Not able to hear 'noise' when writing random values AudioBuffer in iOS

Question

I am using EZAudio and trying to write some samples generated by my softaware to an AudioBuffer provided by this library https://github.com/syedhali/EZAudio as seen in the example "Playback By Manual Override".

My code looks like this...

// Completely override the output callback function
- (void)
                 output:(EZOutput *)output
callbackWithActionFlags:(AudioUnitRenderActionFlags *)ioActionFlags
            inTimeStamp:(const AudioTimeStamp *)inTimeStamp
            inBusNumber:(UInt32)inBusNumber
         inNumberFrames:(UInt32)inNumberFrames
                 ioData:(AudioBufferList *)ioData {
    //grab latest sample from sample queue
    if (currentAudioPiece == nil || currentAudioPiece.duration >= currentAudioPieceIndex) {
        self.currentAudioPiece = sampleQueue.dequeue;
    }
    AudioBuffer audioBuffer = ioData->mBuffers[0];


    if (true) {
        for (int i = 0; i < audioBuffer.mDataByteSize; i++) {
            uint8_t rofl[2048];
            arc4random_buf(&rofl, 2048);
            audioBuffer.mData = rofl;
        }

        return;
    }

    //... more code that I'll debug later...'

Essentially I am unable to get a sanity check that a random bunch of memory playing back should make some noise. I think the problem is with "audioBuffer.mData = rofl;". I'm rather confused about working with memory at void*.

Answer 1

jn_pdx is correct, you need to copy/fill mData instead of reassigning it.

- (void)
                 output:(EZOutput *)output
callbackWithActionFlags:(AudioUnitRenderActionFlags *)ioActionFlags
            inTimeStamp:(const AudioTimeStamp *)inTimeStamp
            inBusNumber:(UInt32)inBusNumber
         inNumberFrames:(UInt32)inNumberFrames
                 ioData:(AudioBufferList *)ioData {
    //grab latest sample from sample queue
    if (currentAudioPiece == nil || currentAudioPiece.duration >= currentAudioPieceIndex) {
        self.currentAudioPiece = sampleQueue.dequeue;
    }
    AudioBuffer audioBuffer = ioData->mBuffers[0];


    if (true) {
        arc4random_buf(audioBuffer.mData, audioBuffer.mDataByteSize);

        return;
    }