iOS：解码YUY2视频帧

Question

我正在尝试使用YUY2视频并在iOS设备上一次显示一帧。我最终将使用YUY2数据流，但目前我正在使用录制的文件。

不幸的是，我似乎无法正确转换。我正在使用CoreVideo，我的代码基于一堆从互联网上拼凑而成的零碎例子。目前我正在收视频垃圾。

到目前为止，这是我的代码，谢谢你看看：

import UIKit
import AVKit
import AVFoundation
import CoreGraphics

class ViewController: UIViewController {

    var url: URL!
    var buffer: Data!
    var image: UIImage!

    override func viewDidLoad() {
        super.viewDidLoad()
        let path = Bundle.main.path(forResource: "gst-video", ofType: "yuy2")!
        self.url = URL(fileURLWithPath: path)

        // Examining the video file in a Hex Editor shows the frame size of 614400
        let data = try! Data(contentsOf: self.url)
        let sub = data.subdata(in: 0..<614400)
        self.buffer = sub

    }

    override func viewDidAppear(_ animated: Bool) {
        super.viewDidAppear(animated)

        var pixelBufferOut: CVPixelBuffer?
        let attributes : [NSObject:AnyObject] = [
            kCVPixelBufferCGImageCompatibilityKey : true as AnyObject,
            kCVPixelBufferCGBitmapContextCompatibilityKey : true as AnyObject,
        ]

        CVPixelBufferCreateWithBytes(kCFAllocatorDefault, 640, 480, kCVPixelFormatType_422YpCbCr8_yuvs, UnsafeMutablePointer(&buffer), 8, nil, nil, attributes as CFDictionary, &pixelBufferOut)

        guard let pixelBuffer = pixelBufferOut else {
            return
        }

        CVPixelBufferLockBaseAddress(pixelBuffer, CVPixelBufferLockFlags(rawValue: 0))

        let ciImage = CIImage(cvPixelBuffer: pixelBuffer)
        let ciContext = CIContext(options: nil)
        let frameImage = ciContext.createCGImage(ciImage, from: ciImage.extent)

        let frame = UIImage(cgImage: frameImage!)
        print(frame.cgImage)

        self.image = frame

        let imageView = UIImageView()
        imageView.image = frame

        imageView.frame.origin = CGPoint(x: 8, y: 32)
        imageView.frame.size = frame.size

        view.addSubview(imageView)

        CVPixelBufferUnlockBaseAddress(pixelBuffer, CVPixelBufferLockFlags(rawValue: 0))

    }
}