I didn't get to dig much further into it, but for those of you who suggested ideas:
- not always the same frame. The first three failures were within seconds of each other, possibly the same frame. I tried again the next night and it got through that part of the video, but crashed a minute later - I was able to play the video using a different app (Ubuntu's built-in Videos app from an old Ubuntu release, maybe 20.04)
Nah, it's not a bug in VLC. It's a bug in whatever janky patches Ubuntu applies to the entire ecosystem, including VLC. Somehow or another they screw things up.
I had the same thought as you at first, and was so unimpressed with buggy ass VLC on Linux Mint I was going to revert to the 2.x version, when I first built my distro. It wouldn't compile however, so I was forced to go to the latest 3.x. It turned out to work fine. The problems I had on Ubuntu just vanished and it was rock solid.
Now VLC did turn out to have some actual problems in the end that shifted me to MPV permanently. But nothing like crashing the whole system. That's all Ubuntu right there.
It's Ubuntu. Trust me.
This is why I built my own distro. It took a while for me to re-learn which are actually good or bad apps. I had spent so long using the garbage Ubuntu versions only to find that the same apps, when compiled from scratch on my vanilla distro, work just fine and are way more solid and reliable.
VLC was one of those. But really, you should be using MPV instead as it's a far superior video player, or Audacious (in classic WinAmp/XMMS mode) for playing audio. VLC just sucks.
Hope this helps.