Output is getting horizontally flipped

[WilsonNet]

mpv version and platform

mpv 0.34 Windows 10

mpv 0.34.0-116-gd92cf77be5 Copyright © 2000-2021 mpv/MPlayer/mplayer2 projects
 built on Sun Dec 26 19:50:16 +08 2021
FFmpeg library versions:
   libavutil       57.13.100
   libavcodec      59.15.101
   libavformat     59.10.100
   libswscale      6.1.102
   libavfilter     8.21.100
   libswresample   4.0.100
FFmpeg version: git-2021-12-25-0c8741f8

Description

Tried to export a clip with the default settings. Pressed W, 1 for the first part, 2 for the last part, e to encode. It worked, but the output was horizontally flipped.

[ekisu]

Need logs, and a sample file, if possible. Does this happen with every file?

[WilsonNet]

Need logs, and a sample file, if possible. Does this happen with every file?

Yes it happens with every file, here is a log

mpv.log log.txt

This was reproducible with Sintel using this command:

mpv.exe --log-file=c:\mpv.log https://www.youtube.com/watch?v=eRsGyueVLvQ

And repeating the steps described in the issue

Here is the output: watchv=eRsGyueVLvQ-[00.12.750-00.32.459]-audio.zip

I imagine that this line is useful:

[  31.481][v][webm] Command line: mpv https://www.youtube.com/watch?v=eRsGyueVLvQ --start=0:00:12.750 --end=0:00:32.459 --loop-file=no --no-pause --ovc=libvpx --oac=libvorbis --aid=1 --vid=1 --sid=no --sub-ass-override=yes --sub-ass-vsfilter-aspect-compat=yes --sub-auto=fuzzy --sub-delay=0.000000 --video-rotate=0 --deinterlace=no --vf-add=lavfi-colormatrix=bt709:bt601 --vf-add=lavfi-eq=contrast=0.99:saturation=1:brightness=-0.005 --ovcopts-add=threads=4 --ovcopts-add=auto-alt-ref=1 --ovcopts-add=lag-in-frames=25 --ovcopts-add=quality=good --ovcopts-add=cpu-used=0 --ovcopts-add=b=1014k --ovcopts-add=crf=10 --o=C:\Users\wilso/watchv=eRsGyueVLvQ-[00.12.750-00.32.459]-audio.webm 
[  31.481][d][cplayer] Run command: subprocess, flags=64, args=[args="mpv,https://www.youtube.com/watch?v=eRsGyueVLvQ,--start=0:00:12.750,--end=0:00:32.459,--loop-file=no,--no-pause,--ovc=libvpx,--oac=libvorbis,--aid=1,--vid=1,--sid=no,--sub-ass-override=yes,--sub-ass-vsfilter-aspect-compat=yes,--sub-auto=fuzzy,--sub-delay=0.000000,--video-rotate=0,--deinterlace=no,--vf-add=lavfi-colormatrix=bt709:bt601,--vf-add=lavfi-eq=contrast=0.99:saturation=1:brightness=-0.005,--ovcopts-add=threads=4,--ovcopts-add=auto-alt-ref=1,--ovcopts-add=lag-in-frames=25,--ovcopts-add=quality=good,--ovcopts-add=cpu-used=0,--ovcopts-add=b=1014k,--ovcopts-add=crf=10,--o=C:\\Users\\wilso/watchv=eRsGyueVLvQ-[00.12.750-00.32.459]-audio.webm", playback_only="no", capture_size="67108864", capture_stdout="yes", capture_stderr="no", detach="no", env="", stdin_data="", passthrough_stdin="no"]