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/*
* Copyright (c) 2011 The WebRTC project authors. All Rights Reserved.
*
* Use of this source code is governed by a BSD-style license
* that can be found in the LICENSE file in the root of the source
* tree. An additional intellectual property rights grant can be found
* in the file PATENTS. All contributing project authors may
* be found in the AUTHORS file in the root of the source tree.
*/
/******************************************************************
iLBC Speech Coder ANSI-C Source Code
WebRtcIlbcfix_DoThePlc.c
******************************************************************/
#include "modules/audio_coding/codecs/ilbc/do_plc.h"
#include "modules/audio_coding/codecs/ilbc/bw_expand.h"
#include "modules/audio_coding/codecs/ilbc/comp_corr.h"
#include "modules/audio_coding/codecs/ilbc/constants.h"
#include "modules/audio_coding/codecs/ilbc/defines.h"
/*----------------------------------------------------------------*
* Packet loss concealment routine. Conceals a residual signal
* and LP parameters. If no packet loss, update state.
*---------------------------------------------------------------*/
void WebRtcIlbcfix_DoThePlc(
int16_t *PLCresidual, /* (o) concealed residual */
int16_t *PLClpc, /* (o) concealed LP parameters */
int16_t PLI, /* (i) packet loss indicator
0 - no PL, 1 = PL */
int16_t *decresidual, /* (i) decoded residual */
int16_t *lpc, /* (i) decoded LPC (only used for no PL) */
size_t inlag, /* (i) pitch lag */
IlbcDecoder *iLBCdec_inst
/* (i/o) decoder instance */
){
size_t i;
int32_t cross, ener, cross_comp, ener_comp = 0;
int32_t measure, maxMeasure, energy;
int32_t noise_energy_threshold_30dB;
int16_t max, crossSquareMax, crossSquare;
size_t j, lag, randlag;
int16_t tmp1, tmp2;
int16_t shift1, shift2, shift3, shiftMax;
int16_t scale3;
size_t corrLen;
int32_t tmpW32, tmp2W32;
int16_t use_gain;
int16_t tot_gain;
int16_t max_perSquare;
int16_t scale1, scale2;
int16_t totscale;
int32_t nom;
int16_t denom;
int16_t pitchfact;
size_t use_lag;
int ind;
int16_t randvec[BLOCKL_MAX];
/* Packet Loss */
if (PLI == 1) {
(*iLBCdec_inst).consPLICount += 1;
/* if previous frame not lost,
determine pitch pred. gain */
if (iLBCdec_inst->prevPLI != 1) {
/* Maximum 60 samples are correlated, preserve as high accuracy
as possible without getting overflow */
max = WebRtcSpl_MaxAbsValueW16((*iLBCdec_inst).prevResidual,
iLBCdec_inst->blockl);
scale3 = (WebRtcSpl_GetSizeInBits(max)<<1) - 25;
if (scale3 < 0) {
scale3 = 0;
}
/* Store scale for use when interpolating between the
* concealment and the received packet */
iLBCdec_inst->prevScale = scale3;
/* Search around the previous lag +/-3 to find the
best pitch period */
lag = inlag - 3;
/* Guard against getting outside the frame */
corrLen = (size_t)WEBRTC_SPL_MIN(60, iLBCdec_inst->blockl-(inlag+3));
WebRtcIlbcfix_CompCorr( &cross, &ener,
iLBCdec_inst->prevResidual, lag, iLBCdec_inst->blockl, corrLen, scale3);
/* Normalize and store cross^2 and the number of shifts */
shiftMax = WebRtcSpl_GetSizeInBits(WEBRTC_SPL_ABS_W32(cross))-15;
crossSquareMax = (int16_t)((
(int16_t)WEBRTC_SPL_SHIFT_W32(cross, -shiftMax) *
(int16_t)WEBRTC_SPL_SHIFT_W32(cross, -shiftMax)) >> 15);
for (j=inlag-2;j<=inlag+3;j++) {
WebRtcIlbcfix_CompCorr( &cross_comp, &ener_comp,
iLBCdec_inst->prevResidual, j, iLBCdec_inst->blockl, corrLen, scale3);
/* Use the criteria (corr*corr)/energy to compare if
this lag is better or not. To avoid the division,
do a cross multiplication */
shift1 = WebRtcSpl_GetSizeInBits(WEBRTC_SPL_ABS_W32(cross_comp))-15;
crossSquare = (int16_t)((
(int16_t)WEBRTC_SPL_SHIFT_W32(cross_comp, -shift1) *
(int16_t)WEBRTC_SPL_SHIFT_W32(cross_comp, -shift1)) >> 15);
shift2 = WebRtcSpl_GetSizeInBits(ener)-15;
measure = (int16_t)WEBRTC_SPL_SHIFT_W32(ener, -shift2) * crossSquare;
shift3 = WebRtcSpl_GetSizeInBits(ener_comp)-15;
maxMeasure = (int16_t)WEBRTC_SPL_SHIFT_W32(ener_comp, -shift3) *
crossSquareMax;
/* Calculate shift value, so that the two measures can
be put in the same Q domain */
if(2 * shiftMax + shift3 > 2 * shift1 + shift2) {
tmp1 =
WEBRTC_SPL_MIN(31, 2 * shiftMax + shift3 - 2 * shift1 - shift2);
tmp2 = 0;
} else {
tmp1 = 0;
tmp2 =
WEBRTC_SPL_MIN(31, 2 * shift1 + shift2 - 2 * shiftMax - shift3);
}
if ((measure>>tmp1) > (maxMeasure>>tmp2)) {
/* New lag is better => record lag, measure and domain */
lag = j;
crossSquareMax = crossSquare;
cross = cross_comp;
shiftMax = shift1;
ener = ener_comp;
}
}
/* Calculate the periodicity for the lag with the maximum correlation.
Definition of the periodicity:
abs(corr(vec1, vec2))/(sqrt(energy(vec1))*sqrt(energy(vec2)))
Work in the Square domain to simplify the calculations
max_perSquare is less than 1 (in Q15)
*/
tmp2W32=WebRtcSpl_DotProductWithScale(&iLBCdec_inst->prevResidual[iLBCdec_inst->blockl-corrLen],
&iLBCdec_inst->prevResidual[iLBCdec_inst->blockl-corrLen],
corrLen, scale3);
if ((tmp2W32>0)&&(ener_comp>0)) {
/* norm energies to int16_t, compute the product of the energies and
use the upper int16_t as the denominator */
scale1=(int16_t)WebRtcSpl_NormW32(tmp2W32)-16;
tmp1=(int16_t)WEBRTC_SPL_SHIFT_W32(tmp2W32, scale1);
scale2=(int16_t)WebRtcSpl_NormW32(ener)-16;
tmp2=(int16_t)WEBRTC_SPL_SHIFT_W32(ener, scale2);
denom = (int16_t)((tmp1 * tmp2) >> 16); /* in Q(scale1+scale2-16) */
/* Square the cross correlation and norm it such that max_perSquare
will be in Q15 after the division */
totscale = scale1+scale2-1;
tmp1 = (int16_t)WEBRTC_SPL_SHIFT_W32(cross, (totscale>>1));
tmp2 = (int16_t)WEBRTC_SPL_SHIFT_W32(cross, totscale-(totscale>>1));
nom = tmp1 * tmp2;
max_perSquare = (int16_t)WebRtcSpl_DivW32W16(nom, denom);
} else {
max_perSquare = 0;
}
}
/* previous frame lost, use recorded lag and gain */
else {
lag = iLBCdec_inst->prevLag;
max_perSquare = iLBCdec_inst->perSquare;
}
/* Attenuate signal and scale down pitch pred gain if
several frames lost consecutively */
use_gain = 32767; /* 1.0 in Q15 */
if (iLBCdec_inst->consPLICount*iLBCdec_inst->blockl>320) {
use_gain = 29491; /* 0.9 in Q15 */
} else if (iLBCdec_inst->consPLICount*iLBCdec_inst->blockl>640) {
use_gain = 22938; /* 0.7 in Q15 */
} else if (iLBCdec_inst->consPLICount*iLBCdec_inst->blockl>960) {
use_gain = 16384; /* 0.5 in Q15 */
} else if (iLBCdec_inst->consPLICount*iLBCdec_inst->blockl>1280) {
use_gain = 0; /* 0.0 in Q15 */
}
/* Compute mixing factor of picth repeatition and noise:
for max_per>0.7 set periodicity to 1.0
0.4<max_per<0.7 set periodicity to (maxper-0.4)/0.7-0.4)
max_per<0.4 set periodicity to 0.0
*/
if (max_perSquare>7868) { /* periodicity > 0.7 (0.7^4=0.2401 in Q15) */
pitchfact = 32767;
} else if (max_perSquare>839) { /* 0.4 < periodicity < 0.7 (0.4^4=0.0256 in Q15) */
/* find best index and interpolate from that */
ind = 5;
while ((max_perSquare<WebRtcIlbcfix_kPlcPerSqr[ind])&&(ind>0)) {
ind--;
}
/* pitch fact is approximated by first order */
tmpW32 = (int32_t)WebRtcIlbcfix_kPlcPitchFact[ind] +
((WebRtcIlbcfix_kPlcPfSlope[ind] *
(max_perSquare - WebRtcIlbcfix_kPlcPerSqr[ind])) >> 11);
pitchfact = (int16_t)WEBRTC_SPL_MIN(tmpW32, 32767); /* guard against overflow */
} else { /* periodicity < 0.4 */
pitchfact = 0;
}
/* avoid repetition of same pitch cycle (buzzyness) */
use_lag = lag;
if (lag<80) {
use_lag = 2*lag;
}
/* compute concealed residual */
noise_energy_threshold_30dB = (int32_t)iLBCdec_inst->blockl * 900;
energy = 0;
for (i=0; i<iLBCdec_inst->blockl; i++) {
/* noise component - 52 < randlagFIX < 117 */
iLBCdec_inst->seed = (int16_t)(iLBCdec_inst->seed * 31821 + 13849);
randlag = 53 + (iLBCdec_inst->seed & 63);
if (randlag > i) {
randvec[i] =
iLBCdec_inst->prevResidual[iLBCdec_inst->blockl + i - randlag];
} else {
randvec[i] = iLBCdec_inst->prevResidual[i - randlag];
}
/* pitch repeatition component */
if (use_lag > i) {
PLCresidual[i] =
iLBCdec_inst->prevResidual[iLBCdec_inst->blockl + i - use_lag];
} else {
PLCresidual[i] = PLCresidual[i - use_lag];
}
/* Attinuate total gain for each 10 ms */
if (i<80) {
tot_gain=use_gain;
} else if (i<160) {
tot_gain = (int16_t)((31130 * use_gain) >> 15); /* 0.95*use_gain */
} else {
tot_gain = (int16_t)((29491 * use_gain) >> 15); /* 0.9*use_gain */
}
/* mix noise and pitch repeatition */
PLCresidual[i] = (int16_t)((tot_gain *
((pitchfact * PLCresidual[i] + (32767 - pitchfact) * randvec[i] +
16384) >> 15)) >> 15);
/* Compute energy until threshold for noise energy is reached */
if (energy < noise_energy_threshold_30dB) {
energy += PLCresidual[i] * PLCresidual[i];
}
}
/* less than 30 dB, use only noise */
if (energy < noise_energy_threshold_30dB) {
for (i=0; i<iLBCdec_inst->blockl; i++) {
PLCresidual[i] = randvec[i];
}
}
/* use the old LPC */
WEBRTC_SPL_MEMCPY_W16(PLClpc, (*iLBCdec_inst).prevLpc, LPC_FILTERORDER+1);
/* Update state in case there are multiple frame losses */
iLBCdec_inst->prevLag = lag;
iLBCdec_inst->perSquare = max_perSquare;
}
/* no packet loss, copy input */
else {
WEBRTC_SPL_MEMCPY_W16(PLCresidual, decresidual, iLBCdec_inst->blockl);
WEBRTC_SPL_MEMCPY_W16(PLClpc, lpc, (LPC_FILTERORDER+1));
iLBCdec_inst->consPLICount = 0;
}
/* update state */
iLBCdec_inst->prevPLI = PLI;
WEBRTC_SPL_MEMCPY_W16(iLBCdec_inst->prevLpc, PLClpc, (LPC_FILTERORDER+1));
WEBRTC_SPL_MEMCPY_W16(iLBCdec_inst->prevResidual, PLCresidual, iLBCdec_inst->blockl);
return;
}
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