Stream microphone audio in Swift 5 - ios

Question

I have a working connection between 2 IOS-Devices. Sending a live-stream from one camera to the other device works. But now i want to send mic-audio and this does not work. I get no error, but i just receive "click"-noices.
I also can see, that bytes are transmitted, but i do not know, where the failure is.
Below you find the sending and the receiving functions. I also insert the streaming-function, which works fine for transmitting video.
sender:
func recorder() {
let settings : Dictionary = ["AVSampleRateKey" : 44100.0,
"AVNumberOfChannelsKey" : 1,
"AVFormatIDKey" : 1819304813,
"AVLinearPCMIsNonInterleaved" : 0,
"AVLinearPCMIsBigEndianKey" : 0,
"AVLinearPCMBitDepthKey" : 16,
"AVLinearPCMIsFloatKey" : 0]
audioFormat = AVAudioFormat.init(settings: settings)
audioEngine = AVAudioEngine.init()
audioEngine?.inputNode.installTap(onBus: 0, bufferSize: 4410, format: audioEngine?.inputNode.outputFormat(forBus: 0), block: {buffer, when in
let audioBuffer = buffer.audioBufferList.pointee.mBuffers
let data : Data = Data.init(bytes: audioBuffer.mData!, count: Int(audioBuffer.mDataByteSize))
let arraySize = Int(buffer.frameLength)
let samples = Array(UnsafeBufferPointer(start: buffer.floatChannelData![0], count:arraySize))
self.streamData(data: data, len: 4410)
})
// Start audio engine
self.audioEngine?.prepare()
do {
try self.audioEngine?.start()
}
catch {
NSLog("cannot start audio engine")
}
if(self.audioEngine?.isRunning == true){
NSLog("Audioengine is running")
}
}
sender streamData (working fine for e.g. video)
func streamData(data : Data, len : Int)
{
var baseCaseCondition : Bool = false
var _len : Int = len
var _byteIndex : Int = 0
func recursiveBlock(block: #escaping (()->Void)->Void) -> ()->Void {
return { block(recursiveBlock(block: block)) }
}
let aRecursiveBlock :()->Void = recursiveBlock {recurse in
baseCaseCondition = (data.count > 0 && _byteIndex < data.count) ? true : false
if ((baseCaseCondition)) {
_len = (data.count - _byteIndex) == 0 ? 1 : (data.count - _byteIndex) < len ? (data.count - _byteIndex) : len
NSLog("START | byteIndex: %lu/%lu writing len: %lu", _byteIndex, data.count, _len)
var bytes = [UInt8](repeating:0, count:_len)
data.copyBytes(to: &bytes, from: _byteIndex ..< _byteIndex+_len )
_byteIndex += (self.outputStream?.write(&bytes, maxLength: _len))!
NSLog("END | byteIndex: %lu/%lu wrote len: %lu", _byteIndex, data.count, _len)
recurse()
}
}
if (self.outputStream!.hasSpaceAvailable){
aRecursiveBlock();
}
}
receiver:
func stream(_ aStream: Stream, handle eventCode: Stream.Event) {
...
case Stream.Event.hasBytesAvailable:
var thePCMBuffer : AVAudioPCMBuffer = AVAudioPCMBuffer.init(pcmFormat: (self.audioEngine?.inputNode.outputFormat(forBus: 0))!, frameCapacity: AVAudioFrameCount(mlen))!
thePCMBuffer.frameLength = thePCMBuffer.frameCapacity
let channels = UnsafeBufferPointer(start: thePCMBuffer.floatChannelData, count: Int(thePCMBuffer.format.channelCount))
_ = mdata?.copyBytes(to: UnsafeMutableBufferPointer(start: channels[0], count: Int(thePCMBuffer.frameLength)))
if((self.player?.isPlaying) != nil){
DispatchQueue.global(qos: .background).async {
// Background Thread
DispatchQueue.main.async {
// Run UI Updates
self.player?.scheduleBuffer(thePCMBuffer, completionHandler: {
NSLog("Scheduled buffer")
NSLog("\(self.player!.isPlaying)")
let arraySize = Int(thePCMBuffer.frameLength)
let samples = Array(UnsafeBufferPointer(start: thePCMBuffer.floatChannelData![0], count:arraySize))
for sample in samples{
NSLog("\(sample)")
}
})
}
}
}
}
mdata = Data.init()
mlen = DATA_LENGTH
}
break;
...
}

Answer 1

Found the solution i guess. I tried with one simulator and one real device. Now i read, that there es a problem because of different sample-rates. Running on 2 devices (or 2 simulators) just works fine.