mplayer -ss 670 -frames 1 -vo jpeg -nosound movie.avi

mencoder -ss 670 -frames 500 -o output.avi -oac copy -ovc copy src.avi
mencoder -ss 670 -frames 500 -o output.avi -oac copy -ovc divx4 -vop scale -zoom -xy 160 -ofps 15 src.avi