There are nearly 300 video formats around us, but the commonly-used video formats are only about 30 like avi, mov, mp4, vob, swf, flv, 3gp, 3g2, mkv, rm, xvid, mpg, mod, m4v, mts, rmvb, wmv, asx, etc.. Various portable players and windows media players support limited video formats. So it always...