audio extraction problem: 4 channels, DiscreteInOrder; single track works, four separate tracks doesn't

I’m still having an issue extracting audio from a file which has an audio channel layout with kAudioChannelLayoutTag_DiscreteInOrder, and four channels, and each of the channels is labeled kAudioChannelLabel_Discrete_0/1/2/3

 

I’m setting kQTMovieAudioExtractionMoviePropertyID_AllChannelsDiscrete to disable any mixing, but what I want to get is a single interleaved buffer with these 4 mono channels.

 

If I use a source file with the first audio format listed below (four separate audio tracks), I get a badCallOrderErr from MovieAudioExtractionFillBuffer.  But if I use the source file shown below that, which is a single track with four channels, I’m able to extract the audio correctly.   Both files report the exact same audio channel layout.

 

Is this by design?   Am I only able to extract audio from a track at a time, or should I be able to get a resulting audio buffer that interleaved the available audio tracks?   I thought this should be possible.

 

Any help is much appreciated – this is a customer blocking issue for us.

 

Thanks!

Kirk

 

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1) Audio format:

24-bit Integer (Big Endian), Mono, 48.000 kHz

24-bit Integer (Big Endian), Mono, 48.000 kHz

24-bit Integer (Big Endian), Mono, 48.000 kHz

24-bit Integer (Big Endian), Mono, 48.000 kHz

 

CQuickTimeIn::Open: Retrieved audio channel layout, [4] channels, tag [0x00930004].

CQuickTimeIn::Open: Channel description [0], flags [0x00000000], label [0x00010000].

CQuickTimeIn::Open: Channel description [1], flags [0x00000000], label [0x00010001].

CQuickTimeIn::Open: Channel description [2], flags [0x00000000], label [0x00010002].

CQuickTimeIn::Open: Channel description [3], flags [0x00000000], label [0x00010003].

 

2) Audio format:

24-bit Integer (Big Endian), 4 Channels, 48.000 kHz

 

CQuickTimeIn::Open: Retrieved audio channel layout, [4] channels, tag [0x00930004].

CQuickTimeIn::Open: Channel description [0], flags [0x00000000], label [0x00010000].

CQuickTimeIn::Open: Channel description [1], flags [0x00000000], label [0x00010001].

CQuickTimeIn::Open: Channel description [2], flags [0x00000000], label [0x00010002].

CQuickTimeIn::Open: Channel description [3], flags [0x00000000], label [0x00010003].

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Kirk Marple
Chief Software Architect, VP of Engineering
Agnostic Media, Inc.
e: email@hidden
w: www.agnostic-media.com