FFmpeg
Data Structures | Macros | Functions | Variables
ac3enc.c File Reference
#include <stdint.h>
#include "libavutil/attributes.h"
#include "libavutil/avassert.h"
#include "libavutil/channel_layout.h"
#include "libavutil/crc.h"
#include "libavutil/emms.h"
#include "libavutil/internal.h"
#include "libavutil/mem.h"
#include "libavutil/mem_internal.h"
#include "libavutil/opt.h"
#include "libavutil/thread.h"
#include "avcodec.h"
#include "codec_internal.h"
#include "config_components.h"
#include "encode.h"
#include "me_cmp.h"
#include "put_bits.h"
#include "audiodsp.h"
#include "ac3dsp.h"
#include "ac3.h"
#include "ac3defs.h"
#include "ac3tab.h"
#include "ac3enc.h"
#include "eac3enc.h"

Go to the source code of this file.

Data Structures

struct  AC3Mant
 

Macros

#define SAMPLETYPE_SIZE(ctx)
 
#define CMIXLEV_NUM_OPTIONS   3
 
#define SURMIXLEV_NUM_OPTIONS   3
 
#define EXTMIXLEV_NUM_OPTIONS   8
 
#define OFFSET(param)   offsetof(AC3EncodeContext, options.param)
 
#define AC3ENC_PARAM   (AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_ENCODING_PARAM)
 
#define FLT_OPTION_THRESHOLD   0.01
 
#define EXP_DIFF_THRESHOLD   500
 Exponent Difference Threshold. More...
 
#define CRC16_POLY   ((1 << 0) | (1 << 2) | (1 << 15) | (1 << 16))
 CRC-16 Polynomial. More...
 

Functions

static int validate_float_option (float v, const float *v_list, int v_list_size)
 
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)
 
static int ac3_validate_metadata (AC3EncodeContext *s)
 Validate metadata options as set by AVOption system. More...
 
static void ac3_adjust_frame_size (AC3EncodeContext *s)
 Adjust the frame size to make the average bit rate match the target bit rate. More...
 
void ff_ac3_compute_coupling_strategy (AC3EncodeContext *s)
 Set the initial coupling strategy parameters prior to coupling analysis. More...
 
static void ac3_apply_rematrixing (AC3EncodeContext *s)
 Apply stereo rematrixing to coefficients based on rematrixing flags. More...
 
static av_cold void exponent_init (void)
 
static void extract_exponents (AC3EncodeContext *s)
 
static void compute_exp_strategy (AC3EncodeContext *s)
 
static void encode_exponents_blk_ch (uint8_t *exp, int nb_exps, int exp_strategy, int cpl)
 Update the exponents so that they are the ones the decoder will decode. More...
 
static void encode_exponents (AC3EncodeContext *s)
 
static int count_exponent_bits (AC3EncodeContext *s)
 
static void ac3_group_exponents (AC3EncodeContext *s)
 Group exponents. More...
 
static void ac3_process_exponents (AC3EncodeContext *s)
 Calculate final exponents from the supplied MDCT coefficients and exponent shift. More...
 
static void count_frame_bits_fixed (AC3EncodeContext *s)
 
static av_cold void bit_alloc_init (AC3EncodeContext *s)
 
static void count_frame_bits (AC3EncodeContext *s)
 
static void bit_alloc_masking (AC3EncodeContext *s)
 
static void reset_block_bap (AC3EncodeContext *s)
 
static void count_mantissa_bits_init (uint16_t mant_cnt[AC3_MAX_BLOCKS][16])
 Initialize mantissa counts. More...
 
static void count_mantissa_bits_update_ch (AC3EncodeContext *s, int ch, uint16_t mant_cnt[AC3_MAX_BLOCKS][16], int start, int end)
 Update mantissa bit counts for all blocks in 1 channel in a given bandwidth range. More...
 
static int count_mantissa_bits (AC3EncodeContext *s)
 
static int bit_alloc (AC3EncodeContext *s, int snr_offset)
 Run the bit allocation with a given SNR offset. More...
 
static int cbr_bit_allocation (AC3EncodeContext *s)
 
static int ac3_compute_bit_allocation (AC3EncodeContext *s)
 
static int sym_quant (int c, int e, int levels)
 Symmetric quantization on 'levels' levels. More...
 
static int asym_quant (int c, int e, int qbits)
 Asymmetric quantization on 2^qbits levels. More...
 
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)
 Quantize a set of mantissas for a single channel in a single block. More...
 
static void ac3_quantize_mantissas (AC3EncodeContext *s)
 Quantize mantissas using coefficients, exponents, and bit allocation pointers. More...
 
static void ac3_output_frame_header (AC3EncodeContext *s, PutBitContext *pb)
 
static void output_audio_block (AC3EncodeContext *s, PutBitContext *pb, int blk)
 
static unsigned int mul_poly (unsigned int a, unsigned int b, unsigned int poly)
 
static unsigned int pow_poly (unsigned int a, unsigned int n, unsigned int poly)
 
static void output_frame_end (AC3EncodeContext *s, PutBitContext *pb)
 
static void ac3_output_frame (AC3EncodeContext *s, unsigned char *frame)
 Write the frame to the output bitstream. More...
 
int ff_ac3_encode_frame (AVCodecContext *avctx, AVPacket *avpkt, const AVFrame *frame, int *got_packet_ptr)
 
static void dprint_options (AC3EncodeContext *s)
 
av_cold int ff_ac3_encode_close (AVCodecContext *avctx)
 Finalize encoding and free any memory allocated by the encoder. More...
 
static av_cold void set_channel_info (AVCodecContext *avctx)
 
static av_cold int validate_options (AC3EncodeContext *s)
 
static av_cold void set_bandwidth (AC3EncodeContext *s)
 
static av_cold int allocate_buffers (AC3EncodeContext *s)
 
av_cold int ff_ac3_encode_init (AVCodecContext *avctx)
 

Variables

static const float cmixlev_options [CMIXLEV_NUM_OPTIONS]
 
static const float surmixlev_options [SURMIXLEV_NUM_OPTIONS]
 
static const float extmixlev_options [EXTMIXLEV_NUM_OPTIONS]
 
const AVOption ff_ac3_enc_options []
 
const AVClass ff_ac3enc_class
 
const FFCodecDefault ff_ac3_enc_defaults []
 
static uint8_t exponent_group_tab [2][3][256]
 LUT for number of exponent groups. More...
 
const AVChannelLayout ff_ac3_ch_layouts [19]
 List of supported channel layouts. More...
 
static const uint8_t ac3_enc_channel_map [8][2][6]
 Table to remap channels from SMPTE order to AC-3 order. More...
 
static const uint8_t ac3_bandwidth_tab [5][3][19]
 LUT to select the bandwidth code based on the bit rate, sample rate, and number of full-bandwidth channels. More...
 
static const int8_t ac3_coupling_start_tab [6][3][19]
 LUT to select the coupling start band based on the bit rate, sample rate, and number of full-bandwidth channels. More...
 
static const uint8_t exp_strategy_reuse_tab [4][6]
 Table used to select exponent strategy based on exponent reuse block interval. More...
 

Detailed Description

The simplest AC-3 encoder.

Definition in file ac3enc.c.

Macro Definition Documentation

◆ SAMPLETYPE_SIZE

#define SAMPLETYPE_SIZE (   ctx)
Value:
(sizeof(float) == sizeof(int32_t) ? sizeof(float) : \
(ctx)->fixed_point ? sizeof(int32_t) : sizeof(float))

Definition at line 55 of file ac3enc.c.

◆ CMIXLEV_NUM_OPTIONS

#define CMIXLEV_NUM_OPTIONS   3

Definition at line 63 of file ac3enc.c.

◆ SURMIXLEV_NUM_OPTIONS

#define SURMIXLEV_NUM_OPTIONS   3

Definition at line 68 of file ac3enc.c.

◆ EXTMIXLEV_NUM_OPTIONS

#define EXTMIXLEV_NUM_OPTIONS   8

Definition at line 73 of file ac3enc.c.

◆ OFFSET

#define OFFSET (   param)    offsetof(AC3EncodeContext, options.param)

Definition at line 82 of file ac3enc.c.

◆ AC3ENC_PARAM

#define AC3ENC_PARAM   (AV_OPT_FLAG_AUDIO_PARAM | AV_OPT_FLAG_ENCODING_PARAM)

Definition at line 83 of file ac3enc.c.

◆ FLT_OPTION_THRESHOLD

#define FLT_OPTION_THRESHOLD   0.01

Definition at line 279 of file ac3enc.c.

◆ EXP_DIFF_THRESHOLD

#define EXP_DIFF_THRESHOLD   500

Exponent Difference Threshold.

New exponents are sent if their SAD exceed this number.

Definition at line 649 of file ac3enc.c.

◆ CRC16_POLY

#define CRC16_POLY   ((1 << 0) | (1 << 2) | (1 << 15) | (1 << 16))

CRC-16 Polynomial.

Definition at line 1883 of file ac3enc.c.

Function Documentation

◆ validate_float_option()

static int validate_float_option ( float  v,
const float v_list,
int  v_list_size 
)
static

Definition at line 281 of file ac3enc.c.

Referenced by validate_mix_level().

◆ validate_mix_level()

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 
)
static

Definition at line 297 of file ac3enc.c.

Referenced by ac3_validate_metadata().

◆ ac3_validate_metadata()

static int ac3_validate_metadata ( AC3EncodeContext s)
static

Validate metadata options as set by AVOption system.

These values can optionally be changed per-frame.

Parameters
sAC-3 encoder private context

Definition at line 321 of file ac3enc.c.

Referenced by ff_ac3_encode_frame(), and validate_options().

◆ ac3_adjust_frame_size()

static void ac3_adjust_frame_size ( AC3EncodeContext s)
static

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.

Parameters
sAC-3 encoder private context

Definition at line 494 of file ac3enc.c.

Referenced by ff_ac3_encode_frame().

◆ ff_ac3_compute_coupling_strategy()

void ff_ac3_compute_coupling_strategy ( AC3EncodeContext s)

Set the initial coupling strategy parameters prior to coupling analysis.

Parameters
sAC-3 encoder private context

Definition at line 511 of file ac3enc.c.

Referenced by encode_frame().

◆ ac3_apply_rematrixing()

static void ac3_apply_rematrixing ( AC3EncodeContext s)
static

Apply stereo rematrixing to coefficients based on rematrixing flags.

Parameters
sAC-3 encoder private context

Definition at line 582 of file ac3enc.c.

Referenced by ff_ac3_encode_frame().

◆ exponent_init()

static av_cold void exponent_init ( void  )
static

Definition at line 616 of file ac3enc.c.

Referenced by ff_ac3_encode_init().

◆ extract_exponents()

static void extract_exponents ( AC3EncodeContext s)
static

Definition at line 635 of file ac3enc.c.

Referenced by ac3_process_exponents().

◆ compute_exp_strategy()

static void compute_exp_strategy ( AC3EncodeContext s)
static

Definition at line 665 of file ac3enc.c.

Referenced by ac3_process_exponents().

◆ encode_exponents_blk_ch()

static void encode_exponents_blk_ch ( uint8_t *  exp,
int  nb_exps,
int  exp_strategy,
int  cpl 
)
static

Update the exponents so that they are the ones the decoder will decode.

Parameters
[in,out]exparray of exponents for 1 block in 1 channel
nb_expsnumber of exponents in active bandwidth
exp_strategyexponent strategy for the block
cplindicates if the block is in the coupling channel

Definition at line 731 of file ac3enc.c.

Referenced by encode_exponents().

◆ encode_exponents()

static void encode_exponents ( AC3EncodeContext s)
static

Definition at line 804 of file ac3enc.c.

Referenced by ac3_process_exponents().

◆ count_exponent_bits()

static int count_exponent_bits ( AC3EncodeContext s)
static

Definition at line 854 of file ac3enc.c.

Referenced by ac3_compute_bit_allocation().

◆ ac3_group_exponents()

static void ac3_group_exponents ( AC3EncodeContext s)
static

Group exponents.

3 delta-encoded exponents are in each 7-bit group. The number of groups varies depending on exponent strategy and bandwidth.

Parameters
sAC-3 encoder private context

Definition at line 886 of file ac3enc.c.

Referenced by ff_ac3_encode_frame().

◆ ac3_process_exponents()

static void ac3_process_exponents ( AC3EncodeContext s)
static

Calculate final exponents from the supplied MDCT coefficients and exponent shift.

Extract exponents from MDCT coefficients, calculate exponent strategies, and encode final exponents.

Parameters
sAC-3 encoder private context

Definition at line 944 of file ac3enc.c.

Referenced by ff_ac3_encode_frame().

◆ count_frame_bits_fixed()

static void count_frame_bits_fixed ( AC3EncodeContext s)
static

Definition at line 960 of file ac3enc.c.

Referenced by bit_alloc_init().

◆ bit_alloc_init()

static av_cold void bit_alloc_init ( AC3EncodeContext s)
static

Definition at line 1069 of file ac3enc.c.

Referenced by ff_ac3_encode_init().

◆ count_frame_bits()

static void count_frame_bits ( AC3EncodeContext s)
static

Definition at line 1105 of file ac3enc.c.

Referenced by ac3_compute_bit_allocation().

◆ bit_alloc_masking()

static void bit_alloc_masking ( AC3EncodeContext s)
static

Definition at line 1248 of file ac3enc.c.

Referenced by ac3_compute_bit_allocation().

◆ reset_block_bap()

static void reset_block_bap ( AC3EncodeContext s)
static

Definition at line 1278 of file ac3enc.c.

Referenced by bit_alloc(), and cbr_bit_allocation().

◆ count_mantissa_bits_init()

static void count_mantissa_bits_init ( uint16_t  mant_cnt[AC3_MAX_BLOCKS][16])
static

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.

Parameters
[in,out]mant_cntrunning counts for each bap value for each block

Definition at line 1303 of file ac3enc.c.

Referenced by count_mantissa_bits().

◆ count_mantissa_bits_update_ch()

static void count_mantissa_bits_update_ch ( AC3EncodeContext s,
int  ch,
uint16_t  mant_cnt[AC3_MAX_BLOCKS][16],
int  start,
int  end 
)
static

Update mantissa bit counts for all blocks in 1 channel in a given bandwidth range.

Parameters
sAC-3 encoder private context
chchannel index
[in,out]mant_cntrunning counts for each bap value for each block
startstarting coefficient bin
endending coefficient bin

Definition at line 1325 of file ac3enc.c.

Referenced by count_mantissa_bits().

◆ count_mantissa_bits()

static int count_mantissa_bits ( AC3EncodeContext s)
static

Definition at line 1345 of file ac3enc.c.

Referenced by bit_alloc().

◆ bit_alloc()

static int bit_alloc ( AC3EncodeContext s,
int  snr_offset 
)
static

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.

Parameters
sAC-3 encoder private context
snr_offsetSNR offset, 0 to 1023
Returns
the number of bits needed for mantissas if the given SNR offset is is used.

Definition at line 1371 of file ac3enc.c.

Referenced by cbr_bit_allocation(), compute_bit_allocation(), encode_frame(), mp_decode_layer2(), and MPA_encode_frame().

◆ cbr_bit_allocation()

static int cbr_bit_allocation ( AC3EncodeContext s)
static

Definition at line 1402 of file ac3enc.c.

Referenced by ac3_compute_bit_allocation().

◆ ac3_compute_bit_allocation()

static int ac3_compute_bit_allocation ( AC3EncodeContext s)
static

Definition at line 1453 of file ac3enc.c.

Referenced by ff_ac3_encode_frame().

◆ sym_quant()

static int sym_quant ( int  c,
int  e,
int  levels 
)
inlinestatic

Symmetric quantization on 'levels' levels.

Parameters
cunquantized coefficient
eexponent
levelsnumber of quantization levels
Returns
quantized coefficient

Definition at line 1473 of file ac3enc.c.

Referenced by quantize_mantissas_blk_ch().

◆ asym_quant()

static int asym_quant ( int  c,
int  e,
int  qbits 
)
inlinestatic

Asymmetric quantization on 2^qbits levels.

Parameters
cunquantized coefficient
eexponent
qbitsnumber of quantization bits
Returns
quantized coefficient

Definition at line 1489 of file ac3enc.c.

Referenced by quantize_mantissas_blk_ch().

◆ quantize_mantissas_blk_ch()

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 
)
static

Quantize a set of mantissas for a single channel in a single block.

Parameters
sMantissa count context
fixed_coefunquantized fixed-point coefficients
expexponents
bapbit allocation pointer indices
[out]qmantquantized coefficients
start_freqstarting coefficient bin
end_freqending coefficient bin

Definition at line 1513 of file ac3enc.c.

Referenced by ac3_quantize_mantissas().

◆ ac3_quantize_mantissas()

static void ac3_quantize_mantissas ( AC3EncodeContext s)
static

Quantize mantissas using coefficients, exponents, and bit allocation pointers.

Parameters
sAC-3 encoder private context

Definition at line 1608 of file ac3enc.c.

Referenced by ff_ac3_encode_frame().

◆ ac3_output_frame_header()

static void ac3_output_frame_header ( AC3EncodeContext s,
PutBitContext pb 
)
static

Definition at line 1637 of file ac3enc.c.

Referenced by ff_ac3_encode_init().

◆ output_audio_block()

static void output_audio_block ( AC3EncodeContext s,
PutBitContext pb,
int  blk 
)
static

Definition at line 1693 of file ac3enc.c.

Referenced by ac3_output_frame().

◆ mul_poly()

static unsigned int mul_poly ( unsigned int  a,
unsigned int  b,
unsigned int  poly 
)
static

Definition at line 1886 of file ac3enc.c.

Referenced by output_frame_end(), and pow_poly().

◆ pow_poly()

static unsigned int pow_poly ( unsigned int  a,
unsigned int  n,
unsigned int  poly 
)
static

Definition at line 1903 of file ac3enc.c.

Referenced by ff_ac3_encode_init().

◆ output_frame_end()

static void output_frame_end ( AC3EncodeContext s,
PutBitContext pb 
)
static

Definition at line 1920 of file ac3enc.c.

Referenced by ac3_output_frame().

◆ ac3_output_frame()

static void ac3_output_frame ( AC3EncodeContext s,
unsigned char *  frame 
)
static

Write the frame to the output bitstream.

Parameters
sAC-3 encoder private context
frameoutput data buffer

Definition at line 1970 of file ac3enc.c.

Referenced by ff_ac3_encode_frame().

◆ ff_ac3_encode_frame()

int ff_ac3_encode_frame ( AVCodecContext avctx,
AVPacket avpkt,
const AVFrame frame,
int got_packet_ptr 
)

Definition at line 1985 of file ac3enc.c.

◆ dprint_options()

static void dprint_options ( AC3EncodeContext s)
static

Definition at line 2028 of file ac3enc.c.

Referenced by ff_ac3_encode_init().

◆ ff_ac3_encode_close()

av_cold int ff_ac3_encode_close ( AVCodecContext avctx)

Finalize encoding and free any memory allocated by the encoder.

Parameters
avctxCodec context

Definition at line 2158 of file ac3enc.c.

◆ set_channel_info()

static av_cold void set_channel_info ( AVCodecContext avctx)
static

Definition at line 2186 of file ac3enc.c.

Referenced by validate_options().

◆ validate_options()

static av_cold int validate_options ( AC3EncodeContext s)
static

Definition at line 2215 of file ac3enc.c.

Referenced by ff_ac3_encode_init().

◆ set_bandwidth()

static av_cold void set_bandwidth ( AC3EncodeContext s)
static

Definition at line 2342 of file ac3enc.c.

Referenced by ff_ac3_encode_init().

◆ allocate_buffers()

static av_cold int allocate_buffers ( AC3EncodeContext s)
static

Definition at line 2412 of file ac3enc.c.

Referenced by ff_ac3_encode_init().

◆ ff_ac3_encode_init()

av_cold int ff_ac3_encode_init ( AVCodecContext avctx)

Definition at line 2476 of file ac3enc.c.

Referenced by ac3_fixed_encode_init(), and ff_ac3_float_encode_init().

Variable Documentation

◆ cmixlev_options

const float cmixlev_options[CMIXLEV_NUM_OPTIONS]
static
Initial value:

Definition at line 64 of file ac3enc.c.

Referenced by ac3_validate_metadata().

◆ surmixlev_options

const float surmixlev_options[SURMIXLEV_NUM_OPTIONS]
static
Initial value:

Definition at line 69 of file ac3enc.c.

Referenced by ac3_validate_metadata().

◆ extmixlev_options

const float extmixlev_options[EXTMIXLEV_NUM_OPTIONS]
static

◆ ff_ac3_enc_options

const AVOption ff_ac3_enc_options[]

Definition at line 84 of file ac3enc.c.

◆ ff_ac3enc_class

const AVClass ff_ac3enc_class
Initial value:
= {
.class_name = "AC-3 Encoder",
.item_name = av_default_item_name,
.option = ff_ac3_enc_options,
}

Definition at line 134 of file ac3enc.c.

◆ ff_ac3_enc_defaults

const FFCodecDefault ff_ac3_enc_defaults[]
Initial value:
= {
{ "b", "0" },
{ NULL }
}

Definition at line 141 of file ac3enc.c.

◆ exponent_group_tab

uint8_t exponent_group_tab[2][3][256]
static

LUT for number of exponent groups.

exponent_group_tab[coupling][exponent strategy-1][number of coefficients]

Definition at line 150 of file ac3enc.c.

Referenced by ac3_group_exponents(), count_exponent_bits(), encode_exponents_blk_ch(), exponent_init(), and output_audio_block().

◆ ff_ac3_ch_layouts

const AVChannelLayout ff_ac3_ch_layouts[19]

List of supported channel layouts.

Definition at line 156 of file ac3enc.c.

◆ ac3_enc_channel_map

const uint8_t ac3_enc_channel_map[8][2][6]
static
Initial value:
= {
{ { 0, 1, 2, 3, }, { 0, 1, 3, 4, 2, } },
{ { 0, 2, 1, 3, 4, }, { 0, 2, 1, 4, 5, 3 } },
}

Table to remap channels from SMPTE order to AC-3 order.

[channel_mode][lfe][ch]

Definition at line 200 of file ac3enc.c.

Referenced by set_channel_info().

◆ ac3_bandwidth_tab

const uint8_t ac3_bandwidth_tab[5][3][19]
static
Initial value:
= {
{ { 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 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]

Definition at line 211 of file ac3enc.c.

Referenced by set_bandwidth().

◆ ac3_coupling_start_tab

const int8_t ac3_coupling_start_tab[6][3][19]
static

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.

Definition at line 244 of file ac3enc.c.

Referenced by set_bandwidth().

◆ exp_strategy_reuse_tab

const uint8_t exp_strategy_reuse_tab[4][6]
static
Initial value:

Table used to select exponent strategy based on exponent reuse block interval.

Definition at line 654 of file ac3enc.c.

Referenced by compute_exp_strategy().

EXP_D45
#define EXP_D45
Definition: ac3defs.h:43
LEVEL_MINUS_6DB
#define LEVEL_MINUS_6DB
Definition: ac3.h:90
COMMON_CHANNEL_MAP
#define COMMON_CHANNEL_MAP
Definition: ac3tab.h:48
LEVEL_MINUS_4POINT5DB
#define LEVEL_MINUS_4POINT5DB
Definition: ac3.h:89
ff_ac3_enc_options
const AVOption ff_ac3_enc_options[]
Definition: ac3enc.c:84
LEVEL_PLUS_3DB
#define LEVEL_PLUS_3DB
Definition: ac3.h:85
float
float
Definition: af_crystalizer.c:121
LEVEL_MINUS_3DB
#define LEVEL_MINUS_3DB
Definition: ac3.h:88
ctx
AVFormatContext * ctx
Definition: movenc.c:49
EXP_D15
#define EXP_D15
Definition: ac3defs.h:41
LIBAVUTIL_VERSION_INT
#define LIBAVUTIL_VERSION_INT
Definition: version.h:85
NULL
#define NULL
Definition: coverity.c:32
av_default_item_name
const char * av_default_item_name(void *ptr)
Return the context name.
Definition: log.c:237
LEVEL_MINUS_1POINT5DB
#define LEVEL_MINUS_1POINT5DB
Definition: ac3.h:87
LEVEL_ONE
#define LEVEL_ONE
Definition: ac3.h:93
LEVEL_PLUS_1POINT5DB
#define LEVEL_PLUS_1POINT5DB
Definition: ac3.h:86
LEVEL_ZERO
#define LEVEL_ZERO
Definition: ac3.h:92
int32_t
int32_t
Definition: audioconvert.c:56
EXP_D25
#define EXP_D25
Definition: ac3defs.h:42