How to convert MTLTexture to CVpixelBuffer for recording in AVAssetWriter?

Question

I have a requirement to apply filters to live video, and I'm trying to do it in Metal.

But I ran into the problem of converting MTLTexture to CVPixelBuffer after encoding the filter into the destination filter. Link ( https://github.com/oklyc/MetalCameraSample-master-2 )

Here are my codes.

if let pixelBuffer = pixelBuffer {
                CVPixelBufferLockBaseAddress(pixelBuffer, CVPixelBufferLockFlags.init(rawValue: 0))             
                let region = MTLRegionMake2D(0, 0, Int(currentDrawable.layer.drawableSize.width), Int(currentDrawable.layer.drawableSize.height))                    
                let bytesPerPixel = 4;
                let bytesPerRow = CGFloat(bytesPerPixel) * currentDrawable.layer.drawableSize.width

                let tempBuffer = CVPixelBufferGetBaseAddress(pixelBuffer)
                destinationTexture.getBytes(tempBuffer!, bytesPerRow: Int(bytesPerRow), from: region1, mipmapLevel: 0)

                let image = self.imageFromCVPixelBuffer(buffer: pixelBuffer)
                CVPixelBufferUnlockBaseAddress(pixelBuffer, CVPixelBufferLockFlags.init(rawValue: 0))

            }

The imageFromCVPixelBuffer method is as follows.

func imageFromCVPixelBuffer(buffer: CVPixelBuffer) -> UIImage {

    let ciimage = CIImage(cvPixelBuffer: buffer)
    let context = CIContext(options: nil)
    let cgimgage = context.createCGImage(ciimage, from: CGRect(x: 0, y: 0, width: CVPixelBufferGetWidth(buffer), height: CVPixelBufferGetHeight(buffer)))

    let uiimage = UIImage(cgImage: cgimgage!)

    return uiimage
}

Here is a screen shot of rendering an image through metal

Here is a screenshot of the same image that converts MTLTexture to CVPixelBuffer.

Converting MTLtexture to CVPixelBuffer is required to write to AVAssetWriter and then save it to the library.

Answer 1

bytesPerRow . Metal, Metal , . , , CVPixelBuffer. CVPixelBufferGetBytesPerRow().