aacsbr_fixed.c File Reference

AAC Spectral Band Replication decoding functions (fixed-point) Note: Rounding-to-nearest used unless otherwise stated. More...

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

Go to the source code of this file.

Macros
#define	USE_FIXED   1

Functions
static void	aacsbr_func_ptr_init (AACSBRContext *c)
static int	fixed_log (int x)
static int	fixed_exp (int x)
static void	make_bands (int16_t *bands, int start, int stop, int num_bands)
static void	sbr_dequant (SpectralBandReplication *sbr, int id_aac)
	Dequantization and stereo decoding (14496-3 sp04 p203) More...
static void	sbr_hf_inverse_filter (SBRDSPContext *dsp, int(*alpha0)[2], int(*alpha1)[2], const int 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. More...
static void	sbr_chirp (SpectralBandReplication *sbr, SBRData *ch_data)
	Chirp Factors (14496-3 sp04 p214) More...
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) More...
static void	sbr_hf_assemble (int Y1[38][64][2], const int X_high[64][40][2], SpectralBandReplication *sbr, SBRData *ch_data, const int e_a[2])
	Assembling HF Signals (14496-3 sp04 p220) More...

Variables
static VLC	vlc_sbr [10]
static const int	CONST_LN2 = Q31(0.6931471806/256)
static const int	CONST_RECIP_LN2 = Q31(0.7213475204)
static const int	CONST_076923 = Q31(0.76923076923076923077f)
static const int	fixed_log_table [10]
static const int	fixed_exp_table [7]

Detailed Description

AAC Spectral Band Replication decoding functions (fixed-point) Note: Rounding-to-nearest used unless otherwise stated.

Author

Robert Swain ( rob opendot cl )

Stanislav Ocovaj ( stanislav.ocovaj imgtec com )

Definition in file aacsbr_fixed.c.

Macro Definition Documentation

USE_FIXED

#define USE_FIXED   1

Definition at line 57 of file aacsbr_fixed.c.

Function Documentation

aacsbr_func_ptr_init()

static void aacsbr_func_ptr_init ( AACSBRContext *  c )

static

fixed_log()

static int fixed_log ( int  x )

static

Definition at line 87 of file aacsbr_fixed.c.

Referenced by make_bands(), sbr_make_f_derived(), and sbr_make_f_master().

fixed_exp()

static int fixed_exp ( int  x )

static

Definition at line 112 of file aacsbr_fixed.c.

Referenced by encode_block(), and make_bands().

make_bands()

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

static

Definition at line 127 of file aacsbr_fixed.c.

sbr_dequant()

static void sbr_dequant ( SpectralBandReplication *  sbr, int  id_aac  )

static

Dequantization and stereo decoding (14496-3 sp04 p203)

Definition at line 154 of file aacsbr_fixed.c.

sbr_hf_inverse_filter()

static void sbr_hf_inverse_filter ( SBRDSPContext *  dsp, int(*)  alpha0[2], int(*)  alpha1[2], const int  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 236 of file aacsbr_fixed.c.

sbr_chirp()

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

static

Chirp Factors (14496-3 sp04 p214)

Definition at line 370 of file aacsbr_fixed.c.

sbr_gain_calc()

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 400 of file aacsbr_fixed.c.

sbr_hf_assemble()

static void sbr_hf_assemble ( int  Y1[38][64][2], const int  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 489 of file aacsbr_fixed.c.

Variable Documentation

vlc_sbr

VLC vlc_sbr[10]

static

Definition at line 75 of file aacsbr_fixed.c.

CONST_LN2

const int CONST_LN2 = Q31(0.6931471806/256)

static

Definition at line 77 of file aacsbr_fixed.c.

Referenced by make_bands().

CONST_RECIP_LN2

const int CONST_RECIP_LN2 = Q31(0.7213475204)

static

Definition at line 78 of file aacsbr_fixed.c.

Referenced by sbr_make_f_derived(), and sbr_make_f_master().

CONST_076923

const int CONST_076923 = Q31(0.76923076923076923077f)

static

Definition at line 79 of file aacsbr_fixed.c.

Referenced by sbr_make_f_master().

fixed_log_table

const int fixed_log_table[10]

static

Initial value:

=
{
    Q31(1.0/2), Q31(1.0/3), Q31(1.0/4), Q31(1.0/5), Q31(1.0/6),
    Q31(1.0/7), Q31(1.0/8), Q31(1.0/9), Q31(1.0/10), Q31(1.0/11)
}

Definition at line 81 of file aacsbr_fixed.c.

Referenced by fixed_log().

fixed_exp_table

const int fixed_exp_table[7]

static

Initial value:

=
{
    Q31(1.0/2), Q31(1.0/6), Q31(1.0/24), Q31(1.0/120),
    Q31(1.0/720), Q31(1.0/5040), Q31(1.0/40320)
}

Definition at line 106 of file aacsbr_fixed.c.

Referenced by fixed_exp().