UHSDR/UHSDR-active-devel/mchf-eclipse/drivers/freedv/interp.c
2022-11-08 16:13:55 +01:00

332 lines
9.6 KiB
C

/*---------------------------------------------------------------------------*\
FILE........: interp.c
AUTHOR......: David Rowe
DATE CREATED: 9/10/09
Interpolation of 20ms frames to 10ms frames.
\*---------------------------------------------------------------------------*/
/*
Copyright (C) 2009 David Rowe
All rights reserved.
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU Lesser General Public License version 2.1, as
published by the Free Software Foundation. This program is
distributed in the hope that it will be useful, but WITHOUT ANY
WARRANTY; without even the implied warranty of MERCHANTABILITY or
FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
License for more details.
You should have received a copy of the GNU Lesser General Public License
along with this program; if not, see <http://www.gnu.org/licenses/>.
*/
#include <assert.h>
#include <math.h>
#include <string.h>
#include <stdio.h>
#include "defines.h"
#include "interp.h"
#include "lsp.h"
#include "quantise.h"
float sample_log_amp(MODEL *model, float w);
#if 0
/*---------------------------------------------------------------------------*\
FUNCTION....: interp()
AUTHOR......: David Rowe
DATE CREATED: 22/8/10
Given two frames decribed by model parameters 20ms apart, determines
the model parameters of the 10ms frame between them. Assumes
voicing is available for middle (interpolated) frame. Outputs are
amplitudes and Wo for the interpolated frame.
This version can interpolate the amplitudes between two frames of
different Wo and L.
This version works by log linear interpolation, but listening tests
showed it creates problems in background noise, e.g. hts2a and mmt1.
When this function is used (--dec mode) bg noise appears to be
amplitude modulated, and gets louder. The interp_lsp() function
below seems to do a better job.
\*---------------------------------------------------------------------------*/
void interpolate(
MODEL *interp, /* interpolated model params */
MODEL *prev, /* previous frames model params */
MODEL *next, /* next frames model params */
float Wo_min
)
{
int l;
float w,log_amp;
/* Wo depends on voicing of this and adjacent frames */
if (interp->voiced) {
if (prev->voiced && next->voiced)
interp->Wo = (prev->Wo + next->Wo)/2.0;
if (!prev->voiced && next->voiced)
interp->Wo = next->Wo;
if (prev->voiced && !next->voiced)
interp->Wo = prev->Wo;
}
else {
interp->Wo = Wo_min;
}
interp->L = PI/interp->Wo;
/* Interpolate amplitudes using linear interpolation in log domain */
for(l=1; l<=interp->L; l++) {
w = l*interp->Wo;
log_amp = (sample_log_amp(prev, w) + sample_log_amp(next, w))/2.0;
interp->A[l] = powf(10.0, log_amp);
}
}
#endif
/*---------------------------------------------------------------------------*\
FUNCTION....: sample_log_amp()
AUTHOR......: David Rowe
DATE CREATED: 22/8/10
Samples the amplitude envelope at an arbitrary frequency w. Uses
linear interpolation in the log domain to sample between harmonic
amplitudes.
\*---------------------------------------------------------------------------*/
float sample_log_amp(MODEL *model, float w)
{
int m;
float f, log_amp;
assert(w > 0.0); assert (w <= PI);
m = floorf(w/model->Wo + 0.5);
f = (w - m*model->Wo)/w;
assert(f <= 1.0);
if (m < 1) {
log_amp = f*log10f(model->A[1] + 1E-6);
}
else if ((m+1) > model->L) {
log_amp = (1.0-f)*log10f(model->A[model->L] + 1E-6);
}
else {
log_amp = (1.0-f)*log10f(model->A[m] + 1E-6) +
f*log10f(model->A[m+1] + 1E-6);
}
return log_amp;
}
#ifdef NOT_NEEDED
/*---------------------------------------------------------------------------*\
FUNCTION....: interp_lsp()
AUTHOR......: David Rowe
DATE CREATED: 10 Nov 2010
Given two frames decribed by model parameters 20ms apart, determines
the model parameters of the 10ms frame between them. Assumes
voicing is available for middle (interpolated) frame. Outputs are
amplitudes and Wo for the interpolated frame.
This version uses interpolation of LSPs, seems to do a better job
with bg noise.
\*---------------------------------------------------------------------------*/
void interpolate_lsp(
codec2_fft_cfg fft_fwd_cfg,
MODEL *interp, /* interpolated model params */
MODEL *prev, /* previous frames model params */
MODEL *next, /* next frames model params */
float *prev_lsps, /* previous frames LSPs */
float prev_e, /* previous frames LPC energy */
float *next_lsps, /* next frames LSPs */
float next_e, /* next frames LPC energy */
float *ak_interp, /* interpolated aks for this frame */
float *lsps_interp, /* interpolated lsps for this frame */
float Wo_min
)
{
int i;
float e;
float snr;
/* trap corner case where V est is probably wrong */
if (interp->voiced && !prev->voiced && !next->voiced) {
interp->voiced = 0;
}
/* Wo depends on voicing of this and adjacent frames */
if (interp->voiced) {
if (prev->voiced && next->voiced)
interp->Wo = (prev->Wo + next->Wo)/2.0;
if (!prev->voiced && next->voiced)
interp->Wo = next->Wo;
if (prev->voiced && !next->voiced)
interp->Wo = prev->Wo;
}
else {
interp->Wo = Wo_min;
}
interp->L = PI/interp->Wo;
//printf(" interp: prev_v: %d next_v: %d prev_Wo: %f next_Wo: %f\n",
// prev->voiced, next->voiced, prev->Wo, next->Wo);
//printf(" interp: Wo: %1.5f L: %d\n", interp->Wo, interp->L);
/* interpolate LSPs */
for(i=0; i<LPC_ORD; i++) {
lsps_interp[i] = (prev_lsps[i] + next_lsps[i])/2.0;
}
/* Interpolate LPC energy in log domain */
e = powf(10.0, (log10f(prev_e) + log10f(next_e))/2.0);
//printf(" interp: e: %f\n", e);
/* convert back to amplitudes */
lsp_to_lpc(lsps_interp, ak_interp, LPC_ORD);
aks_to_M2(fft_fwd_cfg, ak_interp, LPC_ORD, interp, e, &snr, 0, 0, 1, 1, LPCPF_BETA, LPCPF_GAMMA);
//printf(" interp: ak[1]: %f A[1] %f\n", ak_interp[1], interp->A[1]);
}
#endif
/*---------------------------------------------------------------------------*\
FUNCTION....: interp_Wo()
AUTHOR......: David Rowe
DATE CREATED: 22 May 2012
Interpolates centre 10ms sample of Wo and L samples given two
samples 20ms apart. Assumes voicing is available for centre
(interpolated) frame.
\*---------------------------------------------------------------------------*/
void interp_Wo(
MODEL *interp, /* interpolated model params */
MODEL *prev, /* previous frames model params */
MODEL *next, /* next frames model params */
float Wo_min
)
{
interp_Wo2(interp, prev, next, 0.5, Wo_min);
}
/*---------------------------------------------------------------------------*\
FUNCTION....: interp_Wo2()
AUTHOR......: David Rowe
DATE CREATED: 22 May 2012
Weighted interpolation of two Wo samples.
\*---------------------------------------------------------------------------*/
void interp_Wo2(
MODEL *interp, /* interpolated model params */
MODEL *prev, /* previous frames model params */
MODEL *next, /* next frames model params */
float weight,
float Wo_min
)
{
/* trap corner case where voicing est is probably wrong */
if (interp->voiced && !prev->voiced && !next->voiced) {
interp->voiced = 0;
}
/* Wo depends on voicing of this and adjacent frames */
if (interp->voiced) {
if (prev->voiced && next->voiced)
interp->Wo = (1.0 - weight)*prev->Wo + weight*next->Wo;
if (!prev->voiced && next->voiced)
interp->Wo = next->Wo;
if (prev->voiced && !next->voiced)
interp->Wo = prev->Wo;
}
else {
interp->Wo = Wo_min;
}
interp->L = PI/interp->Wo;
}
/*---------------------------------------------------------------------------*\
FUNCTION....: interp_energy()
AUTHOR......: David Rowe
DATE CREATED: 22 May 2012
Interpolates centre 10ms sample of energy given two samples 20ms
apart.
\*---------------------------------------------------------------------------*/
float interp_energy(float prev_e, float next_e)
{
//return powf(10.0, (log10f(prev_e) + log10f(next_e))/2.0);
return sqrtf(prev_e * next_e); //looks better is math. identical and faster math
}
/*---------------------------------------------------------------------------*\
FUNCTION....: interp_energy2()
AUTHOR......: David Rowe
DATE CREATED: 22 May 2012
Interpolates centre 10ms sample of energy given two samples 20ms
apart.
\*---------------------------------------------------------------------------*/
float interp_energy2(float prev_e, float next_e, float weight)
{
return POW10F((1.0 - weight)*log10f(prev_e) + weight*log10f(next_e));
}
/*---------------------------------------------------------------------------*\
FUNCTION....: interpolate_lsp_ver2()
AUTHOR......: David Rowe
DATE CREATED: 22 May 2012
Weighted interpolation of LSPs.
\*---------------------------------------------------------------------------*/
void interpolate_lsp_ver2(float interp[], float prev[], float next[], float weight, int order)
{
int i;
for(i=0; i<order; i++)
interp[i] = (1.0 - weight)*prev[i] + weight*next[i];
}