iPad stereo audio input bug?

iOS
#1

Hello all. I’ve just started working with oF so I’m a bit of a newb.

I’m trying to get stereo audio input working- iPad can do stereo with use of a usb soundcard) and it appears that oF is hardcoded for mono input:
ofxiPhoneSoundStream.mm in recordingCallback on line 108-111, and 132 for the audioReceived call. I’ve been hacking at it for a few hours and I’m a bit too novice to figure out how to get it working.

I know in theory it should work just fine.
Thoughts?

Thanks!
/Timothy - trash80

#2

I always thought it did record stereo; it just interleaved the results so that buffer[0] = left1, buffer[1] = right1, buffer[2] = left2 etc. But that belief is based purely on a code comment somewhere in the source so who knows if it’s true or not!

#3

Right but as mentioned the number of inputs in another part of the source is hardcoded to 1. So changing the number of inputs to anything other than 0 or 1 results in audioReceived not being called.

ofxiPhoneSoundStream.mm…

static OSStatus recordingCallback(void *inRefCon,
AudioUnitRenderActionFlags *ioActionFlags,
const AudioTimeStamp *inTimeStamp,
UInt32 inBusNumber,
UInt32 inNumberFrames,
AudioBufferList *ioData) {

AudioBufferList list;
**
// redundant
list.mNumberBuffers = 1;
list.mBuffers[0].mData = sampleBuffer;
list.mBuffers[0].mDataByteSize = 2 * inNumberFrames;
list.mBuffers[0].mNumberChannels = 1;**

ioData = &list;
//printf(“No buffers: %d, buffer length: %d bus number: %d\n”, ioData->mNumberBuffers, ioData->mBuffers[0].mDataByteSize, inBusNumber);

// Then:
// Obtain recorded samples

OSStatus status = AudioUnitRender(audioUnit, ioActionFlags, inTimeStamp, 1, inNumberFrames, ioData);
checkStatus(status);
if(status!=noErr) return status;
if(ioData->mNumberBuffers>0) {
int i = 0;
short int *buffer = (short int *) list.mBuffers[i].mData;
for(int j = 0; j < ioData->mBuffers[i].mDataByteSize/2; j++) {
// go through each sample and turn it into a float
tempBuffer[j] = (float)buffer[j]/32767.f;

}
done = true;
if(OFSAptr!=NULL) OFSAptr->audioReceived(tempBuffer, ioData->mBuffers[i].mDataByteSize/2, 1);

}
return noErr;
}

I tried playing around with it to get it working but I suppose I suck. :smiley:
Also note I tried another framework for stereo audio input and it works, though I’d rather use oF than have to convert the rest of my code.

#4

Ah, right I see.

  
mNumberChannels  
The number of interleaved channels in the buffer. If the number is 1, the buffer is noninterleaved

Did you try ofSoundStreamSetup with nInputs as 2 as well as setting mNumberChannels as 2?

Maybe if you posted your code and the error you are getting?