-
- /* normalize */
- {
- int n4 = pwd->block_len / 2;
- mdct_norm = 1.0 / (float) n4;
- }
-
- /* finally compute the MDCT coefficients */
- for (ch = 0; ch < pwd->ahi.channels; ch++) {
- if (pwd->channel_coded[ch]) {
- int16_t *coefs1;
- float *coefs, *exponents, mult, mult1, noise;
- int i, j, n1, last_high_band, esize;
- float exp_power[HIGH_BAND_MAX_SIZE];
-
- coefs1 = pwd->coefs1[ch];
- exponents = pwd->exponents[ch];
- esize = pwd->exponents_bsize[ch];
- mult = pow(10, total_gain * 0.05) / pwd->max_exponent[ch];
- mult *= mdct_norm;
- coefs = pwd->coefs[ch];
- if (pwd->use_noise_coding) {
- mult1 = mult;
- /* very low freqs : noise */
- for (i = 0; i < pwd->coefs_start; i++) {
- *coefs++ =
- pwd->noise_table[pwd->noise_index] *
- exponents[i << bsize >> esize] *
- mult1;
- pwd->noise_index =
- (pwd->noise_index +
- 1) & (NOISE_TAB_SIZE - 1);
- }
-
- n1 = pwd->exponent_high_sizes[bsize];
-
- /* compute power of high bands */
- exponents = pwd->exponents[ch] +
- (pwd->high_band_start[bsize] << bsize);
- last_high_band = 0; /* avoid warning */
- for (j = 0; j < n1; j++) {
- n = pwd->exponent_high_bands[pwd->
- frame_len_bits
- -
- pwd->
- block_len_bits]
- [j];
- if (pwd->high_band_coded[ch][j]) {
- float e2, val;
- e2 = 0;
- for (i = 0; i < n; i++) {
- val = exponents[i << bsize
- >> esize];
- e2 += val * val;
- }
- exp_power[j] = e2 / n;
- last_high_band = j;
- }
- exponents += n << bsize;
- }
-
- /* main freqs and high freqs */
- exponents =
- pwd->exponents[ch] +
- (pwd->coefs_start << bsize);
- for (j = -1; j < n1; j++) {
- if (j < 0) {
- n = pwd->high_band_start[bsize] -
- pwd->coefs_start;
- } else {
- n = pwd->exponent_high_bands[pwd->
- frame_len_bits
- -
- pwd->
- block_len_bits]
- [j];
- }
- if (j >= 0 && pwd->high_band_coded[ch][j]) {
- /* use noise with specified power */
- mult1 =
- sqrt(exp_power[j] /
- exp_power
- [last_high_band]);
- /* XXX: use a table */
- mult1 =
- mult1 * pow(10,
- pwd->
- high_band_values
- [ch][j] * 0.05);
- mult1 =
- mult1 /
- (pwd->max_exponent[ch] *
- pwd->noise_mult);
- mult1 *= mdct_norm;
- for (i = 0; i < n; i++) {
- noise =
- pwd->noise_table[pwd->
- noise_index];
- pwd->noise_index =
- (pwd->noise_index +
- 1) &
- (NOISE_TAB_SIZE -
- 1);
- *coefs++ =
- noise *
- exponents[i << bsize
- >> esize]
- * mult1;
- }
- exponents += n << bsize;
- } else {
- /* coded values + small noise */
- for (i = 0; i < n; i++) {
- noise =
- pwd->noise_table[pwd->
- noise_index];
- pwd->noise_index =
- (pwd->noise_index +
- 1) &
- (NOISE_TAB_SIZE -
- 1);
- *coefs++ =
- ((*coefs1++) +
- noise) *
- exponents[i << bsize
- >> esize]
- * mult;
- }
- exponents += n << bsize;
- }
- }
-
- /* very high freqs : noise */
- n = pwd->block_len - pwd->coefs_end[bsize];
- mult1 =
- mult * exponents[((-1 << bsize)) >> esize];
- for (i = 0; i < n; i++) {
- *coefs++ =
- pwd->noise_table[pwd->noise_index] *
- mult1;
- pwd->noise_index =
- (pwd->noise_index +
- 1) & (NOISE_TAB_SIZE - 1);
- }
- } else {
- /* XXX: optimize more */
- for (i = 0; i < pwd->coefs_start; i++)
- *coefs++ = 0.0;
- n = nb_coefs[ch];
- for (i = 0; i < n; i++) {
- *coefs++ =
- coefs1[i] *
- exponents[i << bsize >> esize] *
- mult;
- }
- n = pwd->block_len - pwd->coefs_end[bsize];
- for (i = 0; i < n; i++)
- *coefs++ = 0.0;
- }
- }
- }
-