Problems with Audio Streams on Mac OS

[ihdream72]

Package version
5.1.1

Environment

• OS: [ Macos ]

I am developing a service where I want to record stream audio from multiple platforms and use Google's Speech to Text service.

const RecordConfig config = RecordConfig(
  encoder: AudioEncoder.pcm16bits,
  sampleRate: 16000,
  numChannels: 1,
);

Stream<Uint8List>? stream = await recorder?.startStream(config);

streamSubscription = stream?.listen((chunk) async {
  Log.d('MACOS PCM => [${DateTime.now()}] ${chunk.length}');
  onStream(chunk);
});

Recording as above works fine on Android, but not on MacOS.
If you look at the logs left behind on MacOS, you'll see the following

flutter: [⭐️] MACOS PCM => [2024-06-04 14:23:10.071288] 1600
flutter: [⭐️] MACOS PCM => [2024-06-04 14:23:10.178055] 1600
flutter: [⭐️] MACOS PCM => [2024-06-04 14:23:10.275184] 1600
flutter: [⭐️] MACOS PCM => [2024-06-04 14:23:10.381623] 1600

• PCM16 Format / 16000 sampleRate => 36000 byte per 1 sec
  However, the logs show that only 1600 bytes come through every 0.1 seconds, or 16000 bytes per second.

Can you confirm this issue?

�I appreciates the your effort.

[ihdream72]

I made the following modifications to the 'record_darwin/darwin/Classes/delegate/RecorderStreamDelegate.swift' file
I did that and it works fine on MacOS.
Please check it out and let me know if you can update it.

private func stream(
    buffer: AVAudioPCMBuffer,
    dstFormat: AVAudioFormat,
    converter: AVAudioConverter,
    recordEventHandler: RecordStreamHandler
  ) -> Void {
   
   ...
   ... 
    // Determine frame capacity
    // let capacity = (UInt32(dstFormat.sampleRate) * dstFormat.channelCount * buffer.frameLength) / (UInt32(buffer.format.sampleRate) * buffer.format.channelCount)
  
       let capacity = (UInt32(dstFormat.sampleRate) * dstFormat.channelCount * buffer.frameLength * 2) / (UInt32(buffer.format.sampleRate) * buffer.format.channelCount)

     ...
     ...
    
  }

[llfbandit]

Thanks, can you fill a PR for this?
Also, it should be tested on iOS since this code is shared between the platforms.