I've got an MKV which I'd like to convert for use with my ATV. The video is h.264; the audio is ac-3, so I would figure that this would be simple. But I've used MKV Tools; I've used Subler; and every time I end up with a file that plays fine in MPlayer and VLC, but which has no audio in Quicktime. Any ideas? I've just started diving into this stuff, so I'm sure I'm overlooking something glaringly obvious and simple.