如何快速创建用于视频捕获输出的缓冲区

Question

我正在构建一个相机扫描应用程序，该应用程序将使用外部SDK解码和处理所需输出的图像帧。 SDK公开的api用于读取视频输出的帧，并且具有类型为buffer: UnsafeMutablePointer<BYTES>的参数，用于实际执行解码。

所以我想将视频帧的输出转换为UnsafeMutablePointer<UInt8>

我按照本教程https://medium.com/ios-os-x-development/ios-camera-frames-extraction-d2c0f80ed05a进行了操作，AVCaptureVideoDataOutputSampleBufferDelegate

我曾尝试将imageData转换为字节，但无法正常工作。

注意：以下是我在Objective C中的SDK中的示例代码，但由于我不知道Objective C，所以无法将其转换为swift。

func captureOutput(_ output: AVCaptureOutput, didOutput sampleBuffer: CMSampleBuffer, from connection: AVCaptureConnection) {

    guard let pixelBuffer: CVPixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer) else {
        return
    }

    let width: Int = CVPixelBufferGetWidth(pixelBuffer)
    let height = CVPixelBufferGetHeight(pixelBuffer)

    let ciImage = CIImage(cvPixelBuffer: pixelBuffer)

    guard let cgImage = context.createCGImage(ciImage, from: ciImage.extent) else {
        return
    }

    guard var imageData = UIImage(cgImage: cgImage).jpegData(compressionQuality: 1.0) else{
        return
    }
    print("Width : \(width) & Height: \(height)")
    print(imageData.count)

    imageData.withUnsafeMutableBytes({(bytes: UnsafeMutablePointer<UInt8>) -> Void in
        // Get Bytes Here
    })

    // I have tried bello code too - not working
    /* let mem = UnsafeMutablePointer<UInt8>.allocate(capacity: imageData.count)
       _  = imageData.copyBytes(to: UnsafeMutableBufferPointer(start: mem, count: 1))

       let imageByte = mem.move()
       mem.deallocate()

       let imageByte = [UInt8](imageData) */

}

Bellow是与我正在使用的SDK配合使用的Objective C示例代码

uint8_t *buffer;

- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputSampleBuffer:(CMSampleBufferRef)sampleBuffer fromConnection:(AVCaptureConnection *)connection
{ // got an image
CVPixelBufferRef pixelBuffer = CMSampleBufferGetImageBuffer(sampleBuffer);
CVPixelBufferLockBaseAddress(pixelBuffer, 0);
size_t width    = CVPixelBufferGetWidth      (pixelBuffer);
size_t height   = CVPixelBufferGetHeight     (pixelBuffer);
size_t pitch    = CVPixelBufferGetBytesPerRow(pixelBuffer);
uint8_t *source = (uint8_t *) CVPixelBufferGetBaseAddress(pixelBuffer);
if (buffer == NULL)
{
    buffer = (uint8_t *) malloc(width * height);
}
for (int y = 0; y < height; y++)
{
    for (int x = 0; x < width; x++)
    {
        int sum;
        sum  =  77 * *source++;
        sum += 151 * *source++;
        sum +=  28 * *source++;
        *buffer++ = sum >> 8;
        source++;
    }
    source += pitch - 4 * width;
}
buffer -= width * height;
CVPixelBufferUnlockBaseAddress(pixelBuffer, 0);

// This works I can use the buffer now in the SDK

}

先谢谢了

因此，我希望能够在UnsafeMutablePointer中获取图像缓冲区。.谢谢