1 /* 2 * Copyright (C) 2016 BlueKitchen GmbH 3 * 4 * Redistribution and use in source and binary forms, with or without 5 * modification, are permitted provided that the following conditions 6 * are met: 7 * 8 * 1. Redistributions of source code must retain the above copyright 9 * notice, this list of conditions and the following disclaimer. 10 * 2. Redistributions in binary form must reproduce the above copyright 11 * notice, this list of conditions and the following disclaimer in the 12 * documentation and/or other materials provided with the distribution. 13 * 3. Neither the name of the copyright holders nor the names of 14 * contributors may be used to endorse or promote products derived 15 * from this software without specific prior written permission. 16 * 4. Any redistribution, use, or modification is done solely for 17 * personal benefit and not for any commercial purpose or for 18 * monetary gain. 19 * 20 * THIS SOFTWARE IS PROVIDED BY BLUEKITCHEN GMBH AND CONTRIBUTORS 21 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 22 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 23 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL MATTHIAS 24 * RINGWALD OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, 26 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS 27 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 28 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 29 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF 30 * THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 31 * SUCH DAMAGE. 32 * 33 * Please inquire about commercial licensing options at 34 * [email protected] 35 * 36 */ 37 38 /* 39 * btstack_sbc_plc.c 40 * 41 */ 42 43 44 #include <stdint.h> 45 #include <stdio.h> 46 #include <stdlib.h> 47 #include <string.h> 48 #include <fcntl.h> 49 #include <unistd.h> 50 #include <math.h> 51 52 #include "btstack_cvsd_plc.h" 53 54 static float rcos[CVSD_OLAL] = { 55 0.99148655,0.96623611,0.92510857,0.86950446, 56 0.80131732,0.72286918,0.63683150,0.54613418, 57 0.45386582,0.36316850,0.27713082,0.19868268, 58 0.13049554,0.07489143,0.03376389,0.00851345}; 59 60 static float CrossCorrelation(int8_t *x, int8_t *y){ 61 float num = 0; 62 float den = 0; 63 float x2 = 0; 64 float y2 = 0; 65 int m; 66 for (m=0;m<CVSD_M;m++){ 67 num+=((float)x[m])*y[m]; 68 x2+=((float)x[m])*x[m]; 69 y2+=((float)y[m])*y[m]; 70 } 71 den = (float)sqrt(x2*y2); 72 return num/den; 73 } 74 75 static int PatternMatch(int8_t *y){ 76 float maxCn = -999999.0; // large negative number 77 int bestmatch = 0; 78 float Cn; 79 int n; 80 for (n=0;n<CVSD_N;n++){ 81 Cn = CrossCorrelation(&y[CVSD_LHIST-CVSD_M], &y[n]); 82 if (Cn>maxCn){ 83 bestmatch=n; 84 maxCn = Cn; 85 } 86 } 87 return bestmatch; 88 } 89 90 static float AmplitudeMatch(int8_t *y, int8_t bestmatch) { 91 int i; 92 float sumx = 0; 93 float sumy = 0.000001f; 94 float sf; 95 96 for (i=0;i<CVSD_FS;i++){ 97 sumx += abs(y[CVSD_LHIST-CVSD_FS+i]); 98 sumy += abs(y[bestmatch+i]); 99 } 100 sf = sumx/sumy; 101 // This is not in the paper, but limit the scaling factor to something reasonable to avoid creating artifacts 102 if (sf<0.75f) sf=0.75f; 103 if (sf>1.2f) sf=1.2f; 104 return sf; 105 } 106 107 static int8_t crop_to_int8(float val){ 108 float croped_val = val; 109 if (croped_val > 127.0) croped_val= 127.0; 110 if (croped_val < -128.0) croped_val=-128.0; 111 return (int8_t) croped_val; 112 } 113 114 115 void btstack_cvsd_plc_init(btstack_cvsd_plc_state_t *plc_state){ 116 plc_state->nbf=0; 117 plc_state->bestlag=0; 118 memset(plc_state->hist, 0, sizeof(plc_state->hist)); 119 } 120 121 void btstack_cvsd_plc_bad_frame(btstack_cvsd_plc_state_t *plc_state, int8_t *out){ 122 float val; 123 int i = 0; 124 float sf = 1; 125 plc_state->nbf++; 126 127 if (plc_state->nbf==1){ 128 // Perform pattern matching to find where to replicate 129 plc_state->bestlag = PatternMatch(plc_state->hist); 130 // the replication begins after the template match 131 plc_state->bestlag += CVSD_M; 132 133 // Compute Scale Factor to Match Amplitude of Substitution Packet to that of Preceding Packet 134 sf = AmplitudeMatch(plc_state->hist, plc_state->bestlag); 135 for (i=0;i<CVSD_OLAL;i++){ 136 val = sf*plc_state->hist[plc_state->bestlag+i]; 137 plc_state->hist[CVSD_LHIST+i] = crop_to_int8(val); 138 } 139 140 for (;i<CVSD_FS;i++){ 141 val = sf*plc_state->hist[plc_state->bestlag+i]; 142 plc_state->hist[CVSD_LHIST+i] = crop_to_int8(val); 143 } 144 145 for (;i<CVSD_FS+CVSD_OLAL;i++){ 146 float left = sf*plc_state->hist[plc_state->bestlag+i]; 147 float right = plc_state->hist[plc_state->bestlag+i]; 148 val = left*rcos[i-CVSD_FS] + right*rcos[CVSD_OLAL-1-i+CVSD_FS]; 149 plc_state->hist[CVSD_LHIST+i] = crop_to_int8(val); 150 } 151 152 for (;i<CVSD_FS+CVSD_RT+CVSD_OLAL;i++){ 153 plc_state->hist[CVSD_LHIST+i] = plc_state->hist[plc_state->bestlag+i]; 154 } 155 } else { 156 for (;i<CVSD_FS+CVSD_RT+CVSD_OLAL;i++){ 157 plc_state->hist[CVSD_LHIST+i] = plc_state->hist[plc_state->bestlag+i]; 158 } 159 } 160 for (i=0;i<CVSD_FS;i++){ 161 out[i] = plc_state->hist[CVSD_LHIST+i]; 162 } 163 164 // shift the history buffer 165 for (i=0;i<CVSD_LHIST+CVSD_RT+CVSD_OLAL;i++){ 166 plc_state->hist[i] = plc_state->hist[i+CVSD_FS]; 167 } 168 } 169 170 void btstack_cvsd_plc_good_frame(btstack_cvsd_plc_state_t *plc_state, int8_t *in, int8_t *out){ 171 float val; 172 int i = 0; 173 if (plc_state->nbf>0){ 174 for (i=0;i<CVSD_RT;i++){ 175 out[i] = plc_state->hist[CVSD_LHIST+i]; 176 } 177 178 for (i=CVSD_RT;i<CVSD_RT+CVSD_OLAL;i++){ 179 float left = plc_state->hist[CVSD_LHIST+i]; 180 float right = in[i]; 181 val = left * rcos[i-CVSD_RT] + right *rcos[CVSD_OLAL+CVSD_RT-1-i]; 182 out[i] = (int8_t)val; 183 } 184 } 185 186 for (;i<CVSD_FS;i++){ 187 out[i] = in[i]; 188 } 189 // Copy the output to the history buffer 190 for (i=0;i<CVSD_FS;i++){ 191 plc_state->hist[CVSD_LHIST+i] = out[i]; 192 } 193 // shift the history buffer 194 for (i=0;i<CVSD_LHIST;i++){ 195 plc_state->hist[i] = plc_state->hist[i+CVSD_FS]; 196 } 197 plc_state->nbf=0; 198 } 199