For anyone having trouble playing 720p mkvs on their pcs. Here’s a guide made by Saigoyume fansubs that should work for you if you’re running Windows XP/Vista or 7. Mac or Linux users dont need this as they can just install mplayer (http://mplayerosx.sttz.ch/)
This guide has been compiled and tested to work with only modern Microsoft Windows Operating Systems (XP,Vista & Seven) and should work on a large range of machine configurations including low spec machines such as netbooks. The lowest specification machine that has been confirmed to play back all our files correctly is an Intel Atom single core 1.6 GHz CPU with 512mb Ram, but you may need to follow the optional steps provided to run perfectly.