guess_dc(s, s->dc_val[0], s->mb_width*2, s->mb_height*2, s->b8_stride, 1);
guess_dc(s, s->dc_val[1], s->mb_width , s->mb_height , s->mb_stride, 0);
guess_dc(s, s->dc_val[2], s->mb_width , s->mb_height , s->mb_stride, 0);
guess_dc(s, s->dc_val[0], s->mb_width*2, s->mb_height*2, s->b8_stride, 1);
guess_dc(s, s->dc_val[1], s->mb_width , s->mb_height , s->mb_stride, 0);
guess_dc(s, s->dc_val[2], s->mb_width , s->mb_height , s->mb_stride, 0);