/libavcodec/ac3enc.c
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- /*
- * The simplest AC-3 encoder
- * Copyright (c) 2000 Fabrice Bellard
- * Copyright (c) 2006-2010 Justin Ruggles <justin.ruggles@gmail.com>
- * Copyright (c) 2006-2010 Prakash Punnoor <prakash@punnoor.de>
- *
- * This file is part of FFmpeg.
- *
- * FFmpeg is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation; either
- * version 2.1 of the License, or (at your option) any later version.
- *
- * FFmpeg is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with FFmpeg; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- */
- /**
- * @file
- * The simplest AC-3 encoder.
- */
- #include <stdint.h>
- #include "libavutil/attributes.h"
- #include "libavutil/avassert.h"
- #include "libavutil/avstring.h"
- #include "libavutil/channel_layout.h"
- #include "libavutil/crc.h"
- #include "libavutil/internal.h"
- #include "libavutil/opt.h"
- #include "avcodec.h"
- #include "internal.h"
- #include "me_cmp.h"
- #include "put_bits.h"
- #include "audiodsp.h"
- #include "ac3dsp.h"
- #include "ac3.h"
- #include "fft.h"
- #include "ac3enc.h"
- #include "eac3enc.h"
- typedef struct AC3Mant {
- int16_t *qmant1_ptr, *qmant2_ptr, *qmant4_ptr; ///< mantissa pointers for bap=1,2,4
- int mant1_cnt, mant2_cnt, mant4_cnt; ///< mantissa counts for bap=1,2,4
- } AC3Mant;
- #define CMIXLEV_NUM_OPTIONS 3
- static const float cmixlev_options[CMIXLEV_NUM_OPTIONS] = {
- LEVEL_MINUS_3DB, LEVEL_MINUS_4POINT5DB, LEVEL_MINUS_6DB
- };
- #define SURMIXLEV_NUM_OPTIONS 3
- static const float surmixlev_options[SURMIXLEV_NUM_OPTIONS] = {
- LEVEL_MINUS_3DB, LEVEL_MINUS_6DB, LEVEL_ZERO
- };
- #define EXTMIXLEV_NUM_OPTIONS 8
- static const float extmixlev_options[EXTMIXLEV_NUM_OPTIONS] = {
- LEVEL_PLUS_3DB, LEVEL_PLUS_1POINT5DB, LEVEL_ONE, LEVEL_MINUS_1POINT5DB,
- LEVEL_MINUS_3DB, LEVEL_MINUS_4POINT5DB, LEVEL_MINUS_6DB, LEVEL_ZERO
- };
- /**
- * LUT for number of exponent groups.
- * exponent_group_tab[coupling][exponent strategy-1][number of coefficients]
- */
- static uint8_t exponent_group_tab[2][3][256];
- /**
- * List of supported channel layouts.
- */
- const uint64_t ff_ac3_channel_layouts[19] = {
- AV_CH_LAYOUT_MONO,
- AV_CH_LAYOUT_STEREO,
- AV_CH_LAYOUT_2_1,
- AV_CH_LAYOUT_SURROUND,
- AV_CH_LAYOUT_2_2,
- AV_CH_LAYOUT_QUAD,
- AV_CH_LAYOUT_4POINT0,
- AV_CH_LAYOUT_5POINT0,
- AV_CH_LAYOUT_5POINT0_BACK,
- (AV_CH_LAYOUT_MONO | AV_CH_LOW_FREQUENCY),
- (AV_CH_LAYOUT_STEREO | AV_CH_LOW_FREQUENCY),
- (AV_CH_LAYOUT_2_1 | AV_CH_LOW_FREQUENCY),
- (AV_CH_LAYOUT_SURROUND | AV_CH_LOW_FREQUENCY),
- (AV_CH_LAYOUT_2_2 | AV_CH_LOW_FREQUENCY),
- (AV_CH_LAYOUT_QUAD | AV_CH_LOW_FREQUENCY),
- (AV_CH_LAYOUT_4POINT0 | AV_CH_LOW_FREQUENCY),
- AV_CH_LAYOUT_5POINT1,
- AV_CH_LAYOUT_5POINT1_BACK,
- 0
- };
- /**
- * LUT to select the bandwidth code based on the bit rate, sample rate, and
- * number of full-bandwidth channels.
- * bandwidth_tab[fbw_channels-1][sample rate code][bit rate code]
- */
- static const uint8_t ac3_bandwidth_tab[5][3][19] = {
- // 32 40 48 56 64 80 96 112 128 160 192 224 256 320 384 448 512 576 640
- { { 0, 0, 0, 12, 16, 32, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48, 48 },
- { 0, 0, 0, 16, 20, 36, 56, 56, 56, 56, 56, 56, 56, 56, 56, 56, 56, 56, 56 },
- { 0, 0, 0, 32, 40, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60 } },
- { { 0, 0, 0, 0, 0, 0, 0, 20, 24, 32, 48, 48, 48, 48, 48, 48, 48, 48, 48 },
- { 0, 0, 0, 0, 0, 0, 4, 24, 28, 36, 56, 56, 56, 56, 56, 56, 56, 56, 56 },
- { 0, 0, 0, 0, 0, 0, 20, 44, 52, 60, 60, 60, 60, 60, 60, 60, 60, 60, 60 } },
- { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 16, 24, 32, 40, 48, 48, 48, 48, 48, 48 },
- { 0, 0, 0, 0, 0, 0, 0, 0, 4, 20, 28, 36, 44, 56, 56, 56, 56, 56, 56 },
- { 0, 0, 0, 0, 0, 0, 0, 0, 20, 40, 48, 60, 60, 60, 60, 60, 60, 60, 60 } },
- { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 12, 24, 32, 48, 48, 48, 48, 48, 48 },
- { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 16, 28, 36, 56, 56, 56, 56, 56, 56 },
- { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 32, 48, 60, 60, 60, 60, 60, 60, 60 } },
- { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 8, 20, 32, 40, 48, 48, 48, 48 },
- { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 12, 24, 36, 44, 56, 56, 56, 56 },
- { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 28, 44, 60, 60, 60, 60, 60, 60 } }
- };
- /**
- * LUT to select the coupling start band based on the bit rate, sample rate, and
- * number of full-bandwidth channels. -1 = coupling off
- * ac3_coupling_start_tab[channel_mode-2][sample rate code][bit rate code]
- *
- * TODO: more testing for optimal parameters.
- * multi-channel tests at 44.1kHz and 32kHz.
- */
- static const int8_t ac3_coupling_start_tab[6][3][19] = {
- // 32 40 48 56 64 80 96 112 128 160 192 224 256 320 384 448 512 576 640
- // 2/0
- { { 0, 0, 0, 0, 0, 0, 0, 1, 1, 7, 8, 11, 12, -1, -1, -1, -1, -1, -1 },
- { 0, 0, 0, 0, 0, 0, 1, 3, 5, 7, 10, 12, 13, -1, -1, -1, -1, -1, -1 },
- { 0, 0, 0, 0, 1, 2, 2, 9, 13, 15, -1, -1, -1, -1, -1, -1, -1, -1, -1 } },
- // 3/0
- { { 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 6, 9, 11, 12, 13, -1, -1, -1, -1 },
- { 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 6, 9, 11, 12, 13, -1, -1, -1, -1 },
- { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 } },
- // 2/1 - untested
- { { 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 6, 9, 11, 12, 13, -1, -1, -1, -1 },
- { 0, 0, 0, 0, 0, 0, 0, 0, 2, 2, 6, 9, 11, 12, 13, -1, -1, -1, -1 },
- { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 } },
- // 3/1
- { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 2, 10, 11, 11, 12, 12, 14, -1 },
- { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 2, 10, 11, 11, 12, 12, 14, -1 },
- { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 } },
- // 2/2 - untested
- { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 2, 10, 11, 11, 12, 12, 14, -1 },
- { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 3, 2, 10, 11, 11, 12, 12, 14, -1 },
- { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 } },
- // 3/2
- { { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 6, 8, 11, 12, 12, -1, -1 },
- { 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 6, 8, 11, 12, 12, -1, -1 },
- { -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1 } },
- };
- /**
- * Adjust the frame size to make the average bit rate match the target bit rate.
- * This is only needed for 11025, 22050, and 44100 sample rates or any E-AC-3.
- *
- * @param s AC-3 encoder private context
- */
- void ff_ac3_adjust_frame_size(AC3EncodeContext *s)
- {
- while (s->bits_written >= s->bit_rate && s->samples_written >= s->sample_rate) {
- s->bits_written -= s->bit_rate;
- s->samples_written -= s->sample_rate;
- }
- s->frame_size = s->frame_size_min +
- 2 * (s->bits_written * s->sample_rate < s->samples_written * s->bit_rate);
- s->bits_written += s->frame_size * 8;
- s->samples_written += AC3_BLOCK_SIZE * s->num_blocks;
- }
- /**
- * Set the initial coupling strategy parameters prior to coupling analysis.
- *
- * @param s AC-3 encoder private context
- */
- void ff_ac3_compute_coupling_strategy(AC3EncodeContext *s)
- {
- int blk, ch;
- int got_cpl_snr;
- int num_cpl_blocks;
- /* set coupling use flags for each block/channel */
- /* TODO: turn coupling on/off and adjust start band based on bit usage */
- for (blk = 0; blk < s->num_blocks; blk++) {
- AC3Block *block = &s->blocks[blk];
- for (ch = 1; ch <= s->fbw_channels; ch++)
- block->channel_in_cpl[ch] = s->cpl_on;
- }
- /* enable coupling for each block if at least 2 channels have coupling
- enabled for that block */
- got_cpl_snr = 0;
- num_cpl_blocks = 0;
- for (blk = 0; blk < s->num_blocks; blk++) {
- AC3Block *block = &s->blocks[blk];
- block->num_cpl_channels = 0;
- for (ch = 1; ch <= s->fbw_channels; ch++)
- block->num_cpl_channels += block->channel_in_cpl[ch];
- block->cpl_in_use = block->num_cpl_channels > 1;
- num_cpl_blocks += block->cpl_in_use;
- if (!block->cpl_in_use) {
- block->num_cpl_channels = 0;
- for (ch = 1; ch <= s->fbw_channels; ch++)
- block->channel_in_cpl[ch] = 0;
- }
- block->new_cpl_strategy = !blk;
- if (blk) {
- for (ch = 1; ch <= s->fbw_channels; ch++) {
- if (block->channel_in_cpl[ch] != s->blocks[blk-1].channel_in_cpl[ch]) {
- block->new_cpl_strategy = 1;
- break;
- }
- }
- }
- block->new_cpl_leak = block->new_cpl_strategy;
- if (!blk || (block->cpl_in_use && !got_cpl_snr)) {
- block->new_snr_offsets = 1;
- if (block->cpl_in_use)
- got_cpl_snr = 1;
- } else {
- block->new_snr_offsets = 0;
- }
- }
- if (!num_cpl_blocks)
- s->cpl_on = 0;
- /* set bandwidth for each channel */
- for (blk = 0; blk < s->num_blocks; blk++) {
- AC3Block *block = &s->blocks[blk];
- for (ch = 1; ch <= s->fbw_channels; ch++) {
- if (block->channel_in_cpl[ch])
- block->end_freq[ch] = s->start_freq[CPL_CH];
- else
- block->end_freq[ch] = s->bandwidth_code * 3 + 73;
- }
- }
- }
- /**
- * Apply stereo rematrixing to coefficients based on rematrixing flags.
- *
- * @param s AC-3 encoder private context
- */
- void ff_ac3_apply_rematrixing(AC3EncodeContext *s)
- {
- int nb_coefs;
- int blk, bnd, i;
- int start, end;
- uint8_t *flags = NULL;
- if (!s->rematrixing_enabled)
- return;
- for (blk = 0; blk < s->num_blocks; blk++) {
- AC3Block *block = &s->blocks[blk];
- if (block->new_rematrixing_strategy)
- flags = block->rematrixing_flags;
- nb_coefs = FFMIN(block->end_freq[1], block->end_freq[2]);
- for (bnd = 0; bnd < block->num_rematrixing_bands; bnd++) {
- if (flags[bnd]) {
- start = ff_ac3_rematrix_band_tab[bnd];
- end = FFMIN(nb_coefs, ff_ac3_rematrix_band_tab[bnd+1]);
- for (i = start; i < end; i++) {
- int32_t lt = block->fixed_coef[1][i];
- int32_t rt = block->fixed_coef[2][i];
- block->fixed_coef[1][i] = (lt + rt) >> 1;
- block->fixed_coef[2][i] = (lt - rt) >> 1;
- }
- }
- }
- }
- }
- /*
- * Initialize exponent tables.
- */
- static av_cold void exponent_init(AC3EncodeContext *s)
- {
- int expstr, i, grpsize;
- for (expstr = EXP_D15-1; expstr <= EXP_D45-1; expstr++) {
- grpsize = 3 << expstr;
- for (i = 12; i < 256; i++) {
- exponent_group_tab[0][expstr][i] = (i + grpsize - 4) / grpsize;
- exponent_group_tab[1][expstr][i] = (i ) / grpsize;
- }
- }
- /* LFE */
- exponent_group_tab[0][0][7] = 2;
- if (CONFIG_EAC3_ENCODER && s->eac3)
- ff_eac3_exponent_init();
- }
- /*
- * Extract exponents from the MDCT coefficients.
- */
- static void extract_exponents(AC3EncodeContext *s)
- {
- int ch = !s->cpl_on;
- int chan_size = AC3_MAX_COEFS * s->num_blocks * (s->channels - ch + 1);
- AC3Block *block = &s->blocks[0];
- s->ac3dsp.extract_exponents(block->exp[ch], block->fixed_coef[ch], chan_size);
- }
- /**
- * Exponent Difference Threshold.
- * New exponents are sent if their SAD exceed this number.
- */
- #define EXP_DIFF_THRESHOLD 500
- /**
- * Table used to select exponent strategy based on exponent reuse block interval.
- */
- static const uint8_t exp_strategy_reuse_tab[4][6] = {
- { EXP_D15, EXP_D15, EXP_D15, EXP_D15, EXP_D15, EXP_D15 },
- { EXP_D15, EXP_D15, EXP_D15, EXP_D15, EXP_D15, EXP_D15 },
- { EXP_D25, EXP_D25, EXP_D15, EXP_D15, EXP_D15, EXP_D15 },
- { EXP_D45, EXP_D25, EXP_D25, EXP_D15, EXP_D15, EXP_D15 }
- };
- /*
- * Calculate exponent strategies for all channels.
- * Array arrangement is reversed to simplify the per-channel calculation.
- */
- static void compute_exp_strategy(AC3EncodeContext *s)
- {
- int ch, blk, blk1;
- for (ch = !s->cpl_on; ch <= s->fbw_channels; ch++) {
- uint8_t *exp_strategy = s->exp_strategy[ch];
- uint8_t *exp = s->blocks[0].exp[ch];
- int exp_diff;
- /* estimate if the exponent variation & decide if they should be
- reused in the next frame */
- exp_strategy[0] = EXP_NEW;
- exp += AC3_MAX_COEFS;
- for (blk = 1; blk < s->num_blocks; blk++, exp += AC3_MAX_COEFS) {
- if (ch == CPL_CH) {
- if (!s->blocks[blk-1].cpl_in_use) {
- exp_strategy[blk] = EXP_NEW;
- continue;
- } else if (!s->blocks[blk].cpl_in_use) {
- exp_strategy[blk] = EXP_REUSE;
- continue;
- }
- } else if (s->blocks[blk].channel_in_cpl[ch] != s->blocks[blk-1].channel_in_cpl[ch]) {
- exp_strategy[blk] = EXP_NEW;
- continue;
- }
- exp_diff = s->mecc.sad[0](NULL, exp, exp - AC3_MAX_COEFS, 16, 16);
- exp_strategy[blk] = EXP_REUSE;
- if (ch == CPL_CH && exp_diff > (EXP_DIFF_THRESHOLD * (s->blocks[blk].end_freq[ch] - s->start_freq[ch]) / AC3_MAX_COEFS))
- exp_strategy[blk] = EXP_NEW;
- else if (ch > CPL_CH && exp_diff > EXP_DIFF_THRESHOLD)
- exp_strategy[blk] = EXP_NEW;
- }
- /* now select the encoding strategy type : if exponents are often
- recoded, we use a coarse encoding */
- blk = 0;
- while (blk < s->num_blocks) {
- blk1 = blk + 1;
- while (blk1 < s->num_blocks && exp_strategy[blk1] == EXP_REUSE)
- blk1++;
- exp_strategy[blk] = exp_strategy_reuse_tab[s->num_blks_code][blk1-blk-1];
- blk = blk1;
- }
- }
- if (s->lfe_on) {
- ch = s->lfe_channel;
- s->exp_strategy[ch][0] = EXP_D15;
- for (blk = 1; blk < s->num_blocks; blk++)
- s->exp_strategy[ch][blk] = EXP_REUSE;
- }
- /* for E-AC-3, determine frame exponent strategy */
- if (CONFIG_EAC3_ENCODER && s->eac3)
- ff_eac3_get_frame_exp_strategy(s);
- }
- /**
- * Update the exponents so that they are the ones the decoder will decode.
- *
- * @param[in,out] exp array of exponents for 1 block in 1 channel
- * @param nb_exps number of exponents in active bandwidth
- * @param exp_strategy exponent strategy for the block
- * @param cpl indicates if the block is in the coupling channel
- */
- static void encode_exponents_blk_ch(uint8_t *exp, int nb_exps, int exp_strategy,
- int cpl)
- {
- int nb_groups, i, k;
- nb_groups = exponent_group_tab[cpl][exp_strategy-1][nb_exps] * 3;
- /* for each group, compute the minimum exponent */
- switch(exp_strategy) {
- case EXP_D25:
- for (i = 1, k = 1-cpl; i <= nb_groups; i++) {
- uint8_t exp_min = exp[k];
- if (exp[k+1] < exp_min)
- exp_min = exp[k+1];
- exp[i-cpl] = exp_min;
- k += 2;
- }
- break;
- case EXP_D45:
- for (i = 1, k = 1-cpl; i <= nb_groups; i++) {
- uint8_t exp_min = exp[k];
- if (exp[k+1] < exp_min)
- exp_min = exp[k+1];
- if (exp[k+2] < exp_min)
- exp_min = exp[k+2];
- if (exp[k+3] < exp_min)
- exp_min = exp[k+3];
- exp[i-cpl] = exp_min;
- k += 4;
- }
- break;
- }
- /* constraint for DC exponent */
- if (!cpl && exp[0] > 15)
- exp[0] = 15;
- /* decrease the delta between each groups to within 2 so that they can be
- differentially encoded */
- for (i = 1; i <= nb_groups; i++)
- exp[i] = FFMIN(exp[i], exp[i-1] + 2);
- i--;
- while (--i >= 0)
- exp[i] = FFMIN(exp[i], exp[i+1] + 2);
- if (cpl)
- exp[-1] = exp[0] & ~1;
- /* now we have the exponent values the decoder will see */
- switch (exp_strategy) {
- case EXP_D25:
- for (i = nb_groups, k = (nb_groups * 2)-cpl; i > 0; i--) {
- uint8_t exp1 = exp[i-cpl];
- exp[k--] = exp1;
- exp[k--] = exp1;
- }
- break;
- case EXP_D45:
- for (i = nb_groups, k = (nb_groups * 4)-cpl; i > 0; i--) {
- exp[k] = exp[k-1] = exp[k-2] = exp[k-3] = exp[i-cpl];
- k -= 4;
- }
- break;
- }
- }
- /*
- * Encode exponents from original extracted form to what the decoder will see.
- * This copies and groups exponents based on exponent strategy and reduces
- * deltas between adjacent exponent groups so that they can be differentially
- * encoded.
- */
- static void encode_exponents(AC3EncodeContext *s)
- {
- int blk, blk1, ch, cpl;
- uint8_t *exp, *exp_strategy;
- int nb_coefs, num_reuse_blocks;
- for (ch = !s->cpl_on; ch <= s->channels; ch++) {
- exp = s->blocks[0].exp[ch] + s->start_freq[ch];
- exp_strategy = s->exp_strategy[ch];
- cpl = (ch == CPL_CH);
- blk = 0;
- while (blk < s->num_blocks) {
- AC3Block *block = &s->blocks[blk];
- if (cpl && !block->cpl_in_use) {
- exp += AC3_MAX_COEFS;
- blk++;
- continue;
- }
- nb_coefs = block->end_freq[ch] - s->start_freq[ch];
- blk1 = blk + 1;
- /* count the number of EXP_REUSE blocks after the current block
- and set exponent reference block numbers */
- s->exp_ref_block[ch][blk] = blk;
- while (blk1 < s->num_blocks && exp_strategy[blk1] == EXP_REUSE) {
- s->exp_ref_block[ch][blk1] = blk;
- blk1++;
- }
- num_reuse_blocks = blk1 - blk - 1;
- /* for the EXP_REUSE case we select the min of the exponents */
- s->ac3dsp.ac3_exponent_min(exp-s->start_freq[ch], num_reuse_blocks,
- AC3_MAX_COEFS);
- encode_exponents_blk_ch(exp, nb_coefs, exp_strategy[blk], cpl);
- exp += AC3_MAX_COEFS * (num_reuse_blocks + 1);
- blk = blk1;
- }
- }
- /* reference block numbers have been changed, so reset ref_bap_set */
- s->ref_bap_set = 0;
- }
- /*
- * Count exponent bits based on bandwidth, coupling, and exponent strategies.
- */
- static int count_exponent_bits(AC3EncodeContext *s)
- {
- int blk, ch;
- int nb_groups, bit_count;
- bit_count = 0;
- for (blk = 0; blk < s->num_blocks; blk++) {
- AC3Block *block = &s->blocks[blk];
- for (ch = !block->cpl_in_use; ch <= s->channels; ch++) {
- int exp_strategy = s->exp_strategy[ch][blk];
- int cpl = (ch == CPL_CH);
- int nb_coefs = block->end_freq[ch] - s->start_freq[ch];
- if (exp_strategy == EXP_REUSE)
- continue;
- nb_groups = exponent_group_tab[cpl][exp_strategy-1][nb_coefs];
- bit_count += 4 + (nb_groups * 7);
- }
- }
- return bit_count;
- }
- /**
- * Group exponents.
- * 3 delta-encoded exponents are in each 7-bit group. The number of groups
- * varies depending on exponent strategy and bandwidth.
- *
- * @param s AC-3 encoder private context
- */
- void ff_ac3_group_exponents(AC3EncodeContext *s)
- {
- int blk, ch, i, cpl;
- int group_size, nb_groups;
- uint8_t *p;
- int delta0, delta1, delta2;
- int exp0, exp1;
- for (blk = 0; blk < s->num_blocks; blk++) {
- AC3Block *block = &s->blocks[blk];
- for (ch = !block->cpl_in_use; ch <= s->channels; ch++) {
- int exp_strategy = s->exp_strategy[ch][blk];
- if (exp_strategy == EXP_REUSE)
- continue;
- cpl = (ch == CPL_CH);
- group_size = exp_strategy + (exp_strategy == EXP_D45);
- nb_groups = exponent_group_tab[cpl][exp_strategy-1][block->end_freq[ch]-s->start_freq[ch]];
- p = block->exp[ch] + s->start_freq[ch] - cpl;
- /* DC exponent */
- exp1 = *p++;
- block->grouped_exp[ch][0] = exp1;
- /* remaining exponents are delta encoded */
- for (i = 1; i <= nb_groups; i++) {
- /* merge three delta in one code */
- exp0 = exp1;
- exp1 = p[0];
- p += group_size;
- delta0 = exp1 - exp0 + 2;
- av_assert2(delta0 >= 0 && delta0 <= 4);
- exp0 = exp1;
- exp1 = p[0];
- p += group_size;
- delta1 = exp1 - exp0 + 2;
- av_assert2(delta1 >= 0 && delta1 <= 4);
- exp0 = exp1;
- exp1 = p[0];
- p += group_size;
- delta2 = exp1 - exp0 + 2;
- av_assert2(delta2 >= 0 && delta2 <= 4);
- block->grouped_exp[ch][i] = ((delta0 * 5 + delta1) * 5) + delta2;
- }
- }
- }
- }
- /**
- * Calculate final exponents from the supplied MDCT coefficients and exponent shift.
- * Extract exponents from MDCT coefficients, calculate exponent strategies,
- * and encode final exponents.
- *
- * @param s AC-3 encoder private context
- */
- void ff_ac3_process_exponents(AC3EncodeContext *s)
- {
- extract_exponents(s);
- compute_exp_strategy(s);
- encode_exponents(s);
- emms_c();
- }
- /*
- * Count frame bits that are based solely on fixed parameters.
- * This only has to be run once when the encoder is initialized.
- */
- static void count_frame_bits_fixed(AC3EncodeContext *s)
- {
- static const uint8_t frame_bits_inc[8] = { 0, 0, 2, 2, 2, 4, 2, 4 };
- int blk;
- int frame_bits;
- /* assumptions:
- * no dynamic range codes
- * bit allocation parameters do not change between blocks
- * no delta bit allocation
- * no skipped data
- * no auxiliary data
- * no E-AC-3 metadata
- */
- /* header */
- frame_bits = 16; /* sync info */
- if (s->eac3) {
- /* bitstream info header */
- frame_bits += 35;
- frame_bits += 1 + 1;
- if (s->num_blocks != 0x6)
- frame_bits++;
- frame_bits++;
- /* audio frame header */
- if (s->num_blocks == 6)
- frame_bits += 2;
- frame_bits += 10;
- /* exponent strategy */
- if (s->use_frame_exp_strategy)
- frame_bits += 5 * s->fbw_channels;
- else
- frame_bits += s->num_blocks * 2 * s->fbw_channels;
- if (s->lfe_on)
- frame_bits += s->num_blocks;
- /* converter exponent strategy */
- if (s->num_blks_code != 0x3)
- frame_bits++;
- else
- frame_bits += s->fbw_channels * 5;
- /* snr offsets */
- frame_bits += 10;
- /* block start info */
- if (s->num_blocks != 1)
- frame_bits++;
- } else {
- frame_bits += 49;
- frame_bits += frame_bits_inc[s->channel_mode];
- }
- /* audio blocks */
- for (blk = 0; blk < s->num_blocks; blk++) {
- if (!s->eac3) {
- /* block switch flags */
- frame_bits += s->fbw_channels;
- /* dither flags */
- frame_bits += s->fbw_channels;
- }
- /* dynamic range */
- frame_bits++;
- /* spectral extension */
- if (s->eac3)
- frame_bits++;
- if (!s->eac3) {
- /* exponent strategy */
- frame_bits += 2 * s->fbw_channels;
- if (s->lfe_on)
- frame_bits++;
- /* bit allocation params */
- frame_bits++;
- if (!blk)
- frame_bits += 2 + 2 + 2 + 2 + 3;
- }
- /* converter snr offset */
- if (s->eac3)
- frame_bits++;
- if (!s->eac3) {
- /* delta bit allocation */
- frame_bits++;
- /* skipped data */
- frame_bits++;
- }
- }
- /* auxiliary data */
- frame_bits++;
- /* CRC */
- frame_bits += 1 + 16;
- s->frame_bits_fixed = frame_bits;
- }
- /*
- * Initialize bit allocation.
- * Set default parameter codes and calculate parameter values.
- */
- static av_cold void bit_alloc_init(AC3EncodeContext *s)
- {
- int ch;
- /* init default parameters */
- s->slow_decay_code = 2;
- s->fast_decay_code = 1;
- s->slow_gain_code = 1;
- s->db_per_bit_code = s->eac3 ? 2 : 3;
- s->floor_code = 7;
- for (ch = 0; ch <= s->channels; ch++)
- s->fast_gain_code[ch] = 4;
- /* initial snr offset */
- s->coarse_snr_offset = 40;
- /* compute real values */
- /* currently none of these values change during encoding, so we can just
- set them once at initialization */
- s->bit_alloc.slow_decay = ff_ac3_slow_decay_tab[s->slow_decay_code] >> s->bit_alloc.sr_shift;
- s->bit_alloc.fast_decay = ff_ac3_fast_decay_tab[s->fast_decay_code] >> s->bit_alloc.sr_shift;
- s->bit_alloc.slow_gain = ff_ac3_slow_gain_tab[s->slow_gain_code];
- s->bit_alloc.db_per_bit = ff_ac3_db_per_bit_tab[s->db_per_bit_code];
- s->bit_alloc.floor = ff_ac3_floor_tab[s->floor_code];
- s->bit_alloc.cpl_fast_leak = 0;
- s->bit_alloc.cpl_slow_leak = 0;
- count_frame_bits_fixed(s);
- }
- /*
- * Count the bits used to encode the frame, minus exponents and mantissas.
- * Bits based on fixed parameters have already been counted, so now we just
- * have to add the bits based on parameters that change during encoding.
- */
- static void count_frame_bits(AC3EncodeContext *s)
- {
- AC3EncOptions *opt = &s->options;
- int blk, ch;
- int frame_bits = 0;
- /* header */
- if (s->eac3) {
- if (opt->eac3_mixing_metadata) {
- if (s->channel_mode > AC3_CHMODE_STEREO)
- frame_bits += 2;
- if (s->has_center)
- frame_bits += 6;
- if (s->has_surround)
- frame_bits += 6;
- frame_bits += s->lfe_on;
- frame_bits += 1 + 1 + 2;
- if (s->channel_mode < AC3_CHMODE_STEREO)
- frame_bits++;
- frame_bits++;
- }
- if (opt->eac3_info_metadata) {
- frame_bits += 3 + 1 + 1;
- if (s->channel_mode == AC3_CHMODE_STEREO)
- frame_bits += 2 + 2;
- if (s->channel_mode >= AC3_CHMODE_2F2R)
- frame_bits += 2;
- frame_bits++;
- if (opt->audio_production_info)
- frame_bits += 5 + 2 + 1;
- frame_bits++;
- }
- /* coupling */
- if (s->channel_mode > AC3_CHMODE_MONO) {
- frame_bits++;
- for (blk = 1; blk < s->num_blocks; blk++) {
- AC3Block *block = &s->blocks[blk];
- frame_bits++;
- if (block->new_cpl_strategy)
- frame_bits++;
- }
- }
- /* coupling exponent strategy */
- if (s->cpl_on) {
- if (s->use_frame_exp_strategy) {
- frame_bits += 5 * s->cpl_on;
- } else {
- for (blk = 0; blk < s->num_blocks; blk++)
- frame_bits += 2 * s->blocks[blk].cpl_in_use;
- }
- }
- } else {
- if (opt->audio_production_info)
- frame_bits += 7;
- if (s->bitstream_id == 6) {
- if (opt->extended_bsi_1)
- frame_bits += 14;
- if (opt->extended_bsi_2)
- frame_bits += 14;
- }
- }
- /* audio blocks */
- for (blk = 0; blk < s->num_blocks; blk++) {
- AC3Block *block = &s->blocks[blk];
- /* coupling strategy */
- if (!s->eac3)
- frame_bits++;
- if (block->new_cpl_strategy) {
- if (!s->eac3)
- frame_bits++;
- if (block->cpl_in_use) {
- if (s->eac3)
- frame_bits++;
- if (!s->eac3 || s->channel_mode != AC3_CHMODE_STEREO)
- frame_bits += s->fbw_channels;
- if (s->channel_mode == AC3_CHMODE_STEREO)
- frame_bits++;
- frame_bits += 4 + 4;
- if (s->eac3)
- frame_bits++;
- else
- frame_bits += s->num_cpl_subbands - 1;
- }
- }
- /* coupling coordinates */
- if (block->cpl_in_use) {
- for (ch = 1; ch <= s->fbw_channels; ch++) {
- if (block->channel_in_cpl[ch]) {
- if (!s->eac3 || block->new_cpl_coords[ch] != 2)
- frame_bits++;
- if (block->new_cpl_coords[ch]) {
- frame_bits += 2;
- frame_bits += (4 + 4) * s->num_cpl_bands;
- }
- }
- }
- }
- /* stereo rematrixing */
- if (s->channel_mode == AC3_CHMODE_STEREO) {
- if (!s->eac3 || blk > 0)
- frame_bits++;
- if (s->blocks[blk].new_rematrixing_strategy)
- frame_bits += block->num_rematrixing_bands;
- }
- /* bandwidth codes & gain range */
- for (ch = 1; ch <= s->fbw_channels; ch++) {
- if (s->exp_strategy[ch][blk] != EXP_REUSE) {
- if (!block->channel_in_cpl[ch])
- frame_bits += 6;
- frame_bits += 2;
- }
- }
- /* coupling exponent strategy */
- if (!s->eac3 && block->cpl_in_use)
- frame_bits += 2;
- /* snr offsets and fast gain codes */
- if (!s->eac3) {
- frame_bits++;
- if (block->new_snr_offsets)
- frame_bits += 6 + (s->channels + block->cpl_in_use) * (4 + 3);
- }
- /* coupling leak info */
- if (block->cpl_in_use) {
- if (!s->eac3 || block->new_cpl_leak != 2)
- frame_bits++;
- if (block->new_cpl_leak)
- frame_bits += 3 + 3;
- }
- }
- s->frame_bits = s->frame_bits_fixed + frame_bits;
- }
- /*
- * Calculate masking curve based on the final exponents.
- * Also calculate the power spectral densities to use in future calculations.
- */
- static void bit_alloc_masking(AC3EncodeContext *s)
- {
- int blk, ch;
- for (blk = 0; blk < s->num_blocks; blk++) {
- AC3Block *block = &s->blocks[blk];
- for (ch = !block->cpl_in_use; ch <= s->channels; ch++) {
- /* We only need psd and mask for calculating bap.
- Since we currently do not calculate bap when exponent
- strategy is EXP_REUSE we do not need to calculate psd or mask. */
- if (s->exp_strategy[ch][blk] != EXP_REUSE) {
- ff_ac3_bit_alloc_calc_psd(block->exp[ch], s->start_freq[ch],
- block->end_freq[ch], block->psd[ch],
- block->band_psd[ch]);
- ff_ac3_bit_alloc_calc_mask(&s->bit_alloc, block->band_psd[ch],
- s->start_freq[ch], block->end_freq[ch],
- ff_ac3_fast_gain_tab[s->fast_gain_code[ch]],
- ch == s->lfe_channel,
- DBA_NONE, 0, NULL, NULL, NULL,
- block->mask[ch]);
- }
- }
- }
- }
- /*
- * Ensure that bap for each block and channel point to the current bap_buffer.
- * They may have been switched during the bit allocation search.
- */
- static void reset_block_bap(AC3EncodeContext *s)
- {
- int blk, ch;
- uint8_t *ref_bap;
- if (s->ref_bap[0][0] == s->bap_buffer && s->ref_bap_set)
- return;
- ref_bap = s->bap_buffer;
- for (ch = 0; ch <= s->channels; ch++) {
- for (blk = 0; blk < s->num_blocks; blk++)
- s->ref_bap[ch][blk] = ref_bap + AC3_MAX_COEFS * s->exp_ref_block[ch][blk];
- ref_bap += AC3_MAX_COEFS * s->num_blocks;
- }
- s->ref_bap_set = 1;
- }
- /**
- * Initialize mantissa counts.
- * These are set so that they are padded to the next whole group size when bits
- * are counted in compute_mantissa_size.
- *
- * @param[in,out] mant_cnt running counts for each bap value for each block
- */
- static void count_mantissa_bits_init(uint16_t mant_cnt[AC3_MAX_BLOCKS][16])
- {
- int blk;
- for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
- memset(mant_cnt[blk], 0, sizeof(mant_cnt[blk]));
- mant_cnt[blk][1] = mant_cnt[blk][2] = 2;
- mant_cnt[blk][4] = 1;
- }
- }
- /**
- * Update mantissa bit counts for all blocks in 1 channel in a given bandwidth
- * range.
- *
- * @param s AC-3 encoder private context
- * @param ch channel index
- * @param[in,out] mant_cnt running counts for each bap value for each block
- * @param start starting coefficient bin
- * @param end ending coefficient bin
- */
- static void count_mantissa_bits_update_ch(AC3EncodeContext *s, int ch,
- uint16_t mant_cnt[AC3_MAX_BLOCKS][16],
- int start, int end)
- {
- int blk;
- for (blk = 0; blk < s->num_blocks; blk++) {
- AC3Block *block = &s->blocks[blk];
- if (ch == CPL_CH && !block->cpl_in_use)
- continue;
- s->ac3dsp.update_bap_counts(mant_cnt[blk],
- s->ref_bap[ch][blk] + start,
- FFMIN(end, block->end_freq[ch]) - start);
- }
- }
- /*
- * Count the number of mantissa bits in the frame based on the bap values.
- */
- static int count_mantissa_bits(AC3EncodeContext *s)
- {
- int ch, max_end_freq;
- LOCAL_ALIGNED_16(uint16_t, mant_cnt, [AC3_MAX_BLOCKS], [16]);
- count_mantissa_bits_init(mant_cnt);
- max_end_freq = s->bandwidth_code * 3 + 73;
- for (ch = !s->cpl_enabled; ch <= s->channels; ch++)
- count_mantissa_bits_update_ch(s, ch, mant_cnt, s->start_freq[ch],
- max_end_freq);
- return s->ac3dsp.compute_mantissa_size(mant_cnt);
- }
- /**
- * Run the bit allocation with a given SNR offset.
- * This calculates the bit allocation pointers that will be used to determine
- * the quantization of each mantissa.
- *
- * @param s AC-3 encoder private context
- * @param snr_offset SNR offset, 0 to 1023
- * @return the number of bits needed for mantissas if the given SNR offset is
- * is used.
- */
- static int bit_alloc(AC3EncodeContext *s, int snr_offset)
- {
- int blk, ch;
- snr_offset = (snr_offset - 240) * 4;
- reset_block_bap(s);
- for (blk = 0; blk < s->num_blocks; blk++) {
- AC3Block *block = &s->blocks[blk];
- for (ch = !block->cpl_in_use; ch <= s->channels; ch++) {
- /* Currently the only bit allocation parameters which vary across
- blocks within a frame are the exponent values. We can take
- advantage of that by reusing the bit allocation pointers
- whenever we reuse exponents. */
- if (s->exp_strategy[ch][blk] != EXP_REUSE) {
- s->ac3dsp.bit_alloc_calc_bap(block->mask[ch], block->psd[ch],
- s->start_freq[ch], block->end_freq[ch],
- snr_offset, s->bit_alloc.floor,
- ff_ac3_bap_tab, s->ref_bap[ch][blk]);
- }
- }
- }
- return count_mantissa_bits(s);
- }
- /*
- * Constant bitrate bit allocation search.
- * Find the largest SNR offset that will allow data to fit in the frame.
- */
- static int cbr_bit_allocation(AC3EncodeContext *s)
- {
- int ch;
- int bits_left;
- int snr_offset, snr_incr;
- bits_left = 8 * s->frame_size - (s->frame_bits + s->exponent_bits);
- if (bits_left < 0)
- return AVERROR(EINVAL);
- snr_offset = s->coarse_snr_offset << 4;
- /* if previous frame SNR offset was 1023, check if current frame can also
- use SNR offset of 1023. if so, skip the search. */
- if ((snr_offset | s->fine_snr_offset[1]) == 1023) {
- if (bit_alloc(s, 1023) <= bits_left)
- return 0;
- }
- while (snr_offset >= 0 &&
- bit_alloc(s, snr_offset) > bits_left) {
- snr_offset -= 64;
- }
- if (snr_offset < 0)
- return AVERROR(EINVAL);
- FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
- for (snr_incr = 64; snr_incr > 0; snr_incr >>= 2) {
- while (snr_offset + snr_incr <= 1023 &&
- bit_alloc(s, snr_offset + snr_incr) <= bits_left) {
- snr_offset += snr_incr;
- FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
- }
- }
- FFSWAP(uint8_t *, s->bap_buffer, s->bap1_buffer);
- reset_block_bap(s);
- s->coarse_snr_offset = snr_offset >> 4;
- for (ch = !s->cpl_on; ch <= s->channels; ch++)
- s->fine_snr_offset[ch] = snr_offset & 0xF;
- return 0;
- }
- /*
- * Perform bit allocation search.
- * Finds the SNR offset value that maximizes quality and fits in the specified
- * frame size. Output is the SNR offset and a set of bit allocation pointers
- * used to quantize the mantissas.
- */
- int ff_ac3_compute_bit_allocation(AC3EncodeContext *s)
- {
- count_frame_bits(s);
- s->exponent_bits = count_exponent_bits(s);
- bit_alloc_masking(s);
- return cbr_bit_allocation(s);
- }
- /**
- * Symmetric quantization on 'levels' levels.
- *
- * @param c unquantized coefficient
- * @param e exponent
- * @param levels number of quantization levels
- * @return quantized coefficient
- */
- static inline int sym_quant(int c, int e, int levels)
- {
- int v = (((levels * c) >> (24 - e)) + levels) >> 1;
- av_assert2(v >= 0 && v < levels);
- return v;
- }
- /**
- * Asymmetric quantization on 2^qbits levels.
- *
- * @param c unquantized coefficient
- * @param e exponent
- * @param qbits number of quantization bits
- * @return quantized coefficient
- */
- static inline int asym_quant(int c, int e, int qbits)
- {
- int m;
- c = (((c * (1<<e)) >> (24 - qbits)) + 1) >> 1;
- m = (1 << (qbits-1));
- if (c >= m)
- c = m - 1;
- av_assert2(c >= -m);
- return c;
- }
- /**
- * Quantize a set of mantissas for a single channel in a single block.
- *
- * @param s Mantissa count context
- * @param fixed_coef unquantized fixed-point coefficients
- * @param exp exponents
- * @param bap bit allocation pointer indices
- * @param[out] qmant quantized coefficients
- * @param start_freq starting coefficient bin
- * @param end_freq ending coefficient bin
- */
- static void quantize_mantissas_blk_ch(AC3Mant *s, int32_t *fixed_coef,
- uint8_t *exp, uint8_t *bap,
- int16_t *qmant, int start_freq,
- int end_freq)
- {
- int i;
- for (i = start_freq; i < end_freq; i++) {
- int c = fixed_coef[i];
- int e = exp[i];
- int v = bap[i];
- if (v)
- switch (v) {
- case 1:
- v = sym_quant(c, e, 3);
- switch (s->mant1_cnt) {
- case 0:
- s->qmant1_ptr = &qmant[i];
- v = 9 * v;
- s->mant1_cnt = 1;
- break;
- case 1:
- *s->qmant1_ptr += 3 * v;
- s->mant1_cnt = 2;
- v = 128;
- break;
- default:
- *s->qmant1_ptr += v;
- s->mant1_cnt = 0;
- v = 128;
- break;
- }
- break;
- case 2:
- v = sym_quant(c, e, 5);
- switch (s->mant2_cnt) {
- case 0:
- s->qmant2_ptr = &qmant[i];
- v = 25 * v;
- s->mant2_cnt = 1;
- break;
- case 1:
- *s->qmant2_ptr += 5 * v;
- s->mant2_cnt = 2;
- v = 128;
- break;
- default:
- *s->qmant2_ptr += v;
- s->mant2_cnt = 0;
- v = 128;
- break;
- }
- break;
- case 3:
- v = sym_quant(c, e, 7);
- break;
- case 4:
- v = sym_quant(c, e, 11);
- switch (s->mant4_cnt) {
- case 0:
- s->qmant4_ptr = &qmant[i];
- v = 11 * v;
- s->mant4_cnt = 1;
- break;
- default:
- *s->qmant4_ptr += v;
- s->mant4_cnt = 0;
- v = 128;
- break;
- }
- break;
- case 5:
- v = sym_quant(c, e, 15);
- break;
- case 14:
- v = asym_quant(c, e, 14);
- break;
- case 15:
- v = asym_quant(c, e, 16);
- break;
- default:
- v = asym_quant(c, e, v - 1);
- break;
- }
- qmant[i] = v;
- }
- }
- /**
- * Quantize mantissas using coefficients, exponents, and bit allocation pointers.
- *
- * @param s AC-3 encoder private context
- */
- void ff_ac3_quantize_mantissas(AC3EncodeContext *s)
- {
- int blk, ch, ch0=0, got_cpl;
- for (blk = 0; blk < s->num_blocks; blk++) {
- AC3Block *block = &s->blocks[blk];
- AC3Mant m = { 0 };
- got_cpl = !block->cpl_in_use;
- for (ch = 1; ch <= s->channels; ch++) {
- if (!got_cpl && ch > 1 && block->channel_in_cpl[ch-1]) {
- ch0 = ch - 1;
- ch = CPL_CH;
- got_cpl = 1;
- }
- quantize_mantissas_blk_ch(&m, block->fixed_coef[ch],
- s->blocks[s->exp_ref_block[ch][blk]].exp[ch],
- s->ref_bap[ch][blk], block->qmant[ch],
- s->start_freq[ch], block->end_freq[ch]);
- if (ch == CPL_CH)
- ch = ch0;
- }
- }
- }
- /*
- * Write the AC-3 frame header to the output bitstream.
- */
- static void ac3_output_frame_header(AC3EncodeContext *s)
- {
- AC3EncOptions *opt = &s->options;
- put_bits(&s->pb, 16, 0x0b77); /* frame header */
- put_bits(&s->pb, 16, 0); /* crc1: will be filled later */
- put_bits(&s->pb, 2, s->bit_alloc.sr_code);
- put_bits(&s->pb, 6, s->frame_size_code + (s->frame_size - s->frame_size_min) / 2);
- put_bits(&s->pb, 5, s->bitstream_id);
- put_bits(&s->pb, 3, s->bitstream_mode);
- put_bits(&s->pb, 3, s->channel_mode);
- if ((s->channel_mode & 0x01) && s->channel_mode != AC3_CHMODE_MONO)
- put_bits(&s->pb, 2, s->center_mix_level);
- if (s->channel_mode & 0x04)
- put_bits(&s->pb, 2, s->surround_mix_level);
- if (s->channel_mode == AC3_CHMODE_STEREO)
- put_bits(&s->pb, 2, opt->dolby_surround_mode);
- put_bits(&s->pb, 1, s->lfe_on); /* LFE */
- put_bits(&s->pb, 5, -opt->dialogue_level);
- put_bits(&s->pb, 1, 0); /* no compression control word */
- put_bits(&s->pb, 1, 0); /* no lang code */
- put_bits(&s->pb, 1, opt->audio_production_info);
- if (opt->audio_production_info) {
- put_bits(&s->pb, 5, opt->mixing_level - 80);
- put_bits(&s->pb, 2, opt->room_type);
- }
- put_bits(&s->pb, 1, opt->copyright);
- put_bits(&s->pb, 1, opt->original);
- if (s->bitstream_id == 6) {
- /* alternate bit stream syntax */
- put_bits(&s->pb, 1, opt->extended_bsi_1);
- if (opt->extended_bsi_1) {
- put_bits(&s->pb, 2, opt->preferred_stereo_downmix);
- put_bits(&s->pb, 3, s->ltrt_center_mix_level);
- put_bits(&s->pb, 3, s->ltrt_surround_mix_level);
- put_bits(&s->pb, 3, s->loro_center_mix_level);
- put_bits(&s->pb, 3, s->loro_surround_mix_level);
- }
- put_bits(&s->pb, 1, opt->extended_bsi_2);
- if (opt->extended_bsi_2) {
- put_bits(&s->pb, 2, opt->dolby_surround_ex_mode);
- put_bits(&s->pb, 2, opt->dolby_headphone_mode);
- put_bits(&s->pb, 1, opt->ad_converter_type);
- put_bits(&s->pb, 9, 0); /* xbsi2 and encinfo : reserved */
- }
- } else {
- put_bits(&s->pb, 1, 0); /* no time code 1 */
- put_bits(&s->pb, 1, 0); /* no time code 2 */
- }
- put_bits(&s->pb, 1, 0); /* no additional bit stream info */
- }
- /*
- * Write one audio block to the output bitstream.
- */
- static void output_audio_block(AC3EncodeContext *s, int blk)
- {
- int ch, i, baie, bnd, got_cpl, av_uninit(ch0);
- AC3Block *block = &s->blocks[blk];
- /* block switching */
- if (!s->eac3) {
- for (ch = 0; ch < s->fbw_channels; ch++)
- put_bits(&s->pb, 1, 0);
- }
- /* dither flags */
- if (!s->eac3) {
- for (ch = 0; ch < s->fbw_channels; ch++)
- put_bits(&s->pb, 1, 1);
- }
- /* dynamic range codes */
- put_bits(&s->pb, 1, 0);
- /* spectral extension */
- if (s->eac3)
- put_bits(&s->pb, 1, 0);
- /* channel coupling */
- if (!s->eac3)
- put_bits(&s->pb, 1, block->new_cpl_strategy);
- if (block->new_cpl_strategy) {
- if (!s->eac3)
- put_bits(&s->pb, 1, block->cpl_in_use);
- if (block->cpl_in_use) {
- int start_sub, end_sub;
- if (s->eac3)
- put_bits(&s->pb, 1, 0); /* enhanced coupling */
- if (!s->eac3 || s->channel_mode != AC3_CHMODE_STEREO) {
- for (ch = 1; ch <= s->fbw_channels; ch++)
- put_bits(&s->pb, 1, block->channel_in_cpl[ch]);
- }
- if (s->channel_mode == AC3_CHMODE_STEREO)
- put_bits(&s->pb, 1, 0); /* phase flags in use */
- start_sub = (s->start_freq[CPL_CH] - 37) / 12;
- end_sub = (s->cpl_end_freq - 37) / 12;
- put_bits(&s->pb, 4, start_sub);
- put_bits(&s->pb, 4, end_sub - 3);
- /* coupling band structure */
- if (s->eac3) {
- put_bits(&s->pb, 1, 0); /* use default */
- } else {
- for (bnd = start_sub+1; bnd < end_sub; bnd++)
- put_bits(&s->pb, 1, ff_eac3_default_cpl_band_struct[bnd]);
- }
- }
- }
- /* coupling coordinates */
- if (block->cpl_in_use) {
- for (ch = 1; ch <= s->fbw_channels; ch++) {
- if (block->channel_in_cpl[ch]) {
- if (!s->eac3 || block->new_cpl_coords[ch] != 2)
- put_bits(&s->pb, 1, block->new_cpl_coords[ch]);
- if (block->new_cpl_coords[ch]) {
- put_bits(&s->pb, 2, block->cpl_master_exp[ch]);
- for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
- put_bits(&s->pb, 4, block->cpl_coord_exp [ch][bnd]);
- put_bits(&s->pb, 4, block->cpl_coord_mant[ch][bnd]);
- }
- }
- }
- }
- }
- /* stereo rematrixing */
- if (s->channel_mode == AC3_CHMODE_STEREO) {
- if (!s->eac3 || blk > 0)
- put_bits(&s->pb, 1, block->new_rematrixing_strategy);
- if (block->new_rematrixing_strategy) {
- /* rematrixing flags */
- for (bnd = 0; bnd < block->num_rematrixing_bands; bnd++)
- put_bits(&s->pb, 1, block->rematrixing_flags[bnd]);
- }
- }
- /* exponent strategy */
- if (!s->eac3) {
- for (ch = !block->cpl_in_use; ch <= s->fbw_channels; ch++)
- put_bits(&s->pb, 2, s->exp_strategy[ch][blk]);
- if (s->lfe_on)
- put_bits(&s->pb, 1, s->exp_strategy[s->lfe_channel][blk]);
- }
- /* bandwidth */
- for (ch = 1; ch <= s->fbw_channels; ch++) {
- if (s->exp_strategy[ch][blk] != EXP_REUSE && !block->channel_in_cpl[ch])
- put_bits(&s->pb, 6, s->bandwidth_code);
- }
- /* exponents */
- for (ch = !block->cpl_in_use; ch <= s->channels; ch++) {
- int nb_groups;
- int cpl = (ch == CPL_CH);
- if (s->exp_strategy[ch][blk] == EXP_REUSE)
- continue;
- /* DC exponent */
- put_bits(&s->pb, 4, block->grouped_exp[ch][0] >> cpl);
- /* exponent groups */
- nb_groups = exponent_group_tab[cpl][s->exp_strategy[ch][blk]-1][block->end_freq[ch]-s->start_freq[ch]];
- for (i = 1; i <= nb_groups; i++)
- put_bits(&s->pb, 7, block->grouped_exp[ch][i]);
- /* gain range info */
- if (ch != s->lfe_channel && !cpl)
- put_bits(&s->pb, 2, 0);
- }
- /* bit allocation info */
- if (!s->eac3) {
- baie = (blk == 0);
- put_bits(&s->pb, 1, baie);
- if (baie) {
- put_bits(&s->pb, 2, s->slow_decay_code);
- put_bits(&s->pb, 2, s->fast_decay_code);
- put_bits(&s->pb, 2, s->slow_gain_code);
- put_bits(&s->pb, 2, s->db_per_bit_code);
- put_bits(&s->pb, 3, s->floor_code);
- }
- }
- /* snr offset */
- if (!s->eac3) {
- put_bits(&s->pb, 1, block->new_snr_offsets);
- if (block->new_snr_offsets) {
- put_bits(&s->pb, 6, s->coarse_snr_offset);
- for (ch = !block->cpl_in_use; ch <= s->channels; ch++) {
- put_bits(&s->pb, 4, s->fine_snr_offset[ch]);
- put_bits(&s->pb, 3, s->fast_gain_code[ch]);
- }
- }
- } else {
- put_bits(&s->pb, 1, 0); /* no converter snr offset */
- }
- /* coupling leak */
- if (block->cpl_in_use) {
- if (!s->eac3 || block->new_cpl_leak != 2)
- put_bits(&s->pb, 1, block->new_cpl_leak);
- if (block->new_cpl_leak) {
- put_bits(&s->pb, 3, s->bit_alloc.cpl_fast_leak);
- put_bits(&s->pb, 3, s->bit_alloc.cpl_slow_leak);
- }
- }…