swift 照片拍摄黑色图像

Question

我正在尝试使用 Swift 设置 AVFoundation 照片捕获。预览 window 工作正常，但是当我按下按钮拍摄照片时，应用程序启动后拍摄的第一张照片是全黑的。我在应用程序的同一实例运行中拍摄的任何后续照片都可以正常工作，但第一张总是只是一个黑色矩形。拍照时预览层也会闪黑。这是我用于相机的代码：

import UIKit
import AVFoundation

class photoCaptureViewController: UIViewController {

let session                     : AVCaptureSession = AVCaptureSession()
var previewLayer                : AVCaptureVideoPreviewLayer!
var output = AVCaptureStillImageOutput()
var capturedImage               : UIImage!

override func viewDidLoad() {
    super.viewDidLoad()

  let device = getFrontCamera()
  var error   : NSError? = nil

  let input   : AVCaptureDeviceInput? = AVCaptureDeviceInput.deviceInputWithDevice(device, error: &error) as? AVCaptureDeviceInput

  if input != nil {
    session.addInput(input)
  }else{
    println(error)
  }

  session.sessionPreset = AVCaptureSessionPresetPhoto

  previewLayer = AVCaptureVideoPreviewLayer.layerWithSession(session) as! AVCaptureVideoPreviewLayer
  previewLayer.frame = CGRectMake(0, 0, 300, 300)
  previewLayer.setAffineTransform( CGAffineTransformTranslate(CGAffineTransformMakeScale(0.33, 0.33), -375, -480) )
  previewLayer.position = CGPointMake((photoButton.layer.position.x + 70), (photoButton.layer.position.y - 45))

  previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;

  self.view.layer.addSublayer(previewLayer)

  self.setPreviewOrientation()

  session.startRunning()

}

func setPreviewOrientation() {
  let previewLayerConnection: AVCaptureConnection = self.previewLayer.connection
  let orientation = AVCaptureVideoOrientation(rawValue: UIDevice.currentDevice().orientation.rawValue)
  previewLayerConnection.videoOrientation = orientation!
}

@IBAction func photoButtonPressed(sender: UIButton)
{

  output.outputSettings = [AVVideoCodecKey: AVVideoCodecJPEG]

  if session.canAddOutput(output)
  {
    session.addOutput(output)
  }

  var videoConnection = output.connectionWithMediaType(AVMediaTypeVideo)

  if videoConnection != nil {
    output.captureStillImageAsynchronouslyFromConnection(output.connectionWithMediaType(AVMediaTypeVideo))
      { (imageDataSampleBuffer, error) -> Void in
        self.capturedImage = UIImage(data: AVCaptureStillImageOutput.jpegStillImageNSDataRepresentation(imageDataSampleBuffer))

        UIImageWriteToSavedPhotosAlbum(self.capturedImage, self,nil, nil)

    }}


}

func getFrontCamera() -> AVCaptureDevice{
  var result : AVCaptureDevice!
  var devices = AVCaptureDevice.devicesWithMediaType(AVMediaTypeVideo)
  for device in devices{
    if (device.position == AVCaptureDevicePosition.Front) {
      result = device as! AVCaptureDevice
    }
  }
  return result
}

}

Answer 1

此问题已通过移动

 output.outputSettings = [AVVideoCodecKey: AVVideoCodecJPEG]

if session.canAddOutput(output)
{
  session.addOutput(output)
}

在 viewDidLoad 下，而不是在照片捕获功能中。

swift 照片拍摄黑色图像

swift photo capture black image

avfoundation

ios

swift