yvu9_to_yuv422

以前在解码indeo video的时候，用到了yvu9，这个比较少见，一般输出驱动都是yuv420或者yuv422,需要转化下：

#include
void yvu9_to_yuv422(uint8_t * yvu90,uint8_t *yvu91, uint8_t *yvu92, uint8_t * dest, int width, int height)
{
    unsigned int x, y;
    for (y = 0; y < height; ++y) {
  uint8_t *Y = yvu90 + y * width;
  uint8_t *Cb = yvu91 + (y >> 2) * (width >> 2);
  uint8_t *Cr = yvu92 + (y >> 2) * (width >> 2);
  for (x = 0; x < width; x += 4) {
      *(dest + 0) = Y[0];
      *(dest + 1) = Cb[0];
      *(dest + 2) = Y[1];
      *(dest + 3) = Cr[0];
      *(dest + 4) = Y[2];
      *(dest + 5) = Cb[0];
      *(dest + 6) = Y[3];
      *(dest + 7) = Cr[0];
      dest += 8;
      Y += 4;
      ++Cb;
      ++Cr;
  }
    }
}