Performance very bad during recording on iOS

[SingleDevOps]

Package version
6.1.2

Environment

• OS: iOS 26.2 / iOS 18.6.2

Describe the bug

Our app runs smoothly until we call startStream with the following RecordConfig:

    final stream = await recorder.startStream(
      RecordConfig(
        encoder: AudioEncoder.pcm16bits,
        device: await selectUSBMic(await recorder.listInputDevices()),
        sampleRate: 48000,
        bitRate: 128000,
        numChannels: 1,
      ),
    );

After which UI animations are extremely choppy and interaction is intermittent.
The recording itself is interspersed with silence and unusable.

We also tried record.start with a file path, but the result is exactly the same.

To Reproduce

It is not really possible to reproduce, because this is in a beta tested TestFlight app in a large Flutter project.

Expected behavior

Smooth animation and uninterrupted recording.

Additional context

On Android this problem does not exist.

[llfbandit]

Thanks for the report.
This is certainly due to audio session.
You can deal with it by enabling it once and for all before recording.

// when entering screen for example
recorder.ios.manageAudioSession(false);
recorder.ios.setAudioSessionActive(true);

// on user interaction, start recording

// when disposing screen
recorder.ios.setAudioSessionActive(false);

Let me know if it helps.

[SingleDevOps]

Thanks for the quick response @llfbandit!
I've implemented your suggestion, but unfortunately the UI lag and choppy animations still persist.
Here's what I've done:

class _MyScreenState extends State<MyScreen> {
  
  final recorder = AudioRecorder();
  
  @override
  void initState() {
    super.initState();
    _manageAudioSession();
  }
  
  void _manageAudioSession() {
    recorder.ios?.manageAudioSession(false);
    recorder.ios?.setAudioSessionActive(true);
  }

 void _disposeAudioSession() {
    recorder.ios?.setAudioSessionActive(false);
  }
  
  // Called when navigating away from the screen:
  Future<void> onNavigateAway() async {
    // ... other logic ...
    _disposeAudioSession();
    // navigate to next screen
  }
}

I also made sure to reuse the same AudioRecorder instance throughout the recording process rather than creating new ones.

On this screen, the recording function is called multiple times. So the flow is:
_manageAudioSession() -> recording for multiple times -> _disposeAudioSession()

Despite these changes, the UI still becomes choppy during startStream() and animations stutter badly.

Any suggestions are greatly appreciated!

[SingleDevOps]

I removed screens from the navigation stack when i get into the recording screen, and the UI no longer stutters.
If there are other issues i will notify you, thanks for the help!