IMG = Lenna.png
WIDTH = 512
HEIGHT = 512
 
OBJS += raw2mat.o
 
CFLAGS += -g -Wall
CFLAGS += -DWIDTH=$(WIDTH) -DHEIGHT=$(HEIGHT)
CFLAGS += `pkg-config --cflags opencv`
LDFLAGS += `pkg-config --libs opencv`
 
PRGLD = $(CXX)
 
%.o: %.c $(DEPS)
        $(CC) -c -o $@ $< $(CFLAGS)
 
%.o: %.cpp $(DEPS)
        $(CXX) -c -o $@ $< $(CFLAGS)
 
 
raw2Mat: $(OBJS)
        $(PRGLD) -o $@ $^ $(CFLAGS) $(LDFLAGS)
 
raw:
        @echo "more format: ffmpeg -pix_fmt list"
        ffmpeg -i $(IMG) -f rawvideo -pix_fmt yuv420p -y img.raw

#include <cv.h>
#include <highgui.h>
#include <stdio.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <assert.h>
 
#define YUV_SIZE(W, H) ((W * H * 3) / 2)
 
int main(void) {
  const int width = WIDTH;
  const int height = HEIGHT;
  const int stride = WIDTH;
  const int buff_size = YUV_SIZE(width, height);
  unsigned char* buff;
  buff = new unsigned char[buff_size];
  {
    int fd = open("img.raw", O_RDONLY);
    if (fd == -1) {
      perror(NULL);
      exit(1);
    }
    int err = read(fd, buff, sizeof(unsigned char) * buff_size);
    assert(err == buff_size * sizeof(unsigned char));
    close(fd);
  }
  cv::Mat Y, U, V;
  {
    unsigned char* v_ptr = buff + stride * height;
    unsigned char* u_ptr = v_ptr + ((stride>>1) * (height>>1));
    Y = cv::Mat(width, height, CV_8UC1, buff, stride);
    U = cv::Mat(width>>1, height>>1, CV_8UC1, u_ptr, stride>>1);
    V = cv::Mat(width>>1, height>>1, CV_8UC1, v_ptr, stride>>1);
  }
 
  cv::Mat U2, V2;
  cv::resize(U, U2, cv::Size(0, 0), 2, 2, cv::INTER_LINEAR);
  cv::resize(V, V2, cv::Size(0, 0), 2, 2, cv::INTER_LINEAR);
 
  cv::Mat plans[] =  {Y, U2, V2};
  cv::Mat YUV;
  cv::merge(plans, 3, YUV);
 
  cv::Mat RGB;
  cv::cvtColor(YUV, RGB, CV_YCrCb2BGR);
 
  cv::namedWindow("Y", CV_WINDOW_AUTOSIZE);
  cv::namedWindow("U", CV_WINDOW_AUTOSIZE);
  cv::namedWindow("V", CV_WINDOW_AUTOSIZE);
 
  cv::imshow("Y", Y);  cv::imshow("U", U);  cv::imshow("V", V);
 
  /* create a window */
  cv::namedWindow("image", CV_WINDOW_AUTOSIZE);
  /* display the image */
  cv::imshow("image", RGB);
  /* wait until user press a key */
  cv::waitKey(0);
  /* free memory */
  cv::destroyWindow("image");
  cv::destroyWindow("Y");
  cv::destroyWindow("U");
  cv::destroyWindow("V");
 
  delete[] buff;
  return 0;
}