Upscaling
There are many available upscaling (interpolation) techniques in mpv, of which this article aims to provide some comparison screenshots.
The source image for all of these is imagemagic's built-in “rose” test pattern, which can be obtained like this:
convert rose: rose.png
Each of the screenshots was obtained like this:
mpv --no-config --pause rose.png --geometry=560x368 -vo opengl-hq:dither-depth=8:scale=SCALER
The resulting output was captured using imagemagick:
import -depth 8 SCALER.png
scale=bilinear
scale=lanczos
scale=mitchell
scale=spline16
scale=spline36
scale=spline64
scale=ewa_lanczos
scale=ewa_lanczos:scale-radius=3.2383154841662362
scale=ewa_lanczossharp
scale=robidoux
scale=robidouxsharp
scale=ewa_ginseng
scale=ewa_hanning
scale=bicubic
scale=gaussian
scale=catmull_rom
scale=nearest
scale=oversample
scale=sharpen3
scale=sharpen5
scale=sinc:scale-radius=16
Some of the upscalers support antiringing, which is a naive technique that attempts to reduce ringing in some cases, but can also introduce artifacts. The antiringing algorithm in mpv is not very sophisticated.
scale=spline36:scale-antiring=1
scale=lanczos:scale-antiring=1
scale=ewa_lanczossharp:scale-antiring=1
