There are some codecs for which you need to buy a license, and put a key in /boot/config.txt. H.264 is included in the price of the RPi3, but not MPEG-2 (DVDs) or VC-1 (WMV), so even if you had MMAL or OpenMAX access, you'd need a license to h/w decode either of those two (viz, MPEG-2 or VC-1) forma...