Domestic Common bt stations, mostly RMVB, RMVB small size and good quality is my favorite format, but not being seen there with RMVB video copyright protection information. Most foreign websites is used XviD encoded AVI (http://www.mininova.org/), a slight increase in the quality of their size is generally under the RMVB twice (a film 700 ~ 1000MB), and recently the electric donkey already appeared with a copyright-protected videos (need to use a special player, to pay to watch), but have been found in other bt stations. As to the use WMV format videos on the few, and mostly some video clips, copyright protection in the WMV video on the more "spread", especially when a lot of copyright protection is asking you to open or even several dozens of rogue Web site (compared to people vomiting) in order to watch video (Microsoft would not have thought of a beginning of such use of DRM), so under normal circumstances is not under the WMV format video online is more a wise choice.