(display a picture in a UIImageView) crash on captureStillImageAsynchronouslyFromConnection - ios

Question

I try to display a picture of the camera in a UIImageView.
I try to debug my application (whit #property (nonatomic,weak) IBOutlet UILabel *messageLabel;
),
-------Line "[output captureStillImageAsynchronouslyFromConnection ..."
I have the value assigned before the call. (self.messageLabel.text = #"before !!"; I never have the value #"Test !!")
the return of the variable result is "OK"
I use Entitlements:
com.apple.security.device.camera
Can you help me debug more detail.
Here is my code
-(NSString*) takePhoto
{
AVCaptureDevice *frontalCamera;
AVCaptureSession *photoSession;
NSString* result;
NSArray *allCameras = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
for ( int i = 0; i < allCameras.count; i++ )
{
AVCaptureDevice *camera = [allCameras objectAtIndex:i];
if ( camera.position == AVCaptureDevicePositionFront )
{
frontalCamera = camera;
}
}
if ( frontalCamera != nil )
{
photoSession = [[AVCaptureSession alloc] init];
NSError *error;
AVCaptureDeviceInput *input =
[AVCaptureDeviceInput deviceInputWithDevice:frontalCamera error:&error];
if ( !error && [photoSession canAddInput:input] )
{
[photoSession addInput:input];
AVCaptureStillImageOutput *output = [[AVCaptureStillImageOutput alloc] init];
[output setOutputSettings:
[[NSDictionary alloc] initWithObjectsAndKeys:AVVideoCodecJPEG,AVVideoCodecKey,nil]];
if ( [photoSession canAddOutput:output] )
{
[photoSession addOutput:output];
AVCaptureConnection *videoConnection = nil;
for (AVCaptureConnection *connection in output.connections)
{
for (AVCaptureInputPort *port in [connection inputPorts])
{
if ([[port mediaType] isEqual:AVMediaTypeVideo] )
{
videoConnection = connection;
break;
}
}
if (videoConnection) { break; }
}
if ( videoConnection )
{
[photoSession startRunning];
result = #"Let's Go ?";
self.messageLabel.text = #"before !!";
[output captureStillImageAsynchronouslyFromConnection:videoConnection
completionHandler:^(CMSampleBufferRef imageDataSampleBuffer, NSError *error) {
self.messageLabel.text = #"Test !!";
if (imageDataSampleBuffer != NULL)
{
NSData *imageData = [AVCaptureStillImageOutput jpegStillImageNSDataRepresentation:imageDataSampleBuffer];
UIImage *photo = [[UIImage alloc] initWithData:imageData];
self.vImage.image = photo;
}
}];
result = #"OK";
}
}
}
}
return result;
}