int i;
int qscale;
static void convert_matrix(int *qmat, UINT16 *qmat16, const UINT16 *quant_matrix, int qscale){    int i;    if (av_fdct == jpeg_fdct_ifast) {        for(i=0;i<64;i++) {            /* 16 <= qscale * quant_matrix[i] <= 7905 */            /* 19952         <= aanscales[i] * qscale * quant_matrix[i]           <= 249205026 */            /* (1<<36)/19952 >= (1<<36)/(aanscales[i] * qscale * quant_matrix[i]) >= (1<<36)/249205026 */            /* 3444240       >= (1<<36)/(aanscales[i] * qscale * quant_matrix[i]) >= 275 */                        qmat[block_permute_op(i)] = (int)((UINT64_C(1) << (QMAT_SHIFT + 11)) /                             (aanscales[i] * qscale * quant_matrix[block_permute_op(i)]));        }    } else {        for(i=0;i<64;i++) {            /* We can safely suppose that 16 <= quant_matrix[i] <= 255               So 16           <= qscale * quant_matrix[i]             <= 7905               so (1<<19) / 16 >= (1<<19) / (qscale * quant_matrix[i]) >= (1<<19) / 7905               so 32768        >= (1<<19) / (qscale * quant_matrix[i]) >= 67            */            qmat[i]   = (1 << QMAT_SHIFT_MMX) / (qscale * quant_matrix[i]);            qmat16[i] = (1 << QMAT_SHIFT_MMX) / (qscale * quant_matrix[block_permute_op(i)]);        }    }}