VC-1 videos played with nvdec or vdpau show green screen

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

- Linux version: Arch Linux
- Kernel Version: Linux desktop 6.6.68-1-lts #1 SMP PREEMPT_DYNAMIC Fri, 27 Dec 2024 15:16:06 +0000 x86_64 GNU/Linux
- GPU Model: 3070
- Mesa/GPU Driver Version: OpenGL version string: 4.6.0 NVIDIA 565.77
- Window Manager and Version: kwin_wayland 6.2.5
- Source of mpv: official Arch Linux mpv package
- Latest known working version:
- Issue started after the following happened:

Reproduction Steps

As reported in issue #4820 (closed without being fixed), playing VC-1 videos with hwdec=nvdec or vdpau causes a green screen to be shown only.
vo=gpu with hwdec=auto-safe and hwdec=auto also results in the same issue, but not specifying hwdec at all fixes the green screen issue.

Expected Behavior

Video to be shown

Actual Behavior

Green screen is shown

Log File

mpv-log.txt

Sample Files

No response

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 green screen with VC-1 playback under hwdec=nvdec and vdpau, then compare it with playback when hwdec is unspecified. Read the attached mpv-log.txt and the discussion of issue #4820 to trace the hardware-decoding path. Done means VC-1 video displays correctly with the affected hardware-decoding modes.