I've written a wrapper for ffmpeg that finds out from the input file what languages it has for audio and subtitles, picks the ideal combination according to my preferences, and creates an output file optimal for me and my TV.

E.g. Czech audio + Czech forced subtitles, if any. Or English audio + full Czech subtitles. Or Slovak. Or however I set it up.

Alternatively, transcode it so that my TV will play it (bitrate, size, 5.1 -> stereo sound).

So if it would be useful to anyone, feel free to test it and enjoy

https://github.com/Cuchulain/video-transcoder