UIImagePickerController slow when there is an active AVSession - ios

Question

I have a UIImagePickerController that can be used for uploading profile images in my social networking application.
It works fine when it is used alone, i.e. no other camera interfering.
In another view, I am using AVCaptureSession and AVCaptureVideoPreviewLayer to embed the camera view inside the view. Here users can upload various photos that they have captured.
This also works fine when it is used alone, i.e. no other camera interfering.
(This is a Tab-Bar Application)
Whenever the AVCapturePreviewLayer is active, and I enter the view with the UIImagePickerController, the imagePicker takes a very long time to load, and sometimes it just freezes.
This is how I initialise the AVSession/AVCapturePreviewLayer:
self.session = [[AVCaptureSession alloc] init];
self.session.sessionPreset = AVCaptureSessionPreset640x480;
self.captureVideoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.session];
self.captureVideoPreviewLayer.frame = self.cameraView.bounds;
[self.captureVideoPreviewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];
[self.cameraView.layer addSublayer:self.captureVideoPreviewLayer];
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
NSError *error = nil;
AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:&error];
if (!input) {
// Handle the error appropriately.
NSLog(#"ERROR: trying to open camera: %#", error);
}else
[self.session addInput:input];
self.stillImageOutput = [[AVCaptureStillImageOutput alloc] init];
NSDictionary *outputSettings = [[NSDictionary alloc] initWithObjectsAndKeys: AVVideoCodecJPEG, AVVideoCodecKey, nil];
[self.stillImageOutput setOutputSettings:outputSettings];
[self.session addOutput:self.stillImageOutput];
This is how i initialise the UIImagePickerController:
self.picker = [[UIImagePickerController alloc] init];
self.picker.delegate = self;
self.picker.allowsEditing = YES;
self.picker.sourceType = UIImagePickerControllerSourceTypeCamera;
[self presentViewController:self.picker animated:YES completion:NULL];
Why does the UIImagePickerController take forever to load when the previewLayer is active in another view?
How can I reduce the loading time for the UIImagePickerController?

Answer 1

Ok. It seems like calling:
[AVSession stopRunning];
in viewDidDisappear:(BOOL)animated
fixes this issue for me.