qadd = (s->qscale - 1) | 1;
if (s->h263_aic && s->mb_intra) qadd = 0; else qadd = (s->qscale - 1) | 1;
static void dct_unquantize_h263_c(MpegEncContext *s,                                   DCTELEM *block, int n, int qscale){    int i, level, qmul, qadd;    int nCoeffs;    if (s->mb_intra) {        if (n < 4)             block[0] = block[0] * s->y_dc_scale;        else            block[0] = block[0] * s->c_dc_scale;        i = 1;        nCoeffs= 64; //does not allways use zigzag table     } else {        i = 0;        nCoeffs= zigzag_end[ s->block_last_index[n] ];    }    qmul = s->qscale << 1;    qadd = (s->qscale - 1) | 1;    for(;i<nCoeffs;i++) {        level = block[i];        if (level) {            if (level < 0) {                level = level * qmul - qadd;            } else {                level = level * qmul + qadd;            }#ifdef PARANOID                if (level < -2048 || level > 2047)                    fprintf(stderr, "unquant error %d %d\n", i, level);#endif            block[i] = level;        }    }}