/*====================================================================================
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 agc2( const float *sig_in, float *sig_out,const short l_trm );
/*---------------------------------------------------------------------*
* enhancer()
*
* Enhancement of the excitation signal before synthesis
*---------------------------------------------------------------------*/
void enhancer(
const short codec_mode, /* i : flag indicating Codec Mode */
const long core_brate, /* i : core bitrate */
const short cbk_index, /* i : */
const short Opt_AMR_WB, /* i : flag indicating AMR-WB IO mode */
const short coder_type, /* i : coding type */
const short L_frame, /* i : frame size */
const float voice_fac, /* i : subframe voicing estimation */
const float stab_fac, /* i : LP filter stablility measure */
const float norm_gain_code, /* i : normalized innovative cb. gain */
const float gain_inov, /* i : gain of the unscaled innovation */
float *gc_threshold, /* i/o: code threshold */
float *code, /* i/o: innovation */
float *pt_exc2, /* i/o: adapt. excitation/total exc. */
const float gain_pit, /* i : Quantized pitch gain */
float *dispMem /* i/o: Phase dispersion algorithm memory */
)
{
float tmp, gain_code, new_norm_gain_code, fac;
short i;
float pit_sharp;
float excp[L_SUBFR];
pit_sharp = gain_pit;
/*-----------------------------------------------------------------*
* Phase dispersion
*
* Enhance noise at low bit rates
*-----------------------------------------------------------------*/
i = 2; /* no dispersion */
if( Opt_AMR_WB )
{
if ( core_brate <= ACELP_6k60 )
{
i = 0; /* high dispersion */
}
else if ( core_brate <= ACELP_8k85 )
{
i = 1; /* low dispersion */
}
}
else if( codec_mode == MODE1 && coder_type != UNVOICED )
{
if ( core_brate <= ACELP_7k20 )
{
i = 0; /* high dispersion */
}
else if ( ( coder_type == GENERIC || coder_type == TRANSITION || coder_type == AUDIO || coder_type == INACTIVE ) && core_brate <= ACELP_9k60 )
{
i = 1; /* low dispersion */
}
}
else if( codec_mode == MODE2 )
{
if( ((coder_type!=VOICED) && cbk_index<=4) || ((coder_type==UNVOICED) && L_frame==L_FRAME && cbk_index<=12) || ((coder_type==UNVOICED) && L_frame==L_FRAME16k && cbk_index<=16))
{
i = 0; /* high dispersion */
}
else if( ((coder_type!=VOICED) && L_frame==L_FRAME && cbk_index<=9) || ((coder_type!=VOICED) && L_frame==L_FRAME16k && cbk_index<=12) )
{
i = 1; /* low dispersion */
}
}
phase_dispersion( norm_gain_code, gain_pit, code, i, dispMem );
/*------------------------------------------------------------
* Noise enhancer
*
* Enhance excitation on noise (modify code gain). If signal is noisy and LPC filter is stable,
* move code gain 1.5 dB towards its threshold. This decreases by 3 dB noise energy variation.
*-----------------------------------------------------------*/
if ( norm_gain_code < *gc_threshold )
{
new_norm_gain_code = (float)(norm_gain_code * 1.19f);
if ( new_norm_gain_code > *gc_threshold )
{
new_norm_gain_code = *gc_threshold;
}
}
else
{
new_norm_gain_code = (float)(norm_gain_code / 1.19f);
if ( new_norm_gain_code < *gc_threshold )
{
new_norm_gain_code = *gc_threshold;
}
}
*gc_threshold = new_norm_gain_code;
/* calculate new code gain */
fac = stab_fac * (0.5f * (1.0f - voice_fac)); /* 1 = unvoiced, 0 = voiced */
gain_code = fac * new_norm_gain_code + (1.0f - fac) * norm_gain_code;
gain_code *= gain_inov;
for (i=0; i<L_SUBFR; i++)
{
code[i] *= gain_code;
}
/*------------------------------------------------------------*
* Pitch enhancer
*
* Enhance excitation on voiced (HP filtering of code). On voiced signal, filter code by a smooth HP
* filter to decrease the energy of code at low frequency
*------------------------------------------------------------*/
if( !Opt_AMR_WB && codec_mode == MODE1 && coder_type == UNVOICED )
{
mvr2r( code, pt_exc2, L_SUBFR );
}
else
{
if ( Opt_AMR_WB && ( core_brate == ACELP_8k85 || core_brate == ACELP_6k60 ) )
{
pit_sharp = gain_pit;
if( pit_sharp > 1.0 )
{
pit_sharp = 1.0;
}
if ( pit_sharp > 0.5 )
{
for (i = 0; i < L_SUBFR; i++)
{
excp[i] = pt_exc2[i] * pit_sharp * 0.25f;
}
}
}
/*-----------------------------------------------------------------
* Do a simple noncasual "sharpening": effectively an FIR
* filter with coefs [-tmp 1.0 -tmp] where tmp = 0 ... 0.25
* This is applied to code and added to exc2
*-----------------------------------------------------------------*/
if( L_frame == L_FRAME16k )
{
tmp = (float)(0.150f*(1.0f+voice_fac)); /* 0.30=voiced, 0=unvoiced */
}
else
{
tmp = (float)(0.125f * (1.0f + voice_fac)); /* 0.25=voiced, 0=unvoiced */
}
pt_exc2[0] += code[0] - (tmp * code[1]);
for ( i=1; i<L_SUBFR-1; i++ )
{
pt_exc2[i] += code[i] - (tmp*code[i-1]) - (tmp*code[i+1]);
}
pt_exc2[L_SUBFR-1] += code[L_SUBFR-1] - (tmp*code[L_SUBFR-2]);
if ( Opt_AMR_WB && ( core_brate == ACELP_8k85 || core_brate == ACELP_6k60 ) )
{
if ( pit_sharp > 0.5f )
{
for (i = 0; i < L_SUBFR; i++)
{
excp[i] += pt_exc2[i];
}
agc2( pt_exc2, excp, L_SUBFR );
mvr2r( excp, pt_exc2, L_SUBFR );
}
}
}
return;
}
/*-----------------------------------------------------------------------*
* agc2()
*
* Adaptive gain control
*-----------------------------------------------------------------------*/
static void agc2(
const float *sig_in, /* i : postfilter input signal */
float *sig_out, /* i/o: postfilter output signal */
const short l_trm /* i : subframe size */
)
{
short i;
float gain_in, gain_out;
float g0, gain;
gain_out = 0.0f;
for(i=0; i<l_trm; i++)
{
gain_out += sig_out[i]*sig_out[i];
}
if (gain_out == 0.0f)
{
return;
}
gain_in = 0.0f;
for(i=0; i<l_trm; i++)
{
gain_in += sig_in[i]*sig_in[i];
}
if (gain_in == 0.0f)
{
g0 = 0.0f;
}
else
{
g0 = (float) sqrt(gain_in / gain_out);
}
gain = g0;
for (i=0; i<l_trm; i++)
{
sig_out[i] *= gain;
}
return;
}