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--- |
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license: mit |
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tags: |
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- stable-diffusion |
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- stable-diffusion-diffusers |
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inference: false |
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library_name: diffusers |
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--- |
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# SDXL-VAE-FP16-Fix |
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SDXL-VAE-FP16-Fix is the [SDXL VAE](https://huggingface.co/stabilityai/sdxl-vae)*, but modified to run in fp16 precision without generating NaNs. |
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| VAE | Decoding in `float32` / `bfloat16` precision | Decoding in `float16` precision | |
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| --------------------- | -------------------------------------------- | ------------------------------- | |
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| SDXL-VAE | ✅ ![](./images/orig-fp32.png) | ⚠️ ![](./images/orig-fp16.png) | |
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| SDXL-VAE-FP16-Fix | ✅ ![](./images/fix-fp32.png) | ✅ ![](./images/fix-fp16.png) | |
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## 🧨 Diffusers Usage |
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Just load this checkpoint via `AutoencoderKL`: |
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```py |
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import torch |
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from diffusers import DiffusionPipeline, AutoencoderKL |
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vae = AutoencoderKL.from_pretrained("madebyollin/sdxl-vae-fp16-fix", torch_dtype=torch.float16) |
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pipe = DiffusionPipeline.from_pretrained("stabilityai/stable-diffusion-xl-base-1.0", vae=vae, torch_dtype=torch.float16, variant="fp16", use_safetensors=True) |
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pipe.to("cuda") |
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refiner = DiffusionPipeline.from_pretrained("stabilityai/stable-diffusion-xl-refiner-1.0", vae=vae, torch_dtype=torch.float16, use_safetensors=True, variant="fp16") |
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refiner.to("cuda") |
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n_steps = 40 |
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high_noise_frac = 0.7 |
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prompt = "A majestic lion jumping from a big stone at night" |
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image = pipe(prompt=prompt, num_inference_steps=n_steps, denoising_end=high_noise_frac, output_type="latent").images |
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image = refiner(prompt=prompt, num_inference_steps=n_steps, denoising_start=high_noise_frac, image=image).images[0] |
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image |
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``` |
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![](https://huggingface.co/datasets/huggingface/documentation-images/resolve/main/diffusers/lion_refined.png) |
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## Automatic1111 Usage |
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1. Download the fixed [sdxl.vae.safetensors](https://huggingface.co/madebyollin/sdxl-vae-fp16-fix/resolve/main/sdxl.vae.safetensors?download=true) file |
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2. Move this `sdxl.vae.safetensors` file into the webui folder under `stable-diffusion-webui/models/VAE` |
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3. In your webui settings, select the fixed VAE you just added |
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4. If you were using the `--no-half-vae` command line arg for SDXL (in `webui-user.bat` or wherever), you can now remove it |
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(Disclaimer - I haven't tested this, just aggregating various instructions I've seen elsewhere :P PRs to improve these instructions are welcomed!) |
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## Details |
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SDXL-VAE generates NaNs in fp16 because the internal activation values are too big: |
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![](./images/activation-magnitudes.jpg) |
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SDXL-VAE-FP16-Fix was created by finetuning the SDXL-VAE to: |
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1. keep the final output the same, but |
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2. make the internal activation values smaller, by |
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3. scaling down weights and biases within the network |
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There are slight discrepancies between the output of SDXL-VAE-FP16-Fix and SDXL-VAE, but the decoded images should be [close enough for most purposes](https://huggingface.co/madebyollin/sdxl-vae-fp16-fix/discussions/7#64c5c0f8e2e5c94bd04eaa80). |
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--- |
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\* `sdxl-vae-fp16-fix` is specifically based on [SDXL-VAE (0.9)](https://huggingface.co/stabilityai/sdxl-vae/discussions/6#64acea3f7ac35b7de0554490), but it works with SDXL 1.0 too |