在OpenCV中从RGB转换为YUYV

Question

Is there a way to convert from RGB to YUYV (YUY 4:2:2) format? I noted that OpenCV has reverse operation, but not RGB to YUYV for some reason. Maybe someone can point to code which does that (even outside of OpenCV library)?

UPDATE

I found libyuv library which may work for this purpose by doing BGR to ARGB conversion and then ARGB to YUY2 format (hopefully this is the same as YUYV 4:2:2). But it doesn't seem to work. Do you happen to know what yuyv buffer dimensions/type should look like? What its stride?

To clarify YUYV and YUY2 are the same formats if it helps.

UPDATE 2 Here is my code of using libyuv library:

  Mat frame;
  // Convert original image im from BGR to BGRA for further use in libyuv
  cvtColor(im, frame, CVX_BGR2BGRA);
  // Actually libyuv requires ARGB (i.e. reverse of BGRA), so I swap channels here
  int from_to[] = { 0,3, 1,2, 2,1, 3,0 };
  mixChannels(&frame, 1, &frame, 1, from_to, 4);
  // This is the most confusing part. Not sure what argb_stride suppose to be - length of a row in bytes or size of single value in the array?
  const uint8_t* argb_data = frame.data;
  int argb_stride = 8;

  // Also it is not clear what size of yuyv frame should be since we duplicate one Y 
  Mat yuyv(frame.rows, frame.cols, CVX_8UC2);
  uint8_t* yuyv_data = yuyv.data;
  int yuyv_stride = 16;
  // Do actual conversion
  libyuv::ARGBToYUY2(argb_data, argb_stride, yuyv_data, yuyv_stride, 
  frame.cols, frame.rows);
  // Then I feed yuyv_data to video stream buffer and see green or purple image instead of video stream.

UPDATE 3

  Mat frame;
  cvtColor(im, frame, CVX_BGR2BGRA);

  // ARGB
  int from_to[] = { 0,3, 1,2, 2,1, 3,0 };
  Mat rgba(frame.size(), frame.type());
  mixChannels(&frame, 1, &rgba, 1, from_to, 4);
  const uint8_t* argb_data = rgba.data;
  int argb_stride = rgba.cols*4;

  Mat yuyv(rgba.rows, rgba.cols, CVX_8UC2);
  uint8_t* yuyv_data = yuyv.data;
  int yuyv_stride = width * 2;
  int res = libyuv::ARGBToYUY2(argb_data, argb_stride, yuyv_data, yuyv_stride, rgba.cols, rgba.rows);

Answer 1

似乎虽然方法被称为ARGBToYUY2，但它需要BGRA的频道顺序（而不是反向）。