I have a bunch of mkv files that I usually run through Quicktime 7 as a pass-through to turn them into .mp4 files which my PS3 will recognise (and Apple TV). With Mountain Lion, all of these files are now silent - each has AC3 audio, and a quick Google tells me that AC3 audio no longer works in Mountain Lion. Is this the case, or am I doing something wrong? Because I now have a whole lot of mkv files that I can't play or convert to watch via the PS3 and Apple TV. This is in addition to avi files no longer playing in Quicktime, which I guess is due to Perian being dead. Anyone found any solutions?