#include <stdint.h>
#include <string.h>
#include "libavutil/common.h"
#include "libavutil/intmath.h"
#include "audiodsp.h"
#include "g729.h"
#include "g729postfilter.h"
#include "celp_math.h"
#include "acelp_filters.h"
#include "acelp_vectors.h"
#include "celp_filters.h"
#include "mathops.h"

Macros
#define	FRAC_BITS 15

Functions
static void	residual_filter (int16_t out, const int16_t filter_coeffs, const int16_t *in, int subframe_size)
	Residual signal calculation (4.2.1 if G.729) More...

static int16_t	long_term_filter (AudioDSPContext adsp, int pitch_delay_int, const int16_t residual, int16_t *residual_filt, int subframe_size)
	long-term postfilter (4.2.1) More...

static int16_t	get_tilt_comp (AudioDSPContext adsp, int16_t lp_gn, const int16_t lp_gd, int16_t speech, int subframe_size)
	Calculate reflection coefficient for tilt compensation filter (4.2.3). More...

static int16_t	apply_tilt_comp (int16_t out, int16_t res_pst, int refl_coeff, int subframe_size, int16_t ht_prev_data)
	Apply tilt compensation filter (4.2.3). More...

void	ff_g729_postfilter (AudioDSPContext adsp, int16_t ht_prev_data, int voicing, const int16_t lp_filter_coeffs, int pitch_delay_int, int16_t residual, int16_t res_filter_data, int16_t pos_filter_data, int16_t speech, int subframe_size)
	Signal postfiltering (4.2) More...

int16_t	ff_g729_adaptive_gain_control (int gain_before, int gain_after, int16_t *speech, int subframe_size, int16_t gain_prev)
	Adaptive gain control (4.2.4) More...

Variables
static const int16_t	ff_g729_interp_filt_short [(ANALYZED_FRAC_DELAYS+1) *SHORT_INT_FILT_LEN]
	short interpolation filter (of length 33, according to spec) for computing signal with non-integer delay More...

static const int16_t	ff_g729_interp_filt_long [(ANALYZED_FRAC_DELAYS+1) *LONG_INT_FILT_LEN]
	long interpolation filter (of length 129, according to spec) for computing signal with non-integer delay More...

static const int16_t	formant_pp_factor_num_pow [10]
	formant_pp_factor_num_pow[i] = FORMANT_PP_FACTOR_NUM^(i+1) More...

static const int16_t	formant_pp_factor_den_pow [10]
	formant_pp_factor_den_pow[i] = FORMANT_PP_FACTOR_DEN^(i+1) More...

Macro Definition Documentation

◆ FRAC_BITS

#define FRAC_BITS 15

Definition at line 36 of file g729postfilter.c.

Function Documentation

◆ residual_filter()

static void residual_filter	(	int16_t *	out,
		const int16_t *	filter_coeffs,
		const int16_t *	in,
		int	subframe_size
	)

static

Residual signal calculation (4.2.1 if G.729)

Parameters

out	[out] output data filtered through A(z/FORMANT_PP_FACTOR_NUM)
filter_coeffs	(3.12) A(z/FORMANT_PP_FACTOR_NUM) filter coefficients
in	input speech data to process
subframe_size	size of one subframe

Note: in buffer must contain 10 items of previous speech data before top of the buffer

Remarks: It is safe to pass the same buffer for input and output.

Definition at line 89 of file g729postfilter.c.

Referenced by ff_g729_postfilter().

◆ long_term_filter()

static int16_t long_term_filter	(	AudioDSPContext *	adsp,
		int	pitch_delay_int,
		const int16_t *	residual,
		int16_t *	residual_filt,
		int	subframe_size
	)

static

long-term postfilter (4.2.1)

Parameters

dsp	initialized DSP context
pitch_delay_int	integer part of the pitch delay in the first subframe
residual	filtering input data
residual_filt	[out] speech signal with applied A(z/FORMANT_PP_FACTOR_NUM) filter
subframe_size	size of subframe

Returns: 0 if long-term prediction gain is less than 3dB, 1 - otherwise

Definition at line 113 of file g729postfilter.c.

Referenced by ff_g729_postfilter().

◆ get_tilt_comp()

static int16_t get_tilt_comp	(	AudioDSPContext *	adsp,
		int16_t *	lp_gn,
		const int16_t *	lp_gd,
		int16_t *	speech,
		int	subframe_size
	)

static

Calculate reflection coefficient for tilt compensation filter (4.2.3).

Parameters

dsp	initialized DSP context
lp_gn	(3.12) coefficients of A(z/FORMANT_PP_FACTOR_NUM) filter
lp_gd	(3.12) coefficients of A(z/FORMANT_PP_FACTOR_DEN) filter
speech	speech to update
subframe_size	size of subframe

Returns: (3.12) reflection coefficient

Remarks: The routine also calculates the gain term for the short-term filter (gf) and multiplies the speech data by 1/gf.

Note: All members of lp_gn, except 10-19 must be equal to zero.

Definition at line 430 of file g729postfilter.c.

Referenced by ff_g729_postfilter().

◆ apply_tilt_comp()

static int16_t apply_tilt_comp	(	int16_t *	out,
		int16_t *	res_pst,
		int	refl_coeff,
		int	subframe_size,
		int16_t	ht_prev_data
	)

static

Apply tilt compensation filter (4.2.3).

Parameters

res_pst	[in/out] residual signal (partially filtered)
k1	(3.12) reflection coefficient
subframe_size	size of subframe
ht_prev_data	previous data for 4.2.3, equation 86

Returns: new value for ht_prev_data

Definition at line 482 of file g729postfilter.c.

Referenced by ff_g729_postfilter().

◆ ff_g729_postfilter()

void ff_g729_postfilter	(	AudioDSPContext *	adsp,
		int16_t *	ht_prev_data,
		int *	voicing,
		const int16_t *	lp_filter_coeffs,
		int	pitch_delay_int,
		int16_t *	residual,
		int16_t *	res_filter_data,
		int16_t *	pos_filter_data,
		int16_t *	speech,
		int	subframe_size
	)

Signal postfiltering (4.2)

Parameters

dsp	initialized DSP context
ht_prev_data	[in/out] (Q12) pointer to variable receiving tilt compensation filter data from previous subframe
voicing	[in/out] (Q0) pointer to variable receiving voicing decision
lp_filter_coeffs	(Q12) LP filter coefficients
pitch_delay_int	integer part of the pitch delay
residual	[in/out] (Q0) residual signal buffer (used in long-term postfilter)
res_filter_data	[in/out] (Q0) speech data of previous subframe
pos_filter_data	[in/out] (Q0) previous speech data for short-term postfilter
speech	[in/out] (Q0) signal buffer
subframe_size	size of subframe

Filtering has the following stages: Long-term postfilter (4.2.1) Short-term postfilter (4.2.2). Tilt-compensation (4.2.3)

Definition at line 520 of file g729postfilter.c.

Referenced by decode_frame().

◆ ff_g729_adaptive_gain_control()

int16_t ff_g729_adaptive_gain_control	(	int	gain_before,
		int	gain_after,
		int16_t *	speech,
		int	subframe_size,
		int16_t	gain_prev
	)

Adaptive gain control (4.2.4)

Parameters

gain_before	gain of speech before applying postfilters
gain_after	gain of speech after applying postfilters
speech	[in/out] signal buffer
subframe_size	length of subframe
gain_prev	(3.12) previous value of gain coefficient

Returns: (3.12) last value of gain coefficient

Definition at line 581 of file g729postfilter.c.

Referenced by decode_frame().

Variable Documentation

◆ ff_g729_interp_filt_short

const int16_t ff_g729_interp_filt_short[(ANALYZED_FRAC_DELAYS+1) *SHORT_INT_FILT_LEN]

static

Initial value:

= {
      0, 31650, 28469, 23705, 18050, 12266,  7041,  2873,
      0, -1597, -2147, -1992, -1492,  -933,  -484,  -188,
}

short interpolation filter (of length 33, according to spec) for computing signal with non-integer delay

Definition at line 43 of file g729postfilter.c.

Referenced by long_term_filter().

◆ ff_g729_interp_filt_long

const int16_t ff_g729_interp_filt_long[(ANALYZED_FRAC_DELAYS+1) *LONG_INT_FILT_LEN]

static

Initial value:

= {
   0, 31915, 29436, 25569, 20676, 15206,  9639,  4439,
   0, -3390, -5579, -6549, -6414, -5392, -3773, -1874,
   0,  1595,  2727,  3303,  3319,  2850,  2030,  1023,
   0,  -887, -1527, -1860, -1876, -1614, -1150,  -579,
   0,   501,   859,  1041,  1044,   892,   631,   315,
   0,  -266,  -453,  -543,  -538,  -455,  -317,  -156,
   0,   130,   218,   258,   253,   212,   147,    72,
   0,   -59,  -101,  -122,  -123,  -106,   -77,   -40,
}

long interpolation filter (of length 129, according to spec) for computing signal with non-integer delay

Definition at line 52 of file g729postfilter.c.

Referenced by long_term_filter().

◆ formant_pp_factor_num_pow

const int16_t formant_pp_factor_num_pow[10]

static

Initial value:

= {
  
  18022, 9912, 5451, 2998, 1649, 907, 499, 274, 151, 83
}

formant_pp_factor_num_pow[i] = FORMANT_PP_FACTOR_NUM^(i+1)

Definition at line 66 of file g729postfilter.c.

Referenced by ff_g729_postfilter().

◆ formant_pp_factor_den_pow

const int16_t formant_pp_factor_den_pow[10]

static

Initial value:

= {
  
  22938, 16057, 11240, 7868, 5508, 3856, 2699, 1889, 1322, 925
}

formant_pp_factor_den_pow[i] = FORMANT_PP_FACTOR_DEN^(i+1)

Definition at line 74 of file g729postfilter.c.

Referenced by ff_g729_postfilter().

Macros

Functions

Variables

Macro Definition Documentation

◆ FRAC_BITS

Function Documentation

◆ residual_filter()

◆ long_term_filter()

◆ get_tilt_comp()

◆ apply_tilt_comp()

◆ ff_g729_postfilter()

◆ ff_g729_adaptive_gain_control()

Variable Documentation

◆ ff_g729_interp_filt_short

◆ ff_g729_interp_filt_long

◆ formant_pp_factor_num_pow

◆ formant_pp_factor_den_pow