| --- |
| license: mit |
| tags: |
| - stable-diffusion |
| - stable-diffusion-diffusers |
| inference: false |
| --- |
| # SDXL-VAE-FP16-Fix |
|
|
| SDXL-VAE-FP16-Fix is the [SDXL VAE](https://huggingface.co/stabilityai/sdxl-vae)*, but modified to run in fp16 precision without generating NaNs. |
| |
| | VAE | Decoding in `float32` / `bfloat16` precision | Decoding in `float16` precision | |
| | --------------------- | -------------------------------------------- | ------------------------------- | |
| | SDXL-VAE | ✅  | ⚠️  | |
| | SDXL-VAE-FP16-Fix | ✅  | ✅  | |
| |
| ## 🧨 Diffusers Usage |
| |
| Just load this checkpoint via `AutoencoderKL`: |
| |
| ```py |
| import torch |
| from diffusers import DiffusionPipeline, AutoencoderKL |
| |
| vae = AutoencoderKL.from_pretrained("madebyollin/sdxl-vae-fp16-fix", torch_dtype=torch.float16) |
| pipe = DiffusionPipeline.from_pretrained("stabilityai/stable-diffusion-xl-base-1.0", vae=vae, torch_dtype=torch.float16, variant="fp16", use_safetensors=True) |
| pipe.to("cuda") |
| |
| refiner = DiffusionPipeline.from_pretrained("stabilityai/stable-diffusion-xl-refiner-1.0", vae=vae, torch_dtype=torch.float16, use_safetensors=True, variant="fp16") |
| refiner.to("cuda") |
| |
| n_steps = 40 |
| high_noise_frac = 0.7 |
| |
| prompt = "A majestic lion jumping from a big stone at night" |
| |
| image = pipe(prompt=prompt, num_inference_steps=n_steps, denoising_end=high_noise_frac, output_type="latent").images |
| image = refiner(prompt=prompt, num_inference_steps=n_steps, denoising_start=high_noise_frac, image=image).images[0] |
| image |
| ``` |
| |
|  |
| |
| ## Automatic1111 Usage |
| |
| 1. Download the fixed [sdxl.vae.safetensors](https://huggingface.co/madebyollin/sdxl-vae-fp16-fix/resolve/main/sdxl.vae.safetensors?download=true) file |
| 2. Move this `sdxl.vae.safetensors` file into the webui folder under `stable-diffusion-webui/models/VAE` |
| 3. In your webui settings, select the fixed VAE you just added |
| 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 |
| |
| (Disclaimer - I haven't tested this, just aggregating various instructions I've seen elsewhere :P PRs to improve these instructions are welcomed!) |
| |
| ## Details |
| |
| SDXL-VAE generates NaNs in fp16 because the internal activation values are too big: |
|  |
| |
| SDXL-VAE-FP16-Fix was created by finetuning the SDXL-VAE to: |
| 1. keep the final output the same, but |
| 2. make the internal activation values smaller, by |
| 3. scaling down weights and biases within the network |
| |
| 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). |
| |
| --- |
| |
| \* `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 |
