This repo contains user shaders for prescaling in mpv.

For the scripts generating these user shaders, check the source branch. For comparison/performance of prescalers, check the Comparison and Performance wiki.

Shaders in gather/ directory and compute/ directory are generally faster but requires recent version of OpenGL. Use these shaders only if they actually work (i.e. no blue screen and no noticeable distortion).

Shaders in vulkan/ directory are using rgba16hf LUT, and required by gpu-api=vulkan and gpu-api=d3d11. Use these shaders if you encountered the following error:

[vo/gpu] Unrecognized/unavailable FORMAT name: 'rgba16f'!

Usage

You only need to download shaders you actually use. The following part of this section assumes that they are in shaders directory in the mpv configure folder (usually ~/.config/mpv/shaders on Linux).

Use glsl-shaders="prescaler.hook" option to load those shaders. (This will override other user shaders, use glsl-shaders-append in that case)

glsl-shaders="~~/shaders/ravu-r3.hook"

All shaders are for one pass only. If you want to have 4x upscaling, trigger the same shader twice. All the shaders here are generated with max-downscaling-ratio set to 1.414213. They will be disabled if upscaling is not necessary.

glsl-shaders-append="~~/shaders/ravu-r3.hook"
glsl-shaders-append="~~/shaders/ravu-r3.hook"

Suffix in the filename indicates the planes that the prescaler will upscale.

• Without any suffix: Works on YUV video, upscale only luma plane. (like the old prescale-luma=... option in mpv).
• -chroma*: Works on YUV video, upscale only chroma plane.
• -yuv: Works on YUV video, upscale all planes after they are merged.
• -rgb: Works on all video, upscale all planes after they are merged and converted to RGB.

For nnedi3 prescaler, neurons and window settings are indicated in the filename.

For ravu prescaler, radius setting is indicated in the filename.

ravu-*-chroma-{center,left} are implementations of ravu, that will use downscaled luma plane to calculate gradient and guide chroma planes upscaling. Due to current limitation of mpv's hook system, there are some caveats for using those shaders:

1. It works with YUV 4:2:0 format only, and will disable itself if size is not matched exactly, this includes odd width/height of luma plane.
2. It will NOT work with luma prescalers (for example ravu-r3.hook). You should use rgb and yuv shaders for further upscaling.
3. You need to explicitly state the chroma location, by choosing one of those chroma-left and chroma-center shaders. If you don't know how to/don't bother to check chroma location of video, or don't watch ancient videos, just choose chroma-left. If you are using auto-profiles.lua, you can use cond:get('video-params/chroma-location','unknown')=='mpeg2/4/h264' for chroma-left shader and cond:get('video-params/chroma-location','unknown')=='mpeg1/jpeg' for chroma-center shader.
4. cscale will still be used to correct minor offset. An EWA scaler like haasnsoft is recommended for the cscale setting.

Known Issue

1. ravu-lite is incompatible with --fbo-format=rgb10_a2 (default for some OpenGL ES implementation). Use rgba16f or rgba16 if available.
2. ravu-r4-{rgb,yuv} causes distortion with lower-end intel card.

License

Shaders in this repo are licensed under terms of LGPLv3. Check the header of each file for details.