I started searching cause I know I've read this here but thought I would just go ahead and ask the pros. I usuanlly bkup main movie only w/out any subtitles and keep english audios except for directors comments or something like that. So usually I'm keeping AC-3/5.1 (usually selected as the default) and AC-3/2; pretty sure the first audio is surround sound and the second is plain stereo.
Recently I've run into a movie that has 2 AC-3/2 audios w/no comments for me to decide which to keep. And I came across another movie that has AC-3/1 (not 2), is that mono?
I guess my question is when bking up just the main movie what audio file(s) should I keep and why? Thanks in advance for and replies!