This is a simple implementation of joint bilateral chroma upsampling. It uses the luma plane as a guide to achieve sharper edges without introducing any ringing.
The repo contains 2 distinct shaders:
JointBilateral.glsl: "Classic version" of what is known as "joint-bilateral". This uses gaussian functions to weight spatial and intensity distances. To understand how this works feel free to read "this paper".FastBilateral.glsl: This is a simplified version of the shader.
Add something like this to your mpv config:
vo=gpu-next
glsl-shader="path/to/shader/JointBilateral.glsl"
gpu-next is required due to the usage of tunable parameters.
You can set the following parameters:
distance_coeff: Controls the shape of the spatial Gaussian filter. Higher values decrease the contribution of pixels more distant to the centre.intensity_coeff: Controls the shape of the Gaussian filter used for intensity-distance weighting. Higher values decrease the contribution of pixels with distant luminosities.
On vo=gpu-next, you can set these settings with --glsl-shader-opts=param1=value1,param2=value2,....
The shaders have very aggressive defaults, which may not work well on all content. If you find the output too harsh, try reducing the coefficients.
