mpv-player / mpv-player/mpv

--cscale-window has no effect on implicit chroma scaling

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os:win
Dominant language
C
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Description

Important Information

Provide following Information:

  • mpv version: v0.37.0-382-g74b4c3c5
  • Windows Version: Windows 11 23H2
  • Source of the mpv binary: shinchiro
  • If known which version of mpv introduced the problem: n/a
  • GPU model, driver and version: AMD RX 6900XT, 24.1.1
Reproduction steps
--no-config --cscale-window=blackman

then compare to:

--no-config --cscale=lanczos --cscale-window=blackman
Expected behavior

There shouldn't be a difference since --cscale=lanczos is implied by default.

Actual behavior

--cscale-window=blackman is not applied to the scaler, so you just get sinc-sinc instead of Blackman windowed-sinc.

See: https://slow.pics/c/8WBMF3Y1 (will need to pixel-peep)

Log file

mpv.log

Sample files

Can be provided.

Contributor guide

No contributing guide indexed for this repository

First steps

  1. Read the whole issue, then the project's contributing guide.
  2. Comment on the issue to say you are picking it up — it saves two people doing the same work.
  3. Fork the repository and make your change on a branch.
  4. Open a pull request that references the issue number.

Research direction

Reproduce the difference between --no-config --cscale-window=blackman and the same command with --cscale=lanczos, using the reported mpv version and sample comparison. Start from the command-line handling for --cscale and --cscale-window, then trace implicit scaler selection. Done means the window setting produces the same result whether or not --cscale=lanczos is explicitly supplied.

Written by the indexing model from the issue text.

Assessment

Tech stack
c
Domain
cli, computer-graphics
Issue type
Bug
Difficulty
3/5
Estimated time
1-2 days
Activity status
Stale
Clarity
Mostly clear
Newbie friendliness
45/100

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