IOS NSInternalInconsistencyException when taking a photo when the application uses iOS9 image in image mode

Question

I have a crash when I try to take a picture (a camera with a front bezel), which only fails when the user uses the image in image mode for a separate video application. Everything works fine if the user does not have an image in the picture. The accident occurs on this line:

[stillImageOutput captureStillImageAsynchronouslyFromConnection:videoConnection completionHandler: ^(CMSampleBufferRef imageSampleBuffer, NSError *error) {

with an error

*** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: '*** -[AVCaptureStillImageOutput captureStillImageAsynchronouslyFromConnection:completionHandler:] - inconsistent state.'

I tried to check if the phone could take pictures at all when using the image in image mode, but the default application for the iOS camera can take a picture (although it may use a different shooting method). stillImageOutputand videoConnectionseem customizable and not zero.

Here is the code leading to this crash if it helps.

avCaptureSession = [[AVCaptureSession alloc] init];
AVCaptureDevice* cameraDevice = [GS60_FriendFeed_ScreenshotSelfie_Preview_View frontFacingCameraIfAvailable];
avCaptureSession.sessionPreset = avCaptureSessionPresetString;

NSError *error = nil;
AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:cameraDevice error:&error];
if (!input) {
    NSLog(@"ERROR: trying to open camera: %@", error);
}
[avCaptureSession addInput:input];
AVCaptureStillImageOutput* stillImageOutput = [[AVCaptureStillImageOutput alloc] init];
NSDictionary *outputSettings = [[NSDictionary alloc] initWithObjectsAndKeys: AVVideoCodecJPEG, AVVideoCodecKey, nil];
[stillImageOutput setOutputSettings:outputSettings];
[avCaptureSession addOutput:stillImageOutput];
[avCaptureSession startRunning];

and later

AVCaptureConnection* videoConnection = nil;
AVCaptureStillImageOutput* stillImageOutput = [[avCaptureSession outputs] objectAtIndex:0];
for (AVCaptureConnection* connection in stillImageOutput.connections) {
    for (AVCaptureInputPort *port in [connection inputPorts]) {
        if ([[port mediaType] isEqual:AVMediaTypeVideo] ) {
            videoConnection = connection;
            break;
        }
    }
    if (videoConnection) { break; }
}

UIInterfaceOrientation orientation = [UIApplication sharedApplication].statusBarOrientation;
AVCaptureVideoOrientation avcaptureOrientation = AVCaptureVideoOrientationPortrait;
if(orientation == UIInterfaceOrientationUnknown) {
    avcaptureOrientation = AVCaptureVideoOrientationPortrait;
} else if(orientation == UIInterfaceOrientationPortrait) {
    avcaptureOrientation = AVCaptureVideoOrientationPortrait;
} else if(orientation == UIInterfaceOrientationPortraitUpsideDown) {
    avcaptureOrientation = AVCaptureVideoOrientationPortraitUpsideDown;
} else if(orientation == UIInterfaceOrientationLandscapeLeft) {
    avcaptureOrientation = AVCaptureVideoOrientationLandscapeLeft;
} else if(orientation == UIInterfaceOrientationLandscapeRight) {
    avcaptureOrientation = AVCaptureVideoOrientationLandscapeRight;
}
[videoConnection setVideoOrientation:avcaptureOrientation];

//this line flips the image so it uses exactly what the preview shows
[videoConnection setVideoMirrored:YES];
[stillImageOutput captureStillImageAsynchronouslyFromConnection:videoConnection completionHandler: ^(CMSampleBufferRef imageSampleBuffer, NSError *error) {
...

I would rather be able to take a photograph, but if this is not possible while the picture in the picture is open, knowing how to detect that we can’t take it, it will still be useful.

Thanks for any help.

Answer 1

Make sure the connection is on and on.

if (!videoConnection || !videoConnection.enabled || !videoConnection.active) {
    // Raise error here / warn user... 
    return;
}
UIInterfaceOrientation orientation = [UIApplication sharedApplication].statusBarOrientation;
AVCaptureVideoOrientation avcaptureOrientation = AVCaptureVideoOrientationPortrait;

Answer 2

This can happen when the capture session is interrupted and cannot be started, which can be caused by a phone call, an alarm, an application in split-screen mode on an iPad, or another application using the picture-in-picture mode.

AVCaptureSessionWasInterrupted, .

:

notification.userInfo[AVCaptureSessionInterruptionReasonKey];

, AVCaptureSessionInterruptionEnded, , .

Apple , .