iOS: error in __connection_block_invoke_2: Connection interrupted

Question

Xcode/iOS 8/AVFoundation related error in console:

error in __connection_block_invoke_2: Connection interrupted

I am just adding AVCaptureVideoDataOutput to Apple's sample app 'AVCamManualUsingtheManualCaptureAPI'

What I added was:

    // CoreImage wants BGRA pixel format
    NSDictionary *outputSettings = @{ (id)kCVPixelBufferPixelFormatTypeKey : [NSNumber numberWithInteger:kCVPixelFormatType_32BGRA]};

    // create and configure video data output
    AVCaptureVideoDataOutput *videoDataOutput = [[AVCaptureVideoDataOutput alloc] init];
    videoDataOutput.videoSettings = outputSettings;
    videoDataOutput.alwaysDiscardsLateVideoFrames = YES;
    [videoDataOutput setSampleBufferDelegate:self queue:sessionQueue];

Above snippet inserted in to sample project:

- (void)viewDidLoad
{
    [super viewDidLoad];

    self.view.autoresizingMask = UIViewAutoresizingFlexibleWidth | UIViewAutoresizingFlexibleHeight;

    self.recordButton.layer.cornerRadius = self.stillButton.layer.cornerRadius = self.cameraButton.layer.cornerRadius = 4;
    self.recordButton.clipsToBounds = self.stillButton.clipsToBounds = self.cameraButton.clipsToBounds = YES;

    // Create the AVCaptureSession
    AVCaptureSession *session = [[AVCaptureSession alloc] init];
    [self setSession:session];

    // Set up preview
    [[self previewView] setSession:session];

    // Check for device authorization
    [self checkDeviceAuthorizationStatus];

    // In general it is not safe to mutate an AVCaptureSession or any of its inputs, outputs, or connections from multiple threads at the same time.
    // Why not do all of this on the main queue?
    // -[AVCaptureSession startRunning] is a blocking call which can take a long time. We dispatch session setup to the sessionQueue so that the main queue isn't blocked (which keeps the UI responsive).

    dispatch_queue_t sessionQueue = dispatch_queue_create("session queue", DISPATCH_QUEUE_SERIAL);
    [self setSessionQueue:sessionQueue];

    dispatch_async(sessionQueue, ^{
        [self setBackgroundRecordingID:UIBackgroundTaskInvalid];

        NSError *error = nil;

        AVCaptureDevice *videoDevice = [AAPLCameraViewController deviceWithMediaType:AVMediaTypeVideo preferringPosition:AVCaptureDevicePositionBack];
        AVCaptureDeviceInput *videoDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:videoDevice error:&error];

        if (error)
        {
            NSLog(@"%@", error);
        }

        [[self session] beginConfiguration];

        if ([session canAddInput:videoDeviceInput])
        {
            [session addInput:videoDeviceInput];
            [self setVideoDeviceInput:videoDeviceInput];
            [self setVideoDevice:videoDeviceInput.device];

            dispatch_async(dispatch_get_main_queue(), ^{
                // Why are we dispatching this to the main queue?
                // Because AVCaptureVideoPreviewLayer is the backing layer for our preview view and UIView can only be manipulated on main thread.
                // Note: As an exception to the above rule, it is not necessary to serialize video orientation changes on the AVCaptureVideoPreviewLayer’s connection with other session manipulation.

                [[(AVCaptureVideoPreviewLayer *)[[self previewView] layer] connection] setVideoOrientation:(AVCaptureVideoOrientation)[self interfaceOrientation]];
            });
        }

        AVCaptureDevice *audioDevice = [[AVCaptureDevice devicesWithMediaType:AVMediaTypeAudio] firstObject];
        AVCaptureDeviceInput *audioDeviceInput = [AVCaptureDeviceInput deviceInputWithDevice:audioDevice error:&error];

        if (error)
        {
            NSLog(@"%@", error);
        }

        if ([session canAddInput:audioDeviceInput])
        {
            [session addInput:audioDeviceInput];
        }

        AVCaptureMovieFileOutput *movieFileOutput = [[AVCaptureMovieFileOutput alloc] init];
        if ([session canAddOutput:movieFileOutput])
        {
            [session addOutput:movieFileOutput];
            AVCaptureConnection *connection = [movieFileOutput connectionWithMediaType:AVMediaTypeVideo];
            if ([connection isVideoStabilizationSupported])
            {
                [connection setEnablesVideoStabilizationWhenAvailable:YES];
            }
            [self setMovieFileOutput:movieFileOutput];
        }

        AVCaptureStillImageOutput *stillImageOutput = [[AVCaptureStillImageOutput alloc] init];
        if ([session canAddOutput:stillImageOutput])
        {
            [stillImageOutput setOutputSettings:@{AVVideoCodecKey : AVVideoCodecJPEG}];
            [session addOutput:stillImageOutput];
            [self setStillImageOutput:stillImageOutput];
        }
            // CoreImage wants BGRA pixel format
NSDictionary *outputSettings = @{ (id)kCVPixelBufferPixelFormatTypeKey : [NSNumber numberWithInteger:kCVPixelFormatType_32BGRA]};

// create and configure video data output
AVCaptureVideoDataOutput *videoDataOutput = [[AVCaptureVideoDataOutput alloc] init];
videoDataOutput.videoSettings = outputSettings;
videoDataOutput.alwaysDiscardsLateVideoFrames = YES;
[videoDataOutput setSampleBufferDelegate:self queue:sessionQueue];

        [[self session] commitConfiguration];

        dispatch_async(dispatch_get_main_queue(), ^{
            [self configureManualHUD];
        });
    });

    self.manualHUDFocusView.hidden = YES;
    self.manualHUDExposureView.hidden = YES;
    self.manualHUDWhiteBalanceView.hidden = YES;
}

I get 'error in __connection_block_invoke_2: Connection interrupted' and also...

-(void) captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection

..delegate never gets called.

All I am trying to do is modify their code to do live Core Image Filters.

Answer 1

So I fixed the issue.

You can't use AVCaptureMovieFileOutput and AVCaptureVideoDataOutput simultaneously. I took out AVCaptureMovieFileOutput, and the AVCaptureVideoDataOutput delegate is called.