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Re: kAudioFileAAC_ADTSType for aac plus?
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Re: kAudioFileAAC_ADTSType for aac plus?


  • Subject: Re: kAudioFileAAC_ADTSType for aac plus?
  • From: Jacobson981 <email@hidden>
  • Date: Wed, 23 Sep 2009 16:24:15 +0300

I've tried it with

AudioFileStreamGetPropertyInfo(inAudioFileStream, kAudioFilePropertyFormatList, &asbdSize, NULL);

and it returned -4 which means "Function or operation not implemented."

I think i had to say that this is for iphone. And it looks like this is not supported in iPhone.




William Stewart wrote:
HE-AAC is a layered audio format - it has a core layer which is AAC (which is what you see here), and then an enhanced layer (which is that for a few extra bits, alot of extra work, you can get a richer format decoded).

We implement this with what we call an AudioFormatList - if you use this property with audio file (and audio format) you will see both 'aac ' and 'aach' listed and then you can chose which format you want to actually decode.

Have a look through AudioFile.h and AudioFormat.h for comments. aqplay also uses audio format lists as an example of how this can be used

Bill

On Sep 15, 2009, at 2:33 AM, Jacobson981 wrote:

i'm using AudioFileStreamOpen to listen aac plus streams.

i initialize queue with kAudioFileAAC_ADTSType.

i get AudioStreamBasicDescription filled in kAudioFileStreamProperty_ReadyToProducePackets with

AudioFileStreamGetProperty(inAudioFileStream, kAudioFileStreamProperty_DataFormat, &descSize, &desc);

it plays perfectly. But,

          NSLog(@"samplerate: %f",asbd.mSampleRate);
          NSLog(@"mBitsPerChannel: %f",asbd.mBitsPerChannel);
          NSLog(@"mChannelsPerFrame: %f",asbd.mChannelsPerFrame);
          NSLog(@"mBytesPerPacket: %f",asbd.mBytesPerPacket);
          NSLog(@"mFramesPerPacket: %f",asbd.mFramesPerPacket);

Outputs:

samplerate: 22050.000000
mBitsPerChannel: 22050.000000
mChannelsPerFrame: 22050.000000
mBytesPerPacket: 22050.000000
mFramesPerPacket: 22050.000000


this means, audio library is unable to correctly identify stream information, right? Why is this? Because of aacp codec?


Is there anything that can be done?


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 >kAudioFileAAC_ADTSType for aac plus? (From: Jacobson981 <email@hidden>)
 >Re: kAudioFileAAC_ADTSType for aac plus? (From: William Stewart <email@hidden>)

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