Re: kAudioFileAAC_ADTSType for aac plus?
Re: kAudioFileAAC_ADTSType for aac plus?
- Subject: Re: kAudioFileAAC_ADTSType for aac plus?
- From: James McCartney <email@hidden>
- Date: Fri, 25 Sep 2009 10:23:02 -0700
This is working for me. afinfo uses kAudioFilePropertyFormatList to
get the format list :
iphone3g:~ root# afinfo short1-aach.aac
File: short1-aach.aac
File type ID: adts
Data format: 2 ch, 22050 Hz, 'aac ' (0x00000000) 0 bits/channel,
0 bytes/packet, 1024 frames/packet, 0 bytes/frame
Channel layout: Stereo (L R)
estimated duration: 8.753 sec
audio bytes: 98738
audio packets: 255
bit rate: 66702 bits per second
packet size upper bound: 1536
maximum packet size: 723
audio data file offset: 0
optimized
format list:
[ 0] format: 2 ch, 44100 Hz, 'aach' (0x00000000) 0 bits/channel,
0 bytes/packet, 2048 frames/packet, 0 bytes/frame
Channel layout: Stereo (L R)
[ 1] format: 2 ch, 22050 Hz, 'aac ' (0x00000000) 0 bits/channel,
0 bytes/packet, 1024 frames/packet, 0 bytes/frame
Channel layout: Stereo (L R)
On Sep 23, 2009, at 6:24 AM, Jacobson981 wrote:
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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