I'm having a few difficulties with some ogm/mkv files -- that I'm NOT having with Windows Media Player.
Specifically, regardless of my selections, the subtitles which are included in files are not displayed. MPC does not trigger or filter through directshow subs, though WMP10 does. Also, in many files with multiple vorbis streams, MPC does not allow me to choose the stream, and instead plays them all concurrently (though, again, WMP10 does not do this). When this happens, the Haali splitter is not activated (though it is in WMP10, also). The audio stream problem is independent of the Dshow filter used. Normally, my MPC uses AC3Filter and WMP uses FFDshow, but switching on either does not rectify (or duplicate) the problem. The video works fine in either case.
I would be happy to give more details if needed. My computer is up-to-date in drivers, software, and hardware.