1 Reply
      Latest reply on Nov 11, 2019 3:03 AM by Tim8872
      Tim8872 Level 1 Level 1 (0 points)

        I want to stream audio on iOS and use for that use-case the AVAudioEngine. So, currently I'm not really sure, what is the best solution for my problem.


        I get the RTP data from the network and want playback this audio data with AVAudioEngine. I use the iOS Network.Framework to receive the network data. Then first I decode my voice data and want to playback it, now.


        Here is my receive code:

        connection.receiveMessage { (data, context, isComplete, error) in
          if isComplete {
          // decode the raw network data with Audio codec G711
          let decodedData = AudioDecoder.decode(enc: data, frames: 160)
          // create PCMBuffer for audio data for playback
          let format = AVAudioFormat(settings: [AVFormatIDKey: NSNumber(value: kAudioFormatALaw), AVSampleRateKey: 8000, AVNumberOfChannelsKey: 1])
          // let format = AVAudioFormat(standardFormatWithSampleRate: 8000, channels: 1)
          let buffer = AVAudioPCMBuffer(pcmFormat: format!, frameCapacity: 160)!
          buffer.frameLength = buffer.frameCapacity
          // TODO: now I have to copy the decodedData --> buffer (AVAudioPCMBuffer)
          if error == nil {
          // recall receive() for next message
          self.receive(on: connection)


        ?How I have to copy my decoded data into the AVAudioPCMBuffer? Currently, my AVAudioPCMBuffer is created, but not contain any audio data.


        Background information: My generell approach would be to cash here in the above code (at ToDo-Line) the PCMBuffer in a collection and playback this collection by the AVAudioEngine (in a background thread).


        My decoded linear data is cashed in an array from type Int16. So the var decodedData is from type [Int16], maybe there is a possibility to consume this data directly? The function scheduleBuffer allows only AVAudioPCMBuffer as input.