HandBrake

s55 and Rodeo, thank you for your view. (Realizing this is out of normal scope for this forum) Thoughts on the syntax for ffmpeg and mkvmerge? I've been unsuccessful with both... s55, why can't I use HandBrake for this? (I don't know what "muxing" is.) (I understand I might need to specify...

Description of problem or question: I'm trying to loop, via batch file, through all my folders and, where subtitles are present, merge them into existing files. Subtitles could be srt/sub/idx/etc., basically any format. Most are English, but a few are other languages. The video files could be MP4, ...