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7743865ffc
ffmpeg/libavcodec/ac3enc.c
Justin Ruggles 7743865ffc ac3enc: store per-block/channel bap pointers by reference block in a 2D array 
rather than in the AC3Block struct.

This will make it easier to access the bap values without having to chase
the reference block pointers each time.
2011-05-28 12:39:28 -04:00

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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 Libav.
*
* Libav 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.
*
* Libav 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 Libav; 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.
*/
//#define DEBUG
//#define ASSERT_LEVEL 2
#include <stdint.h>
#include "libavutil/audioconvert.h"
#include "libavutil/avassert.h"
#include "libavutil/avstring.h"
#include "libavutil/crc.h"
#include "libavutil/opt.h"
#include "avcodec.h"
#include "put_bits.h"
#include "dsputil.h"
#include "ac3dsp.h"
#include "ac3.h"
#include "audioconvert.h"
#include "fft.h"
#ifndef CONFIG_AC3ENC_FLOAT
#define CONFIG_AC3ENC_FLOAT 0
#endif
/** Maximum number of exponent groups. +1 for separate DC exponent. */
#define AC3_MAX_EXP_GROUPS 85
#if CONFIG_AC3ENC_FLOAT
#define MAC_COEF(d,a,b) ((d)+=(a)*(b))
typedef float SampleType;
typedef float CoefType;
typedef float CoefSumType;
#else
#define MAC_COEF(d,a,b) MAC64(d,a,b)
typedef int16_t SampleType;
typedef int32_t CoefType;
typedef int64_t CoefSumType;
#endif
typedef struct AC3MDCTContext {
const SampleType *window; ///< MDCT window function
FFTContext fft; ///< FFT context for MDCT calculation
} AC3MDCTContext;
/**
* Encoding Options used by AVOption.
*/
typedef struct AC3EncOptions {
/* AC-3 metadata options*/
int dialogue_level;
int bitstream_mode;
float center_mix_level;
float surround_mix_level;
int dolby_surround_mode;
int audio_production_info;
int mixing_level;
int room_type;
int copyright;
int original;
int extended_bsi_1;
int preferred_stereo_downmix;
float ltrt_center_mix_level;
float ltrt_surround_mix_level;
float loro_center_mix_level;
float loro_surround_mix_level;
int extended_bsi_2;
int dolby_surround_ex_mode;
int dolby_headphone_mode;
int ad_converter_type;
/* other encoding options */
int allow_per_frame_metadata;
int stereo_rematrixing;
int channel_coupling;
int cpl_start;
} AC3EncOptions;
/**
* Data for a single audio block.
*/
typedef struct AC3Block {
CoefType **mdct_coef; ///< MDCT coefficients
int32_t **fixed_coef; ///< fixed-point MDCT coefficients
uint8_t **exp; ///< original exponents
uint8_t **grouped_exp; ///< grouped exponents
int16_t **psd; ///< psd per frequency bin
int16_t **band_psd; ///< psd per critical band
int16_t **mask; ///< masking curve
uint16_t **qmant; ///< quantized mantissas
uint8_t **cpl_coord_exp; ///< coupling coord exponents (cplcoexp)
uint8_t **cpl_coord_mant; ///< coupling coord mantissas (cplcomant)
uint8_t coeff_shift[AC3_MAX_CHANNELS]; ///< fixed-point coefficient shift values
uint8_t new_rematrixing_strategy; ///< send new rematrixing flags in this block
int num_rematrixing_bands; ///< number of rematrixing bands
uint8_t rematrixing_flags[4]; ///< rematrixing flags
int new_cpl_strategy; ///< send new coupling strategy
int cpl_in_use; ///< coupling in use for this block (cplinu)
uint8_t channel_in_cpl[AC3_MAX_CHANNELS]; ///< channel in coupling (chincpl)
int num_cpl_channels; ///< number of channels in coupling
uint8_t new_cpl_coords; ///< send new coupling coordinates (cplcoe)
uint8_t cpl_master_exp[AC3_MAX_CHANNELS]; ///< coupling coord master exponents (mstrcplco)
int new_snr_offsets; ///< send new SNR offsets
int new_cpl_leak; ///< send new coupling leak info
int end_freq[AC3_MAX_CHANNELS]; ///< end frequency bin (endmant)
} AC3Block;
/**
* AC-3 encoder private context.
*/
typedef struct AC3EncodeContext {
AVClass *av_class; ///< AVClass used for AVOption
AC3EncOptions options; ///< encoding options
PutBitContext pb; ///< bitstream writer context
DSPContext dsp;
AC3DSPContext ac3dsp; ///< AC-3 optimized functions
AC3MDCTContext mdct; ///< MDCT context
AC3Block blocks[AC3_MAX_BLOCKS]; ///< per-block info
int eac3; ///< indicates if this is E-AC-3 vs. AC-3
int bitstream_id; ///< bitstream id (bsid)
int bitstream_mode; ///< bitstream mode (bsmod)
int bit_rate; ///< target bit rate, in bits-per-second
int sample_rate; ///< sampling frequency, in Hz
int frame_size_min; ///< minimum frame size in case rounding is necessary
int frame_size; ///< current frame size in bytes
int frame_size_code; ///< frame size code (frmsizecod)
uint16_t crc_inv[2];
int64_t bits_written; ///< bit count (used to avg. bitrate)
int64_t samples_written; ///< sample count (used to avg. bitrate)
int fbw_channels; ///< number of full-bandwidth channels (nfchans)
int channels; ///< total number of channels (nchans)
int lfe_on; ///< indicates if there is an LFE channel (lfeon)
int lfe_channel; ///< channel index of the LFE channel
int has_center; ///< indicates if there is a center channel
int has_surround; ///< indicates if there are one or more surround channels
int channel_mode; ///< channel mode (acmod)
const uint8_t *channel_map; ///< channel map used to reorder channels
int center_mix_level; ///< center mix level code
int surround_mix_level; ///< surround mix level code
int ltrt_center_mix_level; ///< Lt/Rt center mix level code
int ltrt_surround_mix_level; ///< Lt/Rt surround mix level code
int loro_center_mix_level; ///< Lo/Ro center mix level code
int loro_surround_mix_level; ///< Lo/Ro surround mix level code
int cutoff; ///< user-specified cutoff frequency, in Hz
int bandwidth_code; ///< bandwidth code (0 to 60) (chbwcod)
int start_freq[AC3_MAX_CHANNELS]; ///< start frequency bin (strtmant)
int cpl_end_freq; ///< coupling channel end frequency bin
int cpl_on; ///< coupling turned on for this frame
int cpl_enabled; ///< coupling enabled for all frames
int num_cpl_subbands; ///< number of coupling subbands (ncplsubnd)
int num_cpl_bands; ///< number of coupling bands (ncplbnd)
uint8_t cpl_band_sizes[AC3_MAX_CPL_BANDS]; ///< number of coeffs in each coupling band
int rematrixing_enabled; ///< stereo rematrixing enabled
/* bitrate allocation control */
int slow_gain_code; ///< slow gain code (sgaincod)
int slow_decay_code; ///< slow decay code (sdcycod)
int fast_decay_code; ///< fast decay code (fdcycod)
int db_per_bit_code; ///< dB/bit code (dbpbcod)
int floor_code; ///< floor code (floorcod)
AC3BitAllocParameters bit_alloc; ///< bit allocation parameters
int coarse_snr_offset; ///< coarse SNR offsets (csnroffst)
int fast_gain_code[AC3_MAX_CHANNELS]; ///< fast gain codes (signal-to-mask ratio) (fgaincod)
int fine_snr_offset[AC3_MAX_CHANNELS]; ///< fine SNR offsets (fsnroffst)
int frame_bits_fixed; ///< number of non-coefficient bits for fixed parameters
int frame_bits; ///< all frame bits except exponents and mantissas
int exponent_bits; ///< number of bits used for exponents
SampleType **planar_samples;
uint8_t *bap_buffer;
uint8_t *bap1_buffer;
CoefType *mdct_coef_buffer;
int32_t *fixed_coef_buffer;
uint8_t *exp_buffer;
uint8_t *grouped_exp_buffer;
int16_t *psd_buffer;
int16_t *band_psd_buffer;
int16_t *mask_buffer;
uint16_t *qmant_buffer;
uint8_t *cpl_coord_exp_buffer;
uint8_t *cpl_coord_mant_buffer;
uint8_t exp_strategy[AC3_MAX_CHANNELS][AC3_MAX_BLOCKS]; ///< exponent strategies
uint8_t exp_ref_block[AC3_MAX_CHANNELS][AC3_MAX_BLOCKS]; ///< reference blocks for EXP_REUSE
uint8_t *ref_bap [AC3_MAX_CHANNELS][AC3_MAX_BLOCKS]; ///< bit allocation pointers (bap)
int ref_bap_set; ///< indicates if ref_bap pointers have been set
DECLARE_ALIGNED(32, SampleType, windowed_samples)[AC3_WINDOW_SIZE];
} AC3EncodeContext;
typedef struct AC3Mant {
uint16_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
};
#define OFFSET(param) offsetof(AC3EncodeContext, options.param)
#define AC3ENC_PARAM (AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_ENCODING_PARAM)
#define AC3ENC_TYPE_AC3_FIXED 0
#define AC3ENC_TYPE_AC3 1
#define AC3ENC_TYPE_EAC3 2
#if CONFIG_AC3ENC_FLOAT
#define AC3ENC_TYPE AC3ENC_TYPE_AC3
#include "ac3enc_opts_template.c"
static AVClass ac3enc_class = { "AC-3 Encoder", av_default_item_name,
ac3_options, LIBAVUTIL_VERSION_INT };
#undef AC3ENC_TYPE
#define AC3ENC_TYPE AC3ENC_TYPE_EAC3
#include "ac3enc_opts_template.c"
static AVClass eac3enc_class = { "E-AC-3 Encoder", av_default_item_name,
eac3_options, LIBAVUTIL_VERSION_INT };
#else
#define AC3ENC_TYPE AC3ENC_TYPE_AC3_FIXED
#include "ac3enc_opts_template.c"
static AVClass ac3enc_class = { "Fixed-Point AC-3 Encoder", av_default_item_name,
ac3fixed_options, LIBAVUTIL_VERSION_INT };
#endif
/* prototypes for functions in ac3enc_fixed.c and ac3enc_float.c */
static av_cold void mdct_end(AC3MDCTContext *mdct);
static av_cold int mdct_init(AVCodecContext *avctx, AC3MDCTContext *mdct,
int nbits);
static void apply_window(DSPContext *dsp, SampleType *output, const SampleType *input,
const SampleType *window, unsigned int len);
static int normalize_samples(AC3EncodeContext *s);
static void scale_coefficients(AC3EncodeContext *s);
/**
* 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.
*/
static const int64_t ac3_channel_layouts[] = {
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.
*/
static void 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_FRAME_SIZE;
}
/**
* Deinterleave input samples.
* Channels are reordered from Libav's default order to AC-3 order.
*/
static void deinterleave_input_samples(AC3EncodeContext *s,
const SampleType *samples)
{
int ch, i;
/* deinterleave and remap input samples */
for (ch = 0; ch < s->channels; ch++) {
const SampleType *sptr;
int sinc;
/* copy last 256 samples of previous frame to the start of the current frame */
memcpy(&s->planar_samples[ch][0], &s->planar_samples[ch][AC3_FRAME_SIZE],
AC3_BLOCK_SIZE * sizeof(s->planar_samples[0][0]));
/* deinterleave */
sinc = s->channels;
sptr = samples + s->channel_map[ch];
for (i = AC3_BLOCK_SIZE; i < AC3_FRAME_SIZE+AC3_BLOCK_SIZE; i++) {
s->planar_samples[ch][i] = *sptr;
sptr += sinc;
}
}
}
/**
* Apply the MDCT to input samples to generate frequency coefficients.
* This applies the KBD window and normalizes the input to reduce precision
* loss due to fixed-point calculations.
*/
static void apply_mdct(AC3EncodeContext *s)
{
int blk, ch;
for (ch = 0; ch < s->channels; ch++) {
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
AC3Block *block = &s->blocks[blk];
const SampleType *input_samples = &s->planar_samples[ch][blk * AC3_BLOCK_SIZE];
apply_window(&s->dsp, s->windowed_samples, input_samples, s->mdct.window, AC3_WINDOW_SIZE);
block->coeff_shift[ch+1] = normalize_samples(s);
s->mdct.fft.mdct_calcw(&s->mdct.fft, block->mdct_coef[ch+1],
s->windowed_samples);
}
}
}
static void compute_coupling_strategy(AC3EncodeContext *s)
{
int blk, ch;
int got_cpl_snr;
/* 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 < AC3_MAX_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;
for (blk = 0; blk < AC3_MAX_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;
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;
}
}
/* set bandwidth for each channel */
for (blk = 0; blk < AC3_MAX_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;
}
}
}
/**
* Calculate a single coupling coordinate.
*/
static inline float calc_cpl_coord(float energy_ch, float energy_cpl)
{
float coord = 0.125;
if (energy_cpl > 0)
coord *= sqrtf(energy_ch / energy_cpl);
return coord;
}
/**
* Calculate coupling channel and coupling coordinates.
* TODO: Currently this is only used for the floating-point encoder. I was
* able to make it work for the fixed-point encoder, but quality was
* generally lower in most cases than not using coupling. If a more
* adaptive coupling strategy were to be implemented it might be useful
* at that time to use coupling for the fixed-point encoder as well.
*/
static void apply_channel_coupling(AC3EncodeContext *s)
{
#if CONFIG_AC3ENC_FLOAT
LOCAL_ALIGNED_16(float, cpl_coords, [AC3_MAX_BLOCKS], [AC3_MAX_CHANNELS][16]);
LOCAL_ALIGNED_16(int32_t, fixed_cpl_coords, [AC3_MAX_BLOCKS], [AC3_MAX_CHANNELS][16]);
int blk, ch, bnd, i, j;
CoefSumType energy[AC3_MAX_BLOCKS][AC3_MAX_CHANNELS][16] = {{{0}}};
int num_cpl_coefs = s->num_cpl_subbands * 12;
memset(cpl_coords, 0, AC3_MAX_BLOCKS * sizeof(*cpl_coords));
memset(fixed_cpl_coords, 0, AC3_MAX_BLOCKS * sizeof(*fixed_cpl_coords));
/* calculate coupling channel from fbw channels */
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
AC3Block *block = &s->blocks[blk];
CoefType *cpl_coef = &block->mdct_coef[CPL_CH][s->start_freq[CPL_CH]];
if (!block->cpl_in_use)
continue;
memset(cpl_coef-1, 0, (num_cpl_coefs+4) * sizeof(*cpl_coef));
for (ch = 1; ch <= s->fbw_channels; ch++) {
CoefType *ch_coef = &block->mdct_coef[ch][s->start_freq[CPL_CH]];
if (!block->channel_in_cpl[ch])
continue;
for (i = 0; i < num_cpl_coefs; i++)
cpl_coef[i] += ch_coef[i];
}
/* note: coupling start bin % 4 will always be 1 and num_cpl_coefs
will always be a multiple of 12, so we need to subtract 1 from
the start and add 4 to the length when using optimized
functions which require 16-byte alignment. */
/* coefficients must be clipped to +/- 1.0 in order to be encoded */
s->dsp.vector_clipf(cpl_coef-1, cpl_coef-1, -1.0f, 1.0f, num_cpl_coefs+4);
/* scale coupling coefficients from float to 24-bit fixed-point */
s->ac3dsp.float_to_fixed24(&block->fixed_coef[CPL_CH][s->start_freq[CPL_CH]-1],
cpl_coef-1, num_cpl_coefs+4);
}
/* calculate energy in each band in coupling channel and each fbw channel */
/* TODO: possibly use SIMD to speed up energy calculation */
bnd = 0;
i = s->start_freq[CPL_CH];
while (i < s->cpl_end_freq) {
int band_size = s->cpl_band_sizes[bnd];
for (ch = CPL_CH; ch <= s->fbw_channels; ch++) {
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
AC3Block *block = &s->blocks[blk];
if (!block->cpl_in_use || (ch > CPL_CH && !block->channel_in_cpl[ch]))
continue;
for (j = 0; j < band_size; j++) {
CoefType v = block->mdct_coef[ch][i+j];
MAC_COEF(energy[blk][ch][bnd], v, v);
}
}
}
i += band_size;
bnd++;
}
/* determine which blocks to send new coupling coordinates for */
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
AC3Block *block = &s->blocks[blk];
AC3Block *block0 = blk ? &s->blocks[blk-1] : NULL;
int new_coords = 0;
CoefSumType coord_diff[AC3_MAX_CHANNELS] = {0,};
if (block->cpl_in_use) {
/* calculate coupling coordinates for all blocks and calculate the
average difference between coordinates in successive blocks */
for (ch = 1; ch <= s->fbw_channels; ch++) {
if (!block->channel_in_cpl[ch])
continue;
for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
cpl_coords[blk][ch][bnd] = calc_cpl_coord(energy[blk][ch][bnd],
energy[blk][CPL_CH][bnd]);
if (blk > 0 && block0->cpl_in_use &&
block0->channel_in_cpl[ch]) {
coord_diff[ch] += fabs(cpl_coords[blk-1][ch][bnd] -
cpl_coords[blk ][ch][bnd]);
}
}
coord_diff[ch] /= s->num_cpl_bands;
}
/* send new coordinates if this is the first block, if previous
* block did not use coupling but this block does, the channels
* using coupling has changed from the previous block, or the
* coordinate difference from the last block for any channel is
* greater than a threshold value. */
if (blk == 0) {
new_coords = 1;
} else if (!block0->cpl_in_use) {
new_coords = 1;
} else {
for (ch = 1; ch <= s->fbw_channels; ch++) {
if (block->channel_in_cpl[ch] && !block0->channel_in_cpl[ch]) {
new_coords = 1;
break;
}
}
if (!new_coords) {
for (ch = 1; ch <= s->fbw_channels; ch++) {
if (block->channel_in_cpl[ch] && coord_diff[ch] > 0.04) {
new_coords = 1;
break;
}
}
}
}
}
block->new_cpl_coords = new_coords;
}
/* calculate final coupling coordinates, taking into account reusing of
coordinates in successive blocks */
for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
blk = 0;
while (blk < AC3_MAX_BLOCKS) {
int blk1;
CoefSumType energy_cpl;
AC3Block *block = &s->blocks[blk];
if (!block->cpl_in_use) {
blk++;
continue;
}
energy_cpl = energy[blk][CPL_CH][bnd];
blk1 = blk+1;
while (!s->blocks[blk1].new_cpl_coords && blk1 < AC3_MAX_BLOCKS) {
if (s->blocks[blk1].cpl_in_use)
energy_cpl += energy[blk1][CPL_CH][bnd];
blk1++;
}
for (ch = 1; ch <= s->fbw_channels; ch++) {
CoefType energy_ch;
if (!block->channel_in_cpl[ch])
continue;
energy_ch = energy[blk][ch][bnd];
blk1 = blk+1;
while (!s->blocks[blk1].new_cpl_coords && blk1 < AC3_MAX_BLOCKS) {
if (s->blocks[blk1].cpl_in_use)
energy_ch += energy[blk1][ch][bnd];
blk1++;
}
cpl_coords[blk][ch][bnd] = calc_cpl_coord(energy_ch, energy_cpl);
}
blk = blk1;
}
}
/* calculate exponents/mantissas for coupling coordinates */
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
AC3Block *block = &s->blocks[blk];
if (!block->cpl_in_use || !block->new_cpl_coords)
continue;
s->ac3dsp.float_to_fixed24(fixed_cpl_coords[blk][1],
cpl_coords[blk][1],
s->fbw_channels * 16);
s->ac3dsp.extract_exponents(block->cpl_coord_exp[1],
fixed_cpl_coords[blk][1],
s->fbw_channels * 16);
for (ch = 1; ch <= s->fbw_channels; ch++) {
int bnd, min_exp, max_exp, master_exp;
/* determine master exponent */
min_exp = max_exp = block->cpl_coord_exp[ch][0];
for (bnd = 1; bnd < s->num_cpl_bands; bnd++) {
int exp = block->cpl_coord_exp[ch][bnd];
min_exp = FFMIN(exp, min_exp);
max_exp = FFMAX(exp, max_exp);
}
master_exp = ((max_exp - 15) + 2) / 3;
master_exp = FFMAX(master_exp, 0);
while (min_exp < master_exp * 3)
master_exp--;
for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
block->cpl_coord_exp[ch][bnd] = av_clip(block->cpl_coord_exp[ch][bnd] -
master_exp * 3, 0, 15);
}
block->cpl_master_exp[ch] = master_exp;
/* quantize mantissas */
for (bnd = 0; bnd < s->num_cpl_bands; bnd++) {
int cpl_exp = block->cpl_coord_exp[ch][bnd];
int cpl_mant = (fixed_cpl_coords[blk][ch][bnd] << (5 + cpl_exp + master_exp * 3)) >> 24;
if (cpl_exp == 15)
cpl_mant >>= 1;
else
cpl_mant -= 16;
block->cpl_coord_mant[ch][bnd] = cpl_mant;
}
}
}
if (s->eac3) {
/* set first cpl coords */
int first_cpl_coords[AC3_MAX_CHANNELS];
for (ch = 1; ch <= s->fbw_channels; ch++)
first_cpl_coords[ch] = 1;
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
AC3Block *block = &s->blocks[blk];
for (ch = 1; ch <= s->fbw_channels; ch++) {
if (block->channel_in_cpl[ch]) {
if (first_cpl_coords[ch]) {
block->new_cpl_coords = 2;
first_cpl_coords[ch] = 0;
}
} else {
first_cpl_coords[ch] = 1;
}
}
}
/* set first cpl leak */
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
AC3Block *block = &s->blocks[blk];
if (block->cpl_in_use) {
block->new_cpl_leak = 2;
break;
}
}
}
#endif /* CONFIG_AC3ENC_FLOAT */
}
/**
* Determine rematrixing flags for each block and band.
*/
static void compute_rematrixing_strategy(AC3EncodeContext *s)
{
int nb_coefs;
int blk, bnd, i;
AC3Block *block, *block0;
if (s->channel_mode != AC3_CHMODE_STEREO)
return;
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
block = &s->blocks[blk];
block->new_rematrixing_strategy = !blk;
if (!s->rematrixing_enabled) {
block0 = block;
continue;
}
block->num_rematrixing_bands = 4;
if (block->cpl_in_use) {
block->num_rematrixing_bands -= (s->start_freq[CPL_CH] <= 61);
block->num_rematrixing_bands -= (s->start_freq[CPL_CH] == 37);
if (blk && block->num_rematrixing_bands != block0->num_rematrixing_bands)
block->new_rematrixing_strategy = 1;
}
nb_coefs = FFMIN(block->end_freq[1], block->end_freq[2]);
for (bnd = 0; bnd < block->num_rematrixing_bands; bnd++) {
/* calculate calculate sum of squared coeffs for one band in one block */
int start = ff_ac3_rematrix_band_tab[bnd];
int end = FFMIN(nb_coefs, ff_ac3_rematrix_band_tab[bnd+1]);
CoefSumType sum[4] = {0,};
for (i = start; i < end; i++) {
CoefType lt = block->mdct_coef[1][i];
CoefType rt = block->mdct_coef[2][i];
CoefType md = lt + rt;
CoefType sd = lt - rt;
MAC_COEF(sum[0], lt, lt);
MAC_COEF(sum[1], rt, rt);
MAC_COEF(sum[2], md, md);
MAC_COEF(sum[3], sd, sd);
}
/* compare sums to determine if rematrixing will be used for this band */
if (FFMIN(sum[2], sum[3]) < FFMIN(sum[0], sum[1]))
block->rematrixing_flags[bnd] = 1;
else
block->rematrixing_flags[bnd] = 0;
/* determine if new rematrixing flags will be sent */
if (blk &&
block->rematrixing_flags[bnd] != block0->rematrixing_flags[bnd]) {
block->new_rematrixing_strategy = 1;
}
}
block0 = block;
}
}
/**
* Apply stereo rematrixing to coefficients based on rematrixing flags.
*/
static void apply_rematrixing(AC3EncodeContext *s)
{
int nb_coefs;
int blk, bnd, i;
int start, end;
uint8_t *flags;
if (!s->rematrixing_enabled)
return;
for (blk = 0; blk < AC3_MAX_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;
}
/**
* Extract exponents from the MDCT coefficients.
* This takes into account the normalization that was done to the input samples
* by adjusting the exponents by the exponent shift values.
*/
static void extract_exponents(AC3EncodeContext *s)
{
int blk, ch;
for (ch = !s->cpl_on; ch <= s->channels; ch++) {
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
AC3Block *block = &s->blocks[blk];
s->ac3dsp.extract_exponents(block->exp[ch], block->fixed_coef[ch],
AC3_MAX_COEFS);
}
}
}
/**
* Exponent Difference Threshold.
* New exponents are sent if their SAD exceed this number.
*/
#define EXP_DIFF_THRESHOLD 500
/**
* 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 < AC3_MAX_BLOCKS; blk++, exp += AC3_MAX_COEFS) {
if ((ch == CPL_CH && (!s->blocks[blk].cpl_in_use || !s->blocks[blk-1].cpl_in_use)) ||
(ch > CPL_CH && (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 < AC3_MAX_BLOCKS) {
blk1 = blk + 1;
while (blk1 < AC3_MAX_BLOCKS && exp_strategy[blk1] == EXP_REUSE)
blk1++;
switch (blk1 - blk) {
case 1: exp_strategy[blk] = EXP_D45; break;
case 2:
case 3: exp_strategy[blk] = EXP_D25; break;
default: exp_strategy[blk] = EXP_D15; break;
}
blk = blk1;
}
}
if (s->lfe_on) {
ch = s->lfe_channel;
s->exp_strategy[ch][0] = EXP_D15;
for (blk = 1; blk < AC3_MAX_BLOCKS; blk++)
s->exp_strategy[ch][blk] = EXP_REUSE;
}
}
/**
* Update the exponents so that they are the ones the decoder will decode.
*/
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 < AC3_MAX_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 < AC3_MAX_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;
}
/**
* Group exponents.
* 3 delta-encoded exponents are in each 7-bit group. The number of groups
* varies depending on exponent strategy and bandwidth.
*/
static void group_exponents(AC3EncodeContext *s)
{
int blk, ch, i, cpl;
int group_size, nb_groups, bit_count;
uint8_t *p;
int delta0, delta1, delta2;
int exp0, exp1;
bit_count = 0;
for (blk = 0; blk < AC3_MAX_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]];
bit_count += 4 + (nb_groups * 7);
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;
}
}
}
s->exponent_bits = bit_count;
}
/**
* Calculate final exponents from the supplied MDCT coefficients and exponent shift.
* Extract exponents from MDCT coefficients, calculate exponent strategies,
* and encode final exponents.
*/
static void process_exponents(AC3EncodeContext *s)
{
extract_exponents(s);
compute_exp_strategy(s);
encode_exponents(s);
group_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 auxilliary 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 + 1;
/* audio frame header */
frame_bits += 2;
frame_bits += 10;
/* exponent strategy */
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++)
frame_bits += 2 * s->fbw_channels + s->lfe_on;
/* converter exponent strategy */
frame_bits += s->fbw_channels * 5;
/* snr offsets */
frame_bits += 10;
/* block start info */
frame_bits++;
} else {
frame_bits += 49;
frame_bits += frame_bits_inc[s->channel_mode];
}
/* audio blocks */
for (blk = 0; blk < AC3_MAX_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 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) {
/* coupling */
if (s->channel_mode > AC3_CHMODE_MONO) {
frame_bits++;
for (blk = 1; blk < AC3_MAX_BLOCKS; blk++) {
AC3Block *block = &s->blocks[blk];
frame_bits++;
if (block->new_cpl_strategy)
frame_bits++;
}
}
/* coupling exponent strategy */
for (blk = 0; blk < AC3_MAX_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 < AC3_MAX_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 != 2)
frame_bits++;
if (block->new_cpl_coords) {
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;
}
/**
* Finalize the mantissa bit count by adding in the grouped mantissas.
*/
static int compute_mantissa_size_final(int mant_cnt[5])
{
// bap=1 : 3 mantissas in 5 bits
int bits = (mant_cnt[1] / 3) * 5;
// bap=2 : 3 mantissas in 7 bits
// bap=4 : 2 mantissas in 7 bits
bits += ((mant_cnt[2] / 3) + (mant_cnt[4] >> 1)) * 7;
// bap=3 : each mantissa is 3 bits
bits += mant_cnt[3] * 3;
return 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 < AC3_MAX_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 < AC3_MAX_BLOCKS; blk++)
s->ref_bap[ch][blk] = ref_bap + AC3_MAX_COEFS * s->exp_ref_block[ch][blk];
ref_bap += AC3_MAX_COEFS * AC3_MAX_BLOCKS;
}
s->ref_bap_set = 1;
}
/**
* 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.
* @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;
int mantissa_bits;
int mant_cnt[5];
snr_offset = (snr_offset - 240) << 2;
reset_block_bap(s);
mantissa_bits = 0;
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++) {
AC3Block *block = &s->blocks[blk];
int av_uninit(ch0);
int got_cpl = !block->cpl_in_use;
// initialize grouped mantissa counts. these are set so that they are
// padded to the next whole group size when bits are counted in
// compute_mantissa_size_final
mant_cnt[0] = mant_cnt[3] = 0;
mant_cnt[1] = mant_cnt[2] = 2;
mant_cnt[4] = 1;
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;
}
/* 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]);
}
mantissa_bits += s->ac3dsp.compute_mantissa_size(mant_cnt,
s->ref_bap[ch][blk]+s->start_freq[ch],
block->end_freq[ch]-s->start_freq[ch]);
if (ch == CPL_CH)
ch = ch0;
}
mantissa_bits += compute_mantissa_size_final(mant_cnt);
}
return mantissa_bits;
}
/**
* 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;
}
/**
* Downgrade exponent strategies to reduce the bits used by the exponents.
* This is a fallback for when bit allocation fails with the normal exponent
* strategies. Each time this function is run it only downgrades the
* strategy in 1 channel of 1 block.
* @return non-zero if downgrade was unsuccessful
*/
static int downgrade_exponents(AC3EncodeContext *s)
{
int ch, blk;
for (blk = AC3_MAX_BLOCKS-1; blk >= 0; blk--) {
for (ch = !s->blocks[blk].cpl_in_use; ch <= s->fbw_channels; ch++) {
if (s->exp_strategy[ch][blk] == EXP_D15) {
s->exp_strategy[ch][blk] = EXP_D25;
return 0;
}
}
}
for (blk = AC3_MAX_BLOCKS-1; blk >= 0; blk--) {
for (ch = !s->blocks[blk].cpl_in_use; ch <= s->fbw_channels; ch++) {
if (s->exp_strategy[ch][blk] == EXP_D25) {
s->exp_strategy[ch][blk] = EXP_D45;
return 0;
}
}
}
/* block 0 cannot reuse exponents, so only downgrade D45 to REUSE if
the block number > 0 */
for (blk = AC3_MAX_BLOCKS-1; blk > 0; blk--) {
for (ch = !s->blocks[blk].cpl_in_use; ch <= s->fbw_channels; ch++) {
if (s->exp_strategy[ch][blk] > EXP_REUSE) {
s->exp_strategy[ch][blk] = EXP_REUSE;
return 0;
}
}
}
return -1;
}
/**
* 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.
*/
static int compute_bit_allocation(AC3EncodeContext *s)
{
int ret;
count_frame_bits(s);
bit_alloc_masking(s);
ret = cbr_bit_allocation(s);
while (ret) {
/* fallback 1: disable channel coupling */
if (s->cpl_on) {
s->cpl_on = 0;
compute_coupling_strategy(s);
compute_rematrixing_strategy(s);
apply_rematrixing(s);
process_exponents(s);
ret = compute_bit_allocation(s);
continue;
}
/* fallback 2: downgrade exponents */
if (!downgrade_exponents(s)) {
extract_exponents(s);
encode_exponents(s);
group_exponents(s);
ret = compute_bit_allocation(s);
continue;
}
/* fallbacks were not enough... */
break;
}
return ret;
}
/**
* Symmetric quantization on 'levels' levels.
*/
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.
*/
static inline int asym_quant(int c, int e, int qbits)
{
int lshift, m, v;
lshift = e + qbits - 24;
if (lshift >= 0)
v = c << lshift;
else
v = c >> (-lshift);
/* rounding */
v = (v + 1) >> 1;
m = (1 << (qbits-1));
if (v >= m)
v = m - 1;
av_assert2(v >= -m);
return v & ((1 << qbits)-1);
}
/**
* Quantize a set of mantissas for a single channel in a single block.
*/
static void quantize_mantissas_blk_ch(AC3Mant *s, int32_t *fixed_coef,
uint8_t *exp, uint8_t *bap,
uint16_t *qmant, int start_freq,
int end_freq)
{
int i;
for (i = start_freq; i < end_freq; i++) {
int v;
int c = fixed_coef[i];
int e = exp[i];
int b = bap[i];
switch (b) {
case 0:
v = 0;
break;
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, b - 1);
break;
}
qmant[i] = v;
}
}
/**
* Quantize mantissas using coefficients, exponents, and bit allocation pointers.
*/
static void quantize_mantissas(AC3EncodeContext *s)
{
int blk, ch, ch0=0, got_cpl;
for (blk = 0; blk < AC3_MAX_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 the E-AC-3 frame header to the output bitstream.
*/
static void eac3_output_frame_header(AC3EncodeContext *s)
{
int blk, ch;
AC3EncOptions *opt = &s->options;
put_bits(&s->pb, 16, 0x0b77); /* sync word */
/* BSI header */
put_bits(&s->pb, 2, 0); /* stream type = independent */
put_bits(&s->pb, 3, 0); /* substream id = 0 */
put_bits(&s->pb, 11, (s->frame_size / 2) - 1); /* frame size */
if (s->bit_alloc.sr_shift) {
put_bits(&s->pb, 2, 0x3); /* fscod2 */
put_bits(&s->pb, 2, s->bit_alloc.sr_code); /* sample rate code */
} else {
put_bits(&s->pb, 2, s->bit_alloc.sr_code); /* sample rate code */
put_bits(&s->pb, 2, 0x3); /* number of blocks = 6 */
}
put_bits(&s->pb, 3, s->channel_mode); /* audio coding mode */
put_bits(&s->pb, 1, s->lfe_on); /* LFE channel indicator */
put_bits(&s->pb, 5, s->bitstream_id); /* bitstream id (EAC3=16) */
put_bits(&s->pb, 5, -opt->dialogue_level); /* dialogue normalization level */
put_bits(&s->pb, 1, 0); /* no compression gain */
put_bits(&s->pb, 1, 0); /* no mixing metadata */
/* TODO: mixing metadata */
put_bits(&s->pb, 1, 0); /* no info metadata */
/* TODO: info metadata */
put_bits(&s->pb, 1, 0); /* no additional bit stream info */
/* frame header */
put_bits(&s->pb, 1, 1); /* exponent strategy syntax = each block */
put_bits(&s->pb, 1, 0); /* aht enabled = no */
put_bits(&s->pb, 2, 0); /* snr offset strategy = 1 */
put_bits(&s->pb, 1, 0); /* transient pre-noise processing enabled = no */
put_bits(&s->pb, 1, 0); /* block switch syntax enabled = no */
put_bits(&s->pb, 1, 0); /* dither flag syntax enabled = no */
put_bits(&s->pb, 1, 0); /* bit allocation model syntax enabled = no */
put_bits(&s->pb, 1, 0); /* fast gain codes enabled = no */
put_bits(&s->pb, 1, 0); /* dba syntax enabled = no */
put_bits(&s->pb, 1, 0); /* skip field syntax enabled = no */
put_bits(&s->pb, 1, 0); /* spx enabled = no */
/* coupling strategy use flags */
if (s->channel_mode > AC3_CHMODE_MONO) {
put_bits(&s->pb, 1, s->blocks[0].cpl_in_use);
for (blk = 1; blk < AC3_MAX_BLOCKS; blk++) {
AC3Block *block = &s->blocks[blk];
put_bits(&s->pb, 1, block->new_cpl_strategy);
if (block->new_cpl_strategy)
put_bits(&s->pb, 1, block->cpl_in_use);
}
}
/* exponent strategy */
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++)
for (ch = !s->blocks[blk].cpl_in_use; ch <= s->fbw_channels; ch++)
put_bits(&s->pb, 2, s->exp_strategy[ch][blk]);
if (s->lfe_on) {
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++)
put_bits(&s->pb, 1, s->exp_strategy[s->lfe_channel][blk]);
}
/* E-AC-3 to AC-3 converter exponent strategy (unfortunately not optional...) */
for (ch = 1; ch <= s->fbw_channels; ch++)
put_bits(&s->pb, 5, 0);
/* snr offsets */
put_bits(&s->pb, 6, s->coarse_snr_offset);
put_bits(&s->pb, 4, s->fine_snr_offset[1]);
/* block start info */
put_bits(&s->pb, 1, 0);
}
/**
* Write one audio block to the output bitstream.
*/
static void output_audio_block(AC3EncodeContext *s, int blk)
{
int ch, i, baie, bnd, got_cpl;
int 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 != 2)
put_bits(&s->pb, 1, block->new_cpl_coords);
if (block->new_cpl_coords) {
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_bits(&s->pb, 3, q); break;
case 4: if (q != 128) put_bits(&s->pb, 7, q); break;
case 14: put_bits(&s->pb, 14, q); break;
case 15: put_bits(&s->pb, 16, q); break;
default: put_bits(&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.
*/
static void output_frame(AC3EncodeContext *s, unsigned char *frame)
{
int blk;
init_put_bits(&s->pb, frame, AC3_MAX_CODED_FRAME_SIZE);
if (s->eac3)
eac3_output_frame_header(s);
else
ac3_output_frame_header(s);
for (blk = 0; blk < AC3_MAX_BLOCKS; blk++)
output_audio_block(s, blk);
output_frame_end(s);
}
static void dprint_options(AVCodecContext *avctx)
{
#ifdef DEBUG
AC3EncodeContext *s = avctx->priv_data;
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);
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 0: av_strlcpy(strbuf, "notindicated", 32); break;
case 1: av_strlcpy(strbuf, "large", 32); break;
case 2: 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 0: av_strlcpy(strbuf, "notindicated", 32); break;
case 1: av_strlcpy(strbuf, "on", 32); break;
case 2: 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 0: av_strlcpy(strbuf, "notindicated", 32); break;
case 1: av_strlcpy(strbuf, "ltrt", 32); break;
case 2: 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 0: av_strlcpy(strbuf, "notindicated", 32); break;
case 1: av_strlcpy(strbuf, "on", 32); break;
case 2: 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 0: av_strlcpy(strbuf, "notindicated", 32); break;
case 1: av_strlcpy(strbuf, "on", 32); break;
case 2: 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 0: av_strlcpy(strbuf, "standard", 32); break;
case 1: 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.
*/
static int validate_metadata(AVCodecContext *avctx)
{
AC3EncodeContext *s = avctx->priv_data;
AC3EncOptions *opt = &s->options;
/* validate mixing levels */
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);
}
/* set audio production info flag */
if (opt->mixing_level >= 0 || opt->room_type >= 0) {
if (opt->mixing_level < 0) {
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 < 0)
opt->room_type = 0;
opt->audio_production_info = 1;
} else {
opt->audio_production_info = 0;
}
/* set extended bsi 1 flag */
if ((s->has_center || s->has_surround) &&
(opt->preferred_stereo_downmix >= 0 ||
opt->ltrt_center_mix_level >= 0 ||
opt->ltrt_surround_mix_level >= 0 ||
opt->loro_center_mix_level >= 0 ||
opt->loro_surround_mix_level >= 0)) {
/* default preferred stereo downmix */
if (opt->preferred_stereo_downmix < 0)
opt->preferred_stereo_downmix = 0;
/* 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 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 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);
/* 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);
opt->extended_bsi_1 = 1;
} else {
opt->extended_bsi_1 = 0;
}
/* set extended bsi 2 flag */
if (opt->dolby_surround_ex_mode >= 0 ||
opt->dolby_headphone_mode >= 0 ||
opt->ad_converter_type >= 0) {
/* default dolby surround ex mode */
if (opt->dolby_surround_ex_mode < 0)
opt->dolby_surround_ex_mode = 0;
/* default dolby headphone mode */
if (opt->dolby_headphone_mode < 0)
opt->dolby_headphone_mode = 0;
/* default A/D converter type */
if (opt->ad_converter_type < 0)
opt->ad_converter_type = 0;
opt->extended_bsi_2 = 1;
} else {
opt->extended_bsi_2 = 0;
}
/* set bitstream id for alternate bitstream syntax */
if (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;
}
/**
* Encode a single AC-3 frame.
*/
static int ac3_encode_frame(AVCodecContext *avctx, unsigned char *frame,
int buf_size, void *data)
{
AC3EncodeContext *s = avctx->priv_data;
const SampleType *samples = data;
int ret;
if (!s->eac3 && s->options.allow_per_frame_metadata) {
ret = validate_metadata(avctx);
if (ret)
return ret;
}
if (s->bit_alloc.sr_code == 1 || s->eac3)
adjust_frame_size(s);
deinterleave_input_samples(s, samples);
apply_mdct(s);
scale_coefficients(s);
s->cpl_on = s->cpl_enabled;
compute_coupling_strategy(s);
if (s->cpl_on)
apply_channel_coupling(s);
compute_rematrixing_strategy(s);
apply_rematrixing(s);
process_exponents(s);
ret = compute_bit_allocation(s);
if (ret) {
av_log(avctx, AV_LOG_ERROR, "Bit allocation failed. Try increasing the bitrate.\n");
return ret;
}
quantize_mantissas(s);
output_frame(s, frame);
return s->frame_size;
}
/**
* Finalize encoding and free any memory allocated by the encoder.
*/
static av_cold int ac3_encode_close(AVCodecContext *avctx)
{
int blk, ch;
AC3EncodeContext *s = avctx->priv_data;
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);
for (blk = 0; blk < AC3_MAX_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);
}
mdct_end(&s->mdct);
av_freep(&avctx->coded_frame);
return 0;
}
/**
* Set channel information during initialization.
*/
static av_cold int set_channel_info(AC3EncodeContext *s, int channels,
int64_t *channel_layout)
{
int ch_layout;
if (channels < 1 || channels > AC3_MAX_CHANNELS)
return AVERROR(EINVAL);
if ((uint64_t)*channel_layout > 0x7FF)
return AVERROR(EINVAL);
ch_layout = *channel_layout;
if (!ch_layout)
ch_layout = avcodec_guess_channel_layout(channels, CODEC_ID_AC3, NULL);
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(AVCodecContext *avctx, AC3EncodeContext *s)
{
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;
/* validate bit rate */
if (s->eac3) {
int max_br, min_br, wpf, min_br_dist, min_br_code;
/* calculate min/max bitrate */
max_br = 2048 * s->sample_rate / AC3_FRAME_SIZE * 16;
min_br = ((s->sample_rate + (AC3_FRAME_SIZE-1)) / AC3_FRAME_SIZE) * 16;
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);
}
/* calculate words-per-frame for the selected bitrate */
wpf = (avctx->bit_rate / 16) * AC3_FRAME_SIZE / 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 {
for (i = 0; i < 19; i++) {
if ((ff_ac3_bitrate_tab[i] >> s->bit_alloc.sr_shift)*1000 == avctx->bit_rate)
break;
}
if (i == 19) {
av_log(avctx, AV_LOG_ERROR, "invalid bit rate\n");
return AVERROR(EINVAL);
}
s->frame_size_code = i << 1;
s->frame_size_min = 2 * ff_ac3_frame_size_tab[s->frame_size_code][s->bit_alloc.sr_code];
}
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;
/* 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);
}
if (!s->eac3) {
ret = validate_metadata(avctx);
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 &&
CONFIG_AC3ENC_FLOAT;
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;
int 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 < AC3_MAX_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 < AC3_MAX_BLOCKS; blk++)
s->blocks[blk].end_freq[ch] = 7;
}
/* initialize coupling strategy */
if (s->cpl_enabled) {
if (s->options.cpl_start >= 0) {
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)
s->cpl_enabled = 0;
}
}
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 < AC3_MAX_BLOCKS; blk++)
s->blocks[blk].end_freq[CPL_CH] = s->cpl_end_freq;
}
}
static av_cold int allocate_buffers(AVCodecContext *avctx)
{
int blk, ch;
AC3EncodeContext *s = avctx->priv_data;
int channels = s->channels + 1; /* includes coupling channel */
FF_ALLOC_OR_GOTO(avctx, s->planar_samples, s->channels * sizeof(*s->planar_samples),
alloc_fail);
for (ch = 0; ch < s->channels; ch++) {
FF_ALLOCZ_OR_GOTO(avctx, s->planar_samples[ch],
(AC3_FRAME_SIZE+AC3_BLOCK_SIZE) * sizeof(**s->planar_samples),
alloc_fail);
}
FF_ALLOC_OR_GOTO(avctx, s->bap_buffer, AC3_MAX_BLOCKS * channels *
AC3_MAX_COEFS * sizeof(*s->bap_buffer), alloc_fail);
FF_ALLOC_OR_GOTO(avctx, s->bap1_buffer, AC3_MAX_BLOCKS * channels *
AC3_MAX_COEFS * sizeof(*s->bap1_buffer), alloc_fail);
FF_ALLOCZ_OR_GOTO(avctx, s->mdct_coef_buffer, AC3_MAX_BLOCKS * channels *
AC3_MAX_COEFS * sizeof(*s->mdct_coef_buffer), alloc_fail);
FF_ALLOC_OR_GOTO(avctx, s->exp_buffer, AC3_MAX_BLOCKS * channels *
AC3_MAX_COEFS * sizeof(*s->exp_buffer), alloc_fail);
FF_ALLOC_OR_GOTO(avctx, s->grouped_exp_buffer, AC3_MAX_BLOCKS * channels *
128 * sizeof(*s->grouped_exp_buffer), alloc_fail);
FF_ALLOC_OR_GOTO(avctx, s->psd_buffer, AC3_MAX_BLOCKS * channels *
AC3_MAX_COEFS * sizeof(*s->psd_buffer), alloc_fail);
FF_ALLOC_OR_GOTO(avctx, s->band_psd_buffer, AC3_MAX_BLOCKS * channels *
64 * sizeof(*s->band_psd_buffer), alloc_fail);
FF_ALLOC_OR_GOTO(avctx, s->mask_buffer, AC3_MAX_BLOCKS * channels *
64 * sizeof(*s->mask_buffer), alloc_fail);
FF_ALLOC_OR_GOTO(avctx, s->qmant_buffer, AC3_MAX_BLOCKS * channels *
AC3_MAX_COEFS * sizeof(*s->qmant_buffer), alloc_fail);
if (s->cpl_enabled) {
FF_ALLOC_OR_GOTO(avctx, s->cpl_coord_exp_buffer, AC3_MAX_BLOCKS * channels *
16 * sizeof(*s->cpl_coord_exp_buffer), alloc_fail);
FF_ALLOC_OR_GOTO(avctx, s->cpl_coord_mant_buffer, AC3_MAX_BLOCKS * channels *
16 * sizeof(*s->cpl_coord_mant_buffer), alloc_fail);
}
for (blk = 0; blk < AC3_MAX_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 * (AC3_MAX_BLOCKS * ch + blk)];
block->mdct_coef[ch] = &s->mdct_coef_buffer [AC3_MAX_COEFS * (AC3_MAX_BLOCKS * ch + blk)];
}
}
if (CONFIG_AC3ENC_FLOAT) {
FF_ALLOCZ_OR_GOTO(avctx, s->fixed_coef_buffer, AC3_MAX_BLOCKS * channels *
AC3_MAX_COEFS * sizeof(*s->fixed_coef_buffer), alloc_fail);
for (blk = 0; blk < AC3_MAX_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 * (AC3_MAX_BLOCKS * ch + blk)];
}
} else {
for (blk = 0; blk < AC3_MAX_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);
}
/**
* Initialize the encoder.
*/
static av_cold int ac3_encode_init(AVCodecContext *avctx)
{
AC3EncodeContext *s = avctx->priv_data;
int ret, frame_size_58;
s->eac3 = avctx->codec_id == CODEC_ID_EAC3;
avctx->frame_size = AC3_FRAME_SIZE;
ff_ac3_common_init();
ret = validate_options(avctx, s);
if (ret)
return ret;
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_bandwidth(s);
exponent_init(s);
bit_alloc_init(s);
ret = mdct_init(avctx, &s->mdct, 9);
if (ret)
goto init_fail;
ret = allocate_buffers(avctx);
if (ret)
goto init_fail;
avctx->coded_frame= avcodec_alloc_frame();
dsputil_init(&s->dsp, avctx);
ff_ac3dsp_init(&s->ac3dsp, avctx->flags & CODEC_FLAG_BITEXACT);
dprint_options(avctx);
return 0;
init_fail:
ac3_encode_close(avctx);
return ret;
}
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