Now that we have a dependency on Ogg/Theora/Vorbis libs anyway, we could just as well support recording videos to Ogg/Theora/Vorbis format anyway. And because the codec is much more generic, we could even support recording with effects (scanlines, etc.) and OSD (optionally). This is very useful to make instruction videos for openMSX usage and post them on e.g. YouTube.
I created ticket 2943308 to request recoding of post processing effects. This is not directly related to Ogg/Theora/Vorbis support, so it is better to have it in a separate ticket.