static inline int calc_lowcomp(int a, int b0, int b1, int bin)
{
if (bin < 7) {
return calc_lowcomp1(a, b0, b1, 384);
} else if (bin < 20) {
return calc_lowcomp1(a, b0, b1, 320);
} else {
return FFMAX(a - 128, 0);
}
}
int ff_ac3_bit_alloc_calc_mask(AC3BitAllocParameters *s, int16_t *band_psd,
int start, int end, int fast_gain, int is_lfe,
int dba_mode, int dba_nsegs, uint8_t *dba_offsets,
uint8_t *dba_lengths, uint8_t *dba_values,
int16_t *mask)
{
int16_t excite[AC3_CRITICAL_BANDS]; /* excitation */
int band;
int band_start, band_end, begin, end1;
int lowcomp, fastleak, slowleak;
/* excitation function */
band_start = ff_ac3_bin_to_band_tab[start];
band_end = ff_ac3_bin_to_band_tab[end-1] + 1;
if (band_start == 0)
{
lowcomp = 0;
lowcomp = calc_lowcomp1(lowcomp, band_psd[0], band_psd[1], 384);
excite[0] = band_psd[0] - fast_gain - lowcomp;
lowcomp = calc_lowcomp1(lowcomp, band_psd[1], band_psd[2], 384);
excite[1] = band_psd[1] - fast_gain - lowcomp;
begin = 7;
for (band = 2; band < 7; band++)
{
if (!(is_lfe && band == 6))
lowcomp = calc_lowcomp1(lowcomp, band_psd[band], band_psd[band+1], 384);
fastleak = band_psd[band] - fast_gain;
slowleak = band_psd[band] - s->slow_gain;
excite[band] = fastleak - lowcomp;
if (!(is_lfe && band == 6))
{
if (band_psd[band] <= band_psd[band+1])
{
begin = band + 1;
break;
}
}
}
end1 = FFMIN(band_end, 22);
for (band = begin; band < end1; band++)
{
if (!(is_lfe && band == 6))
lowcomp = calc_lowcomp(lowcomp, band_psd[band], band_psd[band+1], band);
fastleak = FFMAX(fastleak - s->fast_decay, band_psd[band] - fast_gain);
slowleak = FFMAX(slowleak - s->slow_decay, band_psd[band] - s->slow_gain);
excite[band] = FFMAX(fastleak - lowcomp, slowleak);
}
begin = 22;
}
else
{
/* coupling channel */
begin = band_start;
fastleak = (s->cpl_fast_leak << 8) + 768;
slowleak = (s->cpl_slow_leak << 8) + 768;
}
for (band = begin; band < band_end; band++)
{
fastleak = FFMAX(fastleak - s->fast_decay, band_psd[band] - fast_gain);
slowleak = FFMAX(slowleak - s->slow_decay, band_psd[band] - s->slow_gain);
excite[band] = FFMAX(fastleak, slowleak);
}
/* compute masking curve */
for (band = band_start; band < band_end; band++)
{
int tmp = s->db_per_bit - band_psd[band];
if (tmp > 0)
{
excite[band] += tmp >> 2;
}
mask[band] = FFMAX(ff_ac3_hearing_threshold_tab[band >> s->sr_shift][s->sr_code], excite[band]);
}