Here is a helper function I use to get ASBDs. I use floats because they
work with the accelerate framework and they are easier on the eye. When
setting the kExtAudioFileProperty_ClientDataFormat property on your
extAudioFileRef, you should use an ASBD for interleaved, and when setting
ASBDs for audio units you should not use interleaved. So in your case i
would use this function to get ASBDs like this:
AudioStreamBasicDescription extAudioClientASBD = asbdWithInfo(1,2,1);
AudioStreamBasicDescription mixerInputASBD = asbdWithInfo(1,2,0);
AudioStreamBasicDescription asbdWithInfo(Boolean isFloat,int
numberOfChannels,Boolean interleavedIfStereo){
AudioStreamBasicDescription asbd = {0};
int sampleSize = isFloat ? sizeof(float) : sizeof(SInt16);
asbd.mChannelsPerFrame = (numberOfChannels == 1) ? 1 : 2;
asbd.mBitsPerChannel = 8 * sampleSize;
asbd.mFramesPerPacket = 1;
asbd.mSampleRate = 44100.0;
asbd.mBytesPerFrame = interleavedIfStereo ? sampleSize * asbd.
mChannelsPerFrame : sampleSize;
asbd.mBytesPerPacket = asbd.mBytesPerFrame;
asbd.mReserved = 0;
asbd.mFormatID = kAudioFormatLinearPCM;
if (isFloat) {
asbd.mFormatFlags = kAudioFormatFlagIsFloat;
if (interleavedIfStereo) {
if (numberOfChannels == 1) {
asbd.mFormatFlags = asbd.mFormatFlags |
kAudioFormatFlagsNativeEndian | kAudioFormatFlagIsPacked |
kAudioFormatFlagIsNonInterleaved;
}
}
else{
asbd.mFormatFlags = asbd.mFormatFlags |
kAudioFormatFlagIsNonInterleaved | kAudioFormatFlagIsPacked ;
}
}
else{
asbd.mFormatFlags = kAudioFormatFlagIsSignedInteger |
kAudioFormatFlagsNativeEndian | kAudioFormatFlagIsPacked;
if (!interleavedIfStereo) {
if (numberOfChannels > 1) {
asbd.mFormatFlags = asbd.mFormatFlags |
kAudioFormatFlagIsNonInterleaved;
}
}
}
return asbd;
}
On Mon, Jan 12, 2015 at 8:49 AM, Robert Carroll <[email protected]> wrote:
> Can I ask what data type you are using for your samples?
>
> I replaced all references to AudioUnitSampleType with float this morning.
> That gets me correct playback on iOS8, but on iOS7 I get overloaded noise.
> On iOS7 AudioUnitSampleType was working, as was SInt32.
>
> I’m running this on 2 iPads with the two iOS’s. Testing the arch with #if
> __LP64__ shows 32-bit for both devices. I can try switching to a fixed
> width int as per Doug Wyatt;s suggestion. My preference is to find a
> structure that will run on both iOS’s.
>
> rob
>
>
> On Jan 11, 2015, at 8:31 PM, Dave O'Neill <[email protected]> wrote:
>
> Are there any other audio units in your chain? Be sure to set the output
> ASBD of each audio unit to the input ASBD of the audio unit it is connected
> to (downstream). Just as a troubleshooting technique you can try putting
> AUConverters between various audio units to see if that fixes things.
> Maybe you could post your ASBD and we can spot an issue. Instead of using
> AudioUnitSampleType
> just find out what it is typedef'd to and substitute it with that ( you can
> just highlight it and "jump to definition" in Xcode). All of the iOS8
> specific issues I've had were all traced back 32-64 bit issues. Here is a
> handy guide that points out some common gotchas:
> https://developer.apple.com/library/ios/documentation/General/Conceptual/CocoaTouch64BitGuide/ConvertingYourAppto64-Bit/ConvertingYourAppto64-Bit.html#//apple_ref/doc/uid/TP40013501-CH3-SW1
>
>
> On Sun, Jan 11, 2015 at 5:00 PM, Matt Hart <[email protected]> wrote:
>
>> I haven't tested with m4a lossless, but I have played about 14 or so
>> lossless wav simultaneously as well as that many m4a compressed files. They
>> are all buffered though.
>>
>> On Jan 11, 2015, at 7:08 PM, Robert Carroll <[email protected]> wrote:
>>
>> Hi.
>>
>> Thanks. I am doing that with the same function call.
>>
>> Further investigation is pointing to some other issue. My code that reads
>> the ExtAudioFile objects is playing single m4a files, but not multiple
>> files set up on different mixer buses. I was testing with a single A440.if
>> file then with 3 m4a lossless files for C4, E4, G4 which should play
>> simultaneously.
>>
>> On iOS 7 it works, on iOS 8 I get a brief burst of vicious white noise.
>>
>> I’m inclined to think this is back to the storage type for the sample
>> data. Since, I haven’t found an answer to a replacement for the
>> AudioUnitSampleType on iOS, I had reverted my code to using that type.
>>
>> rob
>>
>> On Jan 11, 2015, at 6:25 PM, Matt Hart <[email protected]> wrote:
>>
>> I use this with iOS 8 and 7 without any issues. Did you set the expected
>> client data format onto the audio file property?
>>
>> status = ExtAudioFileSetProperty(_audioFile,
>> kExtAudioFileProperty_ClientDataFormat, sizeof(_targetAudioDescription),
>> &_targetAudioDescription);
>>
>>
>> On Jan 11, 2015, at 1:56 PM, Robert Carroll <[email protected]> wrote:
>>
>> I am attempting to narrow down the options why my audiograph code is
>> failing on iOS 8.
>>
>> I am using ExtAudioFileRead to extract data from applelossless source
>> files and load structs set up for this purpose.
>> The buffers and audioData parts of the struct are typed as
>> AudioUnitSampleType.
>>
>> All of this works as it should on iOS’s up to 7.x. Running on iOS 8.1.2 I
>> can play aiff source files with this code but get distortion if I load the
>> m4a (lossless) files.
>>
>> What changed in iOS 8 with extaudiofile that would account for this issue?
>>
>> thanks
>>
>> rob
>>
>>
>> Robert Carroll
>> RSM Records
>> Toronto
>> http://www.rsmrecords.com
>>
>>
>>
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>>
>>
>>
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