Can't seem to play some .ogm & .mkv or any files like those on Media Player Classic or VLC. Sometimes I get audio only, sometimes I get video only, some of them plays fine. I also have DivX 7 Xvid & won't play on those aswell.
MPC has built in ogm and mkv splitters, but basically no decoders (can handle mp3, aac, vorbis, dts and mpeg-1/2). VLC has built in decoders for various formats as well as splitters for mkv and ogm. In the case of VLC, if it can't play it then that is about it since it doesn't use external decoders. In the case of MPC you would need to install a dshow decoder for whatever stream you can't decode.
The problem I have is with MPC, where the player does, or cannot, play embedded and non-embedded subtitles.