ios - 输出相机帧缓冲区不会出现

Question

我为相机类实现了 AVCaptureVideoDataOutputSampleBufferDelegate

设置所需的视频输入并开始 session ，摄像头工作正常，可以在预览中看到

我也想获得一些处理的像素缓冲区

fileprivate func configureVideoOutput() {
    let videoOutput = AVCaptureVideoDataOutput()
    videoOutput.setSampleBufferDelegate(self, queue: DispatchQueue(label: "sample buffer"))

    if self.session.canAddOutput(videoOutput) {
        print("canAddOutput yes")
        self.session.addOutput(videoOutput)
        print("canAddOutput yes added")
    } else {
        print("canAddOutput no")
    }
}

func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, from connection: AVCaptureConnection!) {
    print("Got a frame!")
}

它打印 "canAddOutput yes added" ok

但它从不打印 "Got a frame!"

Answer 1

必须先设置输出类型

videoOutput.videoSettings = [kCVPixelBufferPixelFormatTypeKey as String: kCVPixelFormatType_32BGRA]

编辑:将委托(delegate)函数改为

public func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {
   print("Got a frame 1!") 
}