[英]AVCapture Session To Capture Image SWIFT
我创建了一个AVCaptureSession来捕获视频输出并通过UIView将其显示给用户。 现在我希望能够单击按钮(takePhoto方法)并在UIImageView中显示会话中的图像。 我试图迭代每个设备连接并尝试保存输出但是没有用。 我的代码如下
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
}
}
}
在启动之前向会话添加输入和输出时,应尝试添加新线程。 在Apple的文档中,他们说
重要提示:startRunning方法是一个阻塞调用,可能需要一些时间,因此您应该在串行队列上执行会话设置,以便不阻止主队列(这使UI保持响应)。 有关规范实现示例,请参阅AVCam for iOS。
尝试在create session方法中使用调度,如下所示
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()
});
});
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