Using mencoder to cut out pieces of video

Following command can be used to cut video starting at 16 seconds - to the end:

=> mencoder -ss 16 -oac copy -ovc copy some_video.avi -o new.avi

this one is to cut starting at 16 seconds to 56 seconds only:

=> mencoder -ss 16 -endpos 56 -oac copy -ovc copy some_video.avi -o new.avi

this is to concatenate a bunch of files into a new one:

=> cat *avi | mencoder -oac copy -ovc copy -o new.avi -