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stages

Model-specific stages for Helios-Distilled T2V inference.

Classes

fastvideo.pipelines.basic.helios.stages.HeliosChunkDecodingStage 

HeliosChunkDecodingStage(vae, pipeline=None)

Bases: DecodingStage

Decode each 9-latent chunk independently, matching official Helios.

Source code in fastvideo/pipelines/stages/decoding.py 
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def __init__(self, vae, pipeline=None) -> None:
    self.vae: ParallelTiledVAE = vae
    self.pipeline = weakref.ref(pipeline) if pipeline else None

fastvideo.pipelines.basic.helios.stages.HeliosInputValidationStage

Bases: InputValidationStage

Validate the intentionally narrow first Helios contribution: T2V.

fastvideo.pipelines.basic.helios.stages.HeliosPyramidDenoisingStage 

HeliosPyramidDenoisingStage(transformer, scheduler, pipeline=None)

Bases: PipelineStage

Generate autoregressive latent chunks with the three-stage DMD sampler.

Source code in fastvideo/pipelines/basic/helios/stages.py 
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def __init__(self, transformer, scheduler, pipeline=None) -> None:
    super().__init__()
    self.transformer = transformer
    self.scheduler = scheduler
    self.pipeline = weakref.ref(pipeline) if pipeline else None

Functions:

fastvideo.pipelines.basic.helios.stages.calculate_shift 

calculate_shift(image_seq_len: int, base_seq_len: int = 256, max_seq_len: int = 4096, base_shift: float = 0.5, max_shift: float = 1.15) -> float

Calculate the dynamic flow shift for a pyramid stage.

Source code in fastvideo/pipelines/basic/helios/pipeline_utils.py 
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def calculate_shift(
    image_seq_len: int,
    base_seq_len: int = 256,
    max_seq_len: int = 4096,
    base_shift: float = 0.5,
    max_shift: float = 1.15,
) -> float:
    """Calculate the dynamic flow shift for a pyramid stage."""
    slope = (max_shift - base_shift) / (max_seq_len - base_seq_len)
    intercept = base_shift - slope * base_seq_len
    return image_seq_len * slope + intercept