I have been suggested two different ffmpeg commands for converting an mkv file to an mp4 while just re-encoding the audio (to aac) and leaving the video portion as is. Here are the two commands:
ffmpeg -loglevel panic -i source.mkv -vcodec copy -c:a aac -strict -2 -ab 160k -ac 2 -ar 48k target.mp4
ffmpeg -i source.mkv -c:v copy -c:a aac -b:a 384k -strict -2 target.mp4
Could someone please explain the difference? OK, more precisely, I am curious about the things the first command does in addition to what the second one does. Is it necessary to use a -log level panic argument? What happens if it's omitted?
I understand the second command thoroughly. But the additional arguments in the first one are confusing me and I didn't find much help in the ffmpeg documentation either. In particular, I want to understand what the -ac, -ar, and -ab arguments accomplish and why are they not used in the second command.