如何AVCaptureSession.sessionPreset到720x1280px（或1/1.77规模的任何东西）

Question

我使用swift3和我的决心，当我使用AVCaptureSessionPresetMedium等它不适合屏幕比例无法改变自定义值（1/1.77）。

let output = AVCaptureVideoDataOutput() 

    output.setSampleBufferDelegate(self, queue: sampleQueue) 

    let metaOutput = AVCaptureMetadataOutput() 
    metaOutput.setMetadataObjectsDelegate(self, queue: faceQueue) 

    session.beginConfiguration() 

//期望的分辨率：720x1280px // session.sessionPreset = AVCaptureSessionPresetMedium;

if session.canAddInput(input) { 
     session.addInput(input) 
    } 
    if session.canAddOutput(output) { 
     output .alwaysDiscardsLateVideoFrames = true; 
     session.addOutput(output) 
     connection1 = output.connection(withMediaType: AVMediaTypeVideo) 
     connection1?.preferredVideoStabilizationMode = AVCaptureVideoStabilizationMode.auto; 
     connection1?.videoOrientation = .portrait 
     connection1?.isVideoMirrored = true; 
    } 
    if session.canAddOutput(metaOutput) { 
     output .alwaysDiscardsLateVideoFrames = true; 
     session.addOutput(metaOutput) 
     connection2 = metaOutput.connection(withMediaType: AVMediaTypeMetadata) 
     connection2?.preferredVideoStabilizationMode = AVCaptureVideoStabilizationMode.auto; 
     connection2?.videoOrientation = .portrait 
     connection2?.isVideoMirrored = true 
    } 

Answer 1

您应该使用AVCaptureSessionPreset1280x720预设。预设以横向表示，但1280x720的捕捉设置与720x1280相同，唯一的区别在于方向。例如有一个应用程序，支持旋转：

func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, from connection: AVCaptureConnection!) 
{ 
    guard let pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer) else { return } 
    cameraImage = CIImage(cvPixelBuffer: pixelBuffer) 
    print(cameraImage?.extent ?? "") 
} 

将打印(0.0, 0.0, 1280.0, 720.0)景观的时候，和(0.0, 0.0, 720.0, 1280.0)人像时。