# 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. import inspect from typing import Callable, List, Optional, Tuple, Union import numpy as np import PIL.Image import torch import torch.utils.checkpoint from transformers import ( CLIPImageProcessor, CLIPTextModelWithProjection, CLIPTokenizer, CLIPVisionModelWithProjection, ) from ....image_processor import VaeImageProcessor from ....models import AutoencoderKL, DualTransformer2DModel, Transformer2DModel, UNet2DConditionModel from ....schedulers import KarrasDiffusionSchedulers from ....utils import deprecate, logging from ....utils.torch_utils import randn_tensor from ...pipeline_utils import DiffusionPipeline, ImagePipelineOutput from .modeling_text_unet import UNetFlatConditionModel logger = logging.get_logger(__name__) # pylint: disable=invalid-name class VersatileDiffusionDualGuidedPipeline(DiffusionPipeline): r""" Pipeline for image-text dual-guided generation using Versatile Diffusion. This model inherits from [`DiffusionPipeline`]. Check the superclass documentation for the generic methods implemented for all pipelines (downloading, saving, running on a particular device, etc.). Parameters: vqvae ([`VQModel`]): Vector-quantized (VQ) model to encode and decode images to and from latent representations. bert ([`LDMBertModel`]): Text-encoder model based on [`~transformers.BERT`]. tokenizer ([`~transformers.BertTokenizer`]): A `BertTokenizer` to tokenize text. unet ([`UNet2DConditionModel`]): A `UNet2DConditionModel` to denoise the encoded image latents. scheduler ([`SchedulerMixin`]): A scheduler to be used in combination with `unet` to denoise the encoded image latents. Can be one of [`DDIMScheduler`], [`LMSDiscreteScheduler`], or [`PNDMScheduler`]. """ model_cpu_offload_seq = "bert->unet->vqvae" tokenizer: CLIPTokenizer image_feature_extractor: CLIPImageProcessor text_encoder: CLIPTextModelWithProjection image_encoder: CLIPVisionModelWithProjection image_unet: UNet2DConditionModel text_unet: UNetFlatConditionModel vae: AutoencoderKL scheduler: KarrasDiffusionSchedulers _optional_components = ["text_unet"] def __init__( self, tokenizer: CLIPTokenizer, image_feature_extractor: CLIPImageProcessor, text_encoder: CLIPTextModelWithProjection, image_encoder: CLIPVisionModelWithProjection, image_unet: UNet2DConditionModel, text_unet: UNetFlatConditionModel, vae: AutoencoderKL, scheduler: KarrasDiffusionSchedulers, ): super().__init__() self.register_modules( tokenizer=tokenizer, image_feature_extractor=image_feature_extractor, text_encoder=text_encoder, image_encoder=image_encoder, image_unet=image_unet, text_unet=text_unet, vae=vae, scheduler=scheduler, ) self.vae_scale_factor = 2 ** (len(self.vae.config.block_out_channels) - 1) self.image_processor = VaeImageProcessor(vae_scale_factor=self.vae_scale_factor) if self.text_unet is not None and ( "dual_cross_attention" not in self.image_unet.config or not self.image_unet.config.dual_cross_attention ): # if loading from a universal checkpoint rather than a saved dual-guided pipeline self._convert_to_dual_attention() def remove_unused_weights(self): self.register_modules(text_unet=None) def _convert_to_dual_attention(self): """ Replace image_unet's `Transformer2DModel` blocks with `DualTransformer2DModel` that contains transformer blocks from both `image_unet` and `text_unet` """ for name, module in self.image_unet.named_modules(): if isinstance(module, Transformer2DModel): parent_name, index = name.rsplit(".", 1) index = int(index) image_transformer = self.image_unet.get_submodule(parent_name)[index] text_transformer = self.text_unet.get_submodule(parent_name)[index] config = image_transformer.config dual_transformer = DualTransformer2DModel( num_attention_heads=config.num_attention_heads, attention_head_dim=config.attention_head_dim, in_channels=config.in_channels, num_layers=config.num_layers, dropout=config.dropout, norm_num_groups=config.norm_num_groups, cross_attention_dim=config.cross_attention_dim, attention_bias=config.attention_bias, sample_size=config.sample_size, num_vector_embeds=config.num_vector_embeds, activation_fn=config.activation_fn, num_embeds_ada_norm=config.num_embeds_ada_norm, ) dual_transformer.transformers[0] = image_transformer dual_transformer.transformers[1] = text_transformer self.image_unet.get_submodule(parent_name)[index] = dual_transformer self.image_unet.register_to_config(dual_cross_attention=True) def _revert_dual_attention(self): """ Revert the image_unet `DualTransformer2DModel` blocks back to `Transformer2DModel` with image_unet weights Call this function if you reuse `image_unet` in another pipeline, e.g. `VersatileDiffusionPipeline` """ for name, module in self.image_unet.named_modules(): if isinstance(module, DualTransformer2DModel): parent_name, index = name.rsplit(".", 1) index = int(index) self.image_unet.get_submodule(parent_name)[index] = module.transformers[0] self.image_unet.register_to_config(dual_cross_attention=False) def _encode_text_prompt(self, prompt, device, num_images_per_prompt, do_classifier_free_guidance): r""" Encodes the prompt into text encoder hidden states. Args: prompt (`str` or `List[str]`): prompt to be encoded device: (`torch.device`): torch device num_images_per_prompt (`int`): number of images that should be generated per prompt do_classifier_free_guidance (`bool`): whether to use classifier free guidance or not """ def normalize_embeddings(encoder_output): embeds = self.text_encoder.text_projection(encoder_output.last_hidden_state) embeds_pooled = encoder_output.text_embeds embeds = embeds / torch.norm(embeds_pooled.unsqueeze(1), dim=-1, keepdim=True) return embeds batch_size = len(prompt) text_inputs = self.tokenizer( prompt, padding="max_length", max_length=self.tokenizer.model_max_length, truncation=True, return_tensors="pt", ) text_input_ids = text_inputs.input_ids untruncated_ids = self.tokenizer(prompt, padding="max_length", return_tensors="pt").input_ids if not torch.equal(text_input_ids, untruncated_ids): removed_text = self.tokenizer.batch_decode(untruncated_ids[:, self.tokenizer.model_max_length - 1 : -1]) logger.warning( "The following part of your input was truncated because CLIP can only handle sequences up to" f" {self.tokenizer.model_max_length} tokens: {removed_text}" ) if hasattr(self.text_encoder.config, "use_attention_mask") and self.text_encoder.config.use_attention_mask: attention_mask = text_inputs.attention_mask.to(device) else: attention_mask = None prompt_embeds = self.text_encoder( text_input_ids.to(device), attention_mask=attention_mask, ) prompt_embeds = normalize_embeddings(prompt_embeds) # duplicate text embeddings for each generation per prompt, using mps friendly method bs_embed, seq_len, _ = prompt_embeds.shape prompt_embeds = prompt_embeds.repeat(1, num_images_per_prompt, 1) prompt_embeds = prompt_embeds.view(bs_embed * num_images_per_prompt, seq_len, -1) # get unconditional embeddings for classifier free guidance if do_classifier_free_guidance: uncond_tokens = [""] * batch_size max_length = text_input_ids.shape[-1] uncond_input = self.tokenizer( uncond_tokens, padding="max_length", max_length=max_length, truncation=True, return_tensors="pt", ) if hasattr(self.text_encoder.config, "use_attention_mask") and self.text_encoder.config.use_attention_mask: attention_mask = uncond_input.attention_mask.to(device) else: attention_mask = None negative_prompt_embeds = self.text_encoder( uncond_input.input_ids.to(device), attention_mask=attention_mask, ) negative_prompt_embeds = normalize_embeddings(negative_prompt_embeds) # 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.repeat(1, num_images_per_prompt, 1) negative_prompt_embeds = negative_prompt_embeds.view(batch_size * num_images_per_prompt, seq_len, -1) # For classifier free guidance, we need to do two forward passes. # Here we concatenate the unconditional and text embeddings into a single batch # to avoid doing two forward passes prompt_embeds = torch.cat([negative_prompt_embeds, prompt_embeds]) return prompt_embeds def _encode_image_prompt(self, prompt, device, num_images_per_prompt, do_classifier_free_guidance): r""" Encodes the prompt into text encoder hidden states. Args: prompt (`str` or `List[str]`): prompt to be encoded device: (`torch.device`): torch device num_images_per_prompt (`int`): number of images that should be generated per prompt do_classifier_free_guidance (`bool`): whether to use classifier free guidance or not """ def normalize_embeddings(encoder_output): embeds = self.image_encoder.vision_model.post_layernorm(encoder_output.last_hidden_state) embeds = self.image_encoder.visual_projection(embeds) embeds_pooled = embeds[:, 0:1] embeds = embeds / torch.norm(embeds_pooled, dim=-1, keepdim=True) return embeds batch_size = len(prompt) if isinstance(prompt, list) else 1 # get prompt text embeddings image_input = self.image_feature_extractor(images=prompt, return_tensors="pt") pixel_values = image_input.pixel_values.to(device).to(self.image_encoder.dtype) image_embeddings = self.image_encoder(pixel_values) image_embeddings = normalize_embeddings(image_embeddings) # duplicate image embeddings for each generation per prompt, using mps friendly method bs_embed, seq_len, _ = image_embeddings.shape image_embeddings = image_embeddings.repeat(1, num_images_per_prompt, 1) image_embeddings = image_embeddings.view(bs_embed * num_images_per_prompt, seq_len, -1) # get unconditional embeddings for classifier free guidance if do_classifier_free_guidance: uncond_images = [np.zeros((512, 512, 3)) + 0.5] * batch_size uncond_images = self.image_feature_extractor(images=uncond_images, return_tensors="pt") pixel_values = uncond_images.pixel_values.to(device).to(self.image_encoder.dtype) negative_prompt_embeds = self.image_encoder(pixel_values) negative_prompt_embeds = normalize_embeddings(negative_prompt_embeds) # 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.repeat(1, num_images_per_prompt, 1) negative_prompt_embeds = negative_prompt_embeds.view(batch_size * num_images_per_prompt, seq_len, -1) # For classifier free guidance, we need to do two forward passes. # Here we concatenate the unconditional and conditional embeddings into a single batch # to avoid doing two forward passes image_embeddings = torch.cat([negative_prompt_embeds, image_embeddings]) return image_embeddings # Copied from diffusers.pipelines.stable_diffusion.pipeline_stable_diffusion.StableDiffusionPipeline.decode_latents def decode_latents(self, latents): deprecation_message = "The decode_latents method is deprecated and will be removed in 1.0.0. Please use VaeImageProcessor.postprocess(...) instead" deprecate("decode_latents", "1.0.0", deprecation_message, standard_warn=False) latents = 1 / self.vae.config.scaling_factor * latents image = self.vae.decode(latents, return_dict=False)[0] image = (image / 2 + 0.5).clamp(0, 1) # we always cast to float32 as this does not cause significant overhead and is compatible with bfloat16 image = image.cpu().permute(0, 2, 3, 1).float().numpy() return image # Copied from diffusers.pipelines.stable_diffusion.pipeline_stable_diffusion.StableDiffusionPipeline.prepare_extra_step_kwargs def prepare_extra_step_kwargs(self, generator, eta): # prepare extra kwargs for the scheduler step, since not all schedulers have the same signature # eta (η) is only used with the DDIMScheduler, it will be ignored for other schedulers. # eta corresponds to η in DDIM paper: https://arxiv.org/abs/2010.02502 # and should be between [0, 1] accepts_eta = "eta" in set(inspect.signature(self.scheduler.step).parameters.keys()) extra_step_kwargs = {} if accepts_eta: extra_step_kwargs["eta"] = eta # check if the scheduler accepts generator accepts_generator = "generator" in set(inspect.signature(self.scheduler.step).parameters.keys()) if accepts_generator: extra_step_kwargs["generator"] = generator return extra_step_kwargs def check_inputs(self, prompt, image, height, width, callback_steps): if not isinstance(prompt, str) and not isinstance(prompt, PIL.Image.Image) and not isinstance(prompt, list): raise ValueError(f"`prompt` has to be of type `str` `PIL.Image` or `list` but is {type(prompt)}") if not isinstance(image, str) and not isinstance(image, PIL.Image.Image) and not isinstance(image, list): raise ValueError(f"`image` has to be of type `str` `PIL.Image` or `list` but is {type(image)}") if height % 8 != 0 or width % 8 != 0: raise ValueError(f"`height` and `width` have to be divisible by 8 but are {height} and {width}.") if (callback_steps is None) or ( callback_steps is not None and (not isinstance(callback_steps, int) or callback_steps <= 0) ): raise ValueError( f"`callback_steps` has to be a positive integer but is {callback_steps} of type" f" {type(callback_steps)}." ) # Copied from diffusers.pipelines.stable_diffusion.pipeline_stable_diffusion.StableDiffusionPipeline.prepare_latents def prepare_latents(self, batch_size, num_channels_latents, height, width, dtype, device, generator, latents=None): shape = ( batch_size, num_channels_latents, int(height) // self.vae_scale_factor, int(width) // self.vae_scale_factor, ) if isinstance(generator, list) and len(generator) != batch_size: raise ValueError( f"You have passed a list of generators of length {len(generator)}, but requested an effective batch" f" size of {batch_size}. Make sure the batch size matches the length of the generators." ) if latents is None: latents = randn_tensor(shape, generator=generator, device=device, dtype=dtype) else: latents = latents.to(device) # scale the initial noise by the standard deviation required by the scheduler latents = latents * self.scheduler.init_noise_sigma return latents def set_transformer_params(self, mix_ratio: float = 0.5, condition_types: Tuple = ("text", "image")): for name, module in self.image_unet.named_modules(): if isinstance(module, DualTransformer2DModel): module.mix_ratio = mix_ratio for i, type in enumerate(condition_types): if type == "text": module.condition_lengths[i] = self.text_encoder.config.max_position_embeddings module.transformer_index_for_condition[i] = 1 # use the second (text) transformer else: module.condition_lengths[i] = 257 module.transformer_index_for_condition[i] = 0 # use the first (image) transformer @torch.no_grad() def __call__( self, prompt: Union[PIL.Image.Image, List[PIL.Image.Image]], image: Union[str, List[str]], text_to_image_strength: float = 0.5, height: Optional[int] = None, width: Optional[int] = None, num_inference_steps: int = 50, guidance_scale: float = 7.5, num_images_per_prompt: Optional[int] = 1, eta: float = 0.0, generator: Optional[Union[torch.Generator, List[torch.Generator]]] = None, latents: Optional[torch.Tensor] = None, output_type: Optional[str] = "pil", return_dict: bool = True, callback: Optional[Callable[[int, int, torch.Tensor], None]] = None, callback_steps: int = 1, **kwargs, ): r""" The call function to the pipeline for generation. Args: prompt (`str` or `List[str]`): The prompt or prompts to guide image generation. height (`int`, *optional*, defaults to `self.image_unet.config.sample_size * self.vae_scale_factor`): The height in pixels of the generated image. width (`int`, *optional*, defaults to `self.image_unet.config.sample_size * self.vae_scale_factor`): The width in pixels of the generated image. num_inference_steps (`int`, *optional*, defaults to 50): The number of denoising steps. More denoising steps usually lead to a higher quality image at the expense of slower inference. guidance_scale (`float`, *optional*, defaults to 7.5): A higher guidance scale value encourages the model to generate images closely linked to the text `prompt` at the expense of lower image quality. Guidance scale is enabled when `guidance_scale > 1`. negative_prompt (`str` or `List[str]`, *optional*): The prompt or prompts to guide what to not include in image generation. If not defined, you need to pass `negative_prompt_embeds` instead. Ignored when not using guidance (`guidance_scale < 1`). num_images_per_prompt (`int`, *optional*, defaults to 1): The number of images to generate per prompt. eta (`float`, *optional*, defaults to 0.0): Corresponds to parameter eta (η) from the [DDIM](https://arxiv.org/abs/2010.02502) paper. Only applies to the [`~schedulers.DDIMScheduler`], and is ignored in other schedulers. generator (`torch.Generator` or `List[torch.Generator]`, *optional*): A [`torch.Generator`](https://pytorch.org/docs/stable/generated/torch.Generator.html) to make generation deterministic. latents (`torch.Tensor`, *optional*): Pre-generated noisy latents sampled from a Gaussian distribution, to be used as inputs for image generation. Can be used to tweak the same generation with different prompts. If not provided, a latents tensor is generated by sampling using the supplied random `generator`. output_type (`str`, *optional*, defaults to `"pil"`): The output format of the generated image. Choose between `PIL.Image` or `np.array`. return_dict (`bool`, *optional*, defaults to `True`): Whether or not to return a [`~pipelines.ImagePipelineOutput`] instead of a plain tuple. callback (`Callable`, *optional*): A function that calls every `callback_steps` steps during inference. The function is called with the following arguments: `callback(step: int, timestep: int, latents: torch.Tensor)`. callback_steps (`int`, *optional*, defaults to 1): The frequency at which the `callback` function is called. If not specified, the callback is called at every step. Examples: ```py >>> from diffusers import VersatileDiffusionDualGuidedPipeline >>> import torch >>> import requests >>> from io import BytesIO >>> from PIL import Image >>> # let's download an initial image >>> url = "https://huggingface.co/datasets/diffusers/images/resolve/main/benz.jpg" >>> response = requests.get(url) >>> image = Image.open(BytesIO(response.content)).convert("RGB") >>> text = "a red car in the sun" >>> pipe = VersatileDiffusionDualGuidedPipeline.from_pretrained( ... "shi-labs/versatile-diffusion", torch_dtype=torch.float16 ... ) >>> pipe.remove_unused_weights() >>> pipe = pipe.to("cuda") >>> generator = torch.Generator(device="cuda").manual_seed(0) >>> text_to_image_strength = 0.75 >>> image = pipe( ... prompt=text, image=image, text_to_image_strength=text_to_image_strength, generator=generator ... ).images[0] >>> image.save("./car_variation.png") ``` Returns: [`~pipelines.ImagePipelineOutput`] or `tuple`: If `return_dict` is `True`, [`~pipelines.ImagePipelineOutput`] is returned, otherwise a `tuple` is returned where the first element is a list with the generated images. """ # 0. Default height and width to unet height = height or self.image_unet.config.sample_size * self.vae_scale_factor width = width or self.image_unet.config.sample_size * self.vae_scale_factor # 1. Check inputs. Raise error if not correct self.check_inputs(prompt, image, height, width, callback_steps) # 2. Define call parameters prompt = [prompt] if not isinstance(prompt, list) else prompt image = [image] if not isinstance(image, list) else image batch_size = len(prompt) device = self._execution_device # 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. do_classifier_free_guidance = guidance_scale > 1.0 # 3. Encode input prompts prompt_embeds = self._encode_text_prompt(prompt, device, num_images_per_prompt, do_classifier_free_guidance) image_embeddings = self._encode_image_prompt(image, device, num_images_per_prompt, do_classifier_free_guidance) dual_prompt_embeddings = torch.cat([prompt_embeds, image_embeddings], dim=1) prompt_types = ("text", "image") # 4. Prepare timesteps self.scheduler.set_timesteps(num_inference_steps, device=device) timesteps = self.scheduler.timesteps # 5. Prepare latent variables num_channels_latents = self.image_unet.config.in_channels latents = self.prepare_latents( batch_size * num_images_per_prompt, num_channels_latents, height, width, dual_prompt_embeddings.dtype, device, generator, latents, ) # 6. Prepare extra step kwargs. extra_step_kwargs = self.prepare_extra_step_kwargs(generator, eta) # 7. Combine the attention blocks of the image and text UNets self.set_transformer_params(text_to_image_strength, prompt_types) # 8. Denoising loop for i, t in enumerate(self.progress_bar(timesteps)): # expand the latents if we are doing classifier free guidance latent_model_input = torch.cat([latents] * 2) if do_classifier_free_guidance else latents latent_model_input = self.scheduler.scale_model_input(latent_model_input, t) # predict the noise residual noise_pred = self.image_unet(latent_model_input, t, encoder_hidden_states=dual_prompt_embeddings).sample # perform guidance if 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, **extra_step_kwargs).prev_sample # call the callback, if provided if callback is not None and i % callback_steps == 0: step_idx = i // getattr(self.scheduler, "order", 1) callback(step_idx, t, latents) if not output_type == "latent": image = self.vae.decode(latents / self.vae.config.scaling_factor, return_dict=False)[0] else: image = latents image = self.image_processor.postprocess(image, output_type=output_type) if not return_dict: return (image,) return ImagePipelineOutput(images=image)