Both gpu-next and hwdec=vulkan causes unstable refresh rate on a monitor in adaptive-sync mode.

mpv Information

mpv v0.38.0-711-g67e087dcae Copyright © 2000-2024 mpv/MPlayer/mplayer2 projects
libplacebo version: v7.349.0 (v7.349.0-5-g82bf46ae)
FFmpeg version: N-116730-g7e5410eadb
FFmpeg library versions:
   libavcodec      61.11.100
   libavdevice     61.2.100
   libavfilter     10.2.102
   libavformat     61.5.101
   libavutil       59.34.100
   libswresample   5.2.100
   libswscale      8.2.100

Other Information

- Linux version: Arch Linux
- Kernel Version: 6.10.5-zen1-1-zen
- GPU Model: [AMD/ATI] Navi 22 [Radeon RX 6700/6700 XT/6750 XT / 6800M/6850M XT] [1002:73df] (rev c0)
- Mesa/GPU Driver Version:Mesa 24.1.6-arch1.1
- Window Manager and Version: KWin 6.1.4-1
- Source mpv: AUR mpv-build-git
- Introduced in version:

Reproduction Steps

It causes unstable refresh rate in adaptive sync mode. There are 5 situations that I have tested.

1. vo=gpu + no hwdec + target-colorspace-hint=yes = stable.
2. vo=gpu-next + no hwdec + target-colorspace-hint=yes = unstable.
3. vo=gpu-next + hwdec=vaapi + target-colorspace-hint=yes = stable.
4. vo=gpu-next + hwdec=vulkan + gpu-context=waylandvk + target-colorspace-hint=yes = unstable
5. vo=gpu-next + no hwdec + gpu-context=waylandvk + target-colorspace-hint=yes = stable

Expected Behavior

No matter gpu-next or hwdec=vulkan, the refresh rate should be as stable as default.

Actual Behavior

They causes issue in adaptive sync mode.

Log File

1. vo=gpu.log
2. vo=gpu-next.log
3. vo=gpu-next_hwdec=vaapi.log
4. vo=gpu-next_hwdec=vulkan.log
5. vo=gpu-next_no-hwdec_waylandvk.log

Sample Files

Any videos, but you can search P81_GlassBlowing2_3840x2160@59.94fps_15200kbps_fmp4

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 five listed configurations on the reported Linux, AMD, Mesa, and KWin setup, then compare the attached logs for vo=gpu, gpu-next, VAAPI, Vulkan, and Wayland Vulkan. Done means adaptive-sync refresh remains stable with gpu-next and hwdec=vulkan while preserving the stable cases.