ios - Camera Freeze when open app while call is running

Question

I have created a camera using AVCaptureSession. I have configured that for both Photo and Video recording modes.

Camera and App is running fine. Also I allowed background music play (If user play song using Music App in iPhone) while open camera or recording video. It is also working fine. (Attached image 2)

I allowed background Music play with the help of this code

    AVAudioSession *session1 = [AVAudioSession sharedInstance];
    [session1 setCategory:AVAudioSessionCategoryPlayAndRecord withOptions:AVAudioSessionCategoryOptionMixWithOthers|AVAudioSessionCategoryOptionDefaultToSpeaker|AVAudioSessionCategoryOptionAllowBluetooth error:nil];
    [session1 setActive:YES error:nil];
    [[UIApplication sharedApplication] beginReceivingRemoteControlEvents];

Now if i receive a call, minimize phone call screen by tapping on Home button and open app and want to open camera screen to capture image / record video, It opens but freeze with a image (Attached image(1)).

Now my requirement is, i want to capture image / record video while on phone call. I looked for another apps, and Snapchat is doing same, and i am able to record video while i am on call.

please help me, how can i achieve this.

Answer 1

You need to use the AVCaptureSessionWasInterruptedNotification and AVCaptureSessionInterruptionEndedNotification callbacks and disconnect the audio capture while the session is interrupted:

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(sessionWasInterrupted:) name:AVCaptureSessionWasInterruptedNotification object:self.session];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(sessionInterruptionEnded:) name:AVCaptureSessionInterruptionEndedNotification object:self.session];
// note that self.session is an AVCaptureSession

-

- (void)sessionWasInterrupted:(NSNotification *)notification {
  NSLog(@"session was interrupted");

  AVCaptureDevice *device = [[self audioInput] device];
  if ([device hasMediaType:AVMediaTypeAudio]) {
    [[self session] removeInput:[self audioInput]];
    [self setAudioInput:nil];
  }
}

- (void)sessionInterruptionEnded:(NSNotification *)notification {
  NSLog(@"session interuption ended");
}
// note that [self audioInput] is a getter for an AVCaptureDeviceInput

This will allow the camera to continue running and allows it to capture stills / silent video

Now as for how to reconnect the audio after the call ends.. let me know if you figure it out, seemed impossible as of iOS 10: Callback when phone call ends? (to resume AVCaptureSession)