/* * 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 "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_4POINT5DB, 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->dsp.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 int 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) << 2; 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 << 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); } } if (!s->eac3) { put_bits(&s->pb, 1, 0); /* no delta bit allocation */ put_bits(&s->pb, 1, 0); /* no data to skip */ } /* mantissas */ got_cpl = !block->cpl_in_use; for (ch = 1; ch <= s->channels; ch++) { int b, q; if (!got_cpl && ch > 1 && block->channel_in_cpl[ch-1]) { ch0 = ch - 1; ch = CPL_CH; got_cpl = 1; } for (i = s->start_freq[ch]; i < block->end_freq[ch]; i++) { q = block->qmant[ch][i]; b = s->ref_bap[ch][blk][i]; switch (b) { case 0: break; case 1: if (q != 128) put_bits (&s->pb, 5, q); break; case 2: if (q != 128) put_bits (&s->pb, 7, q); break; case 3: put_sbits(&s->pb, 3, q); break; case 4: if (q != 128) put_bits (&s->pb, 7, q); break; case 14: put_sbits(&s->pb, 14, q); break; case 15: put_sbits(&s->pb, 16, q); break; default: put_sbits(&s->pb, b-1, q); break; } } if (ch == CPL_CH) ch = ch0; } } /** CRC-16 Polynomial */ #define CRC16_POLY ((1 << 0) | (1 << 2) | (1 << 15) | (1 << 16)) static unsigned int mul_poly(unsigned int a, unsigned int b, unsigned int poly) { unsigned int c; c = 0; while (a) { if (a & 1) c ^= b; a = a >> 1; b = b << 1; if (b & (1 << 16)) b ^= poly; } return c; } static unsigned int pow_poly(unsigned int a, unsigned int n, unsigned int poly) { unsigned int r; r = 1; while (n) { if (n & 1) r = mul_poly(r, a, poly); a = mul_poly(a, a, poly); n >>= 1; } return r; } /* * Fill the end of the frame with 0's and compute the two CRCs. */ static void output_frame_end(AC3EncodeContext *s) { const AVCRC *crc_ctx = av_crc_get_table(AV_CRC_16_ANSI); int frame_size_58, pad_bytes, crc1, crc2_partial, crc2, crc_inv; uint8_t *frame; frame_size_58 = ((s->frame_size >> 2) + (s->frame_size >> 4)) << 1; /* pad the remainder of the frame with zeros */ av_assert2(s->frame_size * 8 - put_bits_count(&s->pb) >= 18); flush_put_bits(&s->pb); frame = s->pb.buf; pad_bytes = s->frame_size - (put_bits_ptr(&s->pb) - frame) - 2; av_assert2(pad_bytes >= 0); if (pad_bytes > 0) memset(put_bits_ptr(&s->pb), 0, pad_bytes); if (s->eac3) { /* compute crc2 */ crc2_partial = av_crc(crc_ctx, 0, frame + 2, s->frame_size - 5); } else { /* compute crc1 */ /* this is not so easy because it is at the beginning of the data... */ crc1 = av_bswap16(av_crc(crc_ctx, 0, frame + 4, frame_size_58 - 4)); crc_inv = s->crc_inv[s->frame_size > s->frame_size_min]; crc1 = mul_poly(crc_inv, crc1, CRC16_POLY); AV_WB16(frame + 2, crc1); /* compute crc2 */ crc2_partial = av_crc(crc_ctx, 0, frame + frame_size_58, s->frame_size - frame_size_58 - 3); } crc2 = av_crc(crc_ctx, crc2_partial, frame + s->frame_size - 3, 1); /* ensure crc2 does not match sync word by flipping crcrsv bit if needed */ if (crc2 == 0x770B) { frame[s->frame_size - 3] ^= 0x1; crc2 = av_crc(crc_ctx, crc2_partial, frame + s->frame_size - 3, 1); } crc2 = av_bswap16(crc2); AV_WB16(frame + s->frame_size - 2, crc2); } /** * Write the frame to the output bitstream. * * @param s AC-3 encoder private context * @param frame output data buffer */ void ff_ac3_output_frame(AC3EncodeContext *s, unsigned char *frame) { int blk; init_put_bits(&s->pb, frame, AC3_MAX_CODED_FRAME_SIZE); s->output_frame_header(s); for (blk = 0; blk < s->num_blocks; blk++) output_audio_block(s, blk); output_frame_end(s); } static void dprint_options(AC3EncodeContext *s) { #ifdef DEBUG AVCodecContext *avctx = s->avctx; AC3EncOptions *opt = &s->options; char strbuf[32]; switch (s->bitstream_id) { case 6: av_strlcpy(strbuf, "AC-3 (alt syntax)", 32); break; case 8: av_strlcpy(strbuf, "AC-3 (standard)", 32); break; case 9: av_strlcpy(strbuf, "AC-3 (dnet half-rate)", 32); break; case 10: av_strlcpy(strbuf, "AC-3 (dnet quater-rate)", 32); break; case 16: av_strlcpy(strbuf, "E-AC-3 (enhanced)", 32); break; default: snprintf(strbuf, 32, "ERROR"); } av_dlog(avctx, "bitstream_id: %s (%d)\n", strbuf, s->bitstream_id); av_dlog(avctx, "sample_fmt: %s\n", av_get_sample_fmt_name(avctx->sample_fmt)); av_get_channel_layout_string(strbuf, 32, s->channels, avctx->channel_layout); av_dlog(avctx, "channel_layout: %s\n", strbuf); av_dlog(avctx, "sample_rate: %d\n", s->sample_rate); av_dlog(avctx, "bit_rate: %d\n", s->bit_rate); av_dlog(avctx, "blocks/frame: %d (code=%d)\n", s->num_blocks, s->num_blks_code); if (s->cutoff) av_dlog(avctx, "cutoff: %d\n", s->cutoff); av_dlog(avctx, "per_frame_metadata: %s\n", opt->allow_per_frame_metadata?"on":"off"); if (s->has_center) av_dlog(avctx, "center_mixlev: %0.3f (%d)\n", opt->center_mix_level, s->center_mix_level); else av_dlog(avctx, "center_mixlev: {not written}\n"); if (s->has_surround) av_dlog(avctx, "surround_mixlev: %0.3f (%d)\n", opt->surround_mix_level, s->surround_mix_level); else av_dlog(avctx, "surround_mixlev: {not written}\n"); if (opt->audio_production_info) { av_dlog(avctx, "mixing_level: %ddB\n", opt->mixing_level); switch (opt->room_type) { case AC3ENC_OPT_NOT_INDICATED: av_strlcpy(strbuf, "notindicated", 32); break; case AC3ENC_OPT_LARGE_ROOM: av_strlcpy(strbuf, "large", 32); break; case AC3ENC_OPT_SMALL_ROOM: av_strlcpy(strbuf, "small", 32); break; default: snprintf(strbuf, 32, "ERROR (%d)", opt->room_type); } av_dlog(avctx, "room_type: %s\n", strbuf); } else { av_dlog(avctx, "mixing_level: {not written}\n"); av_dlog(avctx, "room_type: {not written}\n"); } av_dlog(avctx, "copyright: %s\n", opt->copyright?"on":"off"); av_dlog(avctx, "dialnorm: %ddB\n", opt->dialogue_level); if (s->channel_mode == AC3_CHMODE_STEREO) { switch (opt->dolby_surround_mode) { case AC3ENC_OPT_NOT_INDICATED: av_strlcpy(strbuf, "notindicated", 32); break; case AC3ENC_OPT_MODE_ON: av_strlcpy(strbuf, "on", 32); break; case AC3ENC_OPT_MODE_OFF: av_strlcpy(strbuf, "off", 32); break; default: snprintf(strbuf, 32, "ERROR (%d)", opt->dolby_surround_mode); } av_dlog(avctx, "dsur_mode: %s\n", strbuf); } else { av_dlog(avctx, "dsur_mode: {not written}\n"); } av_dlog(avctx, "original: %s\n", opt->original?"on":"off"); if (s->bitstream_id == 6) { if (opt->extended_bsi_1) { switch (opt->preferred_stereo_downmix) { case AC3ENC_OPT_NOT_INDICATED: av_strlcpy(strbuf, "notindicated", 32); break; case AC3ENC_OPT_DOWNMIX_LTRT: av_strlcpy(strbuf, "ltrt", 32); break; case AC3ENC_OPT_DOWNMIX_LORO: av_strlcpy(strbuf, "loro", 32); break; default: snprintf(strbuf, 32, "ERROR (%d)", opt->preferred_stereo_downmix); } av_dlog(avctx, "dmix_mode: %s\n", strbuf); av_dlog(avctx, "ltrt_cmixlev: %0.3f (%d)\n", opt->ltrt_center_mix_level, s->ltrt_center_mix_level); av_dlog(avctx, "ltrt_surmixlev: %0.3f (%d)\n", opt->ltrt_surround_mix_level, s->ltrt_surround_mix_level); av_dlog(avctx, "loro_cmixlev: %0.3f (%d)\n", opt->loro_center_mix_level, s->loro_center_mix_level); av_dlog(avctx, "loro_surmixlev: %0.3f (%d)\n", opt->loro_surround_mix_level, s->loro_surround_mix_level); } else { av_dlog(avctx, "extended bitstream info 1: {not written}\n"); } if (opt->extended_bsi_2) { switch (opt->dolby_surround_ex_mode) { case AC3ENC_OPT_NOT_INDICATED: av_strlcpy(strbuf, "notindicated", 32); break; case AC3ENC_OPT_MODE_ON: av_strlcpy(strbuf, "on", 32); break; case AC3ENC_OPT_MODE_OFF: av_strlcpy(strbuf, "off", 32); break; default: snprintf(strbuf, 32, "ERROR (%d)", opt->dolby_surround_ex_mode); } av_dlog(avctx, "dsurex_mode: %s\n", strbuf); switch (opt->dolby_headphone_mode) { case AC3ENC_OPT_NOT_INDICATED: av_strlcpy(strbuf, "notindicated", 32); break; case AC3ENC_OPT_MODE_ON: av_strlcpy(strbuf, "on", 32); break; case AC3ENC_OPT_MODE_OFF: av_strlcpy(strbuf, "off", 32); break; default: snprintf(strbuf, 32, "ERROR (%d)", opt->dolby_headphone_mode); } av_dlog(avctx, "dheadphone_mode: %s\n", strbuf); switch (opt->ad_converter_type) { case AC3ENC_OPT_ADCONV_STANDARD: av_strlcpy(strbuf, "standard", 32); break; case AC3ENC_OPT_ADCONV_HDCD: av_strlcpy(strbuf, "hdcd", 32); break; default: snprintf(strbuf, 32, "ERROR (%d)", opt->ad_converter_type); } av_dlog(avctx, "ad_conv_type: %s\n", strbuf); } else { av_dlog(avctx, "extended bitstream info 2: {not written}\n"); } } #endif } #define FLT_OPTION_THRESHOLD 0.01 static int validate_float_option(float v, const float *v_list, int v_list_size) { int i; for (i = 0; i < v_list_size; i++) { if (v < (v_list[i] + FLT_OPTION_THRESHOLD) && v > (v_list[i] - FLT_OPTION_THRESHOLD)) break; } if (i == v_list_size) return -1; return i; } static void validate_mix_level(void *log_ctx, const char *opt_name, float *opt_param, const float *list, int list_size, int default_value, int min_value, int *ctx_param) { int mixlev = validate_float_option(*opt_param, list, list_size); if (mixlev < min_value) { mixlev = default_value; if (*opt_param >= 0.0) { av_log(log_ctx, AV_LOG_WARNING, "requested %s is not valid. using " "default value: %0.3f\n", opt_name, list[mixlev]); } } *opt_param = list[mixlev]; *ctx_param = mixlev; } /** * Validate metadata options as set by AVOption system. * These values can optionally be changed per-frame. * * @param s AC-3 encoder private context */ int ff_ac3_validate_metadata(AC3EncodeContext *s) { AVCodecContext *avctx = s->avctx; AC3EncOptions *opt = &s->options; opt->audio_production_info = 0; opt->extended_bsi_1 = 0; opt->extended_bsi_2 = 0; opt->eac3_mixing_metadata = 0; opt->eac3_info_metadata = 0; /* determine mixing metadata / xbsi1 use */ if (s->channel_mode > AC3_CHMODE_STEREO && opt->preferred_stereo_downmix != AC3ENC_OPT_NONE) { opt->extended_bsi_1 = 1; opt->eac3_mixing_metadata = 1; } if (s->has_center && (opt->ltrt_center_mix_level >= 0 || opt->loro_center_mix_level >= 0)) { opt->extended_bsi_1 = 1; opt->eac3_mixing_metadata = 1; } if (s->has_surround && (opt->ltrt_surround_mix_level >= 0 || opt->loro_surround_mix_level >= 0)) { opt->extended_bsi_1 = 1; opt->eac3_mixing_metadata = 1; } if (s->eac3) { /* determine info metadata use */ if (avctx->audio_service_type != AV_AUDIO_SERVICE_TYPE_MAIN) opt->eac3_info_metadata = 1; if (opt->copyright != AC3ENC_OPT_NONE || opt->original != AC3ENC_OPT_NONE) opt->eac3_info_metadata = 1; if (s->channel_mode == AC3_CHMODE_STEREO && (opt->dolby_headphone_mode != AC3ENC_OPT_NONE || opt->dolby_surround_mode != AC3ENC_OPT_NONE)) opt->eac3_info_metadata = 1; if (s->channel_mode >= AC3_CHMODE_2F2R && opt->dolby_surround_ex_mode != AC3ENC_OPT_NONE) opt->eac3_info_metadata = 1; if (opt->mixing_level != AC3ENC_OPT_NONE || opt->room_type != AC3ENC_OPT_NONE || opt->ad_converter_type != AC3ENC_OPT_NONE) { opt->audio_production_info = 1; opt->eac3_info_metadata = 1; } } else { /* determine audio production info use */ if (opt->mixing_level != AC3ENC_OPT_NONE || opt->room_type != AC3ENC_OPT_NONE) opt->audio_production_info = 1; /* determine xbsi2 use */ if (s->channel_mode >= AC3_CHMODE_2F2R && opt->dolby_surround_ex_mode != AC3ENC_OPT_NONE) opt->extended_bsi_2 = 1; if (s->channel_mode == AC3_CHMODE_STEREO && opt->dolby_headphone_mode != AC3ENC_OPT_NONE) opt->extended_bsi_2 = 1; if (opt->ad_converter_type != AC3ENC_OPT_NONE) opt->extended_bsi_2 = 1; } /* validate AC-3 mixing levels */ if (!s->eac3) { if (s->has_center) { validate_mix_level(avctx, "center_mix_level", &opt->center_mix_level, cmixlev_options, CMIXLEV_NUM_OPTIONS, 1, 0, &s->center_mix_level); } if (s->has_surround) { validate_mix_level(avctx, "surround_mix_level", &opt->surround_mix_level, surmixlev_options, SURMIXLEV_NUM_OPTIONS, 1, 0, &s->surround_mix_level); } } /* validate extended bsi 1 / mixing metadata */ if (opt->extended_bsi_1 || opt->eac3_mixing_metadata) { /* default preferred stereo downmix */ if (opt->preferred_stereo_downmix == AC3ENC_OPT_NONE) opt->preferred_stereo_downmix = AC3ENC_OPT_NOT_INDICATED; if (!s->eac3 || s->has_center) { /* validate Lt/Rt center mix level */ validate_mix_level(avctx, "ltrt_center_mix_level", &opt->ltrt_center_mix_level, extmixlev_options, EXTMIXLEV_NUM_OPTIONS, 5, 0, &s->ltrt_center_mix_level); /* validate Lo/Ro center mix level */ validate_mix_level(avctx, "loro_center_mix_level", &opt->loro_center_mix_level, extmixlev_options, EXTMIXLEV_NUM_OPTIONS, 5, 0, &s->loro_center_mix_level); } if (!s->eac3 || s->has_surround) { /* validate Lt/Rt surround mix level */ validate_mix_level(avctx, "ltrt_surround_mix_level", &opt->ltrt_surround_mix_level, extmixlev_options, EXTMIXLEV_NUM_OPTIONS, 6, 3, &s->ltrt_surround_mix_level); /* validate Lo/Ro surround mix level */ validate_mix_level(avctx, "loro_surround_mix_level", &opt->loro_surround_mix_level, extmixlev_options, EXTMIXLEV_NUM_OPTIONS, 6, 3, &s->loro_surround_mix_level); } } /* validate audio service type / channels combination */ if ((avctx->audio_service_type == AV_AUDIO_SERVICE_TYPE_KARAOKE && avctx->channels == 1) || ((avctx->audio_service_type == AV_AUDIO_SERVICE_TYPE_COMMENTARY || avctx->audio_service_type == AV_AUDIO_SERVICE_TYPE_EMERGENCY || avctx->audio_service_type == AV_AUDIO_SERVICE_TYPE_VOICE_OVER) && avctx->channels > 1)) { av_log(avctx, AV_LOG_ERROR, "invalid audio service type for the " "specified number of channels\n"); return AVERROR(EINVAL); } /* validate extended bsi 2 / info metadata */ if (opt->extended_bsi_2 || opt->eac3_info_metadata) { /* default dolby headphone mode */ if (opt->dolby_headphone_mode == AC3ENC_OPT_NONE) opt->dolby_headphone_mode = AC3ENC_OPT_NOT_INDICATED; /* default dolby surround ex mode */ if (opt->dolby_surround_ex_mode == AC3ENC_OPT_NONE) opt->dolby_surround_ex_mode = AC3ENC_OPT_NOT_INDICATED; /* default A/D converter type */ if (opt->ad_converter_type == AC3ENC_OPT_NONE) opt->ad_converter_type = AC3ENC_OPT_ADCONV_STANDARD; } /* copyright & original defaults */ if (!s->eac3 || opt->eac3_info_metadata) { /* default copyright */ if (opt->copyright == AC3ENC_OPT_NONE) opt->copyright = AC3ENC_OPT_OFF; /* default original */ if (opt->original == AC3ENC_OPT_NONE) opt->original = AC3ENC_OPT_ON; } /* dolby surround mode default */ if (!s->eac3 || opt->eac3_info_metadata) { if (opt->dolby_surround_mode == AC3ENC_OPT_NONE) opt->dolby_surround_mode = AC3ENC_OPT_NOT_INDICATED; } /* validate audio production info */ if (opt->audio_production_info) { if (opt->mixing_level == AC3ENC_OPT_NONE) { av_log(avctx, AV_LOG_ERROR, "mixing_level must be set if " "room_type is set\n"); return AVERROR(EINVAL); } if (opt->mixing_level < 80) { av_log(avctx, AV_LOG_ERROR, "invalid mixing level. must be between " "80dB and 111dB\n"); return AVERROR(EINVAL); } /* default room type */ if (opt->room_type == AC3ENC_OPT_NONE) opt->room_type = AC3ENC_OPT_NOT_INDICATED; } /* set bitstream id for alternate bitstream syntax */ if (!s->eac3 && (opt->extended_bsi_1 || opt->extended_bsi_2)) { if (s->bitstream_id > 8 && s->bitstream_id < 11) { static int warn_once = 1; if (warn_once) { av_log(avctx, AV_LOG_WARNING, "alternate bitstream syntax is " "not compatible with reduced samplerates. writing of " "extended bitstream information will be disabled.\n"); warn_once = 0; } } else { s->bitstream_id = 6; } } return 0; } /** * Finalize encoding and free any memory allocated by the encoder. * * @param avctx Codec context */ av_cold int ff_ac3_encode_close(AVCodecContext *avctx) { int blk, ch; AC3EncodeContext *s = avctx->priv_data; av_freep(&s->windowed_samples); if (s->planar_samples) for (ch = 0; ch < s->channels; ch++) av_freep(&s->planar_samples[ch]); av_freep(&s->planar_samples); av_freep(&s->bap_buffer); av_freep(&s->bap1_buffer); av_freep(&s->mdct_coef_buffer); av_freep(&s->fixed_coef_buffer); av_freep(&s->exp_buffer); av_freep(&s->grouped_exp_buffer); av_freep(&s->psd_buffer); av_freep(&s->band_psd_buffer); av_freep(&s->mask_buffer); av_freep(&s->qmant_buffer); av_freep(&s->cpl_coord_exp_buffer); av_freep(&s->cpl_coord_mant_buffer); for (blk = 0; blk < s->num_blocks; blk++) { AC3Block *block = &s->blocks[blk]; av_freep(&block->mdct_coef); av_freep(&block->fixed_coef); av_freep(&block->exp); av_freep(&block->grouped_exp); av_freep(&block->psd); av_freep(&block->band_psd); av_freep(&block->mask); av_freep(&block->qmant); av_freep(&block->cpl_coord_exp); av_freep(&block->cpl_coord_mant); } s->mdct_end(s); return 0; } /* * Set channel information during initialization. */ static av_cold int set_channel_info(AC3EncodeContext *s, int channels, uint64_t *channel_layout) { int ch_layout; if (channels < 1 || channels > AC3_MAX_CHANNELS) return AVERROR(EINVAL); if (*channel_layout > 0x7FF) return AVERROR(EINVAL); ch_layout = *channel_layout; if (!ch_layout) ch_layout = av_get_default_channel_layout(channels); s->lfe_on = !!(ch_layout & AV_CH_LOW_FREQUENCY); s->channels = channels; s->fbw_channels = channels - s->lfe_on; s->lfe_channel = s->lfe_on ? s->fbw_channels + 1 : -1; if (s->lfe_on) ch_layout -= AV_CH_LOW_FREQUENCY; switch (ch_layout) { case AV_CH_LAYOUT_MONO: s->channel_mode = AC3_CHMODE_MONO; break; case AV_CH_LAYOUT_STEREO: s->channel_mode = AC3_CHMODE_STEREO; break; case AV_CH_LAYOUT_SURROUND: s->channel_mode = AC3_CHMODE_3F; break; case AV_CH_LAYOUT_2_1: s->channel_mode = AC3_CHMODE_2F1R; break; case AV_CH_LAYOUT_4POINT0: s->channel_mode = AC3_CHMODE_3F1R; break; case AV_CH_LAYOUT_QUAD: case AV_CH_LAYOUT_2_2: s->channel_mode = AC3_CHMODE_2F2R; break; case AV_CH_LAYOUT_5POINT0: case AV_CH_LAYOUT_5POINT0_BACK: s->channel_mode = AC3_CHMODE_3F2R; break; default: return AVERROR(EINVAL); } s->has_center = (s->channel_mode & 0x01) && s->channel_mode != AC3_CHMODE_MONO; s->has_surround = s->channel_mode & 0x04; s->channel_map = ff_ac3_enc_channel_map[s->channel_mode][s->lfe_on]; *channel_layout = ch_layout; if (s->lfe_on) *channel_layout |= AV_CH_LOW_FREQUENCY; return 0; } static av_cold int validate_options(AC3EncodeContext *s) { AVCodecContext *avctx = s->avctx; int i, ret, max_sr; /* validate channel layout */ if (!avctx->channel_layout) { av_log(avctx, AV_LOG_WARNING, "No channel layout specified. The " "encoder will guess the layout, but it " "might be incorrect.\n"); } ret = set_channel_info(s, avctx->channels, &avctx->channel_layout); if (ret) { av_log(avctx, AV_LOG_ERROR, "invalid channel layout\n"); return ret; } /* validate sample rate */ /* note: max_sr could be changed from 2 to 5 for E-AC-3 once we find a decoder that supports half sample rate so we can validate that the generated files are correct. */ max_sr = s->eac3 ? 2 : 8; for (i = 0; i <= max_sr; i++) { if ((ff_ac3_sample_rate_tab[i % 3] >> (i / 3)) == avctx->sample_rate) break; } if (i > max_sr) { av_log(avctx, AV_LOG_ERROR, "invalid sample rate\n"); return AVERROR(EINVAL); } s->sample_rate = avctx->sample_rate; s->bit_alloc.sr_shift = i / 3; s->bit_alloc.sr_code = i % 3; s->bitstream_id = s->eac3 ? 16 : 8 + s->bit_alloc.sr_shift; /* select a default bit rate if not set by the user */ if (!avctx->bit_rate) { switch (s->fbw_channels) { case 1: avctx->bit_rate = 96000; break; case 2: avctx->bit_rate = 192000; break; case 3: avctx->bit_rate = 320000; break; case 4: avctx->bit_rate = 384000; break; case 5: avctx->bit_rate = 448000; break; } } /* validate bit rate */ if (s->eac3) { int max_br, min_br, wpf, min_br_dist, min_br_code; int num_blks_code, num_blocks, frame_samples; /* calculate min/max bitrate */ /* TODO: More testing with 3 and 2 blocks. All E-AC-3 samples I've found use either 6 blocks or 1 block, even though 2 or 3 blocks would work as far as the bit rate is concerned. */ for (num_blks_code = 3; num_blks_code >= 0; num_blks_code--) { num_blocks = ((int[]){ 1, 2, 3, 6 })[num_blks_code]; frame_samples = AC3_BLOCK_SIZE * num_blocks; max_br = 2048 * s->sample_rate / frame_samples * 16; min_br = ((s->sample_rate + (frame_samples-1)) / frame_samples) * 16; if (avctx->bit_rate <= max_br) break; } if (avctx->bit_rate < min_br || avctx->bit_rate > max_br) { av_log(avctx, AV_LOG_ERROR, "invalid bit rate. must be %d to %d " "for this sample rate\n", min_br, max_br); return AVERROR(EINVAL); } s->num_blks_code = num_blks_code; s->num_blocks = num_blocks; /* calculate words-per-frame for the selected bitrate */ wpf = (avctx->bit_rate / 16) * frame_samples / s->sample_rate; av_assert1(wpf > 0 && wpf <= 2048); /* find the closest AC-3 bitrate code to the selected bitrate. this is needed for lookup tables for bandwidth and coupling parameter selection */ min_br_code = -1; min_br_dist = INT_MAX; for (i = 0; i < 19; i++) { int br_dist = abs(ff_ac3_bitrate_tab[i] * 1000 - avctx->bit_rate); if (br_dist < min_br_dist) { min_br_dist = br_dist; min_br_code = i; } } /* make sure the minimum frame size is below the average frame size */ s->frame_size_code = min_br_code << 1; while (wpf > 1 && wpf * s->sample_rate / AC3_FRAME_SIZE * 16 > avctx->bit_rate) wpf--; s->frame_size_min = 2 * wpf; } else { int best_br = 0, best_code = 0, best_diff = INT_MAX; for (i = 0; i < 19; i++) { int br = (ff_ac3_bitrate_tab[i] >> s->bit_alloc.sr_shift) * 1000; int diff = abs(br - avctx->bit_rate); if (diff < best_diff) { best_br = br; best_code = i; best_diff = diff; } if (!best_diff) break; } avctx->bit_rate = best_br; s->frame_size_code = best_code << 1; s->frame_size_min = 2 * ff_ac3_frame_size_tab[s->frame_size_code][s->bit_alloc.sr_code]; s->num_blks_code = 0x3; s->num_blocks = 6; } s->bit_rate = avctx->bit_rate; s->frame_size = s->frame_size_min; /* validate cutoff */ if (avctx->cutoff < 0) { av_log(avctx, AV_LOG_ERROR, "invalid cutoff frequency\n"); return AVERROR(EINVAL); } s->cutoff = avctx->cutoff; if (s->cutoff > (s->sample_rate >> 1)) s->cutoff = s->sample_rate >> 1; ret = ff_ac3_validate_metadata(s); if (ret) return ret; s->rematrixing_enabled = s->options.stereo_rematrixing && (s->channel_mode == AC3_CHMODE_STEREO); s->cpl_enabled = s->options.channel_coupling && s->channel_mode >= AC3_CHMODE_STEREO; return 0; } /* * Set bandwidth for all channels. * The user can optionally supply a cutoff frequency. Otherwise an appropriate * default value will be used. */ static av_cold void set_bandwidth(AC3EncodeContext *s) { int blk, ch, av_uninit(cpl_start); if (s->cutoff) { /* calculate bandwidth based on user-specified cutoff frequency */ int fbw_coeffs; fbw_coeffs = s->cutoff * 2 * AC3_MAX_COEFS / s->sample_rate; s->bandwidth_code = av_clip((fbw_coeffs - 73) / 3, 0, 60); } else { /* use default bandwidth setting */ s->bandwidth_code = ac3_bandwidth_tab[s->fbw_channels-1][s->bit_alloc.sr_code][s->frame_size_code/2]; } /* set number of coefficients for each channel */ for (ch = 1; ch <= s->fbw_channels; ch++) { s->start_freq[ch] = 0; for (blk = 0; blk < s->num_blocks; blk++) s->blocks[blk].end_freq[ch] = s->bandwidth_code * 3 + 73; } /* LFE channel always has 7 coefs */ if (s->lfe_on) { s->start_freq[s->lfe_channel] = 0; for (blk = 0; blk < s->num_blocks; blk++) s->blocks[blk].end_freq[ch] = 7; } /* initialize coupling strategy */ if (s->cpl_enabled) { if (s->options.cpl_start != AC3ENC_OPT_AUTO) { cpl_start = s->options.cpl_start; } else { cpl_start = ac3_coupling_start_tab[s->channel_mode-2][s->bit_alloc.sr_code][s->frame_size_code/2]; if (cpl_start < 0) { if (s->options.channel_coupling == AC3ENC_OPT_AUTO) s->cpl_enabled = 0; else cpl_start = 15; } } } if (s->cpl_enabled) { int i, cpl_start_band, cpl_end_band; uint8_t *cpl_band_sizes = s->cpl_band_sizes; cpl_end_band = s->bandwidth_code / 4 + 3; cpl_start_band = av_clip(cpl_start, 0, FFMIN(cpl_end_band-1, 15)); s->num_cpl_subbands = cpl_end_band - cpl_start_band; s->num_cpl_bands = 1; *cpl_band_sizes = 12; for (i = cpl_start_band + 1; i < cpl_end_band; i++) { if (ff_eac3_default_cpl_band_struct[i]) { *cpl_band_sizes += 12; } else { s->num_cpl_bands++; cpl_band_sizes++; *cpl_band_sizes = 12; } } s->start_freq[CPL_CH] = cpl_start_band * 12 + 37; s->cpl_end_freq = cpl_end_band * 12 + 37; for (blk = 0; blk < s->num_blocks; blk++) s->blocks[blk].end_freq[CPL_CH] = s->cpl_end_freq; } } static av_cold int allocate_buffers(AC3EncodeContext *s) { AVCodecContext *avctx = s->avctx; int blk, ch; int channels = s->channels + 1; /* includes coupling channel */ int channel_blocks = channels * s->num_blocks; int total_coefs = AC3_MAX_COEFS * channel_blocks; if (s->allocate_sample_buffers(s)) goto alloc_fail; FF_ALLOC_OR_GOTO(avctx, s->bap_buffer, total_coefs * sizeof(*s->bap_buffer), alloc_fail); FF_ALLOC_OR_GOTO(avctx, s->bap1_buffer, total_coefs * sizeof(*s->bap1_buffer), alloc_fail); FF_ALLOCZ_OR_GOTO(avctx, s->mdct_coef_buffer, total_coefs * sizeof(*s->mdct_coef_buffer), alloc_fail); FF_ALLOC_OR_GOTO(avctx, s->exp_buffer, total_coefs * sizeof(*s->exp_buffer), alloc_fail); FF_ALLOC_OR_GOTO(avctx, s->grouped_exp_buffer, channel_blocks * 128 * sizeof(*s->grouped_exp_buffer), alloc_fail); FF_ALLOC_OR_GOTO(avctx, s->psd_buffer, total_coefs * sizeof(*s->psd_buffer), alloc_fail); FF_ALLOC_OR_GOTO(avctx, s->band_psd_buffer, channel_blocks * 64 * sizeof(*s->band_psd_buffer), alloc_fail); FF_ALLOC_OR_GOTO(avctx, s->mask_buffer, channel_blocks * 64 * sizeof(*s->mask_buffer), alloc_fail); FF_ALLOC_OR_GOTO(avctx, s->qmant_buffer, total_coefs * sizeof(*s->qmant_buffer), alloc_fail); if (s->cpl_enabled) { FF_ALLOC_OR_GOTO(avctx, s->cpl_coord_exp_buffer, channel_blocks * 16 * sizeof(*s->cpl_coord_exp_buffer), alloc_fail); FF_ALLOC_OR_GOTO(avctx, s->cpl_coord_mant_buffer, channel_blocks * 16 * sizeof(*s->cpl_coord_mant_buffer), alloc_fail); } for (blk = 0; blk < s->num_blocks; blk++) { AC3Block *block = &s->blocks[blk]; FF_ALLOCZ_OR_GOTO(avctx, block->mdct_coef, channels * sizeof(*block->mdct_coef), alloc_fail); FF_ALLOCZ_OR_GOTO(avctx, block->exp, channels * sizeof(*block->exp), alloc_fail); FF_ALLOCZ_OR_GOTO(avctx, block->grouped_exp, channels * sizeof(*block->grouped_exp), alloc_fail); FF_ALLOCZ_OR_GOTO(avctx, block->psd, channels * sizeof(*block->psd), alloc_fail); FF_ALLOCZ_OR_GOTO(avctx, block->band_psd, channels * sizeof(*block->band_psd), alloc_fail); FF_ALLOCZ_OR_GOTO(avctx, block->mask, channels * sizeof(*block->mask), alloc_fail); FF_ALLOCZ_OR_GOTO(avctx, block->qmant, channels * sizeof(*block->qmant), alloc_fail); if (s->cpl_enabled) { FF_ALLOCZ_OR_GOTO(avctx, block->cpl_coord_exp, channels * sizeof(*block->cpl_coord_exp), alloc_fail); FF_ALLOCZ_OR_GOTO(avctx, block->cpl_coord_mant, channels * sizeof(*block->cpl_coord_mant), alloc_fail); } for (ch = 0; ch < channels; ch++) { /* arrangement: block, channel, coeff */ block->grouped_exp[ch] = &s->grouped_exp_buffer[128 * (blk * channels + ch)]; block->psd[ch] = &s->psd_buffer [AC3_MAX_COEFS * (blk * channels + ch)]; block->band_psd[ch] = &s->band_psd_buffer [64 * (blk * channels + ch)]; block->mask[ch] = &s->mask_buffer [64 * (blk * channels + ch)]; block->qmant[ch] = &s->qmant_buffer [AC3_MAX_COEFS * (blk * channels + ch)]; if (s->cpl_enabled) { block->cpl_coord_exp[ch] = &s->cpl_coord_exp_buffer [16 * (blk * channels + ch)]; block->cpl_coord_mant[ch] = &s->cpl_coord_mant_buffer[16 * (blk * channels + ch)]; } /* arrangement: channel, block, coeff */ block->exp[ch] = &s->exp_buffer [AC3_MAX_COEFS * (s->num_blocks * ch + blk)]; block->mdct_coef[ch] = &s->mdct_coef_buffer [AC3_MAX_COEFS * (s->num_blocks * ch + blk)]; } } if (!s->fixed_point) { FF_ALLOCZ_OR_GOTO(avctx, s->fixed_coef_buffer, total_coefs * sizeof(*s->fixed_coef_buffer), alloc_fail); for (blk = 0; blk < s->num_blocks; blk++) { AC3Block *block = &s->blocks[blk]; FF_ALLOCZ_OR_GOTO(avctx, block->fixed_coef, channels * sizeof(*block->fixed_coef), alloc_fail); for (ch = 0; ch < channels; ch++) block->fixed_coef[ch] = &s->fixed_coef_buffer[AC3_MAX_COEFS * (s->num_blocks * ch + blk)]; } } else { for (blk = 0; blk < s->num_blocks; blk++) { AC3Block *block = &s->blocks[blk]; FF_ALLOCZ_OR_GOTO(avctx, block->fixed_coef, channels * sizeof(*block->fixed_coef), alloc_fail); for (ch = 0; ch < channels; ch++) block->fixed_coef[ch] = (int32_t *)block->mdct_coef[ch]; } } return 0; alloc_fail: return AVERROR(ENOMEM); } av_cold int ff_ac3_encode_init(AVCodecContext *avctx) { AC3EncodeContext *s = avctx->priv_data; int ret, frame_size_58; s->avctx = avctx; s->eac3 = avctx->codec_id == AV_CODEC_ID_EAC3; ff_ac3_common_init(); ret = validate_options(s); if (ret) return ret; avctx->frame_size = AC3_BLOCK_SIZE * s->num_blocks; avctx->delay = AC3_BLOCK_SIZE; s->bitstream_mode = avctx->audio_service_type; if (s->bitstream_mode == AV_AUDIO_SERVICE_TYPE_KARAOKE) s->bitstream_mode = 0x7; s->bits_written = 0; s->samples_written = 0; /* calculate crc_inv for both possible frame sizes */ frame_size_58 = (( s->frame_size >> 2) + ( s->frame_size >> 4)) << 1; s->crc_inv[0] = pow_poly((CRC16_POLY >> 1), (8 * frame_size_58) - 16, CRC16_POLY); if (s->bit_alloc.sr_code == 1) { frame_size_58 = (((s->frame_size+2) >> 2) + ((s->frame_size+2) >> 4)) << 1; s->crc_inv[1] = pow_poly((CRC16_POLY >> 1), (8 * frame_size_58) - 16, CRC16_POLY); } /* set function pointers */ if (CONFIG_AC3_FIXED_ENCODER && s->fixed_point) { s->mdct_end = ff_ac3_fixed_mdct_end; s->mdct_init = ff_ac3_fixed_mdct_init; s->allocate_sample_buffers = ff_ac3_fixed_allocate_sample_buffers; } else if (CONFIG_AC3_ENCODER || CONFIG_EAC3_ENCODER) { s->mdct_end = ff_ac3_float_mdct_end; s->mdct_init = ff_ac3_float_mdct_init; s->allocate_sample_buffers = ff_ac3_float_allocate_sample_buffers; } if (CONFIG_EAC3_ENCODER && s->eac3) s->output_frame_header = ff_eac3_output_frame_header; else s->output_frame_header = ac3_output_frame_header; set_bandwidth(s); exponent_init(s); bit_alloc_init(s); ret = s->mdct_init(s); if (ret) goto init_fail; ret = allocate_buffers(s); if (ret) goto init_fail; ff_audiodsp_init(&s->adsp); ff_dsputil_init(&s->dsp, avctx); ff_ac3dsp_init(&s->ac3dsp, avctx->flags & CODEC_FLAG_BITEXACT); dprint_options(s); return 0; init_fail: ff_ac3_encode_close(avctx); return ret; }