diffusers/modular_pipelines/wan/denoise.py

# 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 typing import Any

import torch

from ...configuration_utils import FrozenDict
from ...guiders import ClassifierFreeGuidance
from ...models import WanTransformer3DModel
from ...schedulers import UniPCMultistepScheduler
from ...utils import logging
from ..modular_pipeline import (
    BlockState,
    LoopSequentialPipelineBlocks,
    ModularPipelineBlocks,
    PipelineState,
)
from ..modular_pipeline_utils import ComponentSpec, ConfigSpec, InputParam
from .modular_pipeline import WanModularPipeline


logger = logging.get_logger(__name__)  # pylint: disable=invalid-name


class WanLoopBeforeDenoiser(ModularPipelineBlocks):
    model_name = "wan"

    @property
    def description(self) -> str:
        return (
            "step within the denoising loop that prepares the latent input for the denoiser. "
            "This block should be used to compose the `sub_blocks` attribute of a `LoopSequentialPipelineBlocks` "
            "object (e.g. `WanDenoiseLoopWrapper`)"
        )

    @property
    def inputs(self) -> list[InputParam]:
        return [
            InputParam(
                "latents",
                required=True,
                type_hint=torch.Tensor,
                description="The initial latents to use for the denoising process. Can be generated in prepare_latent step.",
            ),
            InputParam(
                "dtype",
                required=True,
                type_hint=torch.dtype,
                description="The dtype of the model inputs. Can be generated in input step.",
            ),
        ]

    @torch.no_grad()
    def __call__(self, components: WanModularPipeline, block_state: BlockState, i: int, t: torch.Tensor):
        block_state.latent_model_input = block_state.latents.to(block_state.dtype)
        return components, block_state


class WanImage2VideoLoopBeforeDenoiser(ModularPipelineBlocks):
    model_name = "wan"

    @property
    def description(self) -> str:
        return (
            "step within the denoising loop that prepares the latent input for the denoiser. "
            "This block should be used to compose the `sub_blocks` attribute of a `LoopSequentialPipelineBlocks` "
            "object (e.g. `WanDenoiseLoopWrapper`)"
        )

    @property
    def inputs(self) -> list[InputParam]:
        return [
            InputParam(
                "latents",
                required=True,
                type_hint=torch.Tensor,
                description="The initial latents to use for the denoising process. Can be generated in prepare_latent step.",
            ),
            InputParam(
                "image_condition_latents",
                required=True,
                type_hint=torch.Tensor,
                description="The image condition latents to use for the denoising process. Can be generated in prepare_first_frame_latents/prepare_first_last_frame_latents step.",
            ),
            InputParam(
                "dtype",
                required=True,
                type_hint=torch.dtype,
                description="The dtype of the model inputs. Can be generated in input step.",
            ),
        ]

    @torch.no_grad()
    def __call__(self, components: WanModularPipeline, block_state: BlockState, i: int, t: torch.Tensor):
        block_state.latent_model_input = torch.cat(
            [block_state.latents, block_state.image_condition_latents], dim=1
        ).to(block_state.dtype)
        return components, block_state


class WanLoopDenoiser(ModularPipelineBlocks):
    model_name = "wan"

    def __init__(
        self,
        guider_input_fields: dict[str, Any] = {"encoder_hidden_states": ("prompt_embeds", "negative_prompt_embeds")},
    ):
        """Initialize a denoiser block that calls the denoiser model. This block is used in Wan2.1.

        Args:
            guider_input_fields: A dictionary that maps each argument expected by the denoiser model
                (for example, "encoder_hidden_states") to data stored on 'block_state'. The value can be either:

                - A tuple of strings. For instance, {"encoder_hidden_states": ("prompt_embeds",
                  "negative_prompt_embeds")} tells the guider to read `block_state.prompt_embeds` and
                  `block_state.negative_prompt_embeds` and pass them as the conditional and unconditional batches of
                  'encoder_hidden_states'.
                - A string. For example, {"encoder_hidden_image": "image_embeds"} makes the guider forward
                  `block_state.image_embeds` for both conditional and unconditional batches.
        """
        if not isinstance(guider_input_fields, dict):
            raise ValueError(f"guider_input_fields must be a dictionary but is {type(guider_input_fields)}")
        self._guider_input_fields = guider_input_fields
        super().__init__()

    @property
    def expected_components(self) -> list[ComponentSpec]:
        return [
            ComponentSpec(
                "guider",
                ClassifierFreeGuidance,
                config=FrozenDict({"guidance_scale": 5.0}),
                default_creation_method="from_config",
            ),
            ComponentSpec("transformer", WanTransformer3DModel),
        ]

    @property
    def description(self) -> str:
        return (
            "Step within the denoising loop that denoise the latents with guidance. "
            "This block should be used to compose the `sub_blocks` attribute of a `LoopSequentialPipelineBlocks` "
            "object (e.g. `WanDenoiseLoopWrapper`)"
        )

    @property
    def inputs(self) -> list[tuple[str, Any]]:
        inputs = [
            InputParam("attention_kwargs"),
            InputParam(
                "num_inference_steps",
                required=True,
                type_hint=int,
                description="The number of inference steps to use for the denoising process. Can be generated in set_timesteps step.",
            ),
        ]
        guider_input_names = []
        for value in self._guider_input_fields.values():
            if isinstance(value, tuple):
                guider_input_names.extend(value)
            else:
                guider_input_names.append(value)

        for name in guider_input_names:
            inputs.append(InputParam(name=name, required=True, type_hint=torch.Tensor))
        return inputs

    @torch.no_grad()
    def __call__(
        self, components: WanModularPipeline, block_state: BlockState, i: int, t: torch.Tensor
    ) -> PipelineState:
        components.guider.set_state(step=i, num_inference_steps=block_state.num_inference_steps, timestep=t)

        # The guider splits model inputs into separate batches for conditional/unconditional predictions.
        # For CFG with guider_inputs = {"encoder_hidden_states": (prompt_embeds, negative_prompt_embeds)}:
        # you will get a guider_state with two batches:
        #   guider_state = [
        #       {"encoder_hidden_states": prompt_embeds, "__guidance_identifier__": "pred_cond"},      # conditional batch
        #       {"encoder_hidden_states": negative_prompt_embeds, "__guidance_identifier__": "pred_uncond"},  # unconditional batch
        #   ]
        # Other guidance methods may return 1 batch (no guidance) or 3+ batches (e.g., PAG, APG).
        guider_state = components.guider.prepare_inputs_from_block_state(block_state, self._guider_input_fields)

        # run the denoiser for each guidance batch
        for guider_state_batch in guider_state:
            components.guider.prepare_models(components.transformer)
            cond_kwargs = guider_state_batch.as_dict()
            cond_kwargs = {
                k: v.to(block_state.dtype) if isinstance(v, torch.Tensor) else v
                for k, v in cond_kwargs.items()
                if k in self._guider_input_fields.keys()
            }

            # Predict the noise residual
            # store the noise_pred in guider_state_batch so that we can apply guidance across all batches
            guider_state_batch.noise_pred = components.transformer(
                hidden_states=block_state.latent_model_input.to(block_state.dtype),
                timestep=t.expand(block_state.latent_model_input.shape[0]).to(block_state.dtype),
                attention_kwargs=block_state.attention_kwargs,
                return_dict=False,
                **cond_kwargs,
            )[0]
            components.guider.cleanup_models(components.transformer)

        # Perform guidance
        block_state.noise_pred = components.guider(guider_state)[0]

        return components, block_state


class Wan22LoopDenoiser(ModularPipelineBlocks):
    model_name = "wan"

    def __init__(
        self,
        guider_input_fields: dict[str, Any] = {"encoder_hidden_states": ("prompt_embeds", "negative_prompt_embeds")},
    ):
        """Initialize a denoiser block that calls the denoiser model. This block is used in Wan2.2.

        Args:
            guider_input_fields: A dictionary that maps each argument expected by the denoiser model
                (for example, "encoder_hidden_states") to data stored on `block_state`. The value can be either:

                - A tuple of strings. For instance, `{"encoder_hidden_states": ("prompt_embeds",
                  "negative_prompt_embeds")}` tells the guider to read `block_state.prompt_embeds` and
                  `block_state.negative_prompt_embeds` and pass them as the conditional and unconditional batches of
                  `encoder_hidden_states`.
                - A string. For example, `{"encoder_hidden_image": "image_embeds"}` makes the guider forward
                  `block_state.image_embeds` for both conditional and unconditional batches.
        """
        if not isinstance(guider_input_fields, dict):
            raise ValueError(f"guider_input_fields must be a dictionary but is {type(guider_input_fields)}")
        self._guider_input_fields = guider_input_fields
        super().__init__()

    @property
    def expected_components(self) -> list[ComponentSpec]:
        return [
            ComponentSpec(
                "guider",
                ClassifierFreeGuidance,
                config=FrozenDict({"guidance_scale": 4.0}),
                default_creation_method="from_config",
            ),
            ComponentSpec(
                "guider_2",
                ClassifierFreeGuidance,
                config=FrozenDict({"guidance_scale": 3.0}),
                default_creation_method="from_config",
            ),
            ComponentSpec("transformer", WanTransformer3DModel),
            ComponentSpec("transformer_2", WanTransformer3DModel),
        ]

    @property
    def description(self) -> str:
        return (
            "Step within the denoising loop that denoise the latents with guidance. "
            "This block should be used to compose the `sub_blocks` attribute of a `LoopSequentialPipelineBlocks` "
            "object (e.g. `WanDenoiseLoopWrapper`)"
        )

    @property
    def expected_configs(self) -> list[ConfigSpec]:
        return [
            ConfigSpec(
                name="boundary_ratio",
                default=0.875,
                description="The boundary ratio to divide the denoising loop into high noise and low noise stages.",
            ),
        ]

    @property
    def inputs(self) -> list[tuple[str, Any]]:
        inputs = [
            InputParam("attention_kwargs"),
            InputParam(
                "num_inference_steps",
                required=True,
                type_hint=int,
                description="The number of inference steps to use for the denoising process. Can be generated in set_timesteps step.",
            ),
        ]
        guider_input_names = []
        for value in self._guider_input_fields.values():
            if isinstance(value, tuple):
                guider_input_names.extend(value)
            else:
                guider_input_names.append(value)

        for name in guider_input_names:
            inputs.append(InputParam(name=name, required=True, type_hint=torch.Tensor))
        return inputs

    @torch.no_grad()
    def __call__(
        self, components: WanModularPipeline, block_state: BlockState, i: int, t: torch.Tensor
    ) -> PipelineState:
        boundary_timestep = components.config.boundary_ratio * components.num_train_timesteps
        if t >= boundary_timestep:
            block_state.current_model = components.transformer
            block_state.guider = components.guider
        else:
            block_state.current_model = components.transformer_2
            block_state.guider = components.guider_2

        block_state.guider.set_state(step=i, num_inference_steps=block_state.num_inference_steps, timestep=t)

        # The guider splits model inputs into separate batches for conditional/unconditional predictions.
        # For CFG with guider_inputs = {"encoder_hidden_states": (prompt_embeds, negative_prompt_embeds)}:
        # you will get a guider_state with two batches:
        #   guider_state = [
        #       {"encoder_hidden_states": prompt_embeds, "__guidance_identifier__": "pred_cond"},      # conditional batch
        #       {"encoder_hidden_states": negative_prompt_embeds, "__guidance_identifier__": "pred_uncond"},  # unconditional batch
        #   ]
        # Other guidance methods may return 1 batch (no guidance) or 3+ batches (e.g., PAG, APG).
        guider_state = block_state.guider.prepare_inputs_from_block_state(block_state, self._guider_input_fields)

        # run the denoiser for each guidance batch
        for guider_state_batch in guider_state:
            block_state.guider.prepare_models(block_state.current_model)
            cond_kwargs = guider_state_batch.as_dict()
            cond_kwargs = {
                k: v.to(block_state.dtype) if isinstance(v, torch.Tensor) else v
                for k, v in cond_kwargs.items()
                if k in self._guider_input_fields.keys()
            }

            # Predict the noise residual
            # store the noise_pred in guider_state_batch so that we can apply guidance across all batches
            guider_state_batch.noise_pred = block_state.current_model(
                hidden_states=block_state.latent_model_input.to(block_state.dtype),
                timestep=t.expand(block_state.latent_model_input.shape[0]).to(block_state.dtype),
                attention_kwargs=block_state.attention_kwargs,
                return_dict=False,
                **cond_kwargs,
            )[0]
            block_state.guider.cleanup_models(block_state.current_model)

        # Perform guidance
        block_state.noise_pred = block_state.guider(guider_state)[0]

        return components, block_state


class WanLoopAfterDenoiser(ModularPipelineBlocks):
    model_name = "wan"

    @property
    def expected_components(self) -> list[ComponentSpec]:
        return [
            ComponentSpec("scheduler", UniPCMultistepScheduler),
        ]

    @property
    def description(self) -> str:
        return (
            "step within the denoising loop that update the latents. "
            "This block should be used to compose the `sub_blocks` attribute of a `LoopSequentialPipelineBlocks` "
            "object (e.g. `WanDenoiseLoopWrapper`)"
        )

    @torch.no_grad()
    def __call__(self, components: WanModularPipeline, block_state: BlockState, i: int, t: torch.Tensor):
        # Perform scheduler step using the predicted output
        latents_dtype = block_state.latents.dtype
        block_state.latents = components.scheduler.step(
            block_state.noise_pred.float(),
            t,
            block_state.latents.float(),
            return_dict=False,
        )[0]

        if block_state.latents.dtype != latents_dtype:
            block_state.latents = block_state.latents.to(latents_dtype)

        return components, block_state


class WanDenoiseLoopWrapper(LoopSequentialPipelineBlocks):
    model_name = "wan"

    @property
    def description(self) -> str:
        return (
            "Pipeline block that iteratively denoise the latents over `timesteps`. "
            "The specific steps with each iteration can be customized with `sub_blocks` attributes"
        )

    @property
    def loop_expected_components(self) -> list[ComponentSpec]:
        return [
            ComponentSpec("scheduler", UniPCMultistepScheduler),
        ]

    @property
    def loop_inputs(self) -> list[InputParam]:
        return [
            InputParam(
                "timesteps",
                required=True,
                type_hint=torch.Tensor,
                description="The timesteps to use for the denoising process. Can be generated in set_timesteps step.",
            ),
            InputParam(
                "num_inference_steps",
                required=True,
                type_hint=int,
                description="The number of inference steps to use for the denoising process. Can be generated in set_timesteps step.",
            ),
        ]

    @torch.no_grad()
    def __call__(self, components: WanModularPipeline, state: PipelineState) -> PipelineState:
        block_state = self.get_block_state(state)

        block_state.num_warmup_steps = max(
            len(block_state.timesteps) - block_state.num_inference_steps * components.scheduler.order, 0
        )

        with self.progress_bar(total=block_state.num_inference_steps) as progress_bar:
            for i, t in enumerate(block_state.timesteps):
                components, block_state = self.loop_step(components, block_state, i=i, t=t)
                if i == len(block_state.timesteps) - 1 or (
                    (i + 1) > block_state.num_warmup_steps and (i + 1) % components.scheduler.order == 0
                ):
                    progress_bar.update()

        self.set_block_state(state, block_state)

        return components, state


class WanDenoiseStep(WanDenoiseLoopWrapper):
    block_classes = [
        WanLoopBeforeDenoiser,
        WanLoopDenoiser(
            guider_input_fields={
                "encoder_hidden_states": ("prompt_embeds", "negative_prompt_embeds"),
            }
        ),
        WanLoopAfterDenoiser,
    ]
    block_names = ["before_denoiser", "denoiser", "after_denoiser"]

    @property
    def description(self) -> str:
        return (
            "Denoise step that iteratively denoise the latents. \n"
            "Its loop logic is defined in `WanDenoiseLoopWrapper.__call__` method \n"
            "At each iteration, it runs blocks defined in `sub_blocks` sequentially:\n"
            " - `WanLoopBeforeDenoiser`\n"
            " - `WanLoopDenoiser`\n"
            " - `WanLoopAfterDenoiser`\n"
            "This block supports text-to-video tasks for wan2.1."
        )


class Wan22DenoiseStep(WanDenoiseLoopWrapper):
    block_classes = [
        WanLoopBeforeDenoiser,
        Wan22LoopDenoiser(
            guider_input_fields={
                "encoder_hidden_states": ("prompt_embeds", "negative_prompt_embeds"),
            }
        ),
        WanLoopAfterDenoiser,
    ]
    block_names = ["before_denoiser", "denoiser", "after_denoiser"]

    @property
    def description(self) -> str:
        return (
            "Denoise step that iteratively denoise the latents. \n"
            "Its loop logic is defined in `WanDenoiseLoopWrapper.__call__` method \n"
            "At each iteration, it runs blocks defined in `sub_blocks` sequentially:\n"
            " - `WanLoopBeforeDenoiser`\n"
            " - `Wan22LoopDenoiser`\n"
            " - `WanLoopAfterDenoiser`\n"
            "This block supports text-to-video tasks for Wan2.2."
        )


class WanImage2VideoDenoiseStep(WanDenoiseLoopWrapper):
    block_classes = [
        WanImage2VideoLoopBeforeDenoiser,
        WanLoopDenoiser(
            guider_input_fields={
                "encoder_hidden_states": ("prompt_embeds", "negative_prompt_embeds"),
                "encoder_hidden_states_image": "image_embeds",
            }
        ),
        WanLoopAfterDenoiser,
    ]
    block_names = ["before_denoiser", "denoiser", "after_denoiser"]

    @property
    def description(self) -> str:
        return (
            "Denoise step that iteratively denoise the latents. \n"
            "Its loop logic is defined in `WanDenoiseLoopWrapper.__call__` method \n"
            "At each iteration, it runs blocks defined in `sub_blocks` sequentially:\n"
            " - `WanImage2VideoLoopBeforeDenoiser`\n"
            " - `WanLoopDenoiser`\n"
            " - `WanLoopAfterDenoiser`\n"
            "This block supports image-to-video tasks for wan2.1."
        )


class Wan22Image2VideoDenoiseStep(WanDenoiseLoopWrapper):
    block_classes = [
        WanImage2VideoLoopBeforeDenoiser,
        Wan22LoopDenoiser(
            guider_input_fields={
                "encoder_hidden_states": ("prompt_embeds", "negative_prompt_embeds"),
            }
        ),
        WanLoopAfterDenoiser,
    ]
    block_names = ["before_denoiser", "denoiser", "after_denoiser"]

    @property
    def description(self) -> str:
        return (
            "Denoise step that iteratively denoise the latents. \n"
            "Its loop logic is defined in `WanDenoiseLoopWrapper.__call__` method \n"
            "At each iteration, it runs blocks defined in `sub_blocks` sequentially:\n"
            " - `WanImage2VideoLoopBeforeDenoiser`\n"
            " - `WanLoopDenoiser`\n"
            " - `WanLoopAfterDenoiser`\n"
            "This block supports image-to-video tasks for Wan2.2."
        )