Encoding occasionally stuck at 0% and never finishes

[Soundtoxin]

mpv version and platform

Guix System GNU/Linux
guix (GNU Guix) 4ee2a660e5f1362d3a72dcdc62ba8ff5612949da

mpv 0.37.0 Copyright © 2000-2023 mpv/MPlayer/mplayer2 projects
libplacebo version: v6.338.1
FFmpeg version: 6.1.1
FFmpeg library versions:
   libavutil       58.29.100
   libavcodec      60.31.102
   libavformat     60.16.100
   libswscale      7.5.100
   libavfilter     9.12.100
   libswresample   4.12.100

Description

Trying to encode a webm from a YouTube video, about a second long. I open the interface with W, set my start and end points, using the second and frames jumps to get it dialed in, listen to preview, it sounds good, then I hit e for encode. I'd say 80% of the time or more I don't have any issues, but occasionally I run into a dud like this and usually I give up because I'm in the middle of watching something, but I decided to explore it more this time.
I have an output directory and max filesize (9200) configure in webm.conf. I don't usually do further tweaking at runtime unless it's a long clip, then I might tell it to make it 720p.

Here is the "file" I'm trying to encode a webm from, I am trying for the range 01.16.009-01.17.044
https://www.youtube.com/watch?v=p4Sn6hEQ6SU

This is such a short clip it should finish basically instantly, but I gave it 5 minutes before closing/killing mpv just in case. No signs of progress in that time. The console showed [webm] Encoding to /home/brad/mpvwebm/watchv=p4Sn6hEQ6SU-[01.16.009-01.17.044]-audio.webm at the bottom until I killed it. I saw Encoding (0%) in the top left the whole time. When pressing q I see a messaged printed cplayer: Exiting... (Quit) in the terminal, but it doesn't actually quit. I still see the process in htop and ps output.
brad 24699 0.4 0.7 815956 128724 pts/12 Sl+ 15:04 0:01 mpv https://www.youtube.com/watch?v=p4Sn6hEQ6SU --start=0:01:16.009 --end=0:01:17.044 --loop-file=no --no-pause --ovc=libvpx --oac=libvorbis --vid=1 --aid=1 --sid=no --video-rotate=0 --ytdl-format=bestvideo[width<=?1920]+bestvideo[height<=?1080]+bestaudio/best --deinterlace=no --sub-ass-override=yes --sub-ass-force-style=Kerning=yes --sub-ass-vsfilter-aspect-compat=yes --sub-auto=fuzzy --sub-pos=100.000000 --sub-delay=0.000000 --sub-speed=1.000000 --sub-scale=1.000000 --sub-font=Source Sans Pro Semibold --sub-font-size=36.000000 --sub-bold=no --sub-italic=no --sub-color=#FFFFFFFF --sub-back-color=#00000000 --sub-border-color=#FF262626 --sub-border-size=3.200000 --sub-shadow-color=#33000000 --sub-shadow-offset=1.000000 --sub-use-margins=yes --sub-margin-x=25 --sub-margin-y=22 --sub-align-x=center --sub-align-y=bottom --sub-spacing=0.500000 --sub-justify=auto --sub-gauss=0.000000 --sub-gray=no --vf-add=lavfi-colormatrix=bt709:bt601 --vf-add=lavfi-eq=contrast=1:saturation=1:brightness=0 --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=71179k --ovcopts-add=crf=10 --o=/home/brad/mpvwebm/watchv=p4Sn6hEQ6SU-[01.16.009-01.17.044]-audio.webm --term-status-msg=Encode time-pos: ${=time-pos}\n
I hit C-c to close mpv from the terminal I launched it from and then it closed for real.

I would also like to note that I had an older version of the script when I first ran into this, but I grabbed a new webm.lua and reattempted and the behavior seems to be the same. I don't recall what my old version was, but it was before the binds to jump to start/end point were added/displayed as that looked new to me after updating. Perhaps there's something strange about this particular file. I last successfully made a webm a little under a week ago (I don't make them that often), so I don't think the functionality is totally broken.

Log file

mpv-log_2024-07-22_15:02:46.txt

I found some other issues and comments that sounded similar like #63 but I'm not sure if the cause is the same.

[Soundtoxin]

Ran into the same problem with another video, stuck at encoding this forever watchv=4eLfu4TAh-k-[11.17.142-11.44.904]-audio.webm with no signs of progress.

[Soundtoxin]

I tried changing output from webm to raw (never tried this option before) and I'm seeing the same behavior. I wish I could cancel the encode and get at the mpv-webm menu again without having to kill and restart mpv.
mpv-log_2024-07-22_18:37:57.txt

[Soundtoxin]

Can't make a webm from this video either. Maybe all YouTube videos are broken now.
https://www.youtube.com/watch?v=L4vVb998Zao