Error 1309 when extracting 5.1ch aif from MOV

Hi folks,

I deal with tons and tons of ProRes MOVs with multiple mono tracks of PCM audio.

Part of my workflow involves extracting the audio track(s) to an external file - ideally a 5.1ch WAV, but since QuickTime doesn't support multichannel WAV, I have to use the AIF container.

Unfortunately, every time I try to export a 5.1ch AIF, I get an error 1309. The behavior is consistent on Windows XP, Vista 7, and Mac OS X 10.4 and 10.5. I can extract a 2 channel downmix just fine, and I can extract mono channels one at a time by disabling all but one audio track, etc... but this is a hassle.

I usually get around this by using ffmpeg to extract the audio tracks to mono WAV files, but this isn't perfect, especially when there are edits in the MOV (usually leads to a desync)

Ideas???

Thanks!
-Derek