Avfoundation - play and record video (along with audio and preview) at the same time

Question

I am trying to record and play video at the same time. Is this possible with avfoundation? Currently, I can do this until I record audio. As soon as I add the audio input to AVCaptureSession and reload everything that I get "AVCaptureSessionWasInterruptedNotification" and the recording stops.

This is how I play the video.

MPMoviePlayerController *moviePlayer = [[MPMoviePlayerController alloc] initWithContentURL:[NSURL fileURLWithPath:path]]; [moviePlayer.view setFrame:self.playerView.bounds]; moviePlayer.useApplicationAudioSession=NO; self.player = moviePlayer; [moviePlayer release]; [self.playerView addSubview:player.view]; [player play]; 

And this is how I record the video:

 NSError *error; AVCamCaptureManager *captureManager = [[AVCamCaptureManager alloc] init]; if ([captureManager setupSessionWithPreset:AVCaptureSessionPresetLow error:&error]) { [self setCaptureManager:captureManager]; AVCaptureVideoPreviewLayer *previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:[captureManager session]]; self.captureVideoPreviewLayer= previewLayer; UIView *view = [self cameraView]; CALayer *viewLayer = [view layer]; [viewLayer setMasksToBounds:YES]; CGRect bounds = [view bounds]; [captureVideoPreviewLayer setFrame:bounds]; if ([captureVideoPreviewLayer isOrientationSupported]) [captureVideoPreviewLayer setOrientation:AVCaptureVideoOrientationPortrait]; [captureVideoPreviewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill]; [[captureManager session] startRunning]; [self setCaptureVideoPreviewLayer:captureVideoPreviewLayer]; if ([[captureManager session] isRunning]) { [captureManager setOrientation:AVCaptureVideoOrientationPortrait]; [captureManager setDelegate:self]; [viewLayer insertSublayer:captureVideoPreviewLayer below:[[viewLayer sublayers] objectAtIndex:0]]; NSString *countString = [[NSString alloc] initWithFormat:@"%d", [[AVCaptureDevice devices] count]]; NSLog(@"Device count: %@",countString); } else { UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Failure" message:@"Failed to start session." delegate:nil cancelButtonTitle:@"Okay" otherButtonTitles:nil]; [alertView show]; [alertView release]; } } else { UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"Input Device Init Failed" message:[error localizedDescription] delegate:nil cancelButtonTitle:@"Okay" otherButtonTitles:nil]; [alertView show]; [alertView release]; } [captureManager release]; if (![[self captureManager] isRecording]) { [[self captureManager] startRecording]; } 

Where I use the "AVCamCaptureManager" from the Apple AVCam sample code.

Answer 1

First install MoviePlayer to use the audio application session:

 moviePlayer.useApplicationAudioSession=YES; 

Then, before calling [[sessionManager session] startRunning] , activate the audio session with its category set to “play and record” and override its property to allow mixing with others.

 // Set audio session category to "play and record" NSError* error = nil; AVAudioSession* audioSession = [AVAudioSession sharedInstance]; if (![audioSession setCategory:AVAudioSessionCategoryPlayAndRecord error:&error]) { NSLog(@"AVAudioSession setCategory failed: %@", [error localizedDescription]); } // Set audio session property "allow mixing" to true so audio can be recorded while it is playing UInt32 allowMixing = true; OSStatus status = AudioSessionSetProperty(kAudioSessionProperty_OverrideCategoryMixWithOthers, sizeof(allowMixing), &allowMixing); if (status != kAudioSessionNoError) { NSLog(@"AudioSessionSetProperty(kAudioSessionProperty_OverrideCategoryMixWithOthers) failed: %ld", status); } // Activate the audio session error = nil; if (![audioSession setActive:YES error:&error]) { NSLog(@"AVAudioSession setActive:YES failed: %@", [error localizedDescription]); } 

Answer 2

It's just that if someone else asks a question ... I got the above work approach that Wertesse suggested, but it also works with AVPlayer (which does not have the useApplicationAudioSession attribute).