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+/*---------------------------------------------------------------------------*\
+
+ 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 "interp.h"
+
+#include <assert.h>
+#include <math.h>
+#include <stdio.h>
+#include <string.h>
+
+#include "defines.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 described 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 described 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];
+}
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