调整 CVPixelBuffer 的大小

Question

我正在尝试将 CVPixelBuffer 大小调整为 128x128。我正在使用 750x750 的分辨率。我目前正在使用 CVPixelBuffer 创建一个新的 CGImage，调整大小然后转换回 CVPixelBuffer。这是我的代码：

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)

但这也不起作用。

任何帮助表示赞赏。谢谢！

Answer 1

尝试这个

func getImageFromSampleBuffer (buffer:CMSampleBuffer) -> UIImage? {
    if let pixelBuffer = CMSampleBufferGetImageBuffer(buffer) {
        let ciImage = CIImage(cvPixelBuffer: pixelBuffer)
        let resizedCIImage = ciImage.applying(CGAffineTransform(scaleX: 128.0 / 750.0, y: 128.0 / 750.0))

        let context = CIContext()
        if let image = context.createCGImage(resizedCIImage, from: resizedCIImage.extent) {
            return UIImage(cgImage: image)
        } 
    }
    return nil
}

这里我假设像素缓冲区是方形的并且大小等于 750x750，您可以更改它以适用于所有宽高比和大小