func: int ff_rle_encode(uint8_t *outbuf, int out_size, const uint8_t *ptr , int bpp, int w, int8_t add, uint8_t xor)
  
  {
  
      int count, x;
  
      uint8_t *out;
  
  
  
      out = outbuf;
  
  
  
  
  
          for(x = 0; x < w; x += count) {
  
              /* see if we can encode the next set of pixels with RLE */
  
              if((count = count_pixels(ptr, w-x, bpp, 1)) > 1) {
  
                  if(out + bpp + 1 > outbuf + out_size) return -1;
  
                  *out++ = (count ^ xor) + add;
  
                  memcpy(out, ptr, bpp);
  
                  out += bpp;
  
              } else {
  
                  /* fall back on uncompressed */
  
                  count = count_pixels(ptr, w-x, bpp, 0);
  
                  *out++ = count - 1;
  
  
  
                  if(out + bpp*count > outbuf + out_size) return -1;
  
                  memcpy(out, ptr, bpp * count);
  
                  out += bpp * count;
  
          }
  
  
  
          ptr += count * bpp;
  
      }
  
  
  
      return out - outbuf;
  
  }
  