Objective c: Send audio data in rtp packet via socket - objective-c

Question

In my app, I have to capture microphone and send audio data in rtp packet. But I only see receive rtp data like iOS RTP live audio receiving or unanswered one.
I used following code with AsuncUdpSocket to sent audio data but it wasn't wrap in rtp packet. Is there any library to wrap my audio data into rtp packet?
initial AsyncUdpSocket:
udpSender = [[GCDAsyncUdpSocket alloc] initWithDelegate:self delegateQueue:dispatch_get_main_queue()];
NSError *error;
[udpSender connectToHost:#"192.168.1.29" onPort:1024 error:&error];
I send audio data in my playback callback function:
static OSStatus playbackCallback(void *inRefCon,
AudioUnitRenderActionFlags *ioActionFlags,
const AudioTimeStamp *inTimeStamp,
UInt32 inBusNumber,
UInt32 inNumberFrames,
AudioBufferList *ioData) {
/**
This is the reference to the object who owns the callback.
*/
AudioProcessor *audioProcessor = (AudioProcessor*) inRefCon;
// iterate over incoming stream an copy to output stream
for (int i=0; i < ioData->mNumberBuffers; i++) {
AudioBuffer buffer = ioData->mBuffers[i];
// find minimum size
UInt32 size = min(buffer.mDataByteSize, [audioProcessor audioBuffer].mDataByteSize);
// copy buffer to audio buffer which gets played after function return
memcpy(buffer.mData, [audioProcessor audioBuffer].mData, size);
// set data size
buffer.mDataByteSize = size;
//Send data to remote server
NSMutableData *data=[[NSMutableData alloc] init];
Float32 *frame = (Float32*)buffer.mData;
[data appendBytes:frame length:size];
if ([udpSender isConnected])
{
[udpSender sendData:data withTimeout:-1 tag:1];
}
}
return noErr;
}
How do I accomplish this?
Thanks.

Answer 1

Finally, here's my solution.
Setup the microphone capture process:
-(void)open {
NSError *error;
m_capture = [[AVCaptureSession alloc]init];
AVCaptureDevice *audioDev = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeAudio];
if (audioDev == nil)
{
printf("Couldn't create audio capture device");
return ;
}
//m_capture.sessionPreset = AVCaptureSessionPresetLow;
// create mic device
AVCaptureDeviceInput *audioIn = [AVCaptureDeviceInput deviceInputWithDevice:audioDev error:&error];
if (error != nil)
{
printf("Couldn't create audio input");
return ;
}
// add mic device in capture object
if ([m_capture canAddInput:audioIn] == NO)
{
printf("Couldn't add audio input");
return ;
}
[m_capture addInput:audioIn];
// export audio data
AVCaptureAudioDataOutput *audioOutput = [[AVCaptureAudioDataOutput alloc] init];
[audioOutput setSampleBufferDelegate:self queue:dispatch_get_main_queue()];
if ([m_capture canAddOutput:audioOutput] == NO)
{
printf("Couldn't add audio output");
return ;
}
[m_capture addOutput:audioOutput];
[audioOutput connectionWithMediaType:AVMediaTypeAudio];
[m_capture startRunning];
return ;
}
Capture the microphone data:
-(void) captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection{
char szBuf[450];
int nSize = sizeof(szBuf);
if (isConnect == YES)
{
if ([self encoderAAC:sampleBuffer aacData:szBuf aacLen:&nSize] == YES)
{
[self sendAudioData:szBuf len:nSize channel:0];
}
}
Initial the socket
-(void)initialSocket{
//Use socket
printf("initialSocket\n");
CFReadStreamRef readStream = NULL;
CFWriteStreamRef writeStream = NULL;
NSString *ip = #"192.168.1.147"; //Your IP Address
uint *port = 22133;
CFStreamCreatePairWithSocketToHost(kCFAllocatorDefault, (__bridge CFStringRef)ip, port, &readStream, &writeStream);
if (readStream && writeStream) {
CFReadStreamSetProperty(readStream, kCFStreamPropertyShouldCloseNativeSocket, kCFBooleanTrue);
CFWriteStreamSetProperty(writeStream, kCFStreamPropertyShouldCloseNativeSocket, kCFBooleanTrue);
iStream = (__bridge NSInputStream *)readStream;
[iStream setDelegate:self];
[iStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
[iStream open];
oStream = (__bridge NSOutputStream *)writeStream;
[oStream setDelegate:self];
[oStream scheduleInRunLoop:[NSRunLoop currentRunLoop] forMode:NSDefaultRunLoopMode];
[oStream open];
}
}
Send data to socket when capture the data form microphone.
-(void)sendAudioData: (char *)buffer len:(int)len channel:(UInt32)channel
{
Float32 *frame = (Float32*)buffer;
[globalData appendBytes:frame length:len];
if (isConnect == YES)
{
if ([oStream streamStatus] == NSStreamStatusOpen)
{
[oStream write:globalData.mutableBytes maxLength:globalData.length];
globalData = [[NSMutableData alloc] init];
}
}
}
Hope this will help someone.