choose audio encoding settings

[SArpnt]

with ffmpeg -i i can see the audio format used in recordings is vorbis, which i assume is just the default that ffmpeg uses. i'd prefer it if i could record with libopus at a custom bitrate, or sometimes flac.

[russelltg]

I recently added --audio-codec (set codec, let ffmpeg decide encoder) and --ffmpeg-audio-encoder (hardcode which encoder to use) flags in main. Agree that a --audio-bitrate flag would be a good addition still.