--image-subs-hdr-peak doesn't work on hdr display

[Jimmy-Z]

mpv Information

mpv v0.41.0-687-gdb7385799 Copyright © 2000-2026 mpv/MPlayer/mplayer2 projects
 built on May 22 2026 00:26:43
libplacebo version: v7.364.0 (v7.360.0-55-g464d6ea-dirty)
FFmpeg version: N-124570-gb67570b76
FFmpeg library versions:
   libavcodec      62.34.100
   libavdevice     62.4.100
   libavfilter     11.17.100
   libavformat     62.18.100
   libavutil       60.31.100
   libswresample   6.4.100
   libswscale      9.7.100

and

mpv v0.41.0 Copyright © 2000-2025 mpv/MPlayer/mplayer2 projects
 built on Dec 25 2025 15:27:46
libplacebo version: v7.358.0 (v7.351.0-106-gbc90ef9-dirty)
FFmpeg version: N-122267-gabb152413
FFmpeg library versions:
   libavcodec      62.23.102
   libavdevice     62.2.100
   libavfilter     11.10.101
   libavformat     62.8.101
   libavutil       60.20.100
   libswresample   6.2.100
   libswscale      9.3.100

Other Information

- Windows version: Microsoft Windows [Version 10.0.26200.8457]
- GPU model, driver and version: nvidia rtx3090, 596.36
- Source of mpv: scoop
- Latest known working version: I don't know any
- Issue started after the following happened:

Reproduction Steps

mpv --no-config --gpu-debug --vo=gpu-next --log-file=mpv.log --image-subs-hdr-peak=10 --blend-subtitles <file>

Expected Behavior

subtitles should be dimmer.

Actual Behavior

subtitles still shows in bright white, seemingly no change from not setting it.

I tried with and without --blend-subtitles, no difference.

I've tried on the 0.41 stable and latest mpv-git on scoop, same behavior.

Log File

mpv.log

Sample Files

I've tested multiple hdr files with pgs subtitles, they behave the same, so I guess there's no need to upload a particular file, correct me if I'm wrong.

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

• I tested and confirmed that the issue exists with the latest release version or newer.
• 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.

[kasper93]

--image-subs-hdr-peak=10

This is luminance value of the subtitle bitmap itself, not the target luminance you want to see. So if you want to tonemapper to make subtitles "less bright", set their peak to value higher then target peak.

[Jimmy-Z]

You're right, apparently I didn't understand what it is supposed to do. setting it to 10000 makes it a little dimmer, but not as dim as I wanted it to be, any suggestions?

I've been looking for a way to dim image subtitles since I've got a hdr display, #13179, so far my solution was to find a text subtitle somewhere and use sub-color.

[danbezerra]

I second Jimmy-Z request. Even at 10000 they are not dim enough. I need the subtitles to be more dim so they don't interfere with my projector dynamic black level algorithm.