Cobra Kai said: Thanks for the info. Was just about to research this.

To elaborate, as it's not quite so straight forward... while you can find MKVtools easily (even though it often goes by the name MoKgVm2DVD), the version of tsMuxer you require is called VoxMac Unofficial build, it's on the videohelp website (address below) and is listed under 'More information and other downloads' - it's the one listed for OSX SnowLeopard. Annoyingly for it to work correctly you need to remove 2 korean language fonts from your Library - it tells you exactly which ones in one of the read me files when you mount the dmg.

http://www.videohelp.com/tools/tsMuxeR
http://www.videohelp.com/tools/MoKgVm2DVD

It's a bit of a pain but easy when you figure it out. Unfortunately I've noticed the audio file names stripped from MKVtools are generic so are clearly stripped of the information about which track is which, you can tell the right order (stream 0, stream 1 etc) but when picking an audio track they all just say whatever language you assign to them in tsMuxer - if anyone can advise of a better demuxer for Mac that retains the audio track names, then I would love to hear about it! Seems so much easier on Windows :(