ios - 在 Swift 中从 AVCaptureSession 捕获静止图像

Question

我有一个在 UIView 中显示实时视频的 AVCaptureSession，我想将视频流的一帧保存为 UIImage。我一直在剖析我在互联网上经常看到的代码，但我在第一行遇到了问题:

if let stillOutput = self.stillImageOutput {
    // Establish an AVCaptureConnection and capture a still image from it.
}

这给我错误“相机”没有名为“stillImageOutput”的成员。代码取决于能够从输出中获取视频连接。

如果有帮助，我可以发布完整的代码块。谢谢!

Answer 1

一旦有了stillImageOutput，您就可以使用以下方法来捕获图像

 stillImageOutput.outputSettings = [AVVideoCodecKey:AVVideoCodecJPEG]
    if captureSession.canAddOutput(stillImageOutput) {
        captureSession.addOutput(stillImageOutput)
    }

    // I had to add timer otherwise quality was messed up in iPad
    var timer = NSTimer.scheduledTimerWithTimeInterval(0.4, target: self, selector: Selector("getImage"), userInfo: nil, repeats: false)

比起我获取图像的函数

func getImage() {

    if let videoConnection = stillImageOutput.connectionWithMediaType(AVMediaTypeVideo) {
        stillImageOutput.captureStillImageAsynchronouslyFromConnection(videoConnection) {
            (imageDataSampleBuffer, error) -> Void in
            let imageData = AVCaptureStillImageOutput.jpegStillImageNSDataRepresentation(imageDataSampleBuffer)

//          Use your image or store to Album

//          UIImageWriteToSavedPhotosAlbum(UIImage(data: imageData), nil, nil, nil)
            self.stopSession()

        }
    }

}

并停止 session 并删除预览层

func stopSession(){


    self.captureSession.stopRunning()
    self.previewLayer?.removeFromSuperlayer()

}