调整CVPixelBuffer的大小

Question

我正在尝试将CVPixelBuffer的大小调整为128x128。我正在使用一台750x750的。我目前正在使用CVPixelBuffer创建一个新的CGImage，我调整它的大小，然后将其转换回CVPixelBuffer。下面是我的代码：

func getImageFromSampleBuffer (buffer:CMSampleBuffer) -> UIImage? {
    if let pixelBuffer = CMSampleBufferGetImageBuffer(buffer) {
        let ciImage = CIImage(cvPixelBuffer: pixelBuffer)
        let context = CIContext()
        let imageRect = CGRect(x: 0, y: 0, width: 128, height: 128)

        if let image = context.createCGImage(ciImage, from: imageRect) {
            let t = CIImage(cgImage: image)
            let new = t.applying(transformation)
            context.render(new, to: pixelBuffer)

            return UIImage(cgImage: image, scale: UIScreen.main.scale, orientation: .right)
        }

    }

    return nil
}

我还尝试过缩放CIImage，然后转换它：

let t = CIImage(cgImage: image)
let transformation = CGAffineTransform(scaleX: 1, y: 2)
let new = t.applying(transformation)
context.render(new, to: pixelBuffer)

但这也不管用。

任何帮助都是非常感谢的。谢谢!