/* Takes s->dstptr to the next macroblock in sequence.  */
static void yop_next_macroblock(YopDecContext *s)
/* Takes s->dstptr to the next macroblock in sequence.  */
static void yop_next_macroblock(YopDecContext *s)
{
    if (s->row_pos == s->frame.linesize[0] - 2) {
        s->dstptr  += s->frame.linesize[0];
        s->row_pos =  0;
    }else {
        s->row_pos += 2;
    }
    s->dstptr += 2;
}