$ find . -type f -name "*.mkv" -exec bash -c 'FILE="$1"; ffmpeg -i "${FILE}" -vn -c:a libmp3lame -y "${FILE%.mkv}.mp3";' _ '{}' \; Convert webm to mp3 $ find . -type ...
if you need stream to chromecast mkv videos or your tv doesn't support mkv, this is a good option, it keeps video codec but convert audio codec to mp3 and merge in a mp4 package. My Intel i5 - 9400f ...