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Artoriuz / glsl-chroma-from-luma-prediction

CfL as a GLSL shader
MIT License
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Discolouration on subtitles #4

Closed Jules-A closed 1 year ago

Jules-A commented 1 year ago

Tested after the changes from master, it doesn't discolour any less but it only seems to be yellow now which is less noticeable: 12: mpv-shot0001

Oddly enough it is slightly less noticeable in mixed and even less so with 4 although you can briefly see blues.

Artoriuz commented 1 year ago

I don't remember the exact value from when I tested this yesterday but I think setting division_limit to 1e-3 fixes this (albeit with quality losses elsewhere).

Jules-A commented 1 year ago

I don't remember the exact value from when I tested this yesterday but I think setting division_limit to 1e-3 fixes this (albeit with quality losses elsewhere).

I tested 1e-3 and 1e-2 and both exhibit the issue still.

Artoriuz commented 1 year ago

Can you retest to see if this is still happening? Many changes were made since last week.

Jules-A commented 1 year ago

Can you retest to see if this is still happening? Many changes were made since last week.

I accidentally deleted the series after I finished it out of habit and don't have a CR sub right now :/ If it helps I tried reproducing on a few other subs with the newer version and didn't manage to spot the issue. Maybe I will try with an image I posted here lol, if that even works.

EDIT: I could only find the image of an already upscaled screenshot and couldn't see it occur on that but not apples to apples...

Artoriuz commented 1 year ago

Alright, thanks. I can't reproduce it on anything I have currently downloaded either so I guess we can close this too.

Jules-A commented 1 year ago

This change: https://github.com/Artoriuz/glsl-chroma-from-luma-prediction/commit/8176605fa3983f3fa7e46566a50f14aba8a6bf90 introduced a decent bit of ringing though. EDIT: Nvm it's only ever so slightly worse, it might have been a previous change or maybe mix always had that much ringing as I was testing 12tap before.

Artoriuz commented 1 year ago

The new spatial filter (polar approximation of lanczos) is sharper than the old one, and I've also loosened the AR a little bit.

I should probably make AR configurable though (and reevaluate the default strength again since things changed...)