Right. I have never understood why each different media player supports a different subset of stuff. As a naive geek who knows very little about multimedia it seems to me that once I have libx264 and libogg and libquicktime installed then every media player I have should be able to support those formats. But clearly that's not the case and there must be something else going on. Do I understand from what you say that VLC, mplayer totem etc don't actually use the same codec libraries but each implement their own? But if that's true what _does_ use these libraries (I see them on my system).
There seem to be complex interactions between players, lower-level media frameworks and individual codec libraries that I clearly don't understand. Can someone explain (or point to docs that explain)?