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# Copyright 2023 Salesforce.com, inc.
# Copyright 2023 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, Union
import PIL.Image
import torch
from transformers import CLIPTokenizer
from ...models import AutoencoderKL, UNet2DConditionModel
from ...schedulers import PNDMScheduler
from ...utils import (
logging,
replace_example_docstring,
)
from ...utils.torch_utils import randn_tensor
from ..pipeline_utils import DiffusionPipeline, ImagePipelineOutput
from .blip_image_processing import BlipImageProcessor
from .modeling_blip2 import Blip2QFormerModel
from .modeling_ctx_clip import ContextCLIPTextModel
logger = logging.get_logger(__name__) # pylint: disable=invalid-name
EXAMPLE_DOC_STRING = """
Examples:
```py
>>> from diffusers.pipelines import BlipDiffusionPipeline
>>> from diffusers.utils import load_image
>>> import torch
>>> blip_diffusion_pipe = BlipDiffusionPipeline.from_pretrained(
... "Salesforce/blipdiffusion", torch_dtype=torch.float16
... ).to("cuda")
>>> cond_subject = "dog"
>>> tgt_subject = "dog"
>>> text_prompt_input = "swimming underwater"
>>> cond_image = load_image(
... "https://huggingface.co/datasets/ayushtues/blipdiffusion_images/resolve/main/dog.jpg"
... )
>>> guidance_scale = 7.5
>>> num_inference_steps = 25
>>> negative_prompt = "over-exposure, under-exposure, saturated, duplicate, out of frame, lowres, cropped, worst quality, low quality, jpeg artifacts, morbid, mutilated, out of frame, ugly, bad anatomy, bad proportions, deformed, blurry, duplicate"
>>> output = blip_diffusion_pipe(
... text_prompt_input,
... cond_image,
... cond_subject,
... tgt_subject,
... guidance_scale=guidance_scale,
... num_inference_steps=num_inference_steps,
... neg_prompt=negative_prompt,
... height=512,
... width=512,
... ).images
>>> output[0].save("image.png")
```
"""
class BlipDiffusionPipeline(DiffusionPipeline):
"""
Pipeline for Zero-Shot Subject Driven Generation using Blip Diffusion.
This model inherits from [`DiffusionPipeline`]. Check the superclass documentation for the generic methods the
library implements for all the pipelines (such as downloading or saving, running on a particular device, etc.)
Args:
tokenizer ([`CLIPTokenizer`]):
Tokenizer for the text encoder
text_encoder ([`ContextCLIPTextModel`]):
Text encoder to encode the text prompt
vae ([`AutoencoderKL`]):
VAE model to map the latents to the image
unet ([`UNet2DConditionModel`]):
Conditional U-Net architecture to denoise the image embedding.
scheduler ([`PNDMScheduler`]):
A scheduler to be used in combination with `unet` to generate image latents.
qformer ([`Blip2QFormerModel`]):
QFormer model to get multi-modal embeddings from the text and image.
image_processor ([`BlipImageProcessor`]):
Image Processor to preprocess and postprocess the image.
ctx_begin_pos (int, `optional`, defaults to 2):
Position of the context token in the text encoder.
"""
model_cpu_offload_seq = "qformer->text_encoder->unet->vae"
def __init__(
self,
tokenizer: CLIPTokenizer,
text_encoder: ContextCLIPTextModel,
vae: AutoencoderKL,
unet: UNet2DConditionModel,
scheduler: PNDMScheduler,
qformer: Blip2QFormerModel,
image_processor: BlipImageProcessor,
ctx_begin_pos: int = 2,
mean: List[float] = None,
std: List[float] = None,
):
super().__init__()
self.register_modules(
tokenizer=tokenizer,
text_encoder=text_encoder,
vae=vae,
unet=unet,
scheduler=scheduler,
qformer=qformer,
image_processor=image_processor,
)
self.register_to_config(ctx_begin_pos=ctx_begin_pos, mean=mean, std=std)
def get_query_embeddings(self, input_image, src_subject):
return self.qformer(image_input=input_image, text_input=src_subject, return_dict=False)
# from the original Blip Diffusion code, speciefies the target subject and augments the prompt by repeating it
def _build_prompt(self, prompts, tgt_subjects, prompt_strength=1.0, prompt_reps=20):
rv = []
for prompt, tgt_subject in zip(prompts, tgt_subjects):
prompt = f"a {tgt_subject} {prompt.strip()}"
# a trick to amplify the prompt
rv.append(", ".join([prompt] * int(prompt_strength * prompt_reps)))
return rv
# Copied from diffusers.pipelines.consistency_models.pipeline_consistency_models.ConsistencyModelPipeline.prepare_latents
def prepare_latents(self, batch_size, num_channels, height, width, dtype, device, generator, latents=None):
shape = (batch_size, num_channels, height, width)
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=device, dtype=dtype)
# scale the initial noise by the standard deviation required by the scheduler
latents = latents * self.scheduler.init_noise_sigma
return latents
def encode_prompt(self, query_embeds, prompt, device=None):
device = device or self._execution_device
# embeddings for prompt, with query_embeds as context
max_len = self.text_encoder.text_model.config.max_position_embeddings
max_len -= self.qformer.config.num_query_tokens
tokenized_prompt = self.tokenizer(
prompt,
padding="max_length",
truncation=True,
max_length=max_len,
return_tensors="pt",
).to(device)
batch_size = query_embeds.shape[0]
ctx_begin_pos = [self.config.ctx_begin_pos] * batch_size
text_embeddings = self.text_encoder(
input_ids=tokenized_prompt.input_ids,
ctx_embeddings=query_embeds,
ctx_begin_pos=ctx_begin_pos,
)[0]
return text_embeddings
@torch.no_grad()
@replace_example_docstring(EXAMPLE_DOC_STRING)
def __call__(
self,
prompt: List[str],
reference_image: PIL.Image.Image,
source_subject_category: List[str],
target_subject_category: List[str],
latents: Optional[torch.FloatTensor] = None,
guidance_scale: float = 7.5,
height: int = 512,
width: int = 512,
num_inference_steps: int = 50,
generator: Optional[Union[torch.Generator, List[torch.Generator]]] = None,
neg_prompt: Optional[str] = "",
prompt_strength: float = 1.0,
prompt_reps: int = 20,
output_type: Optional[str] = "pil",
return_dict: bool = True,
):
"""
Function invoked when calling the pipeline for generation.
Args:
prompt (`List[str]`):
The prompt or prompts to guide the image generation.
reference_image (`PIL.Image.Image`):
The reference image to condition the generation on.
source_subject_category (`List[str]`):
The source subject category.
target_subject_category (`List[str]`):
The target subject category.
latents (`torch.FloatTensor`, *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 will ge generated by random sampling.
guidance_scale (`float`, *optional*, defaults to 7.5):
Guidance scale as defined in [Classifier-Free Diffusion Guidance](https://arxiv.org/abs/2207.12598).
`guidance_scale` is defined as `w` of equation 2. of [Imagen
Paper](https://arxiv.org/pdf/2205.11487.pdf). Guidance scale is enabled by setting `guidance_scale >
1`. Higher guidance scale encourages to generate images that are closely linked to the text `prompt`,
usually at the expense of lower image quality.
height (`int`, *optional*, defaults to 512):
The height of the generated image.
width (`int`, *optional*, defaults to 512):
The width 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.
generator (`torch.Generator` or `List[torch.Generator]`, *optional*):
One or a list of [torch generator(s)](https://pytorch.org/docs/stable/generated/torch.Generator.html)
to make generation deterministic.
neg_prompt (`str`, *optional*, defaults to ""):
The prompt or prompts not to guide the image generation. Ignored when not using guidance (i.e., ignored
if `guidance_scale` is less than `1`).
prompt_strength (`float`, *optional*, defaults to 1.0):
The strength of the prompt. Specifies the number of times the prompt is repeated along with prompt_reps
to amplify the prompt.
prompt_reps (`int`, *optional*, defaults to 20):
The number of times the prompt is repeated along with prompt_strength to amplify the prompt.
output_type (`str`, *optional*, defaults to `"pil"`):
The output format of the generate image. Choose between: `"pil"` (`PIL.Image.Image`), `"np"`
(`np.array`) or `"pt"` (`torch.Tensor`).
return_dict (`bool`, *optional*, defaults to `True`):
Whether or not to return a [`~pipelines.ImagePipelineOutput`] instead of a plain tuple.
Examples:
Returns:
[`~pipelines.ImagePipelineOutput`] or `tuple`
"""
device = self._execution_device
reference_image = self.image_processor.preprocess(
reference_image, image_mean=self.config.mean, image_std=self.config.std, return_tensors="pt"
)["pixel_values"]
reference_image = reference_image.to(device)
if isinstance(prompt, str):
prompt = [prompt]
if isinstance(source_subject_category, str):
source_subject_category = [source_subject_category]
if isinstance(target_subject_category, str):
target_subject_category = [target_subject_category]
batch_size = len(prompt)
prompt = self._build_prompt(
prompts=prompt,
tgt_subjects=target_subject_category,
prompt_strength=prompt_strength,
prompt_reps=prompt_reps,
)
query_embeds = self.get_query_embeddings(reference_image, source_subject_category)
text_embeddings = self.encode_prompt(query_embeds, prompt, device)
do_classifier_free_guidance = guidance_scale > 1.0
if do_classifier_free_guidance:
max_length = self.text_encoder.text_model.config.max_position_embeddings
uncond_input = self.tokenizer(
[neg_prompt] * batch_size,
padding="max_length",
max_length=max_length,
return_tensors="pt",
)
uncond_embeddings = self.text_encoder(
input_ids=uncond_input.input_ids.to(device),
ctx_embeddings=None,
)[0]
# 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
text_embeddings = torch.cat([uncond_embeddings, text_embeddings])
scale_down_factor = 2 ** (len(self.unet.config.block_out_channels) - 1)
latents = self.prepare_latents(
batch_size=batch_size,
num_channels=self.unet.config.in_channels,
height=height // scale_down_factor,
width=width // scale_down_factor,
generator=generator,
latents=latents,
dtype=self.unet.dtype,
device=device,
)
# set timesteps
extra_set_kwargs = {}
self.scheduler.set_timesteps(num_inference_steps, **extra_set_kwargs)
for i, t in enumerate(self.progress_bar(self.scheduler.timesteps)):
# expand the latents if we are doing classifier free guidance
do_classifier_free_guidance = guidance_scale > 1.0
latent_model_input = torch.cat([latents] * 2) if do_classifier_free_guidance else latents
noise_pred = self.unet(
latent_model_input,
timestep=t,
encoder_hidden_states=text_embeddings,
down_block_additional_residuals=None,
mid_block_additional_residual=None,
)["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)
latents = self.scheduler.step(
noise_pred,
t,
latents,
)["prev_sample"]
image = self.vae.decode(latents / self.vae.config.scaling_factor, return_dict=False)[0]
image = self.image_processor.postprocess(image, output_type=output_type)
# Offload all models
self.maybe_free_model_hooks()
if not return_dict:
return (image,)
return ImagePipelineOutput(images=image)
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