There appears to be an "-angle" option but as best I can tell that only
applies to BluRay playlists.
If ffmpeg can't extract angles, can anyone suggest a currently
maintained tool that does?
The closest I've found is tccat from the transcode package which does
exactly this, but transcode is no longer maintained and doesn't build in
recent Linux distribution releases. Getting it to compile or run on a
modern distro would require some patching for updated libraries. When
running under an old version, it's as simple as "tccat -i file.vob -T
1,-1,1 > file_angle_1.vob" to extract angle 1 from file.vob.
If this isn't supported in ffmpeg, might it be possible to implement
based on the transcode/tccat source code?