j = s->intra_scantable.permutated[i];
j= s->idct_permutation[ ff_zigzag_direct[i] ];
static void mpeg_decode_quant_matrix_extension(MpegEncContext *s){    int i, v, j;    dprintf("matrix extension\n");    if (get_bits1(&s->gb)) {        for(i=0;i<64;i++) {            v = get_bits(&s->gb, 8);            j = s->intra_scantable.permutated[i];            s->intra_matrix[j] = v;            s->chroma_intra_matrix[j] = v;        }    }    if (get_bits1(&s->gb)) {        for(i=0;i<64;i++) {            v = get_bits(&s->gb, 8);            j = s->intra_scantable.permutated[i];            s->inter_matrix[j] = v;            s->chroma_inter_matrix[j] = v;        }    }    if (get_bits1(&s->gb)) {        for(i=0;i<64;i++) {            v = get_bits(&s->gb, 8);            j = s->intra_scantable.permutated[i];            s->chroma_intra_matrix[j] = v;        }    }    if (get_bits1(&s->gb)) {        for(i=0;i<64;i++) {            v = get_bits(&s->gb, 8);            j = s->intra_scantable.permutated[i];            s->chroma_inter_matrix[j] = v;        }    }}