ASS subs are not rendered correctly in gpu-next

[Kapppa]

mpv Information

mpv v0.38.0-525-g265056fa Copyright © 2000-2024 mpv/MPlayer/mplayer2 projects
 built on Jun 23 2024 00:07:06
libplacebo version: v7.349.0 (v7.349.0-rc1-3-g1fd3c7b-dirty)
FFmpeg version: N-115975-g0c0e7ec81
FFmpeg library versions:
   libavcodec      61.8.100
   libavdevice     61.2.100
   libavfilter     10.2.102
   libavformat     61.3.104
   libavutil       59.25.100
   libswresample   5.2.100
   libswscale      8.2.100

Other Information

• Windows version: Microsoft Windows [Version 10.0.19045.4291]
• GPU model, driver and version: RTX 3080, 551.86
• Source of mpv: shinchiro latest windows
• Introduced in version: Unknown

Reproduction Steps

Load provided video with gpu-next. --no-config --vo=gpu-next

Expected Behavior

Subs are displayed like in normal rending.

Actual Behavior

Subs are displayed incorrectly, looks like some frames are dropped or the layers are displayed in the wrong order. Instead of being white with a purple border they are just purple.

Log File

Expected Actual

Sample Files

issue.zip

I carefully read all instruction and confirm that I did the following:

• [X] I tested with the latest mpv version to validate that the issue is not already fixed.
• [X] I provided all required information including system and mpv version.
• [X] I produced the log file with the exact same set of files, parameters, and conditions used in "Reproduction Steps", with the addition of --log-file=output.txt.
• [X] I produced the log file while the behaviors described in "Actual Behavior" were actively observed.
• [X] I attached the full, untruncated log file.
• [X] I attached the backtrace in the case of a crash.