iPhone AVFoundation camera orientation

Question

I\'ve been tearing my hair out trying to get the AVFoundation camera to capture a picture in the correct orientation (i.e. the device orientation) but I can\'t get it to wor

Answer 1

Swift 4 & Swift 5.

Here we go:

private var requests = [VNRequest]()
let exifOrientation = exifOrientationFromDeviceOrientation()
let imageRequestHandler = VNImageRequestHandler(cvPixelBuffer: pixelBuffer, orientation: exifOrientation, options: [:])
do {
  try imageRequestHandler.perform(self.requests)
} catch {
  print(error)
}

public func exifOrientationFromDeviceOrientation() -> CGImagePropertyOrientation {
    let curDeviceOrientation = UIDevice.current.orientation
    let exifOrientation: CGImagePropertyOrientation

    switch curDeviceOrientation {
    case UIDeviceOrientation.portraitUpsideDown:  // Device oriented vertically, home button on the top
        exifOrientation = .upMirrored
    case UIDeviceOrientation.landscapeLeft:       // Device oriented horizontally, home button on the right
        exifOrientation = .left
    case UIDeviceOrientation.landscapeRight:      // Device oriented horizontally, home button on the left
        exifOrientation = .right
    case UIDeviceOrientation.portrait:            // Device oriented vertically, home button on the bottom
        exifOrientation = .up
    default:
        exifOrientation = .up
    }
    return exifOrientation
}

Answer 2

there are two things to notice

a) as Brian King wrote - LandscapeRight and LandscapeLeft are swapped in the enumeration. see AVCamCaptureManager example:

// AVCapture and UIDevice have opposite meanings for landscape left and right (AVCapture orientation is the same as UIInterfaceOrientation)
else if (deviceOrientation == UIDeviceOrientationLandscapeLeft)
    orientation = AVCaptureVideoOrientationLandscapeRight;
else if (deviceOrientation == UIDeviceOrientationLandscapeRight)
    orientation = AVCaptureVideoOrientationLandscapeLeft;

b) There are also UIDeviceOrientationFaceUp and UIDeviceOrientationFaceDown states, that if you try to set as the video orientation, your video will fail recording. Make sure you don't use them when calling [UIDevice currentDevice].orientation !

Answer 3

Update the orientation in the preview layer after start the capture session and whenever the device is rotated.

override func viewWillTransition(to size: CGSize, with coordinator: UIViewControllerTransitionCoordinator) {
    coordinator.animate(alongsideTransition: { [weak self] context in
        if let connection = self?.previewLayer?.connection, connection.isVideoOrientationSupported {
            if let orientation = AVCaptureVideoOrientation(orientation: UIDevice.current.orientation) {
                connection.videoOrientation = orientation
            }
        }
    }, completion: nil)
    super.viewWillTransition(to: size, with: coordinator)
}

extension AVCaptureVideoOrientation {
    init?(orientation: UIDeviceOrientation) {
        switch orientation {
        case .landscapeRight: self = .landscapeLeft
        case .landscapeLeft: self = .landscapeRight
        case .portrait: self = .portrait
        case .portraitUpsideDown: self = .portraitUpsideDown
        default: return nil
        }
    }
}

Answer 4

If you're using AVCaptureVideoPreviewLayer you can do the following inside your view controller.

(assuming you have an instance of AVCaptureVideoPreviewLayer called "previewLayer")

- (BOOL)shouldAutorotateToInterfaceOrientation:(UIInterfaceOrientation)interfaceOrientation {
   [self.previewLayer setOrientation:[[UIDevice currentDevice] orientation]];
}

Answer 5

In Swift you should do this:

    videoOutput = AVCaptureVideoDataOutput()
    videoOutput!.setSampleBufferDelegate(self, queue: dispatch_queue_create("sample buffer delegate", DISPATCH_QUEUE_SERIAL))

    if captureSession!.canAddOutput(self.videoOutput) {
        captureSession!.addOutput(self.videoOutput)
    }

    videoOutput!.connectionWithMediaType(AVMediaTypeVideo).videoOrientation = AVCaptureVideoOrientation.PortraitUpsideDown

It works perfectly for me!

Answer 6

You can also create an intermediate CIImage, and grab the properties dictionary

NSDictionary *propDict = [aCIImage properties];
NSString *orientString = [propDict objectForKey:kCGImagePropertyOrientation];

And Transform accordingly :)

I love how easy it is to access all this image metadata in iOS5!