios"
+
+    @property
+    def description(self) -> str:
+        return "Text Encoder step that generates text embeddings to guide the video generation"
+
+    @property
+    def expected_components(self) -> list[ComponentSpec]:
+        return [
+            ComponentSpec("text_encoder", UMT5EncoderModel),
+            ComponentSpec("tokenizer", AutoTokenizer),
+            ComponentSpec(
+                "guider",
+                ClassifierFreeGuidance,
+                config=FrozenDict({"guidance_scale": 5.0}),
+                default_creation_method="from_config",
+            ),
+        ]
+
+    @property
+    def inputs(self) -> list[InputParam]:
+        return [
+            InputParam.template("prompt"),
+            InputParam.template("negative_prompt"),
+            InputParam.template("max_sequence_length"),
+        ]
+
+    @property
+    def intermediate_outputs(self) -> list[OutputParam]:
+        return [
+            OutputParam.template("prompt_embeds"),
+            OutputParam.template("negative_prompt_embeds"),
+        ]
+
+    @staticmethod
+    def check_inputs(prompt, negative_prompt):
+        if prompt is not None and not isinstance(prompt, (str, list)):
+            raise ValueError(f"`prompt` has to be of type `str` or `list` but is {type(prompt)}")
+
+        if negative_prompt is not None and not isinstance(negative_prompt, (str, list)):
+            raise ValueError(f"`negative_prompt` has to be of type `str` or `list` but is {type(negative_prompt)}")
+
+        if prompt is not None and negative_prompt is not None:
+            prompt_list = [prompt] if isinstance(prompt, str) else prompt
+            neg_list = [negative_prompt] if isinstance(negative_prompt, str) else negative_prompt
+            if type(prompt_list) is not type(neg_list):
+                raise TypeError(
+                    f"`negative_prompt` should be the same type to `prompt`, but got {type(negative_prompt)} !="
+                    f" {type(prompt)}."
+                )
+            if len(prompt_list) != len(neg_list):
+                raise ValueError(
+                    f"`negative_prompt` has batch size {len(neg_list)}, but `prompt` has batch size"
+                    f" {len(prompt_list)}. Please make sure that passed `negative_prompt` matches"
+                    " the batch size of `prompt`."
+                )
+
+    @torch.no_grad()
+    def __call__(self, components: HeliosModularPipeline, state: PipelineState) -> PipelineState:
+        block_state = self.get_block_state(state)
+
+        prompt = block_state.prompt
+        negative_prompt = block_state.negative_prompt
+        max_sequence_length = block_state.max_sequence_length
+        device = components._execution_device
+
+        self.check_inputs(prompt, negative_prompt)
+
+        # Encode prompt
+        block_state.prompt_embeds, _ = get_t5_prompt_embeds(
+            text_encoder=components.text_encoder,
+            tokenizer=components.tokenizer,
+            prompt=prompt,
+            max_sequence_length=max_sequence_length,
+            device=device,
+        )
+
+        # Encode negative prompt
+        block_state.negative_prompt_embeds = None
+        if components.requires_unconditional_embeds:
+            negative_prompt = negative_prompt or ""
+            if isinstance(prompt, list) and isinstance(negative_prompt, str):
+                negative_prompt = len(prompt) * [negative_prompt]
+
+            block_state.negative_prompt_embeds, _ = get_t5_prompt_embeds(
+                text_encoder=components.text_encoder,
+                tokenizer=components.tokenizer,
+                prompt=negative_prompt,
+                max_sequence_length=max_sequence_length,
+                device=device,
+            )
+
+        self.set_block_state(state, block_state)
+        return components, state
+
+
+class HeliosImageVaeEncoderStep(ModularPipelineBlocks):
+    """Encodes an input image into VAE latent space for image-to-video generation."""
+
+    model_name = "helios"
+
+    @property
+    def description(self) -> str:
+        return (
+            "Image Encoder step that encodes an input image into VAE latent space, "
+            "producing image_latents (first frame prefix) and fake_image_latents (history seed) "
+            "for image-to-video generation."
+        )
+
+    @property
+    def expected_components(self) -> list[ComponentSpec]:
+        return [
+            ComponentSpec("vae", AutoencoderKLWan),
+            ComponentSpec(
+                "video_processor",
+                VideoProcessor,
+                config=FrozenDict({"vae_scale_factor": 8}),
+                default_creation_method="from_config",
+            ),
+        ]
+
+    @property
+    def inputs(self) -> list[InputParam]:
+        return [
+            InputParam.template("image"),
+            InputParam.template("height", default=384),
+            InputParam.template("width", default=640),
+            InputParam(
+                "num_latent_frames_per_chunk",
+                default=9,
+                type_hint=int,
+                description="Number of latent frames per temporal chunk.",
+            ),
+            InputParam.template("generator"),
+        ]
+
+    @property
+    def intermediate_outputs(self) -> list[OutputParam]:
+        return [
+            OutputParam.template("image_latents"),
+            OutputParam(
+                "fake_image_latents", type_hint=torch.Tensor, description="Fake image latents for history seeding"
+            ),
+        ]
+
+    @torch.no_grad()
+    def __call__(self, components: HeliosModularPipeline, state: PipelineState) -> PipelineState:
+        block_state = self.get_block_state(state)
+
+        vae = components.vae
+        device = components._execution_device
+
+        latents_mean = (
+            torch.tensor(vae.config.latents_mean).view(1, vae.config.z_dim, 1, 1, 1).to(vae.device, vae.dtype)
+        )
+        latents_std = 1.0 / torch.tensor(vae.config.latents_std).view(1, vae.config.z_dim, 1, 1, 1).to(
+            vae.device, vae.dtype
+        )
+
+        # Preprocess image to 4D tensor (B, C, H, W)
+        image = components.video_processor.preprocess(
+            block_state.image, height=block_state.height, width=block_state.width
+        )
+        image_5d = image.unsqueeze(2).to(device=device, dtype=vae.dtype)  # (B, C, 1, H, W)
+
+        # Encode image to get image_latents
+        image_latents = vae.encode(image_5d).latent_dist.sample(generator=block_state.generator)
+        image_latents = (image_latents - latents_mean) * latents_std
+
+        # Encode fake video to get fake_image_latents
+        min_frames = (block_state.num_latent_frames_per_chunk - 1) * components.vae_scale_factor_temporal + 1
+        fake_video = image_5d.repeat(1, 1, min_frames, 1, 1)  # (B, C, min_frames, H, W)
+        fake_latents_full = vae.encode(fake_video).latent_dist.sample(generator=block_state.generator)
+        fake_latents_full = (fake_latents_full - latents_mean) * latents_std
+        fake_image_latents = fake_latents_full[:, :, -1:, :, :]
+
+        block_state.image_latents = image_latents.to(device=device, dtype=torch.float32)
+        block_state.fake_image_latents = fake_image_latents.to(device=device, dtype=torch.float32)
+
+        self.set_block_state(state, block_state)
+        return components, state
+
+
+class HeliosVideoVaeEncoderStep(ModularPipelineBlocks):
+    """Encodes an input video into VAE latent space for video-to-video generation.
+
+    Produces `image_latents` (first frame) and `video_latents` (remaining frames encoded in chunks).
+    """
+
+    model_name = "helios"
+
+    @property
+    def description(self) -> str:
+        return (
+            "Video Encoder step that encodes an input video into VAE latent space, "
+            "producing image_latents (first frame) and video_latents (chunked video frames) "
+            "for video-to-video generation."
+        )
+
+    @property
+    def expected_components(self) -> list[ComponentSpec]:
+        return [
+            ComponentSpec("vae", AutoencoderKLWan),
+            ComponentSpec(
+                "video_processor",
+                VideoProcessor,
+                config=FrozenDict({"vae_scale_factor": 8}),
+                default_creation_method="from_config",
+            ),
+        ]
+
+    @property
+    def inputs(self) -> list[InputParam]:
+        return [
+            InputParam("video", required=True, description="Input video for video-to-video generation"),
+            InputParam.template("height", default=384),
+            InputParam.template("width", default=640),
+            InputParam(
+                "num_latent_frames_per_chunk",
+                default=9,
+                type_hint=int,
+                description="Number of latent frames per temporal chunk.",
+            ),
+            InputParam.template("generator"),
+        ]
+
+    @property
+    def intermediate_outputs(self) -> list[OutputParam]:
+        return [
+            OutputParam.template("image_latents"),
+            OutputParam("video_latents", type_hint=torch.Tensor, description="Encoded video latents (chunked)"),
+        ]
+
+    @torch.no_grad()
+    def __call__(self, components: HeliosModularPipeline, state: PipelineState) -> PipelineState:
+        block_state = self.get_block_state(state)
+
+        vae = components.vae
+        device = components._execution_device
+        num_latent_frames_per_chunk = block_state.num_latent_frames_per_chunk
+
+        latents_mean = (
+            torch.tensor(vae.config.latents_mean).view(1, vae.config.z_dim, 1, 1, 1).to(vae.device, vae.dtype)
+        )
+        latents_std = 1.0 / torch.tensor(vae.config.latents_std).view(1, vae.config.z_dim, 1, 1, 1).to(
+            vae.device, vae.dtype
+        )
+
+        # Preprocess video
+        video = components.video_processor.preprocess_video(
+            block_state.video, height=block_state.height, width=block_state.width
+        )
+        video = video.to(device=device, dtype=vae.dtype)
+
+        # Encode video into latents
+        num_frames = video.shape[2]
+        min_frames = (num_latent_frames_per_chunk - 1) * 4 + 1
+        num_chunks = num_frames // min_frames
+        if num_chunks == 0:
+            raise ValueError(
+                f"Video must have at least {min_frames} frames "
+                f"(got {num_frames} frames). "
+                f"Required: (num_latent_frames_per_chunk - 1) * 4 + 1 = ({num_latent_frames_per_chunk} - 1) * 4 + 1 = {min_frames}"
+            )
+        total_valid_frames = num_chunks * min_frames
+        start_frame = num_frames - total_valid_frames
+
+        # Encode first frame
+        first_frame = video[:, :, 0:1, :, :]
+        image_latents = vae.encode(first_frame).latent_dist.sample(generator=block_state.generator)
+        image_latents = (image_latents - latents_mean) * latents_std
+
+        # Encode remaining frames in chunks
+        latents_chunks = []
+        for i in range(num_chunks):
+            chunk_start = start_frame + i * min_frames
+            chunk_end = chunk_start + min_frames
+            video_chunk = video[:, :, chunk_start:chunk_end, :, :]
+            chunk_latents = vae.encode(video_chunk).latent_dist.sample(generator=block_state.generator)
+            chunk_latents = (chunk_latents - latents_mean) * latents_std
+            latents_chunks.append(chunk_latents)
+        video_latents = torch.cat(latents_chunks, dim=2)
+
+        block_state.image_latents = image_latents.to(device=device, dtype=torch.float32)
+        block_state.video_latents = video_latents.to(device=device, dtype=torch.float32)
+
+        self.set_block_state(state, block_state)
+        return components, state

src/diffusers/modular_pipelines/helios/modular_blocks_helios.py

@@ -0,0 +1,542 @@
+# Copyright 2025 The HuggingFace Team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import torch
+
+from ...utils import logging
+from ..modular_pipeline import AutoPipelineBlocks, ConditionalPipelineBlocks, SequentialPipelineBlocks
+from ..modular_pipeline_utils import InputParam, InsertableDict, OutputParam
+from .before_denoise import (
+    HeliosAdditionalInputsStep,
+    HeliosAddNoiseToImageLatentsStep,
+    HeliosAddNoiseToVideoLatentsStep,
+    HeliosI2VSeedHistoryStep,
+    HeliosPrepareHistoryStep,
+    HeliosSetTimestepsStep,
+    HeliosTextInputStep,
+    HeliosV2VSeedHistoryStep,
+)
+from .decoders import HeliosDecodeStep
+from .denoise import HeliosChunkDenoiseStep, HeliosI2VChunkDenoiseStep
+from .encoders import HeliosImageVaeEncoderStep, HeliosTextEncoderStep, HeliosVideoVaeEncoderStep
+
+
+logger = logging.get_logger(__name__)  # pylint: disable=invalid-name
+
+
+# ====================
+# 1. Vae Encoder
+# ====================
+
+
+# auto_docstring
+class HeliosAutoVaeEncoderStep(AutoPipelineBlocks):
+    """
+    Encoder step that encodes video or image inputs. This is an auto pipeline block.
+       - `HeliosVideoVaeEncoderStep` (video_encoder) is used when `video` is provided.
+       - `HeliosImageVaeEncoderStep` (image_encoder) is used when `image` is provided.
+       - If neither is provided, step will be skipped.
+
+      Components:
+          vae (`AutoencoderKLWan`) video_processor (`VideoProcessor`)
+
+      Inputs:
+          video (`None`, *optional*):
+              Input video for video-to-video generation
+          height (`int`, *optional*, defaults to 384):
+              The height in pixels of the generated image.
+          width (`int`, *optional*, defaults to 640):
+              The width in pixels of the generated image.
+          num_latent_frames_per_chunk (`int`, *optional*, defaults to 9):
+              Number of latent frames per temporal chunk.
+          generator (`Generator`, *optional*):
+              Torch generator for deterministic generation.
+          image (`Image | list`, *optional*):
+              Reference image(s) for denoising. Can be a single image or list of images.
+
+      Outputs:
+          image_latents (`Tensor`):
+              The latent representation of the input image.
+          video_latents (`Tensor`):
+              Encoded video latents (chunked)
+          fake_image_latents (`Tensor`):
+              Fake image latents for history seeding
+    """
+
+    block_classes = [HeliosVideoVaeEncoderStep, HeliosImageVaeEncoderStep]
+    block_names = ["video_encoder", "image_encoder"]
+    block_trigger_inputs = ["video", "image"]
+
+    @property
+    def description(self):
+        return (
+            "Encoder step that encodes video or image inputs. This is an auto pipeline block.\n"
+            " - `HeliosVideoVaeEncoderStep` (video_encoder) is used when `video` is provided.\n"
+            " - `HeliosImageVaeEncoderStep` (image_encoder) is used when `image` is provided.\n"
+            " - If neither is provided, step will be skipped."
+        )
+
+
+# ====================
+# 2. DENOISE
+# ====================
+
+
+# DENOISE (T2V)
+# auto_docstring
+class HeliosCoreDenoiseStep(SequentialPipelineBlocks):
+    """
+    Denoise block that takes encoded conditions and runs the chunk-based denoising process.
+
+      Components:
+          transformer (`HeliosTransformer3DModel`) scheduler (`HeliosScheduler`) guider (`ClassifierFreeGuidance`)
+
+      Inputs:
+          num_videos_per_prompt (`int`, *optional*, defaults to 1):
+              Number of videos to generate per prompt.
+          prompt_embeds (`Tensor`):
+              text embeddings used to guide the image generation. Can be generated from text_encoder step.
+          negative_prompt_embeds (`Tensor`, *optional*):
+              negative text embeddings used to guide the image generation. Can be generated from text_encoder step.
+          height (`int`, *optional*, defaults to 384):
+              The height in pixels of the generated image.
+          width (`int`, *optional*, defaults to 640):
+              The width in pixels of the generated image.
+          num_frames (`int`, *optional*, defaults to 132):
+              Total number of video frames to generate.
+          num_latent_frames_per_chunk (`int`, *optional*, defaults to 9):
+              Number of latent frames per temporal chunk.
+          history_sizes (`list`, *optional*, defaults to [16, 2, 1]):
+              Sizes of long/mid/short history buffers for temporal context.
+          keep_first_frame (`bool`, *optional*, defaults to True):
+              Whether to keep the first frame as a prefix in history.
+          num_inference_steps (`int`, *optional*, defaults to 50):
+              The number of denoising steps.
+          sigmas (`list`, *optional*):
+              Custom sigmas for the denoising process.
+          generator (`Generator`, *optional*):
+              Torch generator for deterministic generation.
+          latents (`Tensor`, *optional*):
+              Pre-generated noisy latents for image generation.
+          timesteps (`Tensor`, *optional*):
+              Timesteps for the denoising process.
+          **denoiser_input_fields (`None`, *optional*):
+              conditional model inputs for the denoiser: e.g. prompt_embeds, negative_prompt_embeds, etc.
+          attention_kwargs (`dict`, *optional*):
+              Additional kwargs for attention processors.
+
+      Outputs:
+          latent_chunks (`list`):
+              List of per-chunk denoised latent tensors
+    """
+
+    model_name = "helios"
+    block_classes = [
+        HeliosTextInputStep,
+        HeliosPrepareHistoryStep,
+        HeliosSetTimestepsStep,
+        HeliosChunkDenoiseStep,
+    ]
+    block_names = ["input", "prepare_history", "set_timesteps", "chunk_denoise"]
+
+    @property
+    def description(self):
+        return "Denoise block that takes encoded conditions and runs the chunk-based denoising process."
+
+    @property
+    def outputs(self):
+        return [OutputParam("latent_chunks", type_hint=list, description="List of per-chunk denoised latent tensors")]
+
+
+# DENOISE (I2V)
+# auto_docstring
+class HeliosI2VCoreDenoiseStep(SequentialPipelineBlocks):
+    """
+    I2V denoise block that seeds history with image latents and uses I2V-aware chunk preparation.
+
+      Components:
+          transformer (`HeliosTransformer3DModel`) scheduler (`HeliosScheduler`) guider (`ClassifierFreeGuidance`)
+
+      Inputs:
+          num_videos_per_prompt (`int`, *optional*, defaults to 1):
+              Number of videos to generate per prompt.
+          prompt_embeds (`Tensor`):
+              text embeddings used to guide the image generation. Can be generated from text_encoder step.
+          negative_prompt_embeds (`Tensor`, *optional*):
+              negative text embeddings used to guide the image generation. Can be generated from text_encoder step.
+          image_latents (`Tensor`):
+              image latents used to guide the image generation. Can be generated from vae_encoder step.
+          fake_image_latents (`Tensor`, *optional*):
+              Fake image latents used as history seed for I2V generation.
+          image_noise_sigma_min (`float`, *optional*, defaults to 0.111):
+              Minimum sigma for image latent noise.
+          image_noise_sigma_max (`float`, *optional*, defaults to 0.135):
+              Maximum sigma for image latent noise.
+          video_noise_sigma_min (`float`, *optional*, defaults to 0.111):
+              Minimum sigma for video/fake-image latent noise.
+          video_noise_sigma_max (`float`, *optional*, defaults to 0.135):
+              Maximum sigma for video/fake-image latent noise.
+          generator (`Generator`, *optional*):
+              Torch generator for deterministic generation.
+          num_frames (`int`, *optional*, defaults to 132):
+              Total number of video frames to generate.
+          num_latent_frames_per_chunk (`int`, *optional*, defaults to 9):
+              Number of latent frames per temporal chunk.
+          history_sizes (`list`, *optional*, defaults to [16, 2, 1]):
+              Sizes of long/mid/short history buffers for temporal context.
+          keep_first_frame (`bool`, *optional*, defaults to True):
+              Whether to keep the first frame as a prefix in history.
+          num_inference_steps (`int`, *optional*, defaults to 50):
+              The number of denoising steps.
+          sigmas (`list`, *optional*):
+              Custom sigmas for the denoising process.
+          latents (`Tensor`, *optional*):
+              Pre-generated noisy latents for image generation.
+          timesteps (`Tensor`, *optional*):
+              Timesteps for the denoising process.
+          **denoiser_input_fields (`None`, *optional*):
+              conditional model inputs for the denoiser: e.g. prompt_embeds, negative_prompt_embeds, etc.
+          attention_kwargs (`dict`, *optional*):
+              Additional kwargs for attention processors.
+
+      Outputs:
+          latent_chunks (`list`):
+              List of per-chunk denoised latent tensors
+    """
+
+    model_name = "helios"
+    block_classes = [
+        HeliosTextInputStep,
+        HeliosAdditionalInputsStep(
+            image_latent_inputs=[InputParam.template("image_latents")],
+            additional_batch_inputs=[
+                InputParam(
+                    "fake_image_latents",
+                    type_hint=torch.Tensor,
+                    description="Fake image latents used as history seed for I2V generation.",
+                ),
+            ],
+        ),
+        HeliosAddNoiseToImageLatentsStep,
+        HeliosPrepareHistoryStep,
+        HeliosI2VSeedHistoryStep,
+        HeliosSetTimestepsStep,
+        HeliosI2VChunkDenoiseStep,
+    ]
+    block_names = [
+        "input",
+        "additional_inputs",
+        "add_noise_image",
+        "prepare_history",
+        "seed_history",
+        "set_timesteps",
+        "chunk_denoise",
+    ]
+
+    @property
+    def description(self):
+        return "I2V denoise block that seeds history with image latents and uses I2V-aware chunk preparation."
+
+    @property
+    def outputs(self):
+        return [OutputParam("latent_chunks", type_hint=list, description="List of per-chunk denoised latent tensors")]
+
+
+# DENOISE (V2V)
+# auto_docstring
+class HeliosV2VCoreDenoiseStep(SequentialPipelineBlocks):
+    """
+    V2V denoise block that seeds history with video latents and uses I2V-aware chunk preparation.
+
+      Components:
+          transformer (`HeliosTransformer3DModel`) scheduler (`HeliosScheduler`) guider (`ClassifierFreeGuidance`)
+
+      Inputs:
+          num_videos_per_prompt (`int`, *optional*, defaults to 1):
+              Number of videos to generate per prompt.
+          prompt_embeds (`Tensor`):
+              text embeddings used to guide the image generation. Can be generated from text_encoder step.
+          negative_prompt_embeds (`Tensor`, *optional*):
+              negative text embeddings used to guide the image generation. Can be generated from text_encoder step.
+          image_latents (`Tensor`, *optional*):
+              image latents used to guide the image generation. Can be generated from vae_encoder step.
+          video_latents (`Tensor`, *optional*):
+              Encoded video latents for V2V generation.
+          num_latent_frames_per_chunk (`int`, *optional*, defaults to 9):
+              Number of latent frames per temporal chunk.
+          image_noise_sigma_min (`float`, *optional*, defaults to 0.111):
+              Minimum sigma for image latent noise.
+          image_noise_sigma_max (`float`, *optional*, defaults to 0.135):
+              Maximum sigma for image latent noise.
+          video_noise_sigma_min (`float`, *optional*, defaults to 0.111):
+              Minimum sigma for video latent noise.
+          video_noise_sigma_max (`float`, *optional*, defaults to 0.135):
+              Maximum sigma for video latent noise.
+          generator (`Generator`, *optional*):
+              Torch generator for deterministic generation.
+          num_frames (`int`, *optional*, defaults to 132):
+              Total number of video frames to generate.
+          history_sizes (`list`, *optional*, defaults to [16, 2, 1]):
+              Sizes of long/mid/short history buffers for temporal context.
+          keep_first_frame (`bool`, *optional*, defaults to True):
+              Whether to keep the first frame as a prefix in history.
+          num_inference_steps (`int`, *optional*, defaults to 50):
+              The number of denoising steps.
+          sigmas (`list`, *optional*):
+              Custom sigmas for the denoising process.
+          latents (`Tensor`, *optional*):
+              Pre-generated noisy latents for image generation.
+          timesteps (`Tensor`, *optional*):
+              Timesteps for the denoising process.
+          **denoiser_input_fields (`None`, *optional*):
+              conditional model inputs for the denoiser: e.g. prompt_embeds, negative_prompt_embeds, etc.
+          attention_kwargs (`dict`, *optional*):
+              Additional kwargs for attention processors.
+
+      Outputs:
+          latent_chunks (`list`):
+              List of per-chunk denoised latent tensors
+    """
+
+    model_name = "helios"
+    block_classes = [
+        HeliosTextInputStep,
+        HeliosAdditionalInputsStep(
+            image_latent_inputs=[InputParam.template("image_latents")],
+            additional_batch_inputs=[
+                InputParam(
+                    "video_latents", type_hint=torch.Tensor, description="Encoded video latents for V2V generation."
+                ),
+            ],
+        ),
+        HeliosAddNoiseToVideoLatentsStep,
+        HeliosPrepareHistoryStep,
+        HeliosV2VSeedHistoryStep,
+        HeliosSetTimestepsStep,
+        HeliosI2VChunkDenoiseStep,
+    ]
+    block_names = [
+        "input",
+        "additional_inputs",
+        "add_noise_video",
+        "prepare_history",
+        "seed_history",
+        "set_timesteps",
+        "chunk_denoise",
+    ]
+
+    @property
+    def description(self):
+        return "V2V denoise block that seeds history with video latents and uses I2V-aware chunk preparation."
+
+    @property
+    def outputs(self):
+        return [OutputParam("latent_chunks", type_hint=list, description="List of per-chunk denoised latent tensors")]
+
+
+# AUTO DENOISE
+# auto_docstring
+class HeliosAutoCoreDenoiseStep(ConditionalPipelineBlocks):
+    """
+    Core denoise step that selects the appropriate denoising block.
+       - `HeliosV2VCoreDenoiseStep` (video2video) for video-to-video tasks.
+       - `HeliosI2VCoreDenoiseStep` (image2video) for image-to-video tasks.
+       - `HeliosCoreDenoiseStep` (text2video) for text-to-video tasks.
+
+      Components:
+          transformer (`HeliosTransformer3DModel`) scheduler (`HeliosScheduler`) guider (`ClassifierFreeGuidance`)
+
+      Inputs:
+          num_videos_per_prompt (`int`, *optional*, defaults to 1):
+              Number of videos to generate per prompt.
+          prompt_embeds (`Tensor`):
+              text embeddings used to guide the image generation. Can be generated from text_encoder step.
+          negative_prompt_embeds (`Tensor`, *optional*):
+              negative text embeddings used to guide the image generation. Can be generated from text_encoder step.
+          image_latents (`Tensor`, *optional*):
+              image latents used to guide the image generation. Can be generated from vae_encoder step.
+          video_latents (`Tensor`, *optional*):
+              Encoded video latents for V2V generation.
+          num_latent_frames_per_chunk (`int`, *optional*, defaults to 9):
+              Number of latent frames per temporal chunk.
+          image_noise_sigma_min (`float`, *optional*, defaults to 0.111):
+              Minimum sigma for image latent noise.
+          image_noise_sigma_max (`float`, *optional*, defaults to 0.135):
+              Maximum sigma for image latent noise.
+          video_noise_sigma_min (`float`, *optional*, defaults to 0.111):
+              Minimum sigma for video latent noise.
+          video_noise_sigma_max (`float`, *optional*, defaults to 0.135):
+              Maximum sigma for video latent noise.
+          generator (`Generator`, *optional*):
+              Torch generator for deterministic generation.
+          num_frames (`int`, *optional*, defaults to 132):
+              Total number of video frames to generate.
+          history_sizes (`list`):
+              Sizes of long/mid/short history buffers for temporal context.
+          keep_first_frame (`bool`, *optional*, defaults to True):
+              Whether to keep the first frame as a prefix in history.
+          num_inference_steps (`int`, *optional*, defaults to 50):
+              The number of denoising steps.
+          sigmas (`list`):
+              Custom sigmas for the denoising process.
+          latents (`Tensor`, *optional*):
+              Pre-generated noisy latents for image generation.
+          timesteps (`Tensor`, *optional*):
+              Timesteps for the denoising process.
+          **denoiser_input_fields (`None`, *optional*):
+              conditional model inputs for the denoiser: e.g. prompt_embeds, negative_prompt_embeds, etc.
+          attention_kwargs (`dict`, *optional*):
+              Additional kwargs for attention processors.
+          fake_image_latents (`Tensor`, *optional*):
+              Fake image latents used as history seed for I2V generation.
+          height (`int`, *optional*, defaults to 384):
+              The height in pixels of the generated image.
+          width (`int`, *optional*, defaults to 640):
+              The width in pixels of the generated image.
+
+      Outputs:
+          latent_chunks (`list`):
+              List of per-chunk denoised latent tensors
+    """
+
+    block_classes = [HeliosV2VCoreDenoiseStep, HeliosI2VCoreDenoiseStep, HeliosCoreDenoiseStep]
+    block_names = ["video2video", "image2video", "text2video"]
+    block_trigger_inputs = ["video_latents", "fake_image_latents"]
+    default_block_name = "text2video"
+
+    def select_block(self, video_latents=None, fake_image_latents=None):
+        if video_latents is not None:
+            return "video2video"
+        elif fake_image_latents is not None:
+            return "image2video"
+        return None
+
+    @property
+    def description(self):
+        return (
+            "Core denoise step that selects the appropriate denoising block.\n"
+            " - `HeliosV2VCoreDenoiseStep` (video2video) for video-to-video tasks.\n"
+            " - `HeliosI2VCoreDenoiseStep` (image2video) for image-to-video tasks.\n"
+            " - `HeliosCoreDenoiseStep` (text2video) for text-to-video tasks."
+        )
+
+
+AUTO_BLOCKS = InsertableDict(
+    [
+        ("text_encoder", HeliosTextEncoderStep()),
+        ("vae_encoder", HeliosAutoVaeEncoderStep()),
+        ("denoise", HeliosAutoCoreDenoiseStep()),
+        ("decode", HeliosDecodeStep()),
+    ]
+)
+
+# ====================
+# 3. Auto Blocks
+# ====================
+
+
+# auto_docstring
+class HeliosAutoBlocks(SequentialPipelineBlocks):
+    """
+    Auto Modular pipeline for text-to-video, image-to-video, and video-to-video tasks using Helios.
+
+      Supported workflows:
+        - `text2video`: requires `prompt`
+        - `image2video`: requires `prompt`, `image`
+        - `video2video`: requires `prompt`, `video`
+
+      Components:
+          text_encoder (`UMT5EncoderModel`) tokenizer (`AutoTokenizer`) guider (`ClassifierFreeGuidance`) vae
+          (`AutoencoderKLWan`) video_processor (`VideoProcessor`) transformer (`HeliosTransformer3DModel`) scheduler
+          (`HeliosScheduler`)
+
+      Inputs:
+          prompt (`str`):
+              The prompt or prompts to guide image generation.
+          negative_prompt (`str`, *optional*):
+              The prompt or prompts not to guide the image generation.
+          max_sequence_length (`int`, *optional*, defaults to 512):
+              Maximum sequence length for prompt encoding.
+          video (`None`, *optional*):
+              Input video for video-to-video generation
+          height (`int`, *optional*, defaults to 384):
+              The height in pixels of the generated image.
+          width (`int`, *optional*, defaults to 640):
+              The width in pixels of the generated image.
+          num_latent_frames_per_chunk (`int`, *optional*, defaults to 9):
+              Number of latent frames per temporal chunk.
+          generator (`Generator`, *optional*):
+              Torch generator for deterministic generation.
+          image (`Image | list`, *optional*):
+              Reference image(s) for denoising. Can be a single image or list of images.
+          num_videos_per_prompt (`int`, *optional*, defaults to 1):
+              Number of videos to generate per prompt.
+          image_latents (`Tensor`, *optional*):
+              image latents used to guide the image generation. Can be generated from vae_encoder step.
+          video_latents (`Tensor`, *optional*):
+              Encoded video latents for V2V generation.
+          image_noise_sigma_min (`float`, *optional*, defaults to 0.111):
+              Minimum sigma for image latent noise.
+          image_noise_sigma_max (`float`, *optional*, defaults to 0.135):
+              Maximum sigma for image latent noise.
+          video_noise_sigma_min (`float`, *optional*, defaults to 0.111):
+              Minimum sigma for video latent noise.
+          video_noise_sigma_max (`float`, *optional*, defaults to 0.135):
+              Maximum sigma for video latent noise.
+          num_frames (`int`, *optional*, defaults to 132):
+              Total number of video frames to generate.
+          history_sizes (`list`):
+              Sizes of long/mid/short history buffers for temporal context.
+          keep_first_frame (`bool`, *optional*, defaults to True):
+              Whether to keep the first frame as a prefix in history.
+          num_inference_steps (`int`, *optional*, defaults to 50):
+              The number of denoising steps.
+          sigmas (`list`):
+              Custom sigmas for the denoising process.
+          latents (`Tensor`, *optional*):
+              Pre-generated noisy latents for image generation.
+          timesteps (`Tensor`, *optional*):
+              Timesteps for the denoising process.
+          **denoiser_input_fields (`None`, *optional*):
+              conditional model inputs for the denoiser: e.g. prompt_embeds, negative_prompt_embeds, etc.
+          attention_kwargs (`dict`, *optional*):
+              Additional kwargs for attention processors.
+          fake_image_latents (`Tensor`, *optional*):
+              Fake image latents used as history seed for I2V generation.
+          output_type (`str`, *optional*, defaults to np):
+              Output format: 'pil', 'np', 'pt'.
+
+      Outputs:
+          videos (`list`):
+              The generated videos.
+    """
+
+    model_name = "helios"
+
+    block_classes = AUTO_BLOCKS.values()
+    block_names = AUTO_BLOCKS.keys()
+
+    _workflow_map = {
+        "text2video": {"prompt": True},
+        "image2video": {"prompt": True, "image": True},
+        "video2video": {"prompt": True, "video": True},
+    }
+
+    @property
+    def description(self):
+        return "Auto Modular pipeline for text-to-video, image-to-video, and video-to-video tasks using Helios."
+
+    @property
+    def outputs(self):
+        return [OutputParam.template("videos")]

src/diffusers/modular_pipelines/helios/modular_blocks_helios_pyramid.py

@@ -0,0 +1,520 @@
+# Copyright 2025 The HuggingFace Team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import torch
+
+from ...utils import logging
+from ..modular_pipeline import AutoPipelineBlocks, ConditionalPipelineBlocks, SequentialPipelineBlocks
+from ..modular_pipeline_utils import InputParam, InsertableDict, OutputParam
+from .before_denoise import (
+    HeliosAdditionalInputsStep,
+    HeliosAddNoiseToImageLatentsStep,
+    HeliosAddNoiseToVideoLatentsStep,
+    HeliosI2VSeedHistoryStep,
+    HeliosPrepareHistoryStep,
+    HeliosTextInputStep,
+    HeliosV2VSeedHistoryStep,
+)
+from .decoders import HeliosDecodeStep
+from .denoise import HeliosPyramidChunkDenoiseStep, HeliosPyramidI2VChunkDenoiseStep
+from .encoders import HeliosImageVaeEncoderStep, HeliosTextEncoderStep, HeliosVideoVaeEncoderStep
+
+
+logger = logging.get_logger(__name__)  # pylint: disable=invalid-name
+
+
+# ====================
+# 1. Vae Encoder
+# ====================
+
+
+# auto_docstring
+class HeliosPyramidAutoVaeEncoderStep(AutoPipelineBlocks):
+    """
+    Encoder step that encodes video or image inputs. This is an auto pipeline block.
+       - `HeliosVideoVaeEncoderStep` (video_encoder) is used when `video` is provided.
+       - `HeliosImageVaeEncoderStep` (image_encoder) is used when `image` is provided.
+       - If neither is provided, step will be skipped.
+
+      Components:
+          vae (`AutoencoderKLWan`) video_processor (`VideoProcessor`)
+
+      Inputs:
+          video (`None`, *optional*):
+              Input video for video-to-video generation
+          height (`int`, *optional*, defaults to 384):
+              The height in pixels of the generated image.
+          width (`int`, *optional*, defaults to 640):
+              The width in pixels of the generated image.
+          num_latent_frames_per_chunk (`int`, *optional*, defaults to 9):
+              Number of latent frames per temporal chunk.
+          generator (`Generator`, *optional*):
+              Torch generator for deterministic generation.
+          image (`Image | list`, *optional*):
+              Reference image(s) for denoising. Can be a single image or list of images.
+
+      Outputs:
+          image_latents (`Tensor`):
+              The latent representation of the input image.
+          video_latents (`Tensor`):
+              Encoded video latents (chunked)
+          fake_image_latents (`Tensor`):
+              Fake image latents for history seeding
+    """
+
+    block_classes = [HeliosVideoVaeEncoderStep, HeliosImageVaeEncoderStep]
+    block_names = ["video_encoder", "image_encoder"]
+    block_trigger_inputs = ["video", "image"]
+
+    @property
+    def description(self):
+        return (
+            "Encoder step that encodes video or image inputs. This is an auto pipeline block.\n"
+            " - `HeliosVideoVaeEncoderStep` (video_encoder) is used when `video` is provided.\n"
+            " - `HeliosImageVaeEncoderStep` (image_encoder) is used when `image` is provided.\n"
+            " - If neither is provided, step will be skipped."
+        )
+
+
+# ====================
+# 2. DENOISE
+# ====================
+
+
+# DENOISE (T2V)
+# auto_docstring
+class HeliosPyramidCoreDenoiseStep(SequentialPipelineBlocks):
+    """
+    T2V pyramid denoise block with progressive multi-resolution denoising.
+
+      Components:
+          transformer (`HeliosTransformer3DModel`) scheduler (`HeliosScheduler`) guider
+          (`ClassifierFreeZeroStarGuidance`)
+
+      Inputs:
+          num_videos_per_prompt (`int`, *optional*, defaults to 1):
+              Number of videos to generate per prompt.
+          prompt_embeds (`Tensor`):
+              text embeddings used to guide the image generation. Can be generated from text_encoder step.
+          negative_prompt_embeds (`Tensor`, *optional*):
+              negative text embeddings used to guide the image generation. Can be generated from text_encoder step.
+          height (`int`, *optional*, defaults to 384):
+              The height in pixels of the generated image.
+          width (`int`, *optional*, defaults to 640):
+              The width in pixels of the generated image.
+          num_frames (`int`, *optional*, defaults to 132):
+              Total number of video frames to generate.
+          num_latent_frames_per_chunk (`int`, *optional*, defaults to 9):
+              Number of latent frames per temporal chunk.
+          history_sizes (`list`, *optional*, defaults to [16, 2, 1]):
+              Sizes of long/mid/short history buffers for temporal context.
+          keep_first_frame (`bool`, *optional*, defaults to True):
+              Whether to keep the first frame as a prefix in history.
+          pyramid_num_inference_steps_list (`list`, *optional*, defaults to [10, 10, 10]):
+              Number of denoising steps per pyramid stage.
+          generator (`Generator`, *optional*):
+              Torch generator for deterministic generation.
+          latents (`Tensor`, *optional*):
+              Pre-generated noisy latents for image generation.
+          **denoiser_input_fields (`None`, *optional*):
+              conditional model inputs for the denoiser: e.g. prompt_embeds, negative_prompt_embeds, etc.
+          attention_kwargs (`dict`, *optional*):
+              Additional kwargs for attention processors.
+
+      Outputs:
+          latent_chunks (`list`):
+              List of per-chunk denoised latent tensors
+    """
+
+    model_name = "helios-pyramid"
+    block_classes = [
+        HeliosTextInputStep,
+        HeliosPrepareHistoryStep,
+        HeliosPyramidChunkDenoiseStep,
+    ]
+    block_names = ["input", "prepare_history", "pyramid_chunk_denoise"]
+
+    @property
+    def description(self):
+        return "T2V pyramid denoise block with progressive multi-resolution denoising."
+
+    @property
+    def outputs(self):
+        return [OutputParam("latent_chunks", type_hint=list, description="List of per-chunk denoised latent tensors")]
+
+
+# DENOISE (I2V)
+# auto_docstring
+class HeliosPyramidI2VCoreDenoiseStep(SequentialPipelineBlocks):
+    """
+    I2V pyramid denoise block with progressive multi-resolution denoising.
+
+      Components:
+          transformer (`HeliosTransformer3DModel`) scheduler (`HeliosScheduler`) guider
+          (`ClassifierFreeZeroStarGuidance`)
+
+      Inputs:
+          num_videos_per_prompt (`int`, *optional*, defaults to 1):
+              Number of videos to generate per prompt.
+          prompt_embeds (`Tensor`):
+              text embeddings used to guide the image generation. Can be generated from text_encoder step.
+          negative_prompt_embeds (`Tensor`, *optional*):
+              negative text embeddings used to guide the image generation. Can be generated from text_encoder step.
+          image_latents (`Tensor`):
+              image latents used to guide the image generation. Can be generated from vae_encoder step.
+          fake_image_latents (`Tensor`, *optional*):
+              Fake image latents used as history seed for I2V generation.
+          image_noise_sigma_min (`float`, *optional*, defaults to 0.111):
+              Minimum sigma for image latent noise.
+          image_noise_sigma_max (`float`, *optional*, defaults to 0.135):
+              Maximum sigma for image latent noise.
+          video_noise_sigma_min (`float`, *optional*, defaults to 0.111):
+              Minimum sigma for video/fake-image latent noise.
+          video_noise_sigma_max (`float`, *optional*, defaults to 0.135):
+              Maximum sigma for video/fake-image latent noise.
+          generator (`Generator`, *optional*):
+              Torch generator for deterministic generation.
+          num_frames (`int`, *optional*, defaults to 132):
+              Total number of video frames to generate.
+          num_latent_frames_per_chunk (`int`, *optional*, defaults to 9):
+              Number of latent frames per temporal chunk.
+          history_sizes (`list`, *optional*, defaults to [16, 2, 1]):
+              Sizes of long/mid/short history buffers for temporal context.
+          keep_first_frame (`bool`, *optional*, defaults to True):
+              Whether to keep the first frame as a prefix in history.
+          pyramid_num_inference_steps_list (`list`, *optional*, defaults to [10, 10, 10]):
+              Number of denoising steps per pyramid stage.
+          latents (`Tensor`, *optional*):
+              Pre-generated noisy latents for image generation.
+          **denoiser_input_fields (`None`, *optional*):
+              conditional model inputs for the denoiser: e.g. prompt_embeds, negative_prompt_embeds, etc.
+          attention_kwargs (`dict`, *optional*):
+              Additional kwargs for attention processors.
+
+      Outputs:
+          latent_chunks (`list`):
+              List of per-chunk denoised latent tensors
+    """
+
+    model_name = "helios-pyramid"
+    block_classes = [
+        HeliosTextInputStep,
+        HeliosAdditionalInputsStep(
+            image_latent_inputs=[InputParam.template("image_latents")],
+            additional_batch_inputs=[
+                InputParam(
+                    "fake_image_latents",
+                    type_hint=torch.Tensor,
+                    description="Fake image latents used as history seed for I2V generation.",
+                ),
+            ],
+        ),
+        HeliosAddNoiseToImageLatentsStep,
+        HeliosPrepareHistoryStep,
+        HeliosI2VSeedHistoryStep,
+        HeliosPyramidI2VChunkDenoiseStep,
+    ]
+    block_names = [
+        "input",
+        "additional_inputs",
+        "add_noise_image",
+        "prepare_history",
+        "seed_history",
+        "pyramid_chunk_denoise",
+    ]
+
+    @property
+    def description(self):
+        return "I2V pyramid denoise block with progressive multi-resolution denoising."
+
+    @property
+    def outputs(self):
+        return [OutputParam("latent_chunks", type_hint=list, description="List of per-chunk denoised latent tensors")]
+
+
+# DENOISE (V2V)
+# auto_docstring
+class HeliosPyramidV2VCoreDenoiseStep(SequentialPipelineBlocks):
+    """
+    V2V pyramid denoise block with progressive multi-resolution denoising.
+
+      Components:
+          transformer (`HeliosTransformer3DModel`) scheduler (`HeliosScheduler`) guider
+          (`ClassifierFreeZeroStarGuidance`)
+
+      Inputs:
+          num_videos_per_prompt (`int`, *optional*, defaults to 1):
+              Number of videos to generate per prompt.
+          prompt_embeds (`Tensor`):
+              text embeddings used to guide the image generation. Can be generated from text_encoder step.
+          negative_prompt_embeds (`Tensor`, *optional*):
+              negative text embeddings used to guide the image generation. Can be generated from text_encoder step.
+          image_latents (`Tensor`, *optional*):
+              image latents used to guide the image generation. Can be generated from vae_encoder step.
+          video_latents (`Tensor`, *optional*):
+              Encoded video latents for V2V generation.
+          num_latent_frames_per_chunk (`int`, *optional*, defaults to 9):
+              Number of latent frames per temporal chunk.
+          image_noise_sigma_min (`float`, *optional*, defaults to 0.111):
+              Minimum sigma for image latent noise.
+          image_noise_sigma_max (`float`, *optional*, defaults to 0.135):
+              Maximum sigma for image latent noise.
+          video_noise_sigma_min (`float`, *optional*, defaults to 0.111):
+              Minimum sigma for video latent noise.
+          video_noise_sigma_max (`float`, *optional*, defaults to 0.135):
+              Maximum sigma for video latent noise.
+          generator (`Generator`, *optional*):
+              Torch generator for deterministic generation.
+          num_frames (`int`, *optional*, defaults to 132):
+              Total number of video frames to generate.
+          history_sizes (`list`, *optional*, defaults to [16, 2, 1]):
+              Sizes of long/mid/short history buffers for temporal context.
+          keep_first_frame (`bool`, *optional*, defaults to True):
+              Whether to keep the first frame as a prefix in history.
+          pyramid_num_inference_steps_list (`list`, *optional*, defaults to [10, 10, 10]):
+              Number of denoising steps per pyramid stage.
+          latents (`Tensor`, *optional*):
+              Pre-generated noisy latents for image generation.
+          **denoiser_input_fields (`None`, *optional*):
+              conditional model inputs for the denoiser: e.g. prompt_embeds, negative_prompt_embeds, etc.
+          attention_kwargs (`dict`, *optional*):
+              Additional kwargs for attention processors.
+
+      Outputs:
+          latent_chunks (`list`):
+              List of per-chunk denoised latent tensors
+    """
+
+    model_name = "helios-pyramid"
+    block_classes = [
+        HeliosTextInputStep,
+        HeliosAdditionalInputsStep(
+            image_latent_inputs=[InputParam.template("image_latents")],
+            additional_batch_inputs=[
+                InputParam(
+                    "video_latents", type_hint=torch.Tensor, description="Encoded video latents for V2V generation."
+                ),
+            ],
+        ),
+        HeliosAddNoiseToVideoLatentsStep,
+        HeliosPrepareHistoryStep,
+        HeliosV2VSeedHistoryStep,
+        HeliosPyramidI2VChunkDenoiseStep,
+    ]
+    block_names = [
+        "input",
+        "additional_inputs",
+        "add_noise_video",
+        "prepare_history",
+        "seed_history",
+        "pyramid_chunk_denoise",
+    ]
+
+    @property
+    def description(self):
+        return "V2V pyramid denoise block with progressive multi-resolution denoising."
+
+    @property
+    def outputs(self):
+        return [OutputParam("latent_chunks", type_hint=list, description="List of per-chunk denoised latent tensors")]
+
+
+# AUTO DENOISE
+# auto_docstring
+class HeliosPyramidAutoCoreDenoiseStep(ConditionalPipelineBlocks):
+    """
+    Pyramid core denoise step that selects the appropriate denoising block.
+       - `HeliosPyramidV2VCoreDenoiseStep` (video2video) for video-to-video tasks.
+       - `HeliosPyramidI2VCoreDenoiseStep` (image2video) for image-to-video tasks.
+       - `HeliosPyramidCoreDenoiseStep` (text2video) for text-to-video tasks.
+
+      Components:
+          transformer (`HeliosTransformer3DModel`) scheduler (`HeliosScheduler`) guider
+          (`ClassifierFreeZeroStarGuidance`)
+
+      Inputs:
+          num_videos_per_prompt (`int`, *optional*, defaults to 1):
+              Number of videos to generate per prompt.
+          prompt_embeds (`Tensor`):
+              text embeddings used to guide the image generation. Can be generated from text_encoder step.
+          negative_prompt_embeds (`Tensor`, *optional*):
+              negative text embeddings used to guide the image generation. Can be generated from text_encoder step.
+          image_latents (`Tensor`, *optional*):
+              image latents used to guide the image generation. Can be generated from vae_encoder step.
+          video_latents (`Tensor`, *optional*):
+              Encoded video latents for V2V generation.
+          num_latent_frames_per_chunk (`int`, *optional*, defaults to 9):
+              Number of latent frames per temporal chunk.
+          image_noise_sigma_min (`float`, *optional*, defaults to 0.111):
+              Minimum sigma for image latent noise.
+          image_noise_sigma_max (`float`, *optional*, defaults to 0.135):
+              Maximum sigma for image latent noise.
+          video_noise_sigma_min (`float`, *optional*, defaults to 0.111):
+              Minimum sigma for video latent noise.
+          video_noise_sigma_max (`float`, *optional*, defaults to 0.135):
+              Maximum sigma for video latent noise.
+          generator (`Generator`, *optional*):
+              Torch generator for deterministic generation.
+          num_frames (`int`, *optional*, defaults to 132):
+              Total number of video frames to generate.
+          history_sizes (`list`):
+              Sizes of long/mid/short history buffers for temporal context.
+          keep_first_frame (`bool`, *optional*, defaults to True):
+              Whether to keep the first frame as a prefix in history.
+          pyramid_num_inference_steps_list (`list`, *optional*, defaults to [10, 10, 10]):
+              Number of denoising steps per pyramid stage.
+          latents (`Tensor`, *optional*):
+              Pre-generated noisy latents for image generation.
+          **denoiser_input_fields (`None`, *optional*):
+              conditional model inputs for the denoiser: e.g. prompt_embeds, negative_prompt_embeds, etc.
+          attention_kwargs (`dict`, *optional*):
+              Additional kwargs for attention processors.
+          fake_image_latents (`Tensor`, *optional*):
+              Fake image latents used as history seed for I2V generation.
+          height (`int`, *optional*, defaults to 384):
+              The height in pixels of the generated image.
+          width (`int`, *optional*, defaults to 640):
+              The width in pixels of the generated image.
+
+      Outputs:
+          latent_chunks (`list`):
+              List of per-chunk denoised latent tensors
+    """
+
+    block_classes = [HeliosPyramidV2VCoreDenoiseStep, HeliosPyramidI2VCoreDenoiseStep, HeliosPyramidCoreDenoiseStep]
+    block_names = ["video2video", "image2video", "text2video"]
+    block_trigger_inputs = ["video_latents", "fake_image_latents"]
+    default_block_name = "text2video"
+
+    def select_block(self, video_latents=None, fake_image_latents=None):
+        if video_latents is not None:
+            return "video2video"
+        elif fake_image_latents is not None:
+            return "image2video"
+        return None
+
+    @property
+    def description(self):
+        return (
+            "Pyramid core denoise step that selects the appropriate denoising block.\n"
+            " - `HeliosPyramidV2VCoreDenoiseStep` (video2video) for video-to-video tasks.\n"
+            " - `HeliosPyramidI2VCoreDenoiseStep` (image2video) for image-to-video tasks.\n"
+            " - `HeliosPyramidCoreDenoiseStep` (text2video) for text-to-video tasks."
+        )
+
+
+# ====================
+# 3. Auto Blocks
+# ====================
+
+PYRAMID_AUTO_BLOCKS = InsertableDict(
+    [
+        ("text_encoder", HeliosTextEncoderStep()),
+        ("vae_encoder", HeliosPyramidAutoVaeEncoderStep()),
+        ("denoise", HeliosPyramidAutoCoreDenoiseStep()),
+        ("decode", HeliosDecodeStep()),
+    ]
+)
+
+
+# auto_docstring
+class HeliosPyramidAutoBlocks(SequentialPipelineBlocks):
+    """
+    Auto Modular pipeline for pyramid progressive generation (T2V/I2V/V2V) using Helios.
+
+      Supported workflows:
+        - `text2video`: requires `prompt`
+        - `image2video`: requires `prompt`, `image`
+        - `video2video`: requires `prompt`, `video`
+
+      Components:
+          text_encoder (`UMT5EncoderModel`) tokenizer (`AutoTokenizer`) guider (`ClassifierFreeGuidance`) vae
+          (`AutoencoderKLWan`) video_processor (`VideoProcessor`) transformer (`HeliosTransformer3DModel`) scheduler
+          (`HeliosScheduler`)
+
+      Inputs:
+          prompt (`str`):
+              The prompt or prompts to guide image generation.
+          negative_prompt (`str`, *optional*):
+              The prompt or prompts not to guide the image generation.
+          max_sequence_length (`int`, *optional*, defaults to 512):
+              Maximum sequence length for prompt encoding.
+          video (`None`, *optional*):
+              Input video for video-to-video generation
+          height (`int`, *optional*, defaults to 384):
+              The height in pixels of the generated image.
+          width (`int`, *optional*, defaults to 640):
+              The width in pixels of the generated image.
+          num_latent_frames_per_chunk (`int`, *optional*, defaults to 9):
+              Number of latent frames per temporal chunk.
+          generator (`Generator`, *optional*):
+              Torch generator for deterministic generation.
+          image (`Image | list`, *optional*):
+              Reference image(s) for denoising. Can be a single image or list of images.
+          num_videos_per_prompt (`int`, *optional*, defaults to 1):
+              Number of videos to generate per prompt.
+          image_latents (`Tensor`, *optional*):
+              image latents used to guide the image generation. Can be generated from vae_encoder step.
+          video_latents (`Tensor`, *optional*):
+              Encoded video latents for V2V generation.
+          image_noise_sigma_min (`float`, *optional*, defaults to 0.111):
+              Minimum sigma for image latent noise.
+          image_noise_sigma_max (`float`, *optional*, defaults to 0.135):
+              Maximum sigma for image latent noise.
+          video_noise_sigma_min (`float`, *optional*, defaults to 0.111):
+              Minimum sigma for video latent noise.
+          video_noise_sigma_max (`float`, *optional*, defaults to 0.135):
+              Maximum sigma for video latent noise.
+          num_frames (`int`, *optional*, defaults to 132):
+              Total number of video frames to generate.
+          history_sizes (`list`):
+              Sizes of long/mid/short history buffers for temporal context.
+          keep_first_frame (`bool`, *optional*, defaults to True):
+              Whether to keep the first frame as a prefix in history.
+          pyramid_num_inference_steps_list (`list`, *optional*, defaults to [10, 10, 10]):
+              Number of denoising steps per pyramid stage.
+          latents (`Tensor`, *optional*):
+              Pre-generated noisy latents for image generation.
+          **denoiser_input_fields (`None`, *optional*):
+              conditional model inputs for the denoiser: e.g. prompt_embeds, negative_prompt_embeds, etc.
+          attention_kwargs (`dict`, *optional*):
+              Additional kwargs for attention processors.
+          fake_image_latents (`Tensor`, *optional*):
+              Fake image latents used as history seed for I2V generation.
+          output_type (`str`, *optional*, defaults to np):
+              Output format: 'pil', 'np', 'pt'.
+
+      Outputs:
+          videos (`list`):
+              The generated videos.
+    """
+
+    model_name = "helios-pyramid"
+
+    block_classes = PYRAMID_AUTO_BLOCKS.values()
+    block_names = PYRAMID_AUTO_BLOCKS.keys()
+
+    _workflow_map = {
+        "text2video": {"prompt": True},
+        "image2video": {"prompt": True, "image": True},
+        "video2video": {"prompt": True, "video": True},
+    }
+
+    @property
+    def description(self):
+        return "Auto Modular pipeline for pyramid progressive generation (T2V/I2V/V2V) using Helios."
+
+    @property
+    def outputs(self):
+        return [OutputParam.template("videos")]

src/diffusers/modular_pipelines/helios/modular_blocks_helios_pyramid_distilled.py

@@ -0,0 +1,530 @@
+# Copyright 2025 The HuggingFace Team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import torch
+
+from ...utils import logging
+from ..modular_pipeline import AutoPipelineBlocks, ConditionalPipelineBlocks, SequentialPipelineBlocks
+from ..modular_pipeline_utils import InputParam, InsertableDict, OutputParam
+from .before_denoise import (
+    HeliosAdditionalInputsStep,
+    HeliosAddNoiseToImageLatentsStep,
+    HeliosAddNoiseToVideoLatentsStep,
+    HeliosI2VSeedHistoryStep,
+    HeliosPrepareHistoryStep,
+    HeliosTextInputStep,
+    HeliosV2VSeedHistoryStep,
+)
+from .decoders import HeliosDecodeStep
+from .denoise import HeliosPyramidDistilledChunkDenoiseStep, HeliosPyramidDistilledI2VChunkDenoiseStep
+from .encoders import HeliosImageVaeEncoderStep, HeliosTextEncoderStep, HeliosVideoVaeEncoderStep
+
+
+logger = logging.get_logger(__name__)  # pylint: disable=invalid-name
+
+
+# ====================
+# 1. Vae Encoder
+# ====================
+
+
+# auto_docstring
+class HeliosPyramidDistilledAutoVaeEncoderStep(AutoPipelineBlocks):
+    """
+    Encoder step for distilled pyramid pipeline.
+       - `HeliosVideoVaeEncoderStep` (video_encoder) is used when `video` is provided.
+       - `HeliosImageVaeEncoderStep` (image_encoder) is used when `image` is provided.
+       - If neither is provided, step will be skipped.
+
+      Components:
+          vae (`AutoencoderKLWan`) video_processor (`VideoProcessor`)
+
+      Inputs:
+          video (`None`, *optional*):
+              Input video for video-to-video generation
+          height (`int`, *optional*, defaults to 384):
+              The height in pixels of the generated image.
+          width (`int`, *optional*, defaults to 640):
+              The width in pixels of the generated image.
+          num_latent_frames_per_chunk (`int`, *optional*, defaults to 9):
+              Number of latent frames per temporal chunk.
+          generator (`Generator`, *optional*):
+              Torch generator for deterministic generation.
+          image (`Image | list`, *optional*):
+              Reference image(s) for denoising. Can be a single image or list of images.
+
+      Outputs:
+          image_latents (`Tensor`):
+              The latent representation of the input image.
+          video_latents (`Tensor`):
+              Encoded video latents (chunked)
+          fake_image_latents (`Tensor`):
+              Fake image latents for history seeding
+    """
+
+    block_classes = [HeliosVideoVaeEncoderStep, HeliosImageVaeEncoderStep]
+    block_names = ["video_encoder", "image_encoder"]
+    block_trigger_inputs = ["video", "image"]
+
+    @property
+    def description(self):
+        return (
+            "Encoder step for distilled pyramid pipeline.\n"
+            " - `HeliosVideoVaeEncoderStep` (video_encoder) is used when `video` is provided.\n"
+            " - `HeliosImageVaeEncoderStep` (image_encoder) is used when `image` is provided.\n"
+            " - If neither is provided, step will be skipped."
+        )
+
+
+# ====================
+# 2. DENOISE
+# ====================
+
+
+# DENOISE (T2V)
+# auto_docstring
+class HeliosPyramidDistilledCoreDenoiseStep(SequentialPipelineBlocks):
+    """
+    T2V distilled pyramid denoise block with DMD scheduler and no CFG.
+
+      Components:
+          transformer (`HeliosTransformer3DModel`) scheduler (`HeliosScheduler`) guider (`ClassifierFreeGuidance`)
+
+      Inputs:
+          num_videos_per_prompt (`int`, *optional*, defaults to 1):
+              Number of videos to generate per prompt.
+          prompt_embeds (`Tensor`):
+              text embeddings used to guide the image generation. Can be generated from text_encoder step.
+          negative_prompt_embeds (`Tensor`, *optional*):
+              negative text embeddings used to guide the image generation. Can be generated from text_encoder step.
+          height (`int`, *optional*, defaults to 384):
+              The height in pixels of the generated image.
+          width (`int`, *optional*, defaults to 640):
+              The width in pixels of the generated image.
+          num_frames (`int`, *optional*, defaults to 132):
+              Total number of video frames to generate.
+          num_latent_frames_per_chunk (`int`, *optional*, defaults to 9):
+              Number of latent frames per temporal chunk.
+          history_sizes (`list`, *optional*, defaults to [16, 2, 1]):
+              Sizes of long/mid/short history buffers for temporal context.
+          keep_first_frame (`bool`, *optional*, defaults to True):
+              Whether to keep the first frame as a prefix in history.
+          pyramid_num_inference_steps_list (`list`, *optional*, defaults to [10, 10, 10]):
+              Number of denoising steps per pyramid stage.
+          generator (`Generator`, *optional*):
+              Torch generator for deterministic generation.
+          latents (`Tensor`, *optional*):
+              Pre-generated noisy latents for image generation.
+          **denoiser_input_fields (`None`, *optional*):
+              conditional model inputs for the denoiser: e.g. prompt_embeds, negative_prompt_embeds, etc.
+          is_amplify_first_chunk (`bool`, *optional*, defaults to True):
+              Whether to double the first chunk's timesteps via the scheduler for amplified generation.
+          attention_kwargs (`dict`, *optional*):
+              Additional kwargs for attention processors.
+
+      Outputs:
+          latent_chunks (`list`):
+              List of per-chunk denoised latent tensors
+    """
+
+    model_name = "helios-pyramid"
+    block_classes = [
+        HeliosTextInputStep,
+        HeliosPrepareHistoryStep,
+        HeliosPyramidDistilledChunkDenoiseStep,
+    ]
+    block_names = ["input", "prepare_history", "pyramid_chunk_denoise"]
+
+    @property
+    def description(self):
+        return "T2V distilled pyramid denoise block with DMD scheduler and no CFG."
+
+    @property
+    def outputs(self):
+        return [OutputParam("latent_chunks", type_hint=list, description="List of per-chunk denoised latent tensors")]
+
+
+# DENOISE (I2V)
+# auto_docstring
+class HeliosPyramidDistilledI2VCoreDenoiseStep(SequentialPipelineBlocks):
+    """
+    I2V distilled pyramid denoise block with DMD scheduler and no CFG.
+
+      Components:
+          transformer (`HeliosTransformer3DModel`) scheduler (`HeliosScheduler`) guider (`ClassifierFreeGuidance`)
+
+      Inputs:
+          num_videos_per_prompt (`int`, *optional*, defaults to 1):
+              Number of videos to generate per prompt.
+          prompt_embeds (`Tensor`):
+              text embeddings used to guide the image generation. Can be generated from text_encoder step.
+          negative_prompt_embeds (`Tensor`, *optional*):
+              negative text embeddings used to guide the image generation. Can be generated from text_encoder step.
+          image_latents (`Tensor`):
+              image latents used to guide the image generation. Can be generated from vae_encoder step.
+          fake_image_latents (`Tensor`, *optional*):
+              Fake image latents used as history seed for I2V generation.
+          image_noise_sigma_min (`float`, *optional*, defaults to 0.111):
+              Minimum sigma for image latent noise.
+          image_noise_sigma_max (`float`, *optional*, defaults to 0.135):
+              Maximum sigma for image latent noise.
+          video_noise_sigma_min (`float`, *optional*, defaults to 0.111):
+              Minimum sigma for video/fake-image latent noise.
+          video_noise_sigma_max (`float`, *optional*, defaults to 0.135):
+              Maximum sigma for video/fake-image latent noise.
+          generator (`Generator`, *optional*):
+              Torch generator for deterministic generation.
+          num_frames (`int`, *optional*, defaults to 132):
+              Total number of video frames to generate.
+          num_latent_frames_per_chunk (`int`, *optional*, defaults to 9):
+              Number of latent frames per temporal chunk.
+          history_sizes (`list`, *optional*, defaults to [16, 2, 1]):
+              Sizes of long/mid/short history buffers for temporal context.
+          keep_first_frame (`bool`, *optional*, defaults to True):
+              Whether to keep the first frame as a prefix in history.
+          pyramid_num_inference_steps_list (`list`, *optional*, defaults to [10, 10, 10]):
+              Number of denoising steps per pyramid stage.
+          latents (`Tensor`, *optional*):
+              Pre-generated noisy latents for image generation.
+          **denoiser_input_fields (`None`, *optional*):
+              conditional model inputs for the denoiser: e.g. prompt_embeds, negative_prompt_embeds, etc.
+          is_amplify_first_chunk (`bool`, *optional*, defaults to True):
+              Whether to double the first chunk's timesteps via the scheduler for amplified generation.
+          attention_kwargs (`dict`, *optional*):
+              Additional kwargs for attention processors.
+
+      Outputs:
+          latent_chunks (`list`):
+              List of per-chunk denoised latent tensors
+    """
+
+    model_name = "helios-pyramid"
+    block_classes = [
+        HeliosTextInputStep,
+        HeliosAdditionalInputsStep(
+            image_latent_inputs=[InputParam.template("image_latents")],
+            additional_batch_inputs=[
+                InputParam(
+                    "fake_image_latents",
+                    type_hint=torch.Tensor,
+                    description="Fake image latents used as history seed for I2V generation.",
+                ),
+            ],
+        ),
+        HeliosAddNoiseToImageLatentsStep,
+        HeliosPrepareHistoryStep,
+        HeliosI2VSeedHistoryStep,
+        HeliosPyramidDistilledI2VChunkDenoiseStep,
+    ]
+    block_names = [
+        "input",
+        "additional_inputs",
+        "add_noise_image",
+        "prepare_history",
+        "seed_history",
+        "pyramid_chunk_denoise",
+    ]
+
+    @property
+    def description(self):
+        return "I2V distilled pyramid denoise block with DMD scheduler and no CFG."
+
+    @property
+    def outputs(self):
+        return [OutputParam("latent_chunks", type_hint=list, description="List of per-chunk denoised latent tensors")]
+
+
+# DENOISE (V2V)
+# auto_docstring
+class HeliosPyramidDistilledV2VCoreDenoiseStep(SequentialPipelineBlocks):
+    """
+    V2V distilled pyramid denoise block with DMD scheduler and no CFG.
+
+      Components:
+          transformer (`HeliosTransformer3DModel`) scheduler (`HeliosScheduler`) guider (`ClassifierFreeGuidance`)
+
+      Inputs:
+          num_videos_per_prompt (`int`, *optional*, defaults to 1):
+              Number of videos to generate per prompt.
+          prompt_embeds (`Tensor`):
+              text embeddings used to guide the image generation. Can be generated from text_encoder step.
+          negative_prompt_embeds (`Tensor`, *optional*):
+              negative text embeddings used to guide the image generation. Can be generated from text_encoder step.
+          image_latents (`Tensor`, *optional*):
+              image latents used to guide the image generation. Can be generated from vae_encoder step.
+          video_latents (`Tensor`, *optional*):
+              Encoded video latents for V2V generation.
+          num_latent_frames_per_chunk (`int`, *optional*, defaults to 9):
+              Number of latent frames per temporal chunk.
+          image_noise_sigma_min (`float`, *optional*, defaults to 0.111):
+              Minimum sigma for image latent noise.
+          image_noise_sigma_max (`float`, *optional*, defaults to 0.135):
+              Maximum sigma for image latent noise.
+          video_noise_sigma_min (`float`, *optional*, defaults to 0.111):
+              Minimum sigma for video latent noise.
+          video_noise_sigma_max (`float`, *optional*, defaults to 0.135):
+              Maximum sigma for video latent noise.
+          generator (`Generator`, *optional*):
+              Torch generator for deterministic generation.
+          num_frames (`int`, *optional*, defaults to 132):
+              Total number of video frames to generate.
+          history_sizes (`list`, *optional*, defaults to [16, 2, 1]):
+              Sizes of long/mid/short history buffers for temporal context.
+          keep_first_frame (`bool`, *optional*, defaults to True):
+              Whether to keep the first frame as a prefix in history.
+          pyramid_num_inference_steps_list (`list`, *optional*, defaults to [10, 10, 10]):
+              Number of denoising steps per pyramid stage.
+          latents (`Tensor`, *optional*):
+              Pre-generated noisy latents for image generation.
+          **denoiser_input_fields (`None`, *optional*):
+              conditional model inputs for the denoiser: e.g. prompt_embeds, negative_prompt_embeds, etc.
+          is_amplify_first_chunk (`bool`, *optional*, defaults to True):
+              Whether to double the first chunk's timesteps via the scheduler for amplified generation.
+          attention_kwargs (`dict`, *optional*):
+              Additional kwargs for attention processors.
+
+      Outputs:
+          latent_chunks (`list`):
+              List of per-chunk denoised latent tensors
+    """
+
+    model_name = "helios-pyramid"
+    block_classes = [
+        HeliosTextInputStep,
+        HeliosAdditionalInputsStep(
+            image_latent_inputs=[InputParam.template("image_latents")],
+            additional_batch_inputs=[
+                InputParam(
+                    "video_latents", type_hint=torch.Tensor, description="Encoded video latents for V2V generation."
+                ),
+            ],
+        ),
+        HeliosAddNoiseToVideoLatentsStep,
+        HeliosPrepareHistoryStep,
+        HeliosV2VSeedHistoryStep,
+        HeliosPyramidDistilledI2VChunkDenoiseStep,
+    ]
+    block_names = [
+        "input",
+        "additional_inputs",
+        "add_noise_video",
+        "prepare_history",
+        "seed_history",
+        "pyramid_chunk_denoise",
+    ]
+
+    @property
+    def description(self):
+        return "V2V distilled pyramid denoise block with DMD scheduler and no CFG."
+
+    @property
+    def outputs(self):
+        return [OutputParam("latent_chunks", type_hint=list, description="List of per-chunk denoised latent tensors")]
+
+
+# AUTO DENOISE
+# auto_docstring
+class HeliosPyramidDistilledAutoCoreDenoiseStep(ConditionalPipelineBlocks):
+    """
+    Distilled pyramid core denoise step that selects the appropriate denoising block.
+       - `HeliosPyramidDistilledV2VCoreDenoiseStep` (video2video) for video-to-video tasks.
+       - `HeliosPyramidDistilledI2VCoreDenoiseStep` (image2video) for image-to-video tasks.
+       - `HeliosPyramidDistilledCoreDenoiseStep` (text2video) for text-to-video tasks.
+
+      Components:
+          transformer (`HeliosTransformer3DModel`) scheduler (`HeliosScheduler`) guider (`ClassifierFreeGuidance`)
+
+      Inputs:
+          num_videos_per_prompt (`int`, *optional*, defaults to 1):
+              Number of videos to generate per prompt.
+          prompt_embeds (`Tensor`):
+              text embeddings used to guide the image generation. Can be generated from text_encoder step.
+          negative_prompt_embeds (`Tensor`, *optional*):
+              negative text embeddings used to guide the image generation. Can be generated from text_encoder step.
+          image_latents (`Tensor`, *optional*):
+              image latents used to guide the image generation. Can be generated from vae_encoder step.
+          video_latents (`Tensor`, *optional*):
+              Encoded video latents for V2V generation.
+          num_latent_frames_per_chunk (`int`, *optional*, defaults to 9):
+              Number of latent frames per temporal chunk.
+          image_noise_sigma_min (`float`, *optional*, defaults to 0.111):
+              Minimum sigma for image latent noise.
+          image_noise_sigma_max (`float`, *optional*, defaults to 0.135):
+              Maximum sigma for image latent noise.
+          video_noise_sigma_min (`float`, *optional*, defaults to 0.111):
+              Minimum sigma for video latent noise.
+          video_noise_sigma_max (`float`, *optional*, defaults to 0.135):
+              Maximum sigma for video latent noise.
+          generator (`Generator`, *optional*):
+              Torch generator for deterministic generation.
+          num_frames (`int`, *optional*, defaults to 132):
+              Total number of video frames to generate.
+          history_sizes (`list`):
+              Sizes of long/mid/short history buffers for temporal context.
+          keep_first_frame (`bool`, *optional*, defaults to True):
+              Whether to keep the first frame as a prefix in history.
+          pyramid_num_inference_steps_list (`list`, *optional*, defaults to [10, 10, 10]):
+              Number of denoising steps per pyramid stage.
+          latents (`Tensor`, *optional*):
+              Pre-generated noisy latents for image generation.
+          **denoiser_input_fields (`None`, *optional*):
+              conditional model inputs for the denoiser: e.g. prompt_embeds, negative_prompt_embeds, etc.
+          is_amplify_first_chunk (`bool`, *optional*, defaults to True):
+              Whether to double the first chunk's timesteps via the scheduler for amplified generation.
+          attention_kwargs (`dict`, *optional*):
+              Additional kwargs for attention processors.
+          fake_image_latents (`Tensor`, *optional*):
+              Fake image latents used as history seed for I2V generation.
+          height (`int`, *optional*, defaults to 384):
+              The height in pixels of the generated image.
+          width (`int`, *optional*, defaults to 640):
+              The width in pixels of the generated image.
+
+      Outputs:
+          latent_chunks (`list`):
+              List of per-chunk denoised latent tensors
+    """
+
+    block_classes = [
+        HeliosPyramidDistilledV2VCoreDenoiseStep,
+        HeliosPyramidDistilledI2VCoreDenoiseStep,
+        HeliosPyramidDistilledCoreDenoiseStep,
+    ]
+    block_names = ["video2video", "image2video", "text2video"]
+    block_trigger_inputs = ["video_latents", "fake_image_latents"]
+    default_block_name = "text2video"
+
+    def select_block(self, video_latents=None, fake_image_latents=None):
+        if video_latents is not None:
+            return "video2video"
+        elif fake_image_latents is not None:
+            return "image2video"
+        return None
+
+    @property
+    def description(self):
+        return (
+            "Distilled pyramid core denoise step that selects the appropriate denoising block.\n"
+            " - `HeliosPyramidDistilledV2VCoreDenoiseStep` (video2video) for video-to-video tasks.\n"
+            " - `HeliosPyramidDistilledI2VCoreDenoiseStep` (image2video) for image-to-video tasks.\n"
+            " - `HeliosPyramidDistilledCoreDenoiseStep` (text2video) for text-to-video tasks."
+        )
+
+
+# ====================
+# 3. Auto Blocks
+# ====================
+
+DISTILLED_PYRAMID_AUTO_BLOCKS = InsertableDict(
+    [
+        ("text_encoder", HeliosTextEncoderStep()),
+        ("vae_encoder", HeliosPyramidDistilledAutoVaeEncoderStep()),
+        ("denoise", HeliosPyramidDistilledAutoCoreDenoiseStep()),
+        ("decode", HeliosDecodeStep()),
+    ]
+)
+
+
+# auto_docstring
+class HeliosPyramidDistilledAutoBlocks(SequentialPipelineBlocks):
+    """
+    Auto Modular pipeline for distilled pyramid progressive generation (T2V/I2V/V2V) using Helios.
+
+      Supported workflows:
+        - `text2video`: requires `prompt`
+        - `image2video`: requires `prompt`, `image`
+        - `video2video`: requires `prompt`, `video`
+
+      Components:
+          text_encoder (`UMT5EncoderModel`) tokenizer (`AutoTokenizer`) guider (`ClassifierFreeGuidance`) vae
+          (`AutoencoderKLWan`) video_processor (`VideoProcessor`) transformer (`HeliosTransformer3DModel`) scheduler
+          (`HeliosScheduler`)
+
+      Inputs:
+          prompt (`str`):
+              The prompt or prompts to guide image generation.
+          negative_prompt (`str`, *optional*):
+              The prompt or prompts not to guide the image generation.
+          max_sequence_length (`int`, *optional*, defaults to 512):
+              Maximum sequence length for prompt encoding.
+          video (`None`, *optional*):
+              Input video for video-to-video generation
+          height (`int`, *optional*, defaults to 384):
+              The height in pixels of the generated image.
+          width (`int`, *optional*, defaults to 640):
+              The width in pixels of the generated image.
+          num_latent_frames_per_chunk (`int`, *optional*, defaults to 9):
+              Number of latent frames per temporal chunk.
+          generator (`Generator`, *optional*):
+              Torch generator for deterministic generation.
+          image (`Image | list`, *optional*):
+              Reference image(s) for denoising. Can be a single image or list of images.
+          num_videos_per_prompt (`int`, *optional*, defaults to 1):
+              Number of videos to generate per prompt.
+          image_latents (`Tensor`, *optional*):
+              image latents used to guide the image generation. Can be generated from vae_encoder step.
+          video_latents (`Tensor`, *optional*):
+              Encoded video latents for V2V generation.
+          image_noise_sigma_min (`float`, *optional*, defaults to 0.111):
+              Minimum sigma for image latent noise.
+          image_noise_sigma_max (`float`, *optional*, defaults to 0.135):
+              Maximum sigma for image latent noise.
+          video_noise_sigma_min (`float`, *optional*, defaults to 0.111):
+              Minimum sigma for video latent noise.
+          video_noise_sigma_max (`float`, *optional*, defaults to 0.135):
+              Maximum sigma for video latent noise.
+          num_frames (`int`, *optional*, defaults to 132):
+              Total number of video frames to generate.
+          history_sizes (`list`):
+              Sizes of long/mid/short history buffers for temporal context.
+          keep_first_frame (`bool`, *optional*, defaults to True):
+              Whether to keep the first frame as a prefix in history.
+          pyramid_num_inference_steps_list (`list`, *optional*, defaults to [10, 10, 10]):
+              Number of denoising steps per pyramid stage.
+          latents (`Tensor`, *optional*):
+              Pre-generated noisy latents for image generation.
+          **denoiser_input_fields (`None`, *optional*):
+              conditional model inputs for the denoiser: e.g. prompt_embeds, negative_prompt_embeds, etc.
+          is_amplify_first_chunk (`bool`, *optional*, defaults to True):
+              Whether to double the first chunk's timesteps via the scheduler for amplified generation.
+          attention_kwargs (`dict`, *optional*):
+              Additional kwargs for attention processors.
+          fake_image_latents (`Tensor`, *optional*):
+              Fake image latents used as history seed for I2V generation.
+          output_type (`str`, *optional*, defaults to np):
+              Output format: 'pil', 'np', 'pt'.
+
+      Outputs:
+          videos (`list`):
+              The generated videos.
+    """
+
+    model_name = "helios-pyramid"
+
+    block_classes = DISTILLED_PYRAMID_AUTO_BLOCKS.values()
+    block_names = DISTILLED_PYRAMID_AUTO_BLOCKS.keys()
+
+    _workflow_map = {
+        "text2video": {"prompt": True},
+        "image2video": {"prompt": True, "image": True},
+        "video2video": {"prompt": True, "video": True},
+    }
+
+    @property
+    def description(self):
+        return "Auto Modular pipeline for distilled pyramid progressive generation (T2V/I2V/V2V) using Helios."
+
+    @property
+    def outputs(self):
+        return [OutputParam.template("videos")]

src/diffusers/modular_pipelines/helios/modular_pipeline.py

@@ -0,0 +1,87 @@
+# Copyright 2025 The HuggingFace Team. All rights reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+
+from ...loaders import HeliosLoraLoaderMixin
+from ...utils import logging
+from ..modular_pipeline import ModularPipeline
+
+
+logger = logging.get_logger(__name__)  # pylint: disable=invalid-name
+
+
+class HeliosModularPipeline(
+    ModularPipeline,
+    HeliosLoraLoaderMixin,
+):
+    """
+    A ModularPipeline for Helios text-to-video generation.
+
+    > [!WARNING] > This is an experimental feature and is likely to change in the future.
+    """
+
+    default_blocks_name = "HeliosAutoBlocks"
+
+    @property
+    def vae_scale_factor_spatial(self):
+        vae_scale_factor = 8
+        if hasattr(self, "vae") and self.vae is not None:
+            vae_scale_factor = self.vae.config.scale_factor_spatial
+        return vae_scale_factor
+
+    @property
+    def vae_scale_factor_temporal(self):
+        vae_scale_factor = 4
+        if hasattr(self, "vae") and self.vae is not None:
+            vae_scale_factor = self.vae.config.scale_factor_temporal
+        return vae_scale_factor
+
+    @property
+    def num_channels_latents(self):
+        # YiYi TODO: find out default value
+        num_channels_latents = 16
+        if hasattr(self, "transformer") and self.transformer is not None:
+            num_channels_latents = self.transformer.config.in_channels
+        return num_channels_latents
+
+    @property
+    def requires_unconditional_embeds(self):
+        requires_unconditional_embeds = False
+
+        if hasattr(self, "guider") and self.guider is not None:
+            requires_unconditional_embeds = self.guider._enabled and self.guider.num_conditions > 1
+
+        return requires_unconditional_embeds
+
+
+class HeliosPyramidModularPipeline(HeliosModularPipeline):
+    """
+    A ModularPipeline for Helios pyramid (progressive resolution) video generation.
+
+    > [!WARNING] > This is an experimental feature and is likely to change in the future.
+    """
+
+    default_blocks_name = "HeliosPyramidAutoBlocks"
+
+
+class HeliosPyramidDistilledModularPipeline(HeliosModularPipeline):
+    """
+    A ModularPipeline for Helios distilled pyramid video generation using DMD scheduler.
+
+    Uses guidance_scale=1.0 (no CFG) and supports is_amplify_first_chunk for the DMD scheduler.
+
+    > [!WARNING] > This is an experimental feature and is likely to change in the future.
+    """
+
+    default_blocks_name = "HeliosPyramidDistilledAutoBlocks"

src/diffusers/modular_pipelines/modular_pipeline.py

@@ -106,6 +106,16 @@ def _wan_i2v_map_fn(config_dict=None):
         return "WanImage2VideoModularPipeline"
 
 
+def _helios_pyramid_map_fn(config_dict=None):
+    if config_dict is None:
+        return "HeliosPyramidModularPipeline"
+
+    if config_dict.get("is_distilled", False):
+        return "HeliosPyramidDistilledModularPipeline"
+    else:
+        return "HeliosPyramidModularPipeline"
+
+
 MODULAR_PIPELINE_MAPPING = OrderedDict(
     [
         ("stable-diffusion-xl", _create_default_map_fn("StableDiffusionXLModularPipeline")),
@@ -120,6 +130,8 @@ MODULAR_PIPELINE_MAPPING = OrderedDict(
         ("qwenimage-edit-plus", _create_default_map_fn("QwenImageEditPlusModularPipeline")),
         ("qwenimage-layered", _create_default_map_fn("QwenImageLayeredModularPipeline")),
         ("z-image", _create_default_map_fn("ZImageModularPipeline")),
+        ("helios", _create_default_map_fn("HeliosModularPipeline")),
+        ("helios-pyramid", _helios_pyramid_map_fn),
     ]
 )
 

src/diffusers/pipelines/__init__.py

@@ -292,7 +292,12 @@ else:
         "LTXLatentUpsamplePipeline",
         "LTXI2VLongMultiPromptPipeline",
     ]
-    _import_structure["ltx2"] = ["LTX2Pipeline", "LTX2ImageToVideoPipeline", "LTX2LatentUpsamplePipeline"]
+    _import_structure["ltx2"] = [
+        "LTX2Pipeline",
+        "LTX2ConditionPipeline",
+        "LTX2ImageToVideoPipeline",
+        "LTX2LatentUpsamplePipeline",
+    ]
     _import_structure["lumina"] = ["LuminaPipeline", "LuminaText2ImgPipeline"]
     _import_structure["lumina2"] = ["Lumina2Pipeline", "Lumina2Text2ImgPipeline"]
     _import_structure["lucy"] = ["LucyEditPipeline"]
@@ -731,7 +736,7 @@ if TYPE_CHECKING or DIFFUSERS_SLOW_IMPORT:
             LTXLatentUpsamplePipeline,
             LTXPipeline,
         )
-        from .ltx2 import LTX2ImageToVideoPipeline, LTX2LatentUpsamplePipeline, LTX2Pipeline
+        from .ltx2 import LTX2ConditionPipeline, LTX2ImageToVideoPipeline, LTX2LatentUpsamplePipeline, LTX2Pipeline
         from .lucy import LucyEditPipeline
         from .lumina import LuminaPipeline, LuminaText2ImgPipeline
         from .lumina2 import Lumina2Pipeline, Lumina2Text2ImgPipeline

src/diffusers/pipelines/ltx2/__init__.py

@@ -25,6 +25,7 @@ else:
     _import_structure["connectors"] = ["LTX2TextConnectors"]
     _import_structure["latent_upsampler"] = ["LTX2LatentUpsamplerModel"]
     _import_structure["pipeline_ltx2"] = ["LTX2Pipeline"]
+    _import_structure["pipeline_ltx2_condition"] = ["LTX2ConditionPipeline"]
     _import_structure["pipeline_ltx2_image2video"] = ["LTX2ImageToVideoPipeline"]
     _import_structure["pipeline_ltx2_latent_upsample"] = ["LTX2LatentUpsamplePipeline"]
     _import_structure["vocoder"] = ["LTX2Vocoder"]
@@ -40,6 +41,7 @@ if TYPE_CHECKING or DIFFUSERS_SLOW_IMPORT:
         from .connectors import LTX2TextConnectors
         from .latent_upsampler import LTX2LatentUpsamplerModel
         from .pipeline_ltx2 import LTX2Pipeline
+        from .pipeline_ltx2_condition import LTX2ConditionPipeline
         from .pipeline_ltx2_image2video import LTX2ImageToVideoPipeline
         from .pipeline_ltx2_latent_upsample import LTX2LatentUpsamplePipeline
         from .vocoder import LTX2Vocoder

src/diffusers/utils/__init__.py

@@ -86,6 +86,7 @@ from .import_utils import (
     is_inflect_available,
     is_invisible_watermark_available,
     is_kernels_available,
+    is_kernels_version,
     is_kornia_available,
     is_librosa_available,
     is_matplotlib_available,

src/diffusers/utils/dummy_torch_and_transformers_objects.py

@@ -152,6 +152,96 @@ class FluxModularPipeline(metaclass=DummyObject):
         requires_backends(cls, ["torch", "transformers"])
 
 
+class HeliosAutoBlocks(metaclass=DummyObject):
+    _backends = ["torch", "transformers"]
+
+    def __init__(self, *args, **kwargs):
+        requires_backends(self, ["torch", "transformers"])
+
+    @classmethod
+    def from_config(cls, *args, **kwargs):
+        requires_backends(cls, ["torch", "transformers"])
+
+    @classmethod
+    def from_pretrained(cls, *args, **kwargs):
+        requires_backends(cls, ["torch", "transformers"])
+
+
+class HeliosModularPipeline(metaclass=DummyObject):
+    _backends = ["torch", "transformers"]
+
+    def __init__(self, *args, **kwargs):
+        requires_backends(self, ["torch", "transformers"])
+
+    @classmethod
+    def from_config(cls, *args, **kwargs):
+        requires_backends(cls, ["torch", "transformers"])
+
+    @classmethod
+    def from_pretrained(cls, *args, **kwargs):
+        requires_backends(cls, ["torch", "transformers"])
+
+
+class HeliosPyramidAutoBlocks(metaclass=DummyObject):
+    _backends = ["torch", "transformers"]
+
+    def __init__(self, *args, **kwargs):
+        requires_backends(self, ["torch", "transformers"])
+
+    @classmethod
+    def from_config(cls, *args, **kwargs):
+        requires_backends(cls, ["torch", "transformers"])
+
+    @classmethod
+    def from_pretrained(cls, *args, **kwargs):
+        requires_backends(cls, ["torch", "transformers"])
+
+
+class HeliosPyramidDistilledAutoBlocks(metaclass=DummyObject):
+    _backends = ["torch", "transformers"]
+
+    def __init__(self, *args, **kwargs):
+        requires_backends(self, ["torch", "transformers"])
+
+    @classmethod
+    def from_config(cls, *args, **kwargs):
+        requires_backends(cls, ["torch", "transformers"])
+
+    @classmethod
+    def from_pretrained(cls, *args, **kwargs):
+        requires_backends(cls, ["torch", "transformers"])
+
+
+class HeliosPyramidDistilledModularPipeline(metaclass=DummyObject):
+    _backends = ["torch", "transformers"]
+
+    def __init__(self, *args, **kwargs):
+        requires_backends(self, ["torch", "transformers"])
+
+    @classmethod
+    def from_config(cls, *args, **kwargs):
+        requires_backends(cls, ["torch", "transformers"])
+
+    @classmethod
+    def from_pretrained(cls, *args, **kwargs):
+        requires_backends(cls, ["torch", "transformers"])
+
+
+class HeliosPyramidModularPipeline(metaclass=DummyObject):
+    _backends = ["torch", "transformers"]
+
+    def __init__(self, *args, **kwargs):
+        requires_backends(self, ["torch", "transformers"])
+
+    @classmethod
+    def from_config(cls, *args, **kwargs):
+        requires_backends(cls, ["torch", "transformers"])
+
+    @classmethod
+    def from_pretrained(cls, *args, **kwargs):
+        requires_backends(cls, ["torch", "transformers"])
+
+
 class QwenImageAutoBlocks(metaclass=DummyObject):
     _backends = ["torch", "transformers"]
 
@@ -2147,6 +2237,21 @@ class LongCatImagePipeline(metaclass=DummyObject):
         requires_backends(cls, ["torch", "transformers"])
 
 
+class LTX2ConditionPipeline(metaclass=DummyObject):
+    _backends = ["torch", "transformers"]
+
+    def __init__(self, *args, **kwargs):
+        requires_backends(self, ["torch", "transformers"])
+
+    @classmethod
+    def from_config(cls, *args, **kwargs):
+        requires_backends(cls, ["torch", "transformers"])
+
+    @classmethod
+    def from_pretrained(cls, *args, **kwargs):
+        requires_backends(cls, ["torch", "transformers"])
+
+
 class LTX2ImageToVideoPipeline(metaclass=DummyObject):
     _backends = ["torch", "transformers"]
 

src/diffusers/utils/import_utils.py

@@ -724,6 +724,22 @@ def is_transformers_version(operation: str, version: str):
     return compare_versions(parse(_transformers_version), operation, version)
 
 
+@cache
+def is_kernels_version(operation: str, version: str):
+    """
+    Compares the current Kernels version to a given reference with an operation.
+
+    Args:
+        operation (`str`):
+            A string representation of an operator, such as `">"` or `"<="`
+        version (`str`):
+            A version string
+    """
+    if not _kernels_available:
+        return False
+    return compare_versions(parse(_kernels_version), operation, version)
+
+
 @cache
 def is_hf_hub_version(operation: str, version: str):
     """

src/diffusers/video_processor.py

@@ -25,9 +25,9 @@ from .image_processor import VaeImageProcessor, is_valid_image, is_valid_image_i
 class VideoProcessor(VaeImageProcessor):
     r"""Simple video processor."""
 
-    def preprocess_video(self, video, height: int | None = None, width: int | None = None) -> torch.Tensor:
+    def preprocess_video(self, video, height: int | None = None, width: int | None = None, **kwargs) -> torch.Tensor:
         r"""
-        Preprocesses input video(s).
+        Preprocesses input video(s). Keyword arguments will be forwarded to `VaeImageProcessor.preprocess`.
 
         Args:
             video (`list[PIL.Image]`, `list[list[PIL.Image]]`, `torch.Tensor`, `np.array`, `list[torch.Tensor]`, `list[np.array]`):
@@ -49,6 +49,10 @@ class VideoProcessor(VaeImageProcessor):
             width (`int`, *optional*`, defaults to `None`):
                 The width in preprocessed frames of the video. If `None`, will use get_default_height_width()` to get
                 the default width.
+
+        Returns:
+            `torch.Tensor` of shape `(batch_size, num_channels, num_frames, height, width)`:
+                A 5D tensor holding the batched channels-first video(s).
         """
         if isinstance(video, list) and isinstance(video[0], np.ndarray) and video[0].ndim == 5:
             warnings.warn(
@@ -79,7 +83,7 @@ class VideoProcessor(VaeImageProcessor):
                 "Input is in incorrect format. Currently, we only support numpy.ndarray, torch.Tensor, PIL.Image.Image"
             )
 
-        video = torch.stack([self.preprocess(img, height=height, width=width) for img in video], dim=0)
+        video = torch.stack([self.preprocess(img, height=height, width=width, **kwargs) for img in video], dim=0)
 
         # move the number of channels before the number of frames.
         video = video.permute(0, 2, 1, 3, 4)
@@ -87,10 +91,11 @@ class VideoProcessor(VaeImageProcessor):
         return video
 
     def postprocess_video(
-        self, video: torch.Tensor, output_type: str = "np"
+        self, video: torch.Tensor, output_type: str = "np", **kwargs
     ) -> np.ndarray | torch.Tensor | list[PIL.Image.Image]:
         r"""
-        Converts a video tensor to a list of frames for export.
+        Converts a video tensor to a list of frames for export. Keyword arguments will be forwarded to
+        `VaeImageProcessor.postprocess`.
 
         Args:
             video (`torch.Tensor`): The video as a tensor.
@@ -100,7 +105,7 @@ class VideoProcessor(VaeImageProcessor):
         outputs = []
         for batch_idx in range(batch_size):
             batch_vid = video[batch_idx].permute(1, 0, 2, 3)
-            batch_output = self.postprocess(batch_vid, output_type)
+            batch_output = self.postprocess(batch_vid, output_type, **kwargs)
             outputs.append(batch_output)
 
         if output_type == "np":

tests/modular_pipelines/helios/test_modular_pipeline_helios.py

@@ -0,0 +1,166 @@
+# coding=utf-8
+# Copyright 2025 HuggingFace Inc.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+import pytest
+
+from diffusers.modular_pipelines import (
+    HeliosAutoBlocks,
+    HeliosModularPipeline,
+    HeliosPyramidAutoBlocks,
+    HeliosPyramidModularPipeline,
+)
+
+from ..test_modular_pipelines_common import ModularPipelineTesterMixin
+
+
+HELIOS_WORKFLOWS = {
+    "text2video": [
+        ("text_encoder", "HeliosTextEncoderStep"),
+        ("denoise.input", "HeliosTextInputStep"),
+        ("denoise.prepare_history", "HeliosPrepareHistoryStep"),
+        ("denoise.set_timesteps", "HeliosSetTimestepsStep"),
+        ("denoise.chunk_denoise", "HeliosChunkDenoiseStep"),
+        ("decode", "HeliosDecodeStep"),
+    ],
+    "image2video": [
+        ("text_encoder", "HeliosTextEncoderStep"),
+        ("vae_encoder", "HeliosImageVaeEncoderStep"),
+        ("denoise.input", "HeliosTextInputStep"),
+        ("denoise.additional_inputs", "HeliosAdditionalInputsStep"),
+        ("denoise.add_noise_image", "HeliosAddNoiseToImageLatentsStep"),
+        ("denoise.prepare_history", "HeliosPrepareHistoryStep"),
+        ("denoise.seed_history", "HeliosI2VSeedHistoryStep"),
+        ("denoise.set_timesteps", "HeliosSetTimestepsStep"),
+        ("denoise.chunk_denoise", "HeliosI2VChunkDenoiseStep"),
+        ("decode", "HeliosDecodeStep"),
+    ],
+    "video2video": [
+        ("text_encoder", "HeliosTextEncoderStep"),
+        ("vae_encoder", "HeliosVideoVaeEncoderStep"),
+        ("denoise.input", "HeliosTextInputStep"),
+        ("denoise.additional_inputs", "HeliosAdditionalInputsStep"),
+        ("denoise.add_noise_video", "HeliosAddNoiseToVideoLatentsStep"),
+        ("denoise.prepare_history", "HeliosPrepareHistoryStep"),
+        ("denoise.seed_history", "HeliosV2VSeedHistoryStep"),
+        ("denoise.set_timesteps", "HeliosSetTimestepsStep"),
+        ("denoise.chunk_denoise", "HeliosI2VChunkDenoiseStep"),
+        ("decode", "HeliosDecodeStep"),
+    ],
+}
+
+
+class TestHeliosModularPipelineFast(ModularPipelineTesterMixin):
+    pipeline_class = HeliosModularPipeline
+    pipeline_blocks_class = HeliosAutoBlocks
+    pretrained_model_name_or_path = "hf-internal-testing/tiny-helios-modular-pipe"
+
+    params = frozenset(["prompt", "height", "width", "num_frames"])
+    batch_params = frozenset(["prompt"])
+    optional_params = frozenset(["num_inference_steps", "num_videos_per_prompt", "latents"])
+    output_name = "videos"
+    expected_workflow_blocks = HELIOS_WORKFLOWS
+
+    def get_dummy_inputs(self, seed=0):
+        generator = self.get_generator(seed)
+        inputs = {
+            "prompt": "A painting of a squirrel eating a burger",
+            "generator": generator,
+            "num_inference_steps": 2,
+            "height": 16,
+            "width": 16,
+            "num_frames": 9,
+            "max_sequence_length": 16,
+            "output_type": "pt",
+        }
+        return inputs
+
+    @pytest.mark.skip(reason="num_videos_per_prompt")
+    def test_num_images_per_prompt(self):
+        pass
+
+
+HELIOS_PYRAMID_WORKFLOWS = {
+    "text2video": [
+        ("text_encoder", "HeliosTextEncoderStep"),
+        ("denoise.input", "HeliosTextInputStep"),
+        ("denoise.prepare_history", "HeliosPrepareHistoryStep"),
+        ("denoise.pyramid_chunk_denoise", "HeliosPyramidChunkDenoiseStep"),
+        ("decode", "HeliosDecodeStep"),
+    ],
+    "image2video": [
+        ("text_encoder", "HeliosTextEncoderStep"),
+        ("vae_encoder", "HeliosImageVaeEncoderStep"),
+        ("denoise.input", "HeliosTextInputStep"),
+        ("denoise.additional_inputs", "HeliosAdditionalInputsStep"),
+        ("denoise.add_noise_image", "HeliosAddNoiseToImageLatentsStep"),
+        ("denoise.prepare_history", "HeliosPrepareHistoryStep"),
+        ("denoise.seed_history", "HeliosI2VSeedHistoryStep"),
+        ("denoise.pyramid_chunk_denoise", "HeliosPyramidI2VChunkDenoiseStep"),
+        ("decode", "HeliosDecodeStep"),
+    ],
+    "video2video": [
+        ("text_encoder", "HeliosTextEncoderStep"),
+        ("vae_encoder", "HeliosVideoVaeEncoderStep"),
+        ("denoise.input", "HeliosTextInputStep"),
+        ("denoise.additional_inputs", "HeliosAdditionalInputsStep"),
+        ("denoise.add_noise_video", "HeliosAddNoiseToVideoLatentsStep"),
+        ("denoise.prepare_history", "HeliosPrepareHistoryStep"),
+        ("denoise.seed_history", "HeliosV2VSeedHistoryStep"),
+        ("denoise.pyramid_chunk_denoise", "HeliosPyramidI2VChunkDenoiseStep"),
+        ("decode", "HeliosDecodeStep"),
+    ],
+}
+
+
+class TestHeliosPyramidModularPipelineFast(ModularPipelineTesterMixin):
+    pipeline_class = HeliosPyramidModularPipeline
+    pipeline_blocks_class = HeliosPyramidAutoBlocks
+    pretrained_model_name_or_path = "hf-internal-testing/tiny-helios-pyramid-modular-pipe"
+
+    params = frozenset(["prompt", "height", "width", "num_frames"])
+    batch_params = frozenset(["prompt"])
+    optional_params = frozenset(["pyramid_num_inference_steps_list", "num_videos_per_prompt", "latents"])
+    output_name = "videos"
+    expected_workflow_blocks = HELIOS_PYRAMID_WORKFLOWS
+
+    def get_dummy_inputs(self, seed=0):
+        generator = self.get_generator(seed)
+        inputs = {
+            "prompt": "A painting of a squirrel eating a burger",
+            "generator": generator,
+            "pyramid_num_inference_steps_list": [2, 2],
+            "height": 64,
+            "width": 64,
+            "num_frames": 9,
+            "max_sequence_length": 16,
+            "output_type": "pt",
+        }
+        return inputs
+
+    def test_inference_batch_single_identical(self):
+        # Pyramid pipeline injects noise at each stage, so batch vs single can differ more
+        super().test_inference_batch_single_identical(expected_max_diff=5e-1)
+
+    @pytest.mark.skip(reason="Pyramid multi-stage noise makes offload comparison unreliable with tiny models")
+    def test_components_auto_cpu_offload_inference_consistent(self):
+        pass
+
+    @pytest.mark.skip(reason="Pyramid multi-stage noise makes save/load comparison unreliable with tiny models")
+    def test_save_from_pretrained(self):
+        pass
+
+    @pytest.mark.skip(reason="num_videos_per_prompt")
+    def test_num_images_per_prompt(self):
+        pass