Garbled MPEG4 video with VDPAU on nouveau

Important Information

Provide following Information:

• mpv version: master (0.33.0-58-gd5ab5482a9)
• Linux Distribution and Version: Debian bullseye/sid (i.e. testing)
• Source of the mpv binary: Compiled from master.
• If known which version of mpv introduced the problem: Not known
• Window Manager and version: sway v1.5
• GPU driver and version: nouveau (kernel 5.10.2, Mesa 20.3.2, libdrm-nouveau2 2.4.103)
• GPU: NVIDIA GF108M [NVS 5400M]

Reproduction steps

VDPAU_DRIVER=nouveau mpv --no-config --vo=vdpau --hwdec=vdpau --hwdec-codecs=all https://archive.org/download/BigBuckBunny_328/BigBuckBunny.avi

Expected behavior

Watchable video.

Actual behavior

Log file

mpvlog.txt

Sample files

• https://archive.org/download/ElephantsDream/ed_1024.avi
• https://archive.org/download/BigBuckBunny_328/BigBuckBunny.avi

Additional information

Initially I thought this was an issue with nouveau and opened mesa/mesa#3924. However, it turns out that MPlayer is able to play the video correctly using VDPAU:

VDPAU_DRIVER=nouveau mplayer -vo vdpau -vc ffodivxvdpau https://archive.org/download/BigBuckBunny_328/BigBuckBunny.avi

Which suggests this is an issue or incompatibility with mpv, so I'm reporting it here.

Thanks,
Kevin

Start by reproducing the provided mpv command with VDPAU on nouveau and inspect mpvlog.txt, comparing the result with the working MPlayer command. Verify the behavior with the listed Big Buck Bunny and Elephants Dream samples; done means both videos are watchable through mpv's VDPAU path.