I can’t find my post-it notes, so this is a quick reminder for myself (thanks to MisterHowTo.com for the suggestions):

Trim/split video files with mencoder:

mencoder -ss hh:mm:ss -oac copy -ovc copy in.avi -o out.avi mencoder -endpos hh:mm:ss -ovc copy -oac copy in.avi -o out.avi

Remove an audio stream (the first stream has ID 1):

mencoder -aid 1 -ovc copy -oac copy in.avi -o out.avi