/*====================================================================================
EVS Codec 3GPP TS26.443 Jun 30, 2015. Version CR 26.443-0006
====================================================================================*/
#include <math.h>
#include "options.h"
#include "cnst.h"
#include "prot.h"
#include "rom_com.h"
/*---------------------------------------------------------------------*
* Local functions
*---------------------------------------------------------------------*/
static void hp400_12k8(float signal[], const short lg, float mem[]);
static void filt_6k_8k(float signal[], const short lg, float mem[]);
/*---------------------------------------------------------------------*
* hf_cod_init()
*
*
*---------------------------------------------------------------------*/
void hf_cod_init(
float *mem_hp400_enc, /* o: memory of hp 400 Hz filter */
float *mem_hf1_enc, /* o: HF band-pass filter memory */
float *mem_syn_hf_enc, /* o: HF synthesis memory */
float *mem_hf2_enc, /* o: HF band-pass filter memory */
float *gain_alpha /* o: smoothing gain for transitions between active and inactive frames */
)
{
set_f( mem_hp400_enc, 0, 4 );
set_f( mem_hf1_enc, 0, 2*L_FILT16k );
set_f( mem_syn_hf_enc, 0, M16k );
set_f( mem_hf2_enc, 0, 2*L_FILT16k );
*gain_alpha = 1.0;
return;
}
/*---------------------------------------------------------------------*
* hf_cod()
*
*
*---------------------------------------------------------------------*/
void hf_cod(
const long core_brate, /* i : core bitrate */
const float *speech16k, /* i : original speech at 16 kHz */
const float Aq[], /* i : quantized Aq */
const float exc[], /* i : excitation at 12.8 kHz */
float synth[], /* i : 12.8kHz synthesis signal */
short *seed2_enc, /* i/o: random seed for HF noise gen */
float *mem_hp400_enc, /* i/o: memory of hp 400 Hz filter */
float *mem_syn_hf_enc, /* i/o: HF synthesis memory */
float *mem_hf1_enc, /* i/o: HF band-pass filter memory */
float *mem_hf2_enc, /* i/o: HF band-pass filter memory */
const short *dtxHangoverCount,
float *gain_alpha, /* i/o: smoothing gain for transitions between active and inactive frames */
short *hf_gain /* o : HF gain to be transmitted to decoder */
)
{
short i;
float ener_hf, ener_exc, ener_input, fac, HF_syn[L_SUBFR16k], tmp, ener, scale;
float Ap[M16k+1];
float HF_SP[L_SUBFR16k];
float HF_est_gain;
float HF_calc_gain;
float HF_corr_gain;
short HF_gain_ind;
float dist_min, dist;
float HF[L_SUBFR16k]; /* o : HF excitation */
/* Original speech signal as reference for high band gain quantisation */
for (i = 0; i < L_SUBFR16k; i++)
{
HF_SP[i] = speech16k[i];
}
/*-----------------------------------------------------------------*
* generate white noise vector
*-----------------------------------------------------------------*/
for (i=0; i<L_SUBFR16k; i++)
{
HF[i] = (float)own_random(seed2_enc);
}
/*-----------------------------------------------------------------*
* calculate energy scaling factor so that white noise would have the
* same energy as exc12k8
*-----------------------------------------------------------------*/
ener_exc = 0.01f;
for (i=0; i<L_SUBFR; i++)
{
ener_exc += exc[i]*exc[i];
}
ener_hf = 0.01f;
for (i=0; i<L_SUBFR16k; i++)
{
ener_hf += HF[i]*HF[i];
}
scale = (float)(sqrt(ener_exc/ener_hf));
for (i=0; i<L_SUBFR16k; i++)
{
HF[i] *= scale;
}
/*-----------------------------------------------------------------*
* calculate energy scaling factor to respect tilt of synth12k8
* (tilt: 1=voiced, -1=unvoiced)
*-----------------------------------------------------------------*/
hp400_12k8( synth, L_SUBFR, mem_hp400_enc );
ener = 0.001f;
tmp = 0.001f;
for (i=1; i<L_SUBFR; i++)
{
ener += synth[i]*synth[i]; /* ener = r[0] */
tmp += synth[i]*synth[i-1]; /* tmp = r[1] */
}
fac = tmp/ener;
HF_est_gain = (float)(1.0f - fac);
if( core_brate == SID_1k75 || core_brate == FRAME_NO_DATA )
{
/* emphasize HF noise in CNG */
HF_est_gain *= 1.25f; /* full alignment with G.722 and AMR-WB */
}
if (HF_est_gain < 0.1f)
{
HF_est_gain = 0.1f;
}
if (HF_est_gain > 1.0f) /* this condition is not in G.722.2, but in AMR-WB!*/
{
HF_est_gain = 1.0f;
}
/*-----------------------------------------------------------------*
* synthesis of noise: 4.8kHz..5.6kHz --> 6kHz..7kHz
*-----------------------------------------------------------------*/
weight_a( Aq, Ap, 0.6f, M );
syn_filt( Ap, M, HF, HF_syn, L_SUBFR16k, mem_syn_hf_enc + (M16k - M), 1 );
/*-----------------------------------------------------------------*
* high pass filtering (0.9375ms of delay = 15 samples@16k)
*-----------------------------------------------------------------*/
filt_6k_8k( HF_syn, L_SUBFR16k, mem_hf1_enc );
/* filtering of the original signal */
filt_6k_8k( HF_SP, L_SUBFR16k, mem_hf2_enc );
/* check the gain difference */
ener_input = 0.01f;
ener_hf = 0.01f;
for ( i=0; i<L_SUBFR16k; i++ )
{
ener_input += HF_SP[i]*HF_SP[i];
ener_hf += HF_syn[i]*HF_syn[i];
}
HF_calc_gain = (float)sqrt(ener_input/ener_hf);
/* set energy of HF synthesis to energy of original HF:
cross-fade between HF levels in active and inactive frame in hangover period */
*gain_alpha *= (float)(10-(*dtxHangoverCount))/7.0f;
if ((10-(*dtxHangoverCount)) > 6)
{
*gain_alpha = 1.0f;
}
HF_corr_gain = (*gain_alpha)*HF_calc_gain + (1.0f-(*gain_alpha))*HF_est_gain;
HF_corr_gain /= 2.0f; /* to stay in alignlent with AMR-WB legacy decoder where decoded gain is multiplied by 2 */
/* Quantize the correction gain */
dist_min = 100000.0f;
HF_gain_ind = 0;
for ( i = 0; i < 16; i++ )
{
dist = (HF_corr_gain-HP_gain[i])*(HF_corr_gain-HP_gain[i]);
if (dist_min > dist)
{
dist_min = dist;
HF_gain_ind = i;
}
}
*hf_gain = HF_gain_ind;
return;
}
/*-----------------------------------------------------------------------*
* Function hp400_12k8() *
* *
* 2nd order Cheb2 high pass filter with cut off frequency at 400 Hz. *
* Optimized for fixed-point to get the following frequency response : *
* *
* frequency : 0Hz 100Hz 200Hz 300Hz 400Hz 630Hz 1.5kHz 3kHz *
* dB loss : -infdB -30dB -20dB -10dB -3dB +6dB +1dB 0dB *
* *
* Algorithm : *
* *
* y[i] = b[0]*x[i] + b[1]*x[i-1] + b[2]*x[i-2] *
* + a[1]*y[i-1] + a[2]*y[i-2]; *
* *
* short b[3] = {3660, -7320, 3660}; in Q12 *
* short a[3] = {4096, 7320, -3540}; in Q12 *
* *
* float --> b[3] = {0.893554687, -1.787109375, 0.893554687}; *
* a[3] = {1.000000000, 1.787109375, -0.864257812}; *
*-----------------------------------------------------------------------*/
static void hp400_12k8(
float signal[], /* i/o: signal */
const short lg, /* i : lenght of signal */
float mem[] /* i/o: filter memory [4] */
)
{
short i;
float x0, x1, x2;
float yy0, yy1, y2;
yy1 = mem[0];
y2 = mem[1];
x0 = mem[2];
x1 = mem[3];
for(i=0; i<lg; i++)
{
x2 = x1;
x1 = x0;
x0 = signal[i];
yy0 = yy1*a_hp400[1] + y2*a_hp400[2] + x0*b_hp400[0] + x1*b_hp400[1] + x2*b_hp400[2];
signal[i] = yy0;
y2 = yy1;
yy1 = yy0;
}
mem[0] = yy1;
mem[1] = y2;
mem[2] = x0;
mem[3] = x1;
return;
}
/*-------------------------------------------------------------------*
* filt_6k_7k:
*
* 15th order band pass 6kHz to 7kHz FIR filter.
*
* frequency :4kHz 5kHz 5.5kHz 6kHz 6.5kHz 7kHz 7.5kHz 8kHz
* dB loss : -60dB -45dB -13dB -3dB 0dB -3dB -13dB -45dB
* (gain=4.0)
*-------------------------------------------------------------------*/
static void filt_6k_8k(
float signal[], /* i/o: signal */
const short lg, /* i : signal length */
float mem[] /* i/o: filter memory */
)
{
short i, j;
float s, x[L_FRAME48k/NB_SUBFR+(L_FIR-1)];
for( i=0; i<(L_FIR-1); i++ )
{
x[i] = mem[i];
}
for(i=0; i<lg; i++)
{
x[i+(L_FIR-1)] = signal[i];
}
for(i=0; i<lg; i++)
{
s = 0.0;
for( j=0; j<L_FIR; j++ )
{
s += x[i+j] * fir_6k_8k[j];
}
signal[i] = (float)(s*1.0f);
}
for(i=0; i<(L_FIR-1); i++)
{
mem[i] = x[i+lg];
}
return;
}