MPEG-4 Audio == AAC
In QuickTime’s export dialog, “MPEG-4 Audio” is “AAC”. Somehow iMovie and QuickTime are using a different dialog for their export “sound” options. Compare the two lists of compressors below:
Default Sound options when using ‘MovieExportDoUserDialog’
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QuickTime 7 and iMovie’s dialog
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The QT7/iMovie dialog has some clear advantages.
- Shorter
- MPEG-4 Audio is re-worded as AAC (as far as I can tell that’s the only difference). People that see this dialog know what AAC is (most?) and know when they want it. However, I’m doubtful that all know that MPEG-4 Audio gets you AAC (I wasn’t, hence this post).
- “None” is not an option.
- “Linear PCM” takes the place of “None” and the four int and floating point options.
Do we, as QuickTime developers, have access to this friendlier dialog? Do we have to role our own? Those are questions I’m trying to answer on the side. I did minimal research and found nothing. Right now I can’t devote the time required to keep digging.
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February 22nd, 2007 at 1:18 pm
Passing the showUserSettingsDialog flag to ConvertMovieToFile() uses the nicer export dialog (this doesn’t help me, but is interesting to note). I don’t know why MovieExportDoUserDialog() uses a different dialog.
February 22nd, 2007 at 6:07 pm
OK, looks like if you enable the new high resolution audio support on the exporter via QTSetComponentProperty with kQTMovieExporterPropertyID_EnableHighResolutionAudioFeatures, you get the better export dialog:
http://developer.apple.com/documentation/QuickTime/Conceptual/QT7UpdateGuide/Chapter02/chapter2section6.html#//appleref/doc/uid/TP40001163-CH313-659572
Unfortunately I’m using Quicktime for Java which doesn’t expose this API.