1/* 2 * Copyright (c) 2011 The WebRTC project authors. All Rights Reserved. 3 * 4 * Use of this source code is governed by a BSD-style license 5 * that can be found in the LICENSE file in the root of the source 6 * tree. An additional intellectual property rights grant can be found 7 * in the file PATENTS. All contributing project authors may 8 * be found in the AUTHORS file in the root of the source tree. 9 */ 10 11#include <memory.h> 12#include <string.h> 13#ifdef WEBRTC_ANDROID 14#include <stdlib.h> 15#endif 16#include "pitch_estimator.h" 17#include "lpc_analysis.h" 18#include "codec.h" 19 20 21 22void WebRtcIsac_AllPoleFilter(double *InOut, double *Coef, int lengthInOut, int orderCoef){ 23 24 /* the state of filter is assumed to be in InOut[-1] to InOut[-orderCoef] */ 25 double scal; 26 double sum; 27 int n,k; 28 29 //if (fabs(Coef[0]-1.0)<0.001) { 30 if ( (Coef[0] > 0.9999) && (Coef[0] < 1.0001) ) 31 { 32 for(n = 0; n < lengthInOut; n++) 33 { 34 sum = Coef[1] * InOut[-1]; 35 for(k = 2; k <= orderCoef; k++){ 36 sum += Coef[k] * InOut[-k]; 37 } 38 *InOut++ -= sum; 39 } 40 } 41 else 42 { 43 scal = 1.0 / Coef[0]; 44 for(n=0;n<lengthInOut;n++) 45 { 46 *InOut *= scal; 47 for(k=1;k<=orderCoef;k++){ 48 *InOut -= scal*Coef[k]*InOut[-k]; 49 } 50 InOut++; 51 } 52 } 53} 54 55 56void WebRtcIsac_AllZeroFilter(double *In, double *Coef, int lengthInOut, int orderCoef, double *Out){ 57 58 /* the state of filter is assumed to be in In[-1] to In[-orderCoef] */ 59 60 int n, k; 61 double tmp; 62 63 for(n = 0; n < lengthInOut; n++) 64 { 65 tmp = In[0] * Coef[0]; 66 67 for(k = 1; k <= orderCoef; k++){ 68 tmp += Coef[k] * In[-k]; 69 } 70 71 *Out++ = tmp; 72 In++; 73 } 74} 75 76 77 78void WebRtcIsac_ZeroPoleFilter(double *In, double *ZeroCoef, double *PoleCoef, int lengthInOut, int orderCoef, double *Out){ 79 80 /* the state of the zero section is assumed to be in In[-1] to In[-orderCoef] */ 81 /* the state of the pole section is assumed to be in Out[-1] to Out[-orderCoef] */ 82 83 WebRtcIsac_AllZeroFilter(In,ZeroCoef,lengthInOut,orderCoef,Out); 84 WebRtcIsac_AllPoleFilter(Out,PoleCoef,lengthInOut,orderCoef); 85} 86 87 88void WebRtcIsac_AutoCorr( 89 double *r, 90 const double *x, 91 int N, 92 int order 93 ) 94{ 95 int lag, n; 96 double sum, prod; 97 const double *x_lag; 98 99 for (lag = 0; lag <= order; lag++) 100 { 101 sum = 0.0f; 102 x_lag = &x[lag]; 103 prod = x[0] * x_lag[0]; 104 for (n = 1; n < N - lag; n++) { 105 sum += prod; 106 prod = x[n] * x_lag[n]; 107 } 108 sum += prod; 109 r[lag] = sum; 110 } 111 112} 113 114 115void WebRtcIsac_BwExpand(double *out, double *in, double coef, short length) { 116 int i; 117 double chirp; 118 119 chirp = coef; 120 121 out[0] = in[0]; 122 for (i = 1; i < length; i++) { 123 out[i] = chirp * in[i]; 124 chirp *= coef; 125 } 126} 127 128void WebRtcIsac_WeightingFilter(const double *in, double *weiout, double *whiout, WeightFiltstr *wfdata) { 129 130 double tmpbuffer[PITCH_FRAME_LEN + PITCH_WLPCBUFLEN]; 131 double corr[PITCH_WLPCORDER+1], rc[PITCH_WLPCORDER+1]; 132 double apol[PITCH_WLPCORDER+1], apolr[PITCH_WLPCORDER+1]; 133 double rho=0.9, *inp, *dp, *dp2; 134 double whoutbuf[PITCH_WLPCBUFLEN + PITCH_WLPCORDER]; 135 double weoutbuf[PITCH_WLPCBUFLEN + PITCH_WLPCORDER]; 136 double *weo, *who, opol[PITCH_WLPCORDER+1], ext[PITCH_WLPCWINLEN]; 137 int k, n, endpos, start; 138 139 /* Set up buffer and states */ 140 memcpy(tmpbuffer, wfdata->buffer, sizeof(double) * PITCH_WLPCBUFLEN); 141 memcpy(tmpbuffer+PITCH_WLPCBUFLEN, in, sizeof(double) * PITCH_FRAME_LEN); 142 memcpy(wfdata->buffer, tmpbuffer+PITCH_FRAME_LEN, sizeof(double) * PITCH_WLPCBUFLEN); 143 144 dp=weoutbuf; 145 dp2=whoutbuf; 146 for (k=0;k<PITCH_WLPCORDER;k++) { 147 *dp++ = wfdata->weostate[k]; 148 *dp2++ = wfdata->whostate[k]; 149 opol[k]=0.0; 150 } 151 opol[0]=1.0; 152 opol[PITCH_WLPCORDER]=0.0; 153 weo=dp; 154 who=dp2; 155 156 endpos=PITCH_WLPCBUFLEN + PITCH_SUBFRAME_LEN; 157 inp=tmpbuffer + PITCH_WLPCBUFLEN; 158 159 for (n=0; n<PITCH_SUBFRAMES; n++) { 160 /* Windowing */ 161 start=endpos-PITCH_WLPCWINLEN; 162 for (k=0; k<PITCH_WLPCWINLEN; k++) { 163 ext[k]=wfdata->window[k]*tmpbuffer[start+k]; 164 } 165 166 /* Get LPC polynomial */ 167 WebRtcIsac_AutoCorr(corr, ext, PITCH_WLPCWINLEN, PITCH_WLPCORDER); 168 corr[0]=1.01*corr[0]+1.0; /* White noise correction */ 169 WebRtcIsac_LevDurb(apol, rc, corr, PITCH_WLPCORDER); 170 WebRtcIsac_BwExpand(apolr, apol, rho, PITCH_WLPCORDER+1); 171 172 /* Filtering */ 173 WebRtcIsac_ZeroPoleFilter(inp, apol, apolr, PITCH_SUBFRAME_LEN, PITCH_WLPCORDER, weo); 174 WebRtcIsac_ZeroPoleFilter(inp, apolr, opol, PITCH_SUBFRAME_LEN, PITCH_WLPCORDER, who); 175 176 inp+=PITCH_SUBFRAME_LEN; 177 endpos+=PITCH_SUBFRAME_LEN; 178 weo+=PITCH_SUBFRAME_LEN; 179 who+=PITCH_SUBFRAME_LEN; 180 } 181 182 /* Export filter states */ 183 for (k=0;k<PITCH_WLPCORDER;k++) { 184 wfdata->weostate[k]=weoutbuf[PITCH_FRAME_LEN+k]; 185 wfdata->whostate[k]=whoutbuf[PITCH_FRAME_LEN+k]; 186 } 187 188 /* Export output data */ 189 memcpy(weiout, weoutbuf+PITCH_WLPCORDER, sizeof(double) * PITCH_FRAME_LEN); 190 memcpy(whiout, whoutbuf+PITCH_WLPCORDER, sizeof(double) * PITCH_FRAME_LEN); 191} 192 193 194static const double APupper[ALLPASSSECTIONS] = {0.0347, 0.3826}; 195static const double APlower[ALLPASSSECTIONS] = {0.1544, 0.744}; 196 197 198 199void WebRtcIsac_AllpassFilterForDec(double *InOut, 200 const double *APSectionFactors, 201 int lengthInOut, 202 double *FilterState) 203{ 204 //This performs all-pass filtering--a series of first order all-pass sections are used 205 //to filter the input in a cascade manner. 206 int n,j; 207 double temp; 208 for (j=0; j<ALLPASSSECTIONS; j++){ 209 for (n=0;n<lengthInOut;n+=2){ 210 temp = InOut[n]; //store input 211 InOut[n] = FilterState[j] + APSectionFactors[j]*temp; 212 FilterState[j] = -APSectionFactors[j]*InOut[n] + temp; 213 } 214 } 215} 216 217void WebRtcIsac_DecimateAllpass(const double *in, 218 double *state_in, /* array of size: 2*ALLPASSSECTIONS+1 */ 219 int N, /* number of input samples */ 220 double *out) /* array of size N/2 */ 221{ 222 int n; 223 double data_vec[PITCH_FRAME_LEN]; 224 225 /* copy input */ 226 memcpy(data_vec+1, in, sizeof(double) * (N-1)); 227 228 data_vec[0] = state_in[2*ALLPASSSECTIONS]; //the z^(-1) state 229 state_in[2*ALLPASSSECTIONS] = in[N-1]; 230 231 WebRtcIsac_AllpassFilterForDec(data_vec+1, APupper, N, state_in); 232 WebRtcIsac_AllpassFilterForDec(data_vec, APlower, N, state_in+ALLPASSSECTIONS); 233 234 for (n=0;n<N/2;n++) 235 out[n] = data_vec[2*n] + data_vec[2*n+1]; 236 237} 238 239 240 241/* create high-pass filter ocefficients 242 * z = 0.998 * exp(j*2*pi*35/8000); 243 * p = 0.94 * exp(j*2*pi*140/8000); 244 * HP_b = [1, -2*real(z), abs(z)^2]; 245 * HP_a = [1, -2*real(p), abs(p)^2]; */ 246static const double a_coef[2] = { 1.86864659625574, -0.88360000000000}; 247static const double b_coef[2] = {-1.99524591718270, 0.99600400000000}; 248static const float a_coef_float[2] = { 1.86864659625574f, -0.88360000000000f}; 249static const float b_coef_float[2] = {-1.99524591718270f, 0.99600400000000f}; 250 251/* second order high-pass filter */ 252void WebRtcIsac_Highpass(const double *in, double *out, double *state, int N) 253{ 254 int k; 255 256 for (k=0; k<N; k++) { 257 *out = *in + state[1]; 258 state[1] = state[0] + b_coef[0] * *in + a_coef[0] * *out; 259 state[0] = b_coef[1] * *in++ + a_coef[1] * *out++; 260 } 261} 262 263void WebRtcIsac_Highpass_float(const float *in, double *out, double *state, int N) 264{ 265 int k; 266 267 for (k=0; k<N; k++) { 268 *out = (double)*in + state[1]; 269 state[1] = state[0] + b_coef_float[0] * *in + a_coef_float[0] * *out; 270 state[0] = b_coef_float[1] * (double)*in++ + a_coef_float[1] * *out++; 271 } 272} 273