Other helpful stuff around video

Not everything needs to get explained in big documents. Here are smaller single challenges.

Set language in matroska (mkv) files

If the mkv file is ready, but missing some metadata, language can be set with this command:

mkvpropedit <file> --edit track:a1 --set language=eng

The interesting part here is the track information. (a) for audio, (v) for video and (s) for subtitle. While the number after starts with 1.