libavcodec/aacsbr.c File Reference

AAC Spectral Band Replication decoding functions. More...

#include "aac.h"
#include "sbr.h"
#include "aacsbr.h"
#include "aacsbrdata.h"
#include "fft.h"
#include "aacps.h"
#include "sbrdsp.h"
#include "libavutil/libm.h"
#include "libavutil/avassert.h"
#include <stdint.h>
#include <float.h>
#include <math.h>

Go to the source code of this file.

Defines

#define ENVELOPE_ADJUSTMENT_OFFSET   2

#define NOISE_FLOOR_OFFSET   6.0f

#define SBR_INIT_VLC_STATIC(num, size)

#define SBR_VLC_ROW(name)   { name ## _codes, name ## _bits, sizeof(name ## _codes), sizeof(name ## _codes[0]) }

Enumerations

enum {
  T_HUFFMAN_ENV_1_5DB, F_HUFFMAN_ENV_1_5DB, T_HUFFMAN_ENV_BAL_1_5DB, F_HUFFMAN_ENV_BAL_1_5DB,
  T_HUFFMAN_ENV_3_0DB, F_HUFFMAN_ENV_3_0DB, T_HUFFMAN_ENV_BAL_3_0DB, F_HUFFMAN_ENV_BAL_3_0DB,
  T_HUFFMAN_NOISE_3_0DB, T_HUFFMAN_NOISE_BAL_3_0DB
}

SBR VLC tables. More...

enum { FIXFIX, FIXVAR, VARFIX, VARVAR }

bs_frame_class - frame class of current SBR frame (14496-3 sp04 p98) More...

enum { EXTENSION_ID_PS = 2 }

Functions

av_cold void ff_aac_sbr_init (void)

Initialize SBR.

static void sbr_turnoff (SpectralBandReplication *sbr)

Places SBR in pure upsampling mode.

av_cold void ff_aac_sbr_ctx_init (AACContext *ac, SpectralBandReplication *sbr)

Initialize one SBR context.

av_cold void ff_aac_sbr_ctx_close (SpectralBandReplication *sbr)

Close one SBR context.

static int qsort_comparison_function_int16 (const void *a, const void *b)

static int in_table_int16 (const int16_t *table, int last_el, int16_t needle)

static void sbr_make_f_tablelim (SpectralBandReplication *sbr)

Limiter Frequency Band Table (14496-3 sp04 p198).

static unsigned int read_sbr_header (SpectralBandReplication *sbr, GetBitContext *gb)

static int array_min_int16 (const int16_t *array, int nel)

static void make_bands (int16_t *bands, int start, int stop, int num_bands)

static int check_n_master (AVCodecContext *avctx, int n_master, int bs_xover_band)

static int sbr_make_f_master (AACContext *ac, SpectralBandReplication *sbr, SpectrumParameters *spectrum)

Master Frequency Band Table (14496-3 sp04 p194).

static int sbr_hf_calc_npatches (AACContext *ac, SpectralBandReplication *sbr)

High Frequency Generation - Patch Construction (14496-3 sp04 p216 fig. 4.46).

static int sbr_make_f_derived (AACContext *ac, SpectralBandReplication *sbr)

Derived Frequency Band Tables (14496-3 sp04 p197).

static av_always_inline void get_bits1_vector (GetBitContext *gb, uint8_t *vec, int elements)

static int read_sbr_grid (AACContext *ac, SpectralBandReplication *sbr, GetBitContext *gb, SBRData *ch_data)

static void copy_sbr_grid (SBRData *dst, const SBRData *src)

static void read_sbr_dtdf (SpectralBandReplication *sbr, GetBitContext *gb, SBRData *ch_data)

Read how the envelope and noise floor data is delta coded.

static void read_sbr_invf (SpectralBandReplication *sbr, GetBitContext *gb, SBRData *ch_data)

Read inverse filtering data.

static void read_sbr_envelope (SpectralBandReplication *sbr, GetBitContext *gb, SBRData *ch_data, int ch)

static void read_sbr_noise (SpectralBandReplication *sbr, GetBitContext *gb, SBRData *ch_data, int ch)

static void read_sbr_extension (AACContext *ac, SpectralBandReplication *sbr, GetBitContext *gb, int bs_extension_id, int *num_bits_left)

static int read_sbr_single_channel_element (AACContext *ac, SpectralBandReplication *sbr, GetBitContext *gb)

static int read_sbr_channel_pair_element (AACContext *ac, SpectralBandReplication *sbr, GetBitContext *gb)

static unsigned int read_sbr_data (AACContext *ac, SpectralBandReplication *sbr, GetBitContext *gb, int id_aac)

static void sbr_reset (AACContext *ac, SpectralBandReplication *sbr)

int ff_decode_sbr_extension (AACContext *ac, SpectralBandReplication *sbr, GetBitContext *gb_host, int crc, int cnt, int id_aac)

Decode Spectral Band Replication extension data; reference: table 4.55.

static void sbr_dequant (SpectralBandReplication *sbr, int id_aac)

Dequantization and stereo decoding (14496-3 sp04 p203).

static void sbr_qmf_analysis (DSPContext *dsp, FFTContext *mdct, SBRDSPContext *sbrdsp, const float *in, float *x, float z[320], float W[2][32][32][2])

Analysis QMF Bank (14496-3 sp04 p206).

static void sbr_qmf_synthesis (DSPContext *dsp, FFTContext *mdct, SBRDSPContext *sbrdsp, float *out, float X[2][38][64], float mdct_buf[2][64], float *v0, int *v_off, const unsigned int div)

Synthesis QMF Bank (14496-3 sp04 p206) and Downsampled Synthesis QMF Bank (14496-3 sp04 p206).

static void sbr_hf_inverse_filter (SBRDSPContext *dsp, float(*alpha0)[2], float(*alpha1)[2], const float X_low[32][40][2], int k0)

High Frequency Generation (14496-3 sp04 p214+) and Inverse Filtering (14496-3 sp04 p214) Warning: This routine does not seem numerically stable.

static void sbr_chirp (SpectralBandReplication *sbr, SBRData *ch_data)

Chirp Factors (14496-3 sp04 p214).

static int sbr_lf_gen (AACContext *ac, SpectralBandReplication *sbr, float X_low[32][40][2], const float W[2][32][32][2])

Generate the subband filtered lowband.

static int sbr_hf_gen (AACContext *ac, SpectralBandReplication *sbr, float X_high[64][40][2], const float X_low[32][40][2], const float(*alpha0)[2], const float(*alpha1)[2], const float bw_array[5], const uint8_t *t_env, int bs_num_env)

High Frequency Generator (14496-3 sp04 p215).

static int sbr_x_gen (SpectralBandReplication *sbr, float X[2][38][64], const float Y0[38][64][2], const float Y1[38][64][2], const float X_low[32][40][2], int ch)

Generate the subband filtered lowband.

static int sbr_mapping (AACContext *ac, SpectralBandReplication *sbr, SBRData *ch_data, int e_a[2])

High Frequency Adjustment (14496-3 sp04 p217) and Mapping (14496-3 sp04 p217).

static void sbr_env_estimate (float(*e_curr)[48], float X_high[64][40][2], SpectralBandReplication *sbr, SBRData *ch_data)

Estimation of current envelope (14496-3 sp04 p218).

static void sbr_gain_calc (AACContext *ac, SpectralBandReplication *sbr, SBRData *ch_data, const int e_a[2])

Calculation of levels of additional HF signal components (14496-3 sp04 p219) and Calculation of gain (14496-3 sp04 p219).

static void sbr_hf_assemble (float Y1[38][64][2], const float X_high[64][40][2], SpectralBandReplication *sbr, SBRData *ch_data, const int e_a[2])

Assembling HF Signals (14496-3 sp04 p220).

void ff_sbr_apply (AACContext *ac, SpectralBandReplication *sbr, int id_aac, float *L, float *R)

Apply one SBR element to one AAC element.

Variables

static VLC vlc_sbr [10]

static const int8_t vlc_sbr_lav [10]

static const float zero64 [64]

static const int8_t ceil_log2 []

ceil(log2(index+1))

Detailed Description

AAC Spectral Band Replication decoding functions.

Author:: Robert Swain ( rob opendot cl )

Definition in file aacsbr.c.

Define Documentation

#define ENVELOPE_ADJUSTMENT_OFFSET 2

Definition at line 43 of file aacsbr.c.

Referenced by sbr_env_estimate(), sbr_hf_assemble(), sbr_hf_gen(), and sbr_x_gen().

#define NOISE_FLOOR_OFFSET 6.0f

Definition at line 44 of file aacsbr.c.

Referenced by sbr_dequant().

#define SBR_INIT_VLC_STATIC	(	num,
		size		)

Value:

INIT_VLC_STATIC(&vlc_sbr[num], 9, sbr_tmp[num].table_size / sbr_tmp[num].elem_size,     \
                    sbr_tmp[num].sbr_bits ,                      1,                      1, \
                    sbr_tmp[num].sbr_codes, sbr_tmp[num].elem_size, sbr_tmp[num].elem_size, \
                    size)

Definition at line 81 of file aacsbr.c.

Referenced by ff_aac_sbr_init().

#define SBR_VLC_ROW ( name ) { name ## _codes, name ## _bits, sizeof(name ## _codes), sizeof(name ## _codes[0]) }

Definition at line 87 of file aacsbr.c.

Referenced by ff_aac_sbr_init().

Enumeration Type Documentation

anonymous enum

bs_frame_class - frame class of current SBR frame (14496-3 sp04 p98)

Enumerator:

FIXFIX
FIXVAR
VARFIX
VARVAR

Definition at line 65 of file aacsbr.c.

anonymous enum

Enumerator:

EXTENSION_ID_PS

Definition at line 72 of file aacsbr.c.

anonymous enum

SBR VLC tables.

Enumerator:

T_HUFFMAN_ENV_1_5DB
F_HUFFMAN_ENV_1_5DB
T_HUFFMAN_ENV_BAL_1_5DB
F_HUFFMAN_ENV_BAL_1_5DB
T_HUFFMAN_ENV_3_0DB
F_HUFFMAN_ENV_3_0DB
T_HUFFMAN_ENV_BAL_3_0DB
F_HUFFMAN_ENV_BAL_3_0DB
T_HUFFMAN_NOISE_3_0DB
T_HUFFMAN_NOISE_BAL_3_0DB

Definition at line 49 of file aacsbr.c.

Function Documentation

static int array_min_int16	(	const int16_t *	array,
		int	nel
	)			`[static]`

Definition at line 284 of file aacsbr.c.

Referenced by sbr_make_f_master().

static int check_n_master	(	AVCodecContext *	avctx,
		int	n_master,
		int	bs_xover_band
	)			`[static]`

Definition at line 310 of file aacsbr.c.

Referenced by sbr_make_f_master().

static void copy_sbr_grid	(	SBRData *	dst,
		const SBRData *	src
	)			`[static]`

Definition at line 774 of file aacsbr.c.

Referenced by read_sbr_channel_pair_element().

av_cold void ff_aac_sbr_ctx_close ( SpectralBandReplication * sbr )

Close one SBR context.

Definition at line 162 of file aacsbr.c.

Referenced by aac_decode_close(), and che_configure().

av_cold void ff_aac_sbr_ctx_init	(	AACContext *	ac,
		SpectralBandReplication *	sbr
	)

Initialize one SBR context.

Definition at line 143 of file aacsbr.c.

Referenced by che_configure().

av_cold void ff_aac_sbr_init ( void )

Initialize SBR.

Definition at line 90 of file aacsbr.c.

Referenced by aac_decode_init().

int ff_decode_sbr_extension	(	AACContext *	ac,
		SpectralBandReplication *	sbr,
		GetBitContext *	gb_host,
		int	crc,
		int	cnt,
		int	id_aac
	)

Decode Spectral Band Replication extension data; reference: table 4.55.

Decode one SBR element.

Parameters:

	crc	flag indicating the presence of CRC checksum
	cnt	length of TYPE_FIL syntactic element in bytes

Returns:: Returns number of bytes consumed from the TYPE_FIL element.

Definition at line 1069 of file aacsbr.c.

Referenced by decode_extension_payload().

void ff_sbr_apply	(	AACContext *	ac,
		SpectralBandReplication *	sbr,
		int	id_aac,
		float *	L,
		float *	R
	)

Apply one SBR element to one AAC element.

Definition at line 1653 of file aacsbr.c.

Referenced by spectral_to_sample().

static av_always_inline void get_bits1_vector	(	GetBitContext *	gb,
		uint8_t *	vec,
		int	elements
	)			`[static]`

Definition at line 618 of file aacsbr.c.

Referenced by read_sbr_channel_pair_element(), read_sbr_dtdf(), read_sbr_grid(), and read_sbr_single_channel_element().

static int in_table_int16	(	const int16_t *	table,
		int	last_el,
		int16_t	needle
	)			`[inline, static]`

Definition at line 173 of file aacsbr.c.

Referenced by sbr_make_f_tablelim().

static void make_bands	(	int16_t *	bands,
		int	start,
		int	stop,
		int	num_bands
	)			`[static]`

Definition at line 292 of file aacsbr.c.

Referenced by sbr_make_f_master().

static int qsort_comparison_function_int16	(	const void *	a,
		const void *	b
	)			`[static]`

Definition at line 168 of file aacsbr.c.

Referenced by sbr_make_f_master(), and sbr_make_f_tablelim().

static int read_sbr_channel_pair_element	(	AACContext *	ac,
		SpectralBandReplication *	sbr,
		GetBitContext *	gb
	)			`[static]`

Definition at line 965 of file aacsbr.c.

Referenced by read_sbr_data().

static unsigned int read_sbr_data	(	AACContext *	ac,
		SpectralBandReplication *	sbr,
		GetBitContext *	gb,
		int	id_aac
	)			`[static]`

Definition at line 1007 of file aacsbr.c.

Referenced by ff_decode_sbr_extension().

static void read_sbr_dtdf	(	SpectralBandReplication *	sbr,
		GetBitContext *	gb,
		SBRData *	ch_data
	)			`[static]`

Read how the envelope and noise floor data is delta coded.

Definition at line 792 of file aacsbr.c.

Referenced by read_sbr_channel_pair_element(), and read_sbr_single_channel_element().

static void read_sbr_envelope	(	SpectralBandReplication *	sbr,
		GetBitContext *	gb,
		SBRData *	ch_data,
		int	ch
	)			`[static]`

Definition at line 810 of file aacsbr.c.

Referenced by read_sbr_channel_pair_element(), and read_sbr_single_channel_element().

static void read_sbr_extension	(	AACContext *	ac,
		SpectralBandReplication *	sbr,
		GetBitContext *	gb,
		int	bs_extension_id,
		int *	num_bits_left
	)			`[static]`

Definition at line 915 of file aacsbr.c.

Referenced by read_sbr_data().

static int read_sbr_grid	(	AACContext *	ac,
		SpectralBandReplication *	sbr,
		GetBitContext *	gb,
		SBRData *	ch_data
	)			`[static]`

Definition at line 632 of file aacsbr.c.

Referenced by read_sbr_channel_pair_element(), and read_sbr_single_channel_element().

static unsigned int read_sbr_header	(	SpectralBandReplication *	sbr,
		GetBitContext *	gb
	)			`[static]`

Definition at line 230 of file aacsbr.c.

Referenced by ff_decode_sbr_extension().

static void read_sbr_invf	(	SpectralBandReplication *	sbr,
		GetBitContext *	gb,
		SBRData *	ch_data
	)			`[static]`

Read inverse filtering data.

Definition at line 800 of file aacsbr.c.

Referenced by read_sbr_channel_pair_element(), and read_sbr_single_channel_element().

static void read_sbr_noise	(	SpectralBandReplication *	sbr,
		GetBitContext *	gb,
		SBRData *	ch_data,
		int	ch
	)			`[static]`

Definition at line 879 of file aacsbr.c.

Referenced by read_sbr_channel_pair_element(), and read_sbr_single_channel_element().

static int read_sbr_single_channel_element	(	AACContext *	ac,
		SpectralBandReplication *	sbr,
		GetBitContext *	gb
	)			`[static]`

Definition at line 945 of file aacsbr.c.

Referenced by read_sbr_data().

static void sbr_chirp	(	SpectralBandReplication *	sbr,
		SBRData *	ch_data
	)			`[static]`

Chirp Factors (14496-3 sp04 p214).

Definition at line 1290 of file aacsbr.c.

Referenced by ff_sbr_apply().

static void sbr_dequant	(	SpectralBandReplication *	sbr,
		int	id_aac
	)			`[static]`

Dequantization and stereo decoding (14496-3 sp04 p203).

Definition at line 1115 of file aacsbr.c.

Referenced by ff_sbr_apply().

static void sbr_env_estimate	(	float(*)	e_curr[48],
		float	X_high[64][40][2],
		SpectralBandReplication *	sbr,
		SBRData *	ch_data
	)			`[static]`

Estimation of current envelope (14496-3 sp04 p218).

Definition at line 1463 of file aacsbr.c.

Referenced by ff_sbr_apply().

static void sbr_gain_calc	(	AACContext *	ac,
		SpectralBandReplication *	sbr,
		SBRData *	ch_data,
		const int	e_a[2]
	)			`[static]`

Calculation of levels of additional HF signal components (14496-3 sp04 p219) and Calculation of gain (14496-3 sp04 p219).

Definition at line 1509 of file aacsbr.c.

Referenced by ff_sbr_apply().

static void sbr_hf_assemble	(	float	Y1[38][64][2],
		const float	X_high[64][40][2],
		SpectralBandReplication *	sbr,
		SBRData *	ch_data,
		const int	e_a[2]
	)			`[static]`

Assembling HF Signals (14496-3 sp04 p220).

Definition at line 1565 of file aacsbr.c.

Referenced by ff_sbr_apply().

static int sbr_hf_calc_npatches	(	AACContext *	ac,
		SpectralBandReplication *	sbr
	)			`[static]`

High Frequency Generation - Patch Construction (14496-3 sp04 p216 fig. 4.46).

Definition at line 514 of file aacsbr.c.

Referenced by sbr_make_f_derived().

static int sbr_hf_gen	(	AACContext *	ac,
		SpectralBandReplication *	sbr,
		float	X_high[64][40][2],
		const float	X_low[32][40][2],
		const float(*)	alpha0[2],
		const float(*)	alpha1[2],
		const float	bw_array[5],
		const uint8_t *	t_env,
		int	bs_num_env
	)			`[static]`

High Frequency Generator (14496-3 sp04 p215).

Definition at line 1334 of file aacsbr.c.

Referenced by ff_sbr_apply().

static void sbr_hf_inverse_filter	(	SBRDSPContext *	dsp,
		float(*)	alpha0[2],
		float(*)	alpha1[2],
		const float	X_low[32][40][2],
		int	k0
	)			`[static]`

High Frequency Generation (14496-3 sp04 p214+) and Inverse Filtering (14496-3 sp04 p214) Warning: This routine does not seem numerically stable.

Definition at line 1235 of file aacsbr.c.

Referenced by ff_sbr_apply().

static int sbr_lf_gen	(	AACContext *	ac,
		SpectralBandReplication *	sbr,
		float	X_low[32][40][2],
		const float	W[2][32][32][2]
	)			`[static]`

Generate the subband filtered lowband.

Definition at line 1311 of file aacsbr.c.

Referenced by ff_sbr_apply().

static int sbr_make_f_derived	(	AACContext *	ac,
		SpectralBandReplication *	sbr
	)			`[static]`

Derived Frequency Band Tables (14496-3 sp04 p197).

Definition at line 565 of file aacsbr.c.

Referenced by sbr_reset().

static int sbr_make_f_master	(	AACContext *	ac,
		SpectralBandReplication *	sbr,
		SpectrumParameters *	spectrum
	)			`[static]`

Master Frequency Band Table (14496-3 sp04 p194).

Definition at line 327 of file aacsbr.c.

Referenced by sbr_reset().

static void sbr_make_f_tablelim ( SpectralBandReplication * sbr ) [static]

Limiter Frequency Band Table (14496-3 sp04 p198).

Definition at line 183 of file aacsbr.c.

Referenced by read_sbr_header(), and sbr_make_f_derived().

static int sbr_mapping	(	AACContext *	ac,
		SpectralBandReplication *	sbr,
		SBRData *	ch_data,
		int	e_a[2]
	)			`[static]`

High Frequency Adjustment (14496-3 sp04 p217) and Mapping (14496-3 sp04 p217).

Definition at line 1408 of file aacsbr.c.

Referenced by ff_sbr_apply().

static void sbr_qmf_analysis	(	DSPContext *	dsp,
		FFTContext *	mdct,
		SBRDSPContext *	sbrdsp,
		const float *	in,
		float *	x,
		float	z[320],
		float	W[2][32][32][2]
	)			`[static]`

Analysis QMF Bank (14496-3 sp04 p206).

Parameters:

	x	pointer to the beginning of the first sample window
	W	array of complex-valued samples split into subbands

Definition at line 1162 of file aacsbr.c.

Referenced by ff_sbr_apply().

static void sbr_qmf_synthesis	(	DSPContext *	dsp,
		FFTContext *	mdct,
		SBRDSPContext *	sbrdsp,
		float *	out,
		float	X[2][38][64],
		float	mdct_buf[2][64],
		float *	v0,
		int *	v_off,
		const unsigned int	div
	)			`[static]`

Synthesis QMF Bank (14496-3 sp04 p206) and Downsampled Synthesis QMF Bank (14496-3 sp04 p206).

Definition at line 1185 of file aacsbr.c.

Referenced by ff_sbr_apply().

static void sbr_reset	(	AACContext *	ac,
		SpectralBandReplication *	sbr
	)			`[static]`

Definition at line 1048 of file aacsbr.c.

Referenced by ff_decode_sbr_extension().

static void sbr_turnoff ( SpectralBandReplication * sbr ) [static]

Places SBR in pure upsampling mode.

Definition at line 133 of file aacsbr.c.

Referenced by ff_aac_sbr_ctx_init(), read_sbr_data(), sbr_mapping(), and sbr_reset().

static int sbr_x_gen	(	SpectralBandReplication *	sbr,
		float	X[2][38][64],
		const float	Y0[38][64][2],
		const float	Y1[38][64][2],
		const float	X_low[32][40][2],
		int	ch
	)			`[static]`

Generate the subband filtered lowband.

Definition at line 1369 of file aacsbr.c.

Referenced by ff_sbr_apply().

Variable Documentation

const int8_t ceil_log2[] [static]

Initial value:

 {
    0, 1, 2, 2, 3, 3,
}

ceil(log2(index+1))

Definition at line 628 of file aacsbr.c.

Referenced by read_sbr_grid().

VLC vlc_sbr[10] [static]

Definition at line 76 of file aacsbr.c.

const int8_t vlc_sbr_lav[10] [static]

Initial value:

    { 60, 60, 24, 24, 31, 31, 12, 12, 31, 12 }

Definition at line 77 of file aacsbr.c.

Referenced by read_sbr_envelope(), and read_sbr_noise().

const float zero64[64] [static]

Definition at line 79 of file aacsbr.c.

Referenced by sbr_qmf_synthesis().


Defines
#define	ENVELOPE_ADJUSTMENT_OFFSET 2
#define	NOISE_FLOOR_OFFSET 6.0f
#define	SBR_INIT_VLC_STATIC(num, size)
#define	SBR_VLC_ROW(name) { name ## _codes, name ## _bits, sizeof(name ## _codes), sizeof(name ## _codes[0]) }
Enumerations
enum	{ T_HUFFMAN_ENV_1_5DB, F_HUFFMAN_ENV_1_5DB, T_HUFFMAN_ENV_BAL_1_5DB, F_HUFFMAN_ENV_BAL_1_5DB, T_HUFFMAN_ENV_3_0DB, F_HUFFMAN_ENV_3_0DB, T_HUFFMAN_ENV_BAL_3_0DB, F_HUFFMAN_ENV_BAL_3_0DB, T_HUFFMAN_NOISE_3_0DB, T_HUFFMAN_NOISE_BAL_3_0DB }
	SBR VLC tables. More...
enum	{ FIXFIX, FIXVAR, VARFIX, VARVAR }
	bs_frame_class - frame class of current SBR frame (14496-3 sp04 p98) More...
enum	{ EXTENSION_ID_PS = 2 }
Functions
av_cold void	ff_aac_sbr_init (void)
	Initialize SBR.
static void	sbr_turnoff (SpectralBandReplication *sbr)
	Places SBR in pure upsampling mode.
av_cold void	ff_aac_sbr_ctx_init (AACContext ac, SpectralBandReplication sbr)
	Initialize one SBR context.
av_cold void	ff_aac_sbr_ctx_close (SpectralBandReplication *sbr)
	Close one SBR context.
static int	qsort_comparison_function_int16 (const void a, const void b)
static int	in_table_int16 (const int16_t *table, int last_el, int16_t needle)
static void	sbr_make_f_tablelim (SpectralBandReplication *sbr)
	Limiter Frequency Band Table (14496-3 sp04 p198).
static unsigned int	read_sbr_header (SpectralBandReplication sbr, GetBitContext gb)
static int	array_min_int16 (const int16_t *array, int nel)
static void	make_bands (int16_t *bands, int start, int stop, int num_bands)
static int	check_n_master (AVCodecContext *avctx, int n_master, int bs_xover_band)
static int	sbr_make_f_master (AACContext ac, SpectralBandReplication sbr, SpectrumParameters *spectrum)
	Master Frequency Band Table (14496-3 sp04 p194).
static int	sbr_hf_calc_npatches (AACContext ac, SpectralBandReplication sbr)
	High Frequency Generation - Patch Construction (14496-3 sp04 p216 fig. 4.46).
static int	sbr_make_f_derived (AACContext ac, SpectralBandReplication sbr)
	Derived Frequency Band Tables (14496-3 sp04 p197).
static av_always_inline void	get_bits1_vector (GetBitContext gb, uint8_t vec, int elements)
static int	read_sbr_grid (AACContext ac, SpectralBandReplication sbr, GetBitContext gb, SBRData ch_data)
static void	copy_sbr_grid (SBRData dst, const SBRData src)
static void	read_sbr_dtdf (SpectralBandReplication sbr, GetBitContext gb, SBRData *ch_data)
	Read how the envelope and noise floor data is delta coded.
static void	read_sbr_invf (SpectralBandReplication sbr, GetBitContext gb, SBRData *ch_data)
	Read inverse filtering data.
static void	read_sbr_envelope (SpectralBandReplication sbr, GetBitContext gb, SBRData *ch_data, int ch)
static void	read_sbr_noise (SpectralBandReplication sbr, GetBitContext gb, SBRData *ch_data, int ch)
static void	read_sbr_extension (AACContext ac, SpectralBandReplication sbr, GetBitContext gb, int bs_extension_id, int num_bits_left)
static int	read_sbr_single_channel_element (AACContext ac, SpectralBandReplication sbr, GetBitContext *gb)
static int	read_sbr_channel_pair_element (AACContext ac, SpectralBandReplication sbr, GetBitContext *gb)
static unsigned int	read_sbr_data (AACContext ac, SpectralBandReplication sbr, GetBitContext *gb, int id_aac)
static void	sbr_reset (AACContext ac, SpectralBandReplication sbr)
int	ff_decode_sbr_extension (AACContext ac, SpectralBandReplication sbr, GetBitContext *gb_host, int crc, int cnt, int id_aac)
	Decode Spectral Band Replication extension data; reference: table 4.55.
static void	sbr_dequant (SpectralBandReplication *sbr, int id_aac)
	Dequantization and stereo decoding (14496-3 sp04 p203).
static void	sbr_qmf_analysis (DSPContext dsp, FFTContext mdct, SBRDSPContext sbrdsp, const float in, float *x, float z[320], float W[2][32][32][2])
	Analysis QMF Bank (14496-3 sp04 p206).
static void	sbr_qmf_synthesis (DSPContext dsp, FFTContext mdct, SBRDSPContext sbrdsp, float out, float X[2][38][64], float mdct_buf[2][64], float v0, int v_off, const unsigned int div)
	Synthesis QMF Bank (14496-3 sp04 p206) and Downsampled Synthesis QMF Bank (14496-3 sp04 p206).
static void	sbr_hf_inverse_filter (SBRDSPContext dsp, float(alpha0)[2], float(*alpha1)[2], const float X_low[32][40][2], int k0)
	High Frequency Generation (14496-3 sp04 p214+) and Inverse Filtering (14496-3 sp04 p214) Warning: This routine does not seem numerically stable.
static void	sbr_chirp (SpectralBandReplication sbr, SBRData ch_data)
	Chirp Factors (14496-3 sp04 p214).
static int	sbr_lf_gen (AACContext ac, SpectralBandReplication sbr, float X_low[32][40][2], const float W[2][32][32][2])
	Generate the subband filtered lowband.
static int	sbr_hf_gen (AACContext ac, SpectralBandReplication sbr, float X_high[64][40][2], const float X_low[32][40][2], const float(alpha0)[2], const float(alpha1)[2], const float bw_array[5], const uint8_t *t_env, int bs_num_env)
	High Frequency Generator (14496-3 sp04 p215).
static int	sbr_x_gen (SpectralBandReplication *sbr, float X[2][38][64], const float Y0[38][64][2], const float Y1[38][64][2], const float X_low[32][40][2], int ch)
	Generate the subband filtered lowband.
static int	sbr_mapping (AACContext ac, SpectralBandReplication sbr, SBRData *ch_data, int e_a[2])
	High Frequency Adjustment (14496-3 sp04 p217) and Mapping (14496-3 sp04 p217).
static void	sbr_env_estimate (float(e_curr)[48], float X_high[64][40][2], SpectralBandReplication sbr, SBRData *ch_data)
	Estimation of current envelope (14496-3 sp04 p218).
static void	sbr_gain_calc (AACContext ac, SpectralBandReplication sbr, SBRData *ch_data, const int e_a[2])
	Calculation of levels of additional HF signal components (14496-3 sp04 p219) and Calculation of gain (14496-3 sp04 p219).
static void	sbr_hf_assemble (float Y1[38][64][2], const float X_high[64][40][2], SpectralBandReplication sbr, SBRData ch_data, const int e_a[2])
	Assembling HF Signals (14496-3 sp04 p220).
void	ff_sbr_apply (AACContext ac, SpectralBandReplication sbr, int id_aac, float L, float R)
	Apply one SBR element to one AAC element.
Variables
static VLC	vlc_sbr [10]
static const int8_t	vlc_sbr_lav [10]
static const float	zero64 [64]
static const int8_t	ceil_log2 []
	ceil(log2(index+1))