func: static int ipvideo_decode_block_opcode_0xD(IpvideoContext *s, AVFrame *frame)
  {
      int y;
      unsigned char P[2];
      /* 4-color block encoding: each 4x4 block is a different color */
      for (y = 0; y < 8; y++) {
          if (!(y & 3)) {
              P[0] = bytestream2_get_byte(&s->stream_ptr);
              P[1] = bytestream2_get_byte(&s->stream_ptr);
          memset(s->pixel_ptr,     P[0], 4);
          memset(s->pixel_ptr + 4, P[1], 4);
          s->pixel_ptr += s->stride;
      /* report success */
      return 0;