CODEWITHSUNDEEP
iosaudiocore-audiovoipaudiounit
Siddhartha Saif
Siddhartha Saif

Reputation: 69

iOs Play Audio for VOIP App

This is my first post to stackoverflow. At present I am developing an voip app for ios. I want to do something like this. 

//in  a thread
while(callIsOnGoing){
  data = getDataFromNetwork()
  playData()
  sleep(10ms)
}

But problem is that audio in ios works in a "Pull" model(uses callback to get data). But i need to push data to play it. I have tried AudioQueue, but in audioQueue the data i push in buffer outside of callback doesn't get played though callback is called.

Again, i have seen AVCaptureToAudioUnit example by apple(http://developer.apple.com/library/ios/#samplecode/AVCaptureToAudioUnit/Introduction/Intro.html) where they called AudioUnitRender synchronously in case of of a delay audio unit. I tried similar for RemoteI/O Audio unit. But every time it returns OSStatus -50. The code is given below

    //in a separate thread

    do {                                               // 5
      int data_length = [NativeLibraryHelper GetData:(playBuff)];
      if(data_length == 0){

      }else{
        double numberOfFrameCount = data_length / player->audioStreamDesc->mBytesPerFrame;
        currentSampleTime += numberOfFrameCount;

        //AudioUnitRenderActionFlags flags = 0;

        AudioTimeStamp timeStamp;
        memset(&timeStamp, 0, sizeof(AudioTimeStamp));
        timeStamp.mSampleTime = currentSampleTime;
        timeStamp.mFlags |= kAudioTimeStampSampleTimeValid;

        AudioUnitRenderActionFlags flags = 0;
        AudioBuffer buffer;
        buffer.mNumberChannels = player->audioStreamDesc->mChannelsPerFrame;
        buffer.mDataByteSize = data_length;
        buffer.mData = malloc(data_length);
        memcpy(buffer.mData, playBuff, data_length);

        AudioBufferList audBuffList;
        audBuffList.mBuffers[0] = buffer;
        audBuffList.mNumberBuffers = 1;

        printf("Audio REnder call back funciotn called with data size %d\n", data_length);

        status = AudioUnitRender(audioUnitInstance, &flags, &timeStamp, 0, numberOfFrameCount, &audBuffList);
        printf("osstatus %d\n", status);
    }//end if else
    CFRunLoopRunInMode (                           // 6
                        kCFRunLoopDefaultMode,                     // 7
                        0.25,                                      // 8
                        false                                      // 9
                        );
    //} while (aqData.mIsRunning);
    [NSThread sleepForTimeInterval:.05];
}while (player->isRunning == YES);

I am struggling with audio play part for more than one month. Please help. Thanks in advance.

Upvotes: 0

Views: 672

Answers (1)

hotpaw2
hotpaw2

Reputation: 70663

One general solution is to have an async network getdata/read function push data to an intermediate buffer or queue, then have the audio callback read from that intermediate buffer (or read silence if the intermediate buffer/queue is empty).

Upvotes: 1

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