Add UniDiffuser model and pipeline

docs/source/en/_toctree.yml

@@ -230,6 +230,8 @@
       title: UnCLIP
     - local: api/pipelines/latent_diffusion_uncond
       title: Unconditional Latent Diffusion
+    - local: api/pipelines/unidiffuser
+      title: UniDiffuser
     - local: api/pipelines/versatile_diffusion
       title: Versatile Diffusion
     - local: api/pipelines/vq_diffusion

docs/source/en/api/diffusion_pipeline.mdx

@@ -45,3 +45,8 @@ By default diffusion pipelines return an object of class
 By default diffusion pipelines return an object of class
 
 [[autodoc]] pipelines.AudioPipelineOutput
+
+## ImageTextPipelineOutput
+By default diffusion pipelines return an object of class
+
+[[autodoc]] ImageTextPipelineOutput

docs/source/en/api/pipelines/unidiffuser.mdx

@@ -0,0 +1,204 @@
+<!--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.
+-->
+
+# UniDiffuser
+
+The UniDiffuser model was proposed in [One Transformer Fits All Distributions in Multi-Modal Diffusion at Scale](https://arxiv.org/abs/2303.06555) by Fan Bao, Shen Nie, Kaiwen Xue, Chongxuan Li, Shi Pu, Yaole Wang, Gang Yue, Yue Cao, Hang Su, Jun Zhu.
+
+The abstract of the [paper](https://arxiv.org/abs/2303.06555) is the following:
+
+*This paper proposes a unified diffusion framework (dubbed UniDiffuser) to fit all distributions relevant to a set of multi-modal data in one model. Our key insight is -- learning diffusion models for marginal, conditional, and joint distributions can be unified as predicting the noise in the perturbed data, where the perturbation levels (i.e. timesteps) can be different for different modalities. Inspired by the unified view, UniDiffuser learns all distributions simultaneously with a minimal modification to the original diffusion model -- perturbs data in all modalities instead of a single modality, inputs individual timesteps in different modalities, and predicts the noise of all modalities instead of a single modality. UniDiffuser is parameterized by a transformer for diffusion models to handle input types of different modalities. Implemented on large-scale paired image-text data, UniDiffuser is able to perform image, text, text-to-image, image-to-text, and image-text pair generation by setting proper timesteps without additional overhead. In particular, UniDiffuser is able to produce perceptually realistic samples in all tasks and its quantitative results (e.g., the FID and CLIP score) are not only superior to existing general-purpose models but also comparable to the bespoken models (e.g., Stable Diffusion and DALL-E 2) in representative tasks (e.g., text-to-image generation).*
+
+Resources:
+
+* [Paper](https://arxiv.org/abs/2303.06555).
+* [Original Code](https://github.com/thu-ml/unidiffuser).
+
+Available Checkpoints are:
+- *UniDiffuser-v0 (512x512 resolution)* [thu-ml/unidiffuser-v0](https://huggingface.co/thu-ml/unidiffuser-v0)
+- *UniDiffuser-v1 (512x512 resolution)* [thu-ml/unidiffuser-v1](https://huggingface.co/thu-ml/unidiffuser-v1)
+
+This pipeline was contributed by our community member [dg845](https://github.com/dg845).
+
+## Available Pipelines:
+
+| Pipeline | Tasks | Demo | Colab |
+|:---:|:---:|:---:|:---:|
+| [UniDiffuserPipeline](https://github.com/huggingface/diffusers/blob/main/src/diffusers/pipelines/pipeline_unidiffuser.py) | *Joint Image-Text Gen*, *Text-to-Image*, *Image-to-Text*,<br> *Image Gen*, *Text Gen*, *Image Variation*, *Text Variation* | [🤗 Spaces](https://huggingface.co/spaces/thu-ml/unidiffuser) | [![Open In Colab](https://colab.research.google.com/assets/colab-badge.svg)](https://colab.research.google.com/github/huggingface/notebooks/blob/main/diffusers/unidiffuser.ipynb) |
+
+## Usage Examples
+
+Because the UniDiffuser model is trained to model the joint distribution of (image, text) pairs, it is capable of performing a diverse range of generation tasks.
+
+### Unconditional Image and Text Generation
+
+Unconditional generation (where we start from only latents sampled from a standard Gaussian prior) from a [`UniDiffuserPipeline`] will produce a (image, text) pair:
+
+```python
+import torch
+
+from diffusers import UniDiffuserPipeline
+
+device = "cuda"
+model_id_or_path = "thu-ml/unidiffuser-v1"
+pipe = UniDiffuserPipeline.from_pretrained(model_id_or_path, torch_dtype=torch.float16)
+pipe.to(device)
+
+# Unconditional image and text generation. The generation task is automatically inferred.
+sample = pipe(num_inference_steps=20, guidance_scale=8.0)
+image = sample.images[0]
+text = sample.text[0]
+image.save("unidiffuser_joint_sample_image.png")
+print(text)
+```
+
+This is also called "joint" generation in the UniDiffusers paper, since we are sampling from the joint image-text distribution.
+
+Note that the generation task is inferred from the inputs used when calling the pipeline.
+It is also possible to manually specify the unconditional generation task ("mode") manually with [`UniDiffuserPipeline.set_joint_mode`]:
+
+```python
+# Equivalent to the above.
+pipe.set_joint_mode()
+sample = pipe(num_inference_steps=20, guidance_scale=8.0)
+```
+
+When the mode is set manually, subsequent calls to the pipeline will use the set mode without attempting the infer the mode.
+You can reset the mode with [`UniDiffuserPipeline.reset_mode`], after which the pipeline will once again infer the mode.
+
+You can also generate only an image or only text (which the UniDiffuser paper calls "marginal" generation since we sample from the marginal distribution of images and text, respectively):
+
+```python
+# Unlike other generation tasks, image-only and text-only generation don't use classifier-free guidance
+# Image-only generation
+pipe.set_image_mode()
+sample_image = pipe(num_inference_steps=20).images[0]
+# Text-only generation
+pipe.set_text_mode()
+sample_text = pipe(num_inference_steps=20).text[0]
+```
+
+### Text-to-Image Generation
+
+UniDiffuser is also capable of sampling from conditional distributions; that is, the distribution of images conditioned on a text prompt or the distribution of texts conditioned on an image.
+Here is an example of sampling from the conditional image distribution (text-to-image generation or text-conditioned image generation):
+
+```python
+import torch
+
+from diffusers import UniDiffuserPipeline
+
+device = "cuda"
+model_id_or_path = "thu-ml/unidiffuser-v1"
+pipe = UniDiffuserPipeline.from_pretrained(model_id_or_path, torch_dtype=torch.float16)
+pipe.to(device)
+
+# Text-to-image generation
+prompt = "an elephant under the sea"
+
+sample = pipe(prompt=prompt, num_inference_steps=20, guidance_scale=8.0)
+t2i_image = sample.images[0]
+t2i_image.save("unidiffuser_text2img_sample_image.png")
+```
+
+The `text2img` mode requires that either an input `prompt` or `prompt_embeds` be supplied. You can set the `text2img` mode manually with [`UniDiffuserPipeline.set_text_to_image_mode`].
+
+### Image-to-Text Generation
+
+Similarly, UniDiffuser can also produce text samples given an image (image-to-text or image-conditioned text generation):
+
+```python
+import torch
+
+from diffusers import UniDiffuserPipeline
+from diffusers.utils import load_image
+
+device = "cuda"
+model_id_or_path = "thu-ml/unidiffuser-v1"
+pipe = UniDiffuserPipeline.from_pretrained(model_id_or_path, torch_dtype=torch.float16)
+pipe.to(device)
+
+# Image-to-text generation
+image_url = "https://huggingface.co/datasets/hf-internal-testing/diffusers-images/resolve/main/unidiffuser/unidiffuser_example_image.jpg"
+init_image = load_image(image_url).resize((512, 512))
+
+sample = pipe(image=init_image, num_inference_steps=20, guidance_scale=8.0)
+i2t_text = sample.text[0]
+print(i2t_text)
+```
+
+The `img2text` mode requires that an input `image` be supplied. You can set the `img2text` mode manually with [`UniDiffuserPipeline.set_image_to_text_mode`].
+
+### Image Variation
+
+The UniDiffuser authors suggest performing image variation through a "round-trip" generation method, where given an input image, we first perform an image-to-text generation, and the perform a text-to-image generation on the outputs of the first generation.
+This produces a new image which is semantically similar to the input image:
+
+```python
+import torch
+
+from diffusers import UniDiffuserPipeline
+from diffusers.utils import load_image
+
+device = "cuda"
+model_id_or_path = "thu-ml/unidiffuser-v1"
+pipe = UniDiffuserPipeline.from_pretrained(model_id_or_path, torch_dtype=torch.float16)
+pipe.to(device)
+
+# Image variation can be performed with a image-to-text generation followed by a text-to-image generation:
+# 1. Image-to-text generation
+image_url = "https://huggingface.co/datasets/hf-internal-testing/diffusers-images/resolve/main/unidiffuser/unidiffuser_example_image.jpg"
+init_image = load_image(image_url).resize((512, 512))
+
+sample = pipe(image=init_image, num_inference_steps=20, guidance_scale=8.0)
+i2t_text = sample.text[0]
+print(i2t_text)
+
+# 2. Text-to-image generation
+sample = pipe(prompt=i2t_text, num_inference_steps=20, guidance_scale=8.0)
+final_image = sample.images[0]
+final_image.save("unidiffuser_image_variation_sample.png")
+```
+
+### Text Variation
+
+
+Similarly, text variation can be performed on an input prompt with a text-to-image generation followed by a image-to-text generation:
+
+```python
+import torch
+
+from diffusers import UniDiffuserPipeline
+
+device = "cuda"
+model_id_or_path = "thu-ml/unidiffuser-v1"
+pipe = UniDiffuserPipeline.from_pretrained(model_id_or_path, torch_dtype=torch.float16)
+pipe.to(device)
+
+# Text variation can be performed with a text-to-image generation followed by a image-to-text generation:
+# 1. Text-to-image generation
+prompt = "an elephant under the sea"
+
+sample = pipe(prompt=prompt, num_inference_steps=20, guidance_scale=8.0)
+t2i_image = sample.images[0]
+t2i_image.save("unidiffuser_text2img_sample_image.png")
+
+# 2. Image-to-text generation
+sample = pipe(image=t2i_image, num_inference_steps=20, guidance_scale=8.0)
+final_prompt = sample.text[0]
+print(final_prompt)
+```
+
+## UniDiffuserPipeline
+[[autodoc]] UniDiffuserPipeline
+	- all
+	- __call__