/*
- * Common code between AC3 encoder and decoder
- * Copyright (c) 2000 Fabrice Bellard.
+ * Common code between the AC-3 encoder and decoder
+ * Copyright (c) 2000 Fabrice Bellard
*
* This file is part of FFmpeg.
*
*/
/**
- * @file ac3.c
- * Common code between AC3 encoder and decoder.
+ * @file libavcodec/ac3.c
+ * Common code between the AC-3 encoder and decoder.
*/
#include "avcodec.h"
#include "ac3.h"
-#include "bitstream.h"
+#include "get_bits.h"
-static uint8_t bndtab[51];
-static uint8_t masktab[253];
+#if CONFIG_HARDCODED_TABLES
+
+/**
+ * Starting frequency coefficient bin for each critical band.
+ */
+static const uint8_t band_start_tab[51] = {
+ 0, 1, 2, 3, 4, 5, 6, 7, 8, 9,
+ 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
+ 20, 21, 22, 23, 24, 25, 26, 27, 28, 31,
+ 34, 37, 40, 43, 46, 49, 55, 61, 67, 73,
+ 79, 85, 97, 109, 121, 133, 157, 181, 205, 229, 253
+};
+
+/**
+ * Maps each frequency coefficient bin to the critical band that contains it.
+ */
+static const uint8_t bin_to_band_tab[253] = {
+ 0,
+ 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12,
+ 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24,
+ 25, 26, 27, 28, 28, 28, 29, 29, 29, 30, 30, 30,
+ 31, 31, 31, 32, 32, 32, 33, 33, 33, 34, 34, 34,
+ 35, 35, 35, 35, 35, 35, 36, 36, 36, 36, 36, 36,
+ 37, 37, 37, 37, 37, 37, 38, 38, 38, 38, 38, 38,
+ 39, 39, 39, 39, 39, 39, 40, 40, 40, 40, 40, 40,
+ 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41, 41,
+ 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42, 42,
+ 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43, 43,
+ 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44, 44,
+ 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45,
+ 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45, 45,
+ 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46,
+ 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46, 46,
+ 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47,
+ 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47, 47,
+ 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48,
+ 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48,
+ 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49,
+ 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49, 49
+};
+
+#else /* CONFIG_HARDCODED_TABLES */
+static uint8_t band_start_tab[51];
+static uint8_t bin_to_band_tab[253];
+#endif
static inline int calc_lowcomp1(int a, int b0, int b1, int c)
{
}
void ff_ac3_bit_alloc_calc_psd(int8_t *exp, int start, int end, int16_t *psd,
- int16_t *bndpsd)
+ int16_t *band_psd)
{
- int bin, i, j, k, end1, v;
+ int bin, band;
/* exponent mapping to PSD */
- for(bin=start;bin<end;bin++) {
+ for (bin = start; bin < end; bin++) {
psd[bin]=(3072 - (exp[bin] << 7));
}
/* PSD integration */
- j=start;
- k=masktab[start];
+ bin = start;
+ band = bin_to_band_tab[start];
do {
- v=psd[j];
- j++;
- end1 = FFMIN(bndtab[k+1], end);
- for(i=j;i<end1;i++) {
+ int v = psd[bin++];
+ int band_end = FFMIN(band_start_tab[band+1], end);
+ for (; bin < band_end; bin++) {
/* logadd */
- int adr = FFMIN(FFABS(v - psd[j]) >> 1, 255);
- v = FFMAX(v, psd[j]) + ff_ac3_latab[adr];
- j++;
+ int adr = FFMIN(FFABS(v - psd[bin]) >> 1, 255);
+ v = FFMAX(v, psd[bin]) + ff_ac3_log_add_tab[adr];
}
- bndpsd[k]=v;
- k++;
- } while (end > bndtab[k]);
+ band_psd[band++] = v;
+ } while (end > band_start_tab[band]);
}
-void ff_ac3_bit_alloc_calc_mask(AC3BitAllocParameters *s, int16_t *bndpsd,
- int start, int end, int fgain, int is_lfe,
- int deltbae, int deltnseg, uint8_t *deltoffst,
- uint8_t *deltlen, uint8_t *deltba,
- int16_t *mask)
+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[50]; /* excitation */
- int bin, k;
- int bndstrt, bndend, begin, end1, tmp;
+ int band;
+ int band_start, band_end, begin, end1;
int lowcomp, fastleak, slowleak;
/* excitation function */
- bndstrt = masktab[start];
- bndend = masktab[end-1] + 1;
+ band_start = bin_to_band_tab[start];
+ band_end = bin_to_band_tab[end-1] + 1;
- if (bndstrt == 0) {
+ if (band_start == 0) {
lowcomp = 0;
- lowcomp = calc_lowcomp1(lowcomp, bndpsd[0], bndpsd[1], 384);
- excite[0] = bndpsd[0] - fgain - lowcomp;
- lowcomp = calc_lowcomp1(lowcomp, bndpsd[1], bndpsd[2], 384);
- excite[1] = bndpsd[1] - fgain - lowcomp;
+ 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 (bin = 2; bin < 7; bin++) {
- if (!(is_lfe && bin == 6))
- lowcomp = calc_lowcomp1(lowcomp, bndpsd[bin], bndpsd[bin+1], 384);
- fastleak = bndpsd[bin] - fgain;
- slowleak = bndpsd[bin] - s->sgain;
- excite[bin] = fastleak - lowcomp;
- if (!(is_lfe && bin == 6)) {
- if (bndpsd[bin] <= bndpsd[bin+1]) {
- begin = bin + 1;
+ 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=bndend;
- if (end1 > 22) end1=22;
-
- for (bin = begin; bin < end1; bin++) {
- if (!(is_lfe && bin == 6))
- lowcomp = calc_lowcomp(lowcomp, bndpsd[bin], bndpsd[bin+1], bin);
-
- fastleak = FFMAX(fastleak - s->fdecay, bndpsd[bin] - fgain);
- slowleak = FFMAX(slowleak - s->sdecay, bndpsd[bin] - s->sgain);
- excite[bin] = FFMAX(fastleak - lowcomp, slowleak);
+ 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 = bndstrt;
-
- fastleak = (s->cplfleak << 8) + 768;
- slowleak = (s->cplsleak << 8) + 768;
+ begin = band_start;
+ fastleak = (s->cpl_fast_leak << 8) + 768;
+ slowleak = (s->cpl_slow_leak << 8) + 768;
}
- for (bin = begin; bin < bndend; bin++) {
- fastleak = FFMAX(fastleak - s->fdecay, bndpsd[bin] - fgain);
- slowleak = FFMAX(slowleak - s->sdecay, bndpsd[bin] - s->sgain);
- excite[bin] = FFMAX(fastleak, slowleak);
+ 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 (bin = bndstrt; bin < bndend; bin++) {
- tmp = s->dbknee - bndpsd[bin];
+ for (band = band_start; band < band_end; band++) {
+ int tmp = s->db_per_bit - band_psd[band];
if (tmp > 0) {
- excite[bin] += tmp >> 2;
+ excite[band] += tmp >> 2;
}
- mask[bin] = FFMAX(ff_ac3_hth[bin >> s->halfratecod][s->fscod], excite[bin]);
+ mask[band] = FFMAX(ff_ac3_hearing_threshold_tab[band >> s->sr_shift][s->sr_code], excite[band]);
}
/* delta bit allocation */
- if (deltbae == DBA_REUSE || deltbae == DBA_NEW) {
- int band, seg, delta;
+ if (dba_mode == DBA_REUSE || dba_mode == DBA_NEW) {
+ int i, seg, delta;
+ if (dba_nsegs >= 8)
+ return -1;
band = 0;
- for (seg = 0; seg < deltnseg; seg++) {
- band += deltoffst[seg];
- if (deltba[seg] >= 4) {
- delta = (deltba[seg] - 3) << 7;
+ for (seg = 0; seg < dba_nsegs; seg++) {
+ band += dba_offsets[seg];
+ if (band >= 50 || dba_lengths[seg] > 50-band)
+ return -1;
+ if (dba_values[seg] >= 4) {
+ delta = (dba_values[seg] - 3) << 7;
} else {
- delta = (deltba[seg] - 4) << 7;
+ delta = (dba_values[seg] - 4) << 7;
}
- for (k = 0; k < deltlen[seg]; k++) {
- mask[band] += delta;
- band++;
+ for (i = 0; i < dba_lengths[seg]; i++) {
+ mask[band++] += delta;
}
}
}
+ return 0;
}
void ff_ac3_bit_alloc_calc_bap(int16_t *mask, int16_t *psd, int start, int end,
- int snroffset, int floor, uint8_t *bap)
+ int snr_offset, int floor,
+ const uint8_t *bap_tab, uint8_t *bap)
{
- int i, j, k, end1, v, address;
+ int bin, band;
- /* special case, if snroffset is -960, set all bap's to zero */
- if(snroffset == -960) {
+ /* special case, if snr offset is -960, set all bap's to zero */
+ if (snr_offset == -960) {
memset(bap, 0, 256);
return;
}
- i = start;
- j = masktab[start];
+ bin = start;
+ band = bin_to_band_tab[start];
do {
- v = (FFMAX(mask[j] - snroffset - floor, 0) & 0x1FE0) + floor;
- end1 = FFMIN(bndtab[j] + ff_ac3_bndsz[j], end);
- for (k = i; k < end1; k++) {
- address = av_clip((psd[i] - v) >> 5, 0, 63);
- bap[i] = ff_ac3_baptab[address];
- i++;
+ int m = (FFMAX(mask[band] - snr_offset - floor, 0) & 0x1FE0) + floor;
+ int band_end = FFMIN(band_start_tab[band+1], end);
+ for (; bin < band_end; bin++) {
+ int address = av_clip((psd[bin] - m) >> 5, 0, 63);
+ bap[bin] = bap_tab[address];
}
- } while (end > bndtab[j++]);
+ } while (end > band_start_tab[band++]);
}
-/* AC3 bit allocation. The algorithm is the one described in the AC3
+/* AC-3 bit allocation. The algorithm is the one described in the AC-3
spec. */
void ac3_parametric_bit_allocation(AC3BitAllocParameters *s, uint8_t *bap,
int8_t *exp, int start, int end,
- int snroffset, int fgain, int is_lfe,
- int deltbae,int deltnseg,
- uint8_t *deltoffst, uint8_t *deltlen,
- uint8_t *deltba)
+ int snr_offset, 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 psd[256]; /* scaled exponents */
- int16_t bndpsd[50]; /* interpolated exponents */
+ int16_t band_psd[50]; /* interpolated exponents */
int16_t mask[50]; /* masking value */
- ff_ac3_bit_alloc_calc_psd(exp, start, end, psd, bndpsd);
+ ff_ac3_bit_alloc_calc_psd(exp, start, end, psd, band_psd);
- ff_ac3_bit_alloc_calc_mask(s, bndpsd, start, end, fgain, is_lfe,
- deltbae, deltnseg, deltoffst, deltlen, deltba,
- mask);
+ ff_ac3_bit_alloc_calc_mask(s, band_psd, start, end, fast_gain, is_lfe,
+ dba_mode, dba_nsegs, dba_offsets, dba_lengths,
+ dba_values, mask);
- ff_ac3_bit_alloc_calc_bap(mask, psd, start, end, snroffset, s->floor, bap);
+ ff_ac3_bit_alloc_calc_bap(mask, psd, start, end, snr_offset, s->floor,
+ ff_ac3_bap_tab, bap);
}
/**
* note: This function must remain thread safe because it is called by the
* AVParser init code.
*/
-void ac3_common_init(void)
+av_cold void ac3_common_init(void)
{
- int i, j, k, l, v;
+#if !CONFIG_HARDCODED_TABLES
/* compute bndtab and masktab from bandsz */
- k = 0;
- l = 0;
- for(i=0;i<50;i++) {
- bndtab[i] = l;
- v = ff_ac3_bndsz[i];
- for(j=0;j<v;j++) masktab[k++]=i;
- l += v;
+ int bin = 0, band;
+ for (band = 0; band < 50; band++) {
+ int band_end = bin + ff_ac3_critical_band_size_tab[band];
+ band_start_tab[band] = bin;
+ while (bin < band_end)
+ bin_to_band_tab[bin++] = band;
}
- bndtab[50] = l;
+ band_start_tab[50] = bin;
+#endif /* !CONFIG_HARDCODED_TABLES */
}
projects / ffmpeg / blobdiff