将CMSampleBuffer转换为UIImage

Question

我正在尝试将sampleBuffer转换为UIImage并使用colorspaceGray在图像视图中显示它。但它显示为以下图像。我认为转换存在问题。如何转换CMSampleBuffer？

func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, from connection: AVCaptureConnection!) {
    print("buffered")
    let imageBuffer: CVImageBuffer = CMSampleBufferGetImageBuffer(sampleBuffer)!
    CVPixelBufferLockBaseAddress(imageBuffer, CVPixelBufferLockFlags(rawValue: 0))
    let width: Int = CVPixelBufferGetWidth(imageBuffer)
    let height: Int = CVPixelBufferGetHeight(imageBuffer)
    let bytesPerRow: Int = CVPixelBufferGetBytesPerRow(imageBuffer)
    let lumaBuffer = CVPixelBufferGetBaseAddress(imageBuffer)

    //let planeCount : Int = CVPixelBufferGetPlaneCount(imageBuffer)
    let grayColorSpace: CGColorSpace = CGColorSpaceCreateDeviceGray()
    let context: CGContext = CGContext(data: lumaBuffer, width: width, height: height, bitsPerComponent: 8, bytesPerRow: bytesPerRow , space: grayColorSpace, bitmapInfo: CGImageAlphaInfo.none.rawValue)!
    let dstImageFilter: CGImage = context.makeImage()!
    let imageRect : CGRect = CGRect(x: 0, y: 0, width: width, height: height)
    context.draw(dstImageFilter, in: imageRect)
    let image = UIImage(cgImage: dstImageFilter)
    DispatchQueue.main.sync(execute: {() -> Void in
        self.imageTest.image = image
    })
}

Answer 1

转换很简单：

@IBAction func BellAction(_ sender: Any) {
    let searchVC = self.storyboard?.instantiateViewController(withIdentifier:StoryBoardIDs.Notification.rawValue)
    self.navigationController?.pushViewController(searchVC!, animated: true)
}

Answer 2

看起来CMSampleBuffer正在为您提供RGBA数据，然后您可以直接构建灰度图像。您将需要构建一个新的缓冲区，对于每个像素，您执行gray = (pixel.red+pixel.green+pixel.blue)/3之类的操作。或者您需要根据收到的数据创建一个普通的RGBA图像，然后将其转换为灰度。

但是在你的代码中你根本没有过渡。无论那里有什么类型的数据，您都使用CVPixelBufferGetBaseAddress将原始指针带到缓冲区。然后你只需在创建图像时传递相同的指针，该图像假定接收的数据是灰度的。

Answer 3

一种更现代的解决方案，其中包含方向定位，无需进行CGImage转换即可提高性能：

func orientation() -> UIImage.Orientation {
    let curDeviceOrientation = UIDevice.current.orientation
    var exifOrientation: UIImage.Orientation
    switch curDeviceOrientation {
        case UIDeviceOrientation.portraitUpsideDown:  // Device oriented vertically, Home button on the top
            exifOrientation = .left
        case UIDeviceOrientation.landscapeLeft:       // Device oriented horizontally, Home button on the right
            exifOrientation = .upMirrored
        case UIDeviceOrientation.landscapeRight:      // Device oriented horizontally, Home button on the left
            exifOrientation = .down
        case UIDeviceOrientation.portrait:            // Device oriented vertically, Home button on the bottom
            exifOrientation = .up
        default:
            exifOrientation = .up
    }
    return exifOrientation
}

func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputSampleBuffer sampleBuffer: CMSampleBuffer!, from connection: AVCaptureConnection!) {
    guard let imageBuffer: CVPixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer) else { return }
    let ciimage : CIImage = CIImage(cvPixelBuffer: imageBuffer)
    let image = UIImage.init(ciImage: ciimage, scale: 1.0, orientation: orientation())
}