AVCapture Session To Capture Image SWIFT - ios

Question

I have created an AVCaptureSession to capture video output and display it to the user via UIView. Now I want to be able to click a button (takePhoto method) and display the image from the session in an UIImageView. I have tried to iterate through each devices connection and try to save the output but that hasnt worked. The code I have is below
let captureSession = AVCaptureSession()
var stillImageOutput: AVCaptureStillImageOutput!
#IBOutlet var imageView: UIImageView!
#IBOutlet var cameraView: UIView!
// If we find a device we'll store it here for later use
var captureDevice : AVCaptureDevice?
override func viewDidLoad() {
// Do any additional setup after loading the view, typically from a nib.
super.viewDidLoad()
println("I AM AT THE CAMERA")
captureSession.sessionPreset = AVCaptureSessionPresetLow
self.captureDevice = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)
if(captureDevice != nil){
beginSession()
}
}
func beginSession() {
self.stillImageOutput = AVCaptureStillImageOutput()
self.captureSession.addOutput(self.stillImageOutput)
var err : NSError? = nil
self.captureSession.addInput(AVCaptureDeviceInput(device: self.captureDevice, error: &err))
if err != nil {
println("error: \(err?.localizedDescription)")
}
var previewLayer = AVCaptureVideoPreviewLayer(session: self.captureSession)
self.cameraView.layer.addSublayer(previewLayer)
previewLayer?.frame = self.cameraView.layer.frame
captureSession.startRunning()
}
#IBAction func takePhoto(sender: UIButton) {
self.stillImageOutput.captureStillImageAsynchronouslyFromConnection(self.stillImageOutput.connectionWithMediaType(AVMediaTypeVideo)) { (buffer:CMSampleBuffer!, error:NSError!) -> Void in
var image = AVCaptureStillImageOutput.jpegStillImageNSDataRepresentation(buffer)
var data_image = UIImage(data: image)
self.imageView.image = data_image
}
}
}

Answer 1

You should try adding a new thread when adding input and outputs to the session before starting it. In Apple's documentation they state
Important: The startRunning method is a blocking call which can take some time, therefore you should perform session setup on a serial queue so that the main queue isn't blocked (which keeps the UI responsive). See AVCam for iOS for the canonical implementation example.
Try using a dispatch in the create session method such as below
dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0), { // 1
self.captureSession.addOutput(self.stillImageOutput)
self.captureSession.addInput(AVCaptureDeviceInput(device: self.captureDevice, error: &err))
self.captureSession.sessionPreset = AVCaptureSessionPresetPhoto
if err != nil {
println("error: \(err?.localizedDescription)")
}
var previewLayer = AVCaptureVideoPreviewLayer(session: self.captureSession)
previewLayer?.frame = self.cameraView.layer.bounds
previewLayer?.videoGravity = AVLayerVideoGravityResizeAspectFill
dispatch_async(dispatch_get_main_queue(), { // 2
// 3
self.cameraView.layer.addSublayer(previewLayer)
self.captureSession.startRunning()
});
});