My QTMovieExporterMBS class is very popular and from time to time I'm asked for 96 KHz support.
Actually that is supported, but not all people find it. The function you try first is SetSoundFormat, but this one is old and can't handle values above 65 KHz. So you need a different way. And I always suggest: let the user setup this and save the preferences. So you'd try the SetupDialog method which shows this dialog:
But there the higher bit rates are missing. The solution is to set EnableHighResolutionAudio to true like in this code:
The EnableHighResolutionAudio property is new in QuickTime 7 and changes a few things in background. So the SetupDialog now looks like this:
I hope this information helps a few of you.