for f in *.mkv; do ffmpeg -i "$f" -c:v libx264 -crf 22 -c:a aac "$f%.mkv.mp4" done

ffmpeg -i "Young.Sheldon.S07E04.mkv" \ -ss 00:10:00 -to 00:12:30 \ -c copy "sheldon_clip.mkv"

2 00:00:04,500 --> 00:00:07,000 I've been accepted into Caltech.

ffmpeg -i "Young.Sheldon.S07E04.mkv" \ -c:v libx264 -crf 23 -preset medium \ -c:a aac -b:a 128k \ "Young.Sheldon.S07E04_compressed.mp4"