for(i=1;i<8;i++) { block[block_permute_op(i*8)] -= ac_val[i];
if(s->mb_x==0 || s->qscale == s->qscale_table[xy] || n==1 || n==3){  for(i=1;i<8;i++) { block[block_permute_op(i*8)] -= ac_val[i]; } }else{  for(i=1;i<8;i++) { block[block_permute_op(i*8)] -= ROUNDED_DIV(ac_val[i]*s->qscale_table[xy], s->qscale); }
static void mpeg4_inv_pred_ac(MpegEncContext * s, INT16 *block, int n,                              int dir){    int i;    INT16 *ac_val;    /* find prediction */    ac_val = s->ac_val[0][0] + s->block_index[n] * 16;     if (dir == 0) {        /* left prediction */        ac_val -= 16;        for(i=1;i<8;i++) {            block[block_permute_op(i*8)] -= ac_val[i];        }    } else {        /* top prediction */        ac_val -= 16 * s->block_wrap[n];        for(i=1;i<8;i++) {            block[block_permute_op(i)] -= ac_val[i + 8];        }    }}