OSC font varies randomly(?) if filename contains a character not in osd-font

mpv Information

mpv v0.39.0 Copyright © 2000-2024 mpv/MPlayer/mplayer2 projects
 built on Nov 27 2024 18:31:26
libplacebo version: v7.349.0
FFmpeg version: n7.1
FFmpeg library versions:
   libavcodec      61.19.100
   libavdevice     61.3.100
   libavfilter     10.4.100
   libavformat     61.7.100
   libavutil       59.39.100
   libswresample   5.3.100
   libswscale      8.3.100

Other Information

.

Reproduction Steps

Run mpv via e.g. mpv --no-config --include=mpv.conf --input-conf=input.conf -- あ.mkv. Repeatedly cycle the OSC, and the OSD font will change from what is set in mpv.conf (Liberation Mono, which probably contains only ASCII characters) to a fallback font (in my case Noto Sans CJK). If I rename あ.mkv to a.mkv, the problem does not seem to occur.

Example video of the bug where I repeatedly cycle the OSC, notice the OSD font changing:

https://github.com/user-attachments/assets/c47f480d-0d1d-4ffb-b25a-bfb7ebb2ea7a

Expected Behavior

The OSD font should never change from what is set in mpv.conf.

Actual Behavior

The OSD font varies.

Log File

mpv.log

Sample Files

mpv_conf.txt

input_conf.txt

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

• I tested with the latest mpv version to validate that the issue is not already fixed.
• I provided all required information including system and mpv version.
• 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.
• I produced the log file while the behaviors described in "Actual Behavior" were actively observed.
• I attached the full, untruncated log file.
• I attached the backtrace in the case of a crash.

Start by reproducing the issue with the supplied mpv.conf and input.conf, using a filename containing あ, and inspect mpv.log while repeatedly cycling the OSC. Compare the configured Liberation Mono font with the fallback behavior; done means the OSD font remains stable regardless of the media filename.