pipeline.py

# Copyright 2024 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 List, Optional, Tuple, Union

import torch
import torch.nn.functional as F
from diffusers.image_processor import PipelineImageInput, VaeImageProcessor
from diffusers.loaders import (
    FromSingleFileMixin,
    IPAdapterMixin,
    StableDiffusionXLLoraLoaderMixin,
    TextualInversionLoaderMixin,
)
from diffusers.models import (
    AutoencoderKL,
    ControlNetModel,
    ImageProjection,
    UNet2DConditionModel,
)
from diffusers.pipelines.controlnet.multicontrolnet import MultiControlNetModel
from diffusers.pipelines.pipeline_utils import DiffusionPipeline, StableDiffusionMixin
from diffusers.pipelines.stable_diffusion_xl.pipeline_output import (
    StableDiffusionXLPipelineOutput,
)
from diffusers.schedulers import KarrasDiffusionSchedulers
from diffusers.utils.torch_utils import (
    is_compiled_module,
    is_torch_version,
    randn_tensor,
)
from transformers import (
    CLIPImageProcessor,
    CLIPTextModel,
    CLIPTextModelWithProjection,
    CLIPTokenizer,
    CLIPVisionModelWithProjection,
)


def retrieve_timesteps(
    scheduler,
    num_inference_steps: Optional[int] = None,
    device: Optional[Union[str, torch.device]] = None,
    **kwargs,
):
    scheduler.set_timesteps(num_inference_steps, device=device, **kwargs)
    timesteps = scheduler.timesteps

    return timesteps, num_inference_steps


class StableDiffusionXLRecolorPipeline(
    DiffusionPipeline,
    StableDiffusionMixin,
    TextualInversionLoaderMixin,
    StableDiffusionXLLoraLoaderMixin,
    IPAdapterMixin,
    FromSingleFileMixin,
):
    # leave controlnet out on purpose because it iterates with unet
    model_cpu_offload_seq = "text_encoder->text_encoder_2->image_encoder->unet->vae"
    _optional_components = [
        "tokenizer",
        "tokenizer_2",
        "text_encoder",
        "text_encoder_2",
        "feature_extractor",
        "image_encoder",
    ]
    _callback_tensor_inputs = [
        "latents",
        "prompt_embeds",
        "negative_prompt_embeds",
        "add_text_embeds",
        "add_time_ids",
        "negative_pooled_prompt_embeds",
        "negative_add_time_ids",
    ]

    def __init__(
        self,
        vae: AutoencoderKL,
        text_encoder: CLIPTextModel,
        text_encoder_2: CLIPTextModelWithProjection,
        tokenizer: CLIPTokenizer,
        tokenizer_2: CLIPTokenizer,
        unet: UNet2DConditionModel,
        controlnet: Union[
            ControlNetModel,
            List[ControlNetModel],
            Tuple[ControlNetModel],
            MultiControlNetModel,
        ],
        scheduler: KarrasDiffusionSchedulers,
        force_zeros_for_empty_prompt: bool = True,
        add_watermarker: Optional[bool] = None,
        feature_extractor: CLIPImageProcessor = None,
        image_encoder: CLIPVisionModelWithProjection = None,
    ):
        super().__init__()

        if isinstance(controlnet, (list, tuple)):
            controlnet = MultiControlNetModel(controlnet)

        self.register_modules(
            vae=vae,
            text_encoder=text_encoder,
            text_encoder_2=text_encoder_2,
            tokenizer=tokenizer,
            tokenizer_2=tokenizer_2,
            unet=unet,
            controlnet=controlnet,
            scheduler=scheduler,
            feature_extractor=feature_extractor,
            image_encoder=image_encoder,
        )
        self.vae_scale_factor = 2 ** (len(self.vae.config.block_out_channels) - 1)
        self.image_processor = VaeImageProcessor(
            vae_scale_factor=self.vae_scale_factor, do_convert_rgb=True
        )
        self.control_image_processor = VaeImageProcessor(
            vae_scale_factor=self.vae_scale_factor,
            do_convert_rgb=True,
            do_normalize=False,
        )
        self.register_to_config(
            force_zeros_for_empty_prompt=force_zeros_for_empty_prompt
        )

    def encode_prompt(
        self,
        prompt: str,
        negative_prompt: Optional[str] = None,
        device: Optional[torch.device] = None,
        do_classifier_free_guidance: bool = True,
    ):
        device = device or self._execution_device
        prompt = [prompt] if isinstance(prompt, str) else prompt

        if prompt is not None:
            batch_size = len(prompt)

        # Define tokenizers and text encoders
        tokenizers = (
            [self.tokenizer, self.tokenizer_2]
            if self.tokenizer is not None
            else [self.tokenizer_2]
        )
        text_encoders = (
            [self.text_encoder, self.text_encoder_2]
            if self.text_encoder is not None
            else [self.text_encoder_2]
        )

        prompt_2 = prompt

        # textual inversion: process multi-vector tokens if necessary
        prompt_embeds_list = []
        prompts = [prompt, prompt_2]
        for prompt, tokenizer, text_encoder in zip(prompts, tokenizers, text_encoders):
            text_inputs = tokenizer(
                prompt,
                padding="max_length",
                max_length=tokenizer.model_max_length,
                truncation=True,
                return_tensors="pt",
            )

            text_input_ids = text_inputs.input_ids

            prompt_embeds = text_encoder(
                text_input_ids.to(device), output_hidden_states=True
            )

            # We are only ALWAYS interested in the pooled output of the final text encoder
            pooled_prompt_embeds = prompt_embeds[0]
            prompt_embeds = prompt_embeds.hidden_states[-2]
            prompt_embeds_list.append(prompt_embeds)

        prompt_embeds = torch.concat(prompt_embeds_list, dim=-1)

        # get unconditional embeddings for classifier free guidance
        negative_prompt_embeds = None
        negative_pooled_prompt_embeds = None

        if do_classifier_free_guidance:
            negative_prompt = negative_prompt or ""

            negative_prompt_embeds = torch.zeros_like(prompt_embeds)
            negative_pooled_prompt_embeds = torch.zeros_like(pooled_prompt_embeds)

            # normalize str to list
            negative_prompt = [negative_prompt]
            negative_prompt_2 = negative_prompt

            uncond_tokens: List[str]
            uncond_tokens = [negative_prompt, negative_prompt_2]

            negative_prompt_embeds_list = []
            for negative_prompt, tokenizer, text_encoder in zip(
                uncond_tokens, tokenizers, text_encoders
            ):
                max_length = prompt_embeds.shape[1]
                uncond_input = tokenizer(
                    negative_prompt,
                    padding="max_length",
                    max_length=max_length,
                    truncation=True,
                    return_tensors="pt",
                )

                negative_prompt_embeds = text_encoder(
                    uncond_input.input_ids.to(device),
                    output_hidden_states=True,
                )
                # We are only ALWAYS interested in the pooled output of the final text encoder
                negative_pooled_prompt_embeds = negative_prompt_embeds[0]
                negative_prompt_embeds = negative_prompt_embeds.hidden_states[-2]

                negative_prompt_embeds_list.append(negative_prompt_embeds)

            negative_prompt_embeds = torch.concat(negative_prompt_embeds_list, dim=-1)

        prompt_embeds = prompt_embeds.to(dtype=self.text_encoder_2.dtype, device=device)

        bs_embed, seq_len, _ = prompt_embeds.shape
        # duplicate text embeddings for each generation per prompt, using mps friendly method
        prompt_embeds = prompt_embeds.view(bs_embed, seq_len, -1)

        if do_classifier_free_guidance:
            # duplicate unconditional embeddings for each generation per prompt, using mps friendly method
            seq_len = negative_prompt_embeds.shape[1]

            negative_prompt_embeds = negative_prompt_embeds.to(
                dtype=self.text_encoder_2.dtype, device=device
            )

            negative_prompt_embeds = negative_prompt_embeds.view(
                batch_size, seq_len, -1
            )

        pooled_prompt_embeds = pooled_prompt_embeds.view(bs_embed, -1)

        if do_classifier_free_guidance:
            negative_pooled_prompt_embeds = negative_pooled_prompt_embeds.view(
                bs_embed, -1
            )

        return (
            prompt_embeds,
            negative_prompt_embeds,
            pooled_prompt_embeds,
            negative_pooled_prompt_embeds,
        )

    # Copied from diffusers.pipelines.stable_diffusion.pipeline_stable_diffusion.StableDiffusionPipeline.encode_image
    def encode_image(
        self, image, device, num_images_per_prompt, output_hidden_states=None
    ):
        dtype = next(self.image_encoder.parameters()).dtype

        if not isinstance(image, torch.Tensor):
            image = self.feature_extractor(image, return_tensors="pt").pixel_values

        image = image.to(device=device, dtype=dtype)
        if output_hidden_states:
            image_enc_hidden_states = self.image_encoder(
                image, output_hidden_states=True
            ).hidden_states[-2]
            image_enc_hidden_states = image_enc_hidden_states.repeat_interleave(
                num_images_per_prompt, dim=0
            )
            uncond_image_enc_hidden_states = self.image_encoder(
                torch.zeros_like(image), output_hidden_states=True
            ).hidden_states[-2]
            uncond_image_enc_hidden_states = (
                uncond_image_enc_hidden_states.repeat_interleave(
                    num_images_per_prompt, dim=0
                )
            )
            return image_enc_hidden_states, uncond_image_enc_hidden_states
        else:
            image_embeds = self.image_encoder(image).image_embeds
            image_embeds = image_embeds.repeat_interleave(num_images_per_prompt, dim=0)
            uncond_image_embeds = torch.zeros_like(image_embeds)

            return image_embeds, uncond_image_embeds

    def prepare_ip_adapter_image_embeds(
        self,
        ip_adapter_image,
        device,
        do_classifier_free_guidance,
    ):
        image_embeds = []
        if do_classifier_free_guidance:
            negative_image_embeds = []

        if not isinstance(ip_adapter_image, list):
            ip_adapter_image = [ip_adapter_image]

        if len(ip_adapter_image) != len(
            self.unet.encoder_hid_proj.image_projection_layers
        ):
            raise ValueError(
                f"`ip_adapter_image` must have same length as the number of IP Adapters. Got {len(ip_adapter_image)} images and {len(self.unet.encoder_hid_proj.image_projection_layers)} IP Adapters."
            )

        for single_ip_adapter_image, image_proj_layer in zip(
            ip_adapter_image, self.unet.encoder_hid_proj.image_projection_layers
        ):
            output_hidden_state = not isinstance(image_proj_layer, ImageProjection)
            single_image_embeds, single_negative_image_embeds = self.encode_image(
                single_ip_adapter_image, device, 1, output_hidden_state
            )

            image_embeds.append(single_image_embeds[None, :])
            if do_classifier_free_guidance:
                negative_image_embeds.append(single_negative_image_embeds[None, :])

        ip_adapter_image_embeds = []

        for i, single_image_embeds in enumerate(image_embeds):
            if do_classifier_free_guidance:
                single_image_embeds = torch.cat(
                    [negative_image_embeds[i], single_image_embeds], dim=0
                )

            single_image_embeds = single_image_embeds.to(device=device)
            ip_adapter_image_embeds.append(single_image_embeds)

        return ip_adapter_image_embeds

    def prepare_image(self, image, device, dtype, do_classifier_free_guidance=False):
        image = self.control_image_processor.preprocess(image).to(dtype=torch.float32)

        image_batch_size = image.shape[0]

        image = image.repeat_interleave(image_batch_size, dim=0)
        image = image.to(device=device, dtype=dtype)

        if do_classifier_free_guidance:
            image = torch.cat([image] * 2)

        return image

    def prepare_latents(
        self, batch_size, num_channels_latents, height, width, dtype, device
    ):
        shape = (
            batch_size,
            num_channels_latents,
            int(height) // self.vae_scale_factor,
            int(width) // self.vae_scale_factor,
        )

        latents = randn_tensor(shape, device=device, dtype=dtype)

        # scale the initial noise by the standard deviation required by the scheduler
        latents = latents * self.scheduler.init_noise_sigma
        return latents

    @property
    def guidance_scale(self):
        return self._guidance_scale

    # here `guidance_scale` is defined analog to the guidance weight `w` of equation (2)
    # of the Imagen paper: https://arxiv.org/pdf/2205.11487.pdf . `guidance_scale = 1`
    # corresponds to doing no classifier free guidance.
    @property
    def do_classifier_free_guidance(self):
        return self._guidance_scale > 1 and self.unet.config.time_cond_proj_dim is None

    @property
    def denoising_end(self):
        return self._denoising_end

    @property
    def num_timesteps(self):
        return self._num_timesteps

    @torch.no_grad()
    def __call__(
        self,
        image: PipelineImageInput = None,
        num_inference_steps: int = 8,
        guidance_scale: float = 2.0,
        prompt_embeds: Optional[torch.Tensor] = None,
        negative_prompt_embeds: Optional[torch.Tensor] = None,
        pooled_prompt_embeds: Optional[torch.Tensor] = None,
        negative_pooled_prompt_embeds: Optional[torch.Tensor] = None,
        ip_adapter_image: Optional[PipelineImageInput] = None,
        controlnet_conditioning_scale: Union[float, List[float]] = 1.0,
        control_guidance_start: Union[float, List[float]] = 0.0,
        control_guidance_end: Union[float, List[float]] = 1.0,
        **kwargs,
    ):
        controlnet = self.controlnet

        # align format for control guidance
        if not isinstance(control_guidance_start, list) and isinstance(
            control_guidance_end, list
        ):
            control_guidance_start = len(control_guidance_end) * [
                control_guidance_start
            ]
        elif not isinstance(control_guidance_end, list) and isinstance(
            control_guidance_start, list
        ):
            control_guidance_end = len(control_guidance_start) * [control_guidance_end]
        elif not isinstance(control_guidance_start, list) and not isinstance(
            control_guidance_end, list
        ):
            mult = (
                len(controlnet.nets)
                if isinstance(controlnet, MultiControlNetModel)
                else 1
            )
            control_guidance_start, control_guidance_end = (
                mult * [control_guidance_start],
                mult * [control_guidance_end],
            )

        self._guidance_scale = guidance_scale

        # 2. Define call parameters
        batch_size = 1
        device = self._execution_device

        if isinstance(controlnet, MultiControlNetModel) and isinstance(
            controlnet_conditioning_scale, float
        ):
            controlnet_conditioning_scale = [controlnet_conditioning_scale] * len(
                controlnet.nets
            )

        # 3.2 Encode ip_adapter_image
        if ip_adapter_image is not None:
            image_embeds = self.prepare_ip_adapter_image_embeds(
                ip_adapter_image,
                device,
                self.do_classifier_free_guidance,
            )

        # 4. Prepare image
        if isinstance(controlnet, ControlNetModel):
            image = self.prepare_image(
                image=image,
                device=device,
                dtype=controlnet.dtype,
                do_classifier_free_guidance=self.do_classifier_free_guidance,
            )
            height, width = image.shape[-2:]
        elif isinstance(controlnet, MultiControlNetModel):
            images = []

            for image_ in image:
                image_ = self.prepare_image(
                    image=image_,
                    device=device,
                    dtype=controlnet.dtype,
                    do_classifier_free_guidance=self.do_classifier_free_guidance,
                )

                images.append(image_)

            image = images
            height, width = image[0].shape[-2:]
        else:
            assert False

        # 5. Prepare timesteps
        timesteps, num_inference_steps = retrieve_timesteps(
            self.scheduler, num_inference_steps, device
        )
        self._num_timesteps = len(timesteps)

        # 6. Prepare latent variables
        num_channels_latents = self.unet.config.in_channels
        latents = self.prepare_latents(
            batch_size,
            num_channels_latents,
            height,
            width,
            prompt_embeds.dtype,
            device,
        )

        # 7.1 Create tensor stating which controlnets to keep
        controlnet_keep = []
        for i in range(len(timesteps)):
            keeps = [
                1.0 - float(i / len(timesteps) < s or (i + 1) / len(timesteps) > e)
                for s, e in zip(control_guidance_start, control_guidance_end)
            ]
            controlnet_keep.append(
                keeps[0] if isinstance(controlnet, ControlNetModel) else keeps
            )

        # 7.2 Prepare added time ids & embeddings
        add_text_embeds = pooled_prompt_embeds

        add_time_ids = negative_add_time_ids = torch.tensor(
            image[0].shape[-2:] + torch.Size([0, 0]) + image[0].shape[-2:]
        ).unsqueeze(0)

        negative_add_time_ids = add_time_ids

        if self.do_classifier_free_guidance:
            prompt_embeds = torch.cat([negative_prompt_embeds, prompt_embeds], dim=0)
            add_text_embeds = torch.cat(
                [negative_pooled_prompt_embeds, add_text_embeds], dim=0
            )
            add_time_ids = torch.cat([negative_add_time_ids, add_time_ids], dim=0)

        prompt_embeds = prompt_embeds.to(device)
        add_text_embeds = add_text_embeds.to(device)
        add_time_ids = add_time_ids.to(device)

        added_cond_kwargs = {
            "text_embeds": add_text_embeds,
            "time_ids": add_time_ids,
        }

        # 8. Denoising loop
        num_warmup_steps = len(timesteps) - num_inference_steps * self.scheduler.order

        with self.progress_bar(total=num_inference_steps) as progress_bar:
            for i, t in enumerate(timesteps):
                # expand the latents if we are doing classifier free guidance
                latent_model_input = (
                    torch.cat([latents] * 2)
                    if self.do_classifier_free_guidance
                    else latents
                )
                latent_model_input = self.scheduler.scale_model_input(
                    latent_model_input, t
                )

                # controlnet(s) inference
                control_model_input = latent_model_input
                controlnet_prompt_embeds = prompt_embeds
                controlnet_added_cond_kwargs = added_cond_kwargs

                if isinstance(controlnet_keep[i], list):
                    cond_scale = [
                        c * s
                        for c, s in zip(
                            controlnet_conditioning_scale, controlnet_keep[i]
                        )
                    ]
                else:
                    controlnet_cond_scale = controlnet_conditioning_scale
                    if isinstance(controlnet_cond_scale, list):
                        controlnet_cond_scale = controlnet_cond_scale[0]
                    cond_scale = controlnet_cond_scale * controlnet_keep[i]

                down_block_res_samples, mid_block_res_sample = self.controlnet(
                    control_model_input,
                    t,
                    encoder_hidden_states=controlnet_prompt_embeds,
                    controlnet_cond=image,
                    conditioning_scale=cond_scale,
                    guess_mode=False,
                    added_cond_kwargs=controlnet_added_cond_kwargs,
                    return_dict=False,
                )

                if ip_adapter_image is not None:
                    added_cond_kwargs["image_embeds"] = image_embeds

                # predict the noise residual
                noise_pred = self.unet(
                    latent_model_input,
                    t,
                    encoder_hidden_states=prompt_embeds,
                    timestep_cond=None,
                    cross_attention_kwargs={},
                    down_block_additional_residuals=down_block_res_samples,
                    mid_block_additional_residual=mid_block_res_sample,
                    added_cond_kwargs=added_cond_kwargs,
                    return_dict=False,
                )[0]

                # perform guidance
                if self.do_classifier_free_guidance:
                    noise_pred_uncond, noise_pred_text = noise_pred.chunk(2)
                    noise_pred = noise_pred_uncond + guidance_scale * (
                        noise_pred_text - noise_pred_uncond
                    )

                # compute the previous noisy sample x_t -> x_t-1
                latents = self.scheduler.step(
                    noise_pred, t, latents, return_dict=False
                )[0]

                if i == 2:
                    prompt_embeds = prompt_embeds[-1:]
                    add_text_embeds = add_text_embeds[-1:]
                    add_time_ids = add_time_ids[-1:]

                    added_cond_kwargs = {
                        "text_embeds": add_text_embeds,
                        "time_ids": add_time_ids,
                    }

                    controlnet_prompt_embeds = prompt_embeds
                    controlnet_added_cond_kwargs = added_cond_kwargs

                    image = [single_image[-1:] for single_image in image]
                    self._guidance_scale = 0.0

                # call the callback, if provided
                if i == len(timesteps) - 1 or (
                    (i + 1) > num_warmup_steps and (i + 1) % self.scheduler.order == 0
                ):
                    progress_bar.update()

        latents = latents / self.vae.config.scaling_factor
        image = self.vae.decode(latents, return_dict=False)[0]
        image = self.image_processor.postprocess(image)[0]

        # Offload all models
        self.maybe_free_model_hooks()

        return StableDiffusionXLPipelineOutput(images=image)