Since now there is a flag for media foundation video playback, so I suppose the supported video formats must be increased from just mp4 to several more like mkv, etc. which at present it doesn't support. It would be good if more formats are supported as many people like me use browser for everything from media playback to document editing. So it would be nice if the media formats list is extended. You don't have to worry for the codec as the Windows Decryption module would decrypt it.