- /* compute MDCT block size */
- if (s->sample_rate <= 16000) {
- s->frame_len_bits = 9;
- } else if (s->sample_rate <= 22050 ||
- (s->sample_rate <= 32000 && s->version == 1)) {
- s->frame_len_bits = 10;
- } else {
- s->frame_len_bits = 11;
- }
- s->frame_len = 1 << s->frame_len_bits;
- if (s->use_variable_block_len) {
- s->nb_block_sizes = s->frame_len_bits - BLOCK_MIN_BITS + 1;
- } else {
- s->nb_block_sizes = 1;
- }
-
- /* init rate dependant parameters */
- s->use_noise_coding = 1;
- high_freq = s->sample_rate * 0.5;
-
- /* if version 2, then the rates are normalized */
- sample_rate1 = s->sample_rate;
- if (s->version == 2) {
- if (sample_rate1 >= 44100)
- sample_rate1 = 44100;
- else if (sample_rate1 >= 22050)
- sample_rate1 = 22050;
- else if (sample_rate1 >= 16000)
- sample_rate1 = 16000;
- else if (sample_rate1 >= 11025)
- sample_rate1 = 11025;
- else if (sample_rate1 >= 8000)
- sample_rate1 = 8000;
- }
-
- bps = (float)s->bit_rate / (float)(s->nb_channels * s->sample_rate);
- s->byte_offset_bits = av_log2((int)(bps * s->frame_len / 8.0)) + 2;
-
- /* compute high frequency value and choose if noise coding should
- be activated */
- bps1 = bps;
- if (s->nb_channels == 2)
- bps1 = bps * 1.6;
- if (sample_rate1 == 44100) {
- if (bps1 >= 0.61)
- s->use_noise_coding = 0;
- else
- high_freq = high_freq * 0.4;
- } else if (sample_rate1 == 22050) {
- if (bps1 >= 1.16)
- s->use_noise_coding = 0;
- else if (bps1 >= 0.72)
- high_freq = high_freq * 0.7;
- else
- high_freq = high_freq * 0.6;
- } else if (sample_rate1 == 16000) {
- if (bps > 0.5)
- high_freq = high_freq * 0.5;
- else
- high_freq = high_freq * 0.3;
- } else if (sample_rate1 == 11025) {
- high_freq = high_freq * 0.7;
- } else if (sample_rate1 == 8000) {
- if (bps <= 0.625) {
- high_freq = high_freq * 0.5;
- } else if (bps > 0.75) {
- s->use_noise_coding = 0;
- } else {
- high_freq = high_freq * 0.65;
- }
- } else {
- if (bps >= 0.8) {
- high_freq = high_freq * 0.75;
- } else if (bps >= 0.6) {
- high_freq = high_freq * 0.6;
- } else {
- high_freq = high_freq * 0.5;
- }
- }
-#ifdef DEBUG_PARAMS
- printf("flags1=0x%x flags2=0x%x\n", flags1, flags2);
- printf("version=%d channels=%d sample_rate=%d bitrate=%d block_align=%d\n",
- s->version, s->nb_channels, s->sample_rate, s->bit_rate,
- s->block_align);
- printf("bps=%f bps1=%f high_freq=%f bitoffset=%d\n",
- bps, bps1, high_freq, s->byte_offset_bits);
- printf("use_noise_coding=%d use_exp_vlc=%d\n",
- s->use_noise_coding, s->use_exp_vlc);
-#endif
-
- /* compute the scale factor band sizes for each MDCT block size */
- {
- int a, b, pos, lpos, k, block_len, i, j, n;
- const uint8_t *table;
-
- if (s->version == 1) {
- s->coefs_start = 3;
- } else {
- s->coefs_start = 0;
- }
- for(k = 0; k < s->nb_block_sizes; k++) {
- block_len = s->frame_len >> k;
-
- if (s->version == 1) {
- lpos = 0;
- for(i=0;i<25;i++) {
- a = wma_critical_freqs[i];
- b = s->sample_rate;
- pos = ((block_len * 2 * a) + (b >> 1)) / b;
- if (pos > block_len)
- pos = block_len;
- s->exponent_bands[0][i] = pos - lpos;
- if (pos >= block_len) {
- i++;
- break;
- }
- lpos = pos;
- }
- s->exponent_sizes[0] = i;
- } else {
- /* hardcoded tables */
- table = NULL;
- a = s->frame_len_bits - BLOCK_MIN_BITS - k;
- if (a < 3) {
- if (s->sample_rate >= 44100)
- table = exponent_band_44100[a];
- else if (s->sample_rate >= 32000)
- table = exponent_band_32000[a];
- else if (s->sample_rate >= 22050)
- table = exponent_band_22050[a];
- }
- if (table) {
- n = *table++;
- for(i=0;i<n;i++)
- s->exponent_bands[k][i] = table[i];
- s->exponent_sizes[k] = n;
- } else {
- j = 0;
- lpos = 0;
- for(i=0;i<25;i++) {
- a = wma_critical_freqs[i];
- b = s->sample_rate;
- pos = ((block_len * 2 * a) + (b << 1)) / (4 * b);
- pos <<= 2;
- if (pos > block_len)
- pos = block_len;
- if (pos > lpos)
- s->exponent_bands[k][j++] = pos - lpos;
- if (pos >= block_len)
- break;
- lpos = pos;
- }
- s->exponent_sizes[k] = j;
- }
- }
-
- /* max number of coefs */
- s->coefs_end[k] = (s->frame_len - ((s->frame_len * 9) / 100)) >> k;
- /* high freq computation */
- s->high_band_start[k] = (int)((block_len * 2 * high_freq) /
- s->sample_rate + 0.5);
- n = s->exponent_sizes[k];
- j = 0;
- pos = 0;
- for(i=0;i<n;i++) {
- int start, end;
- start = pos;
- pos += s->exponent_bands[k][i];
- end = pos;
- if (start < s->high_band_start[k])
- start = s->high_band_start[k];
- if (end > s->coefs_end[k])
- end = s->coefs_end[k];
- if (end > start)
- s->exponent_high_bands[k][j++] = end - start;
- }
- s->exponent_high_sizes[k] = j;
-#if 0
- trace("%5d: coefs_end=%d high_band_start=%d nb_high_bands=%d: ",
- s->frame_len >> k,
- s->coefs_end[k],
- s->high_band_start[k],
- s->exponent_high_sizes[k]);
- for(j=0;j<s->exponent_high_sizes[k];j++)
- trace(" %d", s->exponent_high_bands[k][j]);
- trace("\n");
-#endif
- }
- }
-
-#ifdef DEBUG_TRACE
- {
- int i, j;
- for(i = 0; i < s->nb_block_sizes; i++) {
- trace("%5d: n=%2d:",
- s->frame_len >> i,
- s->exponent_sizes[i]);
- for(j=0;j<s->exponent_sizes[i];j++)
- trace(" %d", s->exponent_bands[i][j]);
- trace("\n");
- }
- }
-#endif