Changing audio input freezes app for ~10s

[noho501]

Hi everyone,

I tested with both HaishinKit 2.0.9 and 2.1.
When using the iOS Example, while the app is running, I try to switch the microphone position (Top, Bottom, Front).

Result:

• The camera freezes for about 10 seconds, then resumes.
• The microphone does not actually change.

Questions:

• Is there a way to fix the freeze when switching the microphone?
• How can I make the microphone input change work properly?

Code used (same as in the Example):

func pickerView(_ pickerView: UIPickerView, didSelectRow row: Int, inComponent component: Int) {
    let session = AVAudioSession.sharedInstance()
    guard let preferredInput = session.preferredInput,
          let newDataSource = preferredInput.dataSources?[row] else {
        return
    }
    do {
        try preferredInput.setPreferredDataSource(newDataSource)
    } catch {
        logger.warn("can't set supported setPreferredDataSource")
    }

    // App freezes here
    await mixer.attachAudio(AVCaptureDevice.default(for: .audio))
}

Test environment:

• iOS Example from HaishinKit
• HaishinKit version: 2.0.9, 2.1
• Device: (please fill in your iPhone model and iOS version)

Thanks,
Best regards

[shogo4405]

Is there a way to fix the freeze when switching the microphone?

Yes. Starting from around iOS 17 or 18, when AVCaptureSession has isRunning = true, attaching a device causes a freeze.
Therefore, it’s better to stop it once as shown below:

await mixer.stopCapturing()
await mixer.attachAudio(AVCaptureDevice.default(for: .audio))
await mixer.startCapturing()

[shogo4405]

If you want to change the source of the built-in microphone, the following PR will be helpful.

#1770

[noho501]

Thank you so much. I will check it out.

[noho501]

Hi,

When switching microphones, the screen briefly freezes and the experience isn’t very smooth.
Is there a way to change only the input microphone of the audio session without needing to fully reattach the audio, so that the video framerate won’t be affected?

Additionally, is there any way to select a Bluetooth headset as the audio input? At the moment, when I attach audio, I can’t choose a Bluetooth device such as AirPods.

Thank you in advance for your support!

[shogo4405]

It’s not possible. Also, switching AirPods is handled automatically by iOS, so it cannot be changed programmatically.