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 #include <stdint.h> 44 #include <stdio.h> 45 #include <stdlib.h> 46 #include <string.h> 47 #include <fcntl.h> 48 #include <unistd.h> 49 #include <math.h> 50 51 #include "btstack_sbc_plc.h" 52 53 static uint8_t indices0[] = { 0xad, 0x00, 0x00, 0xc5, 0x00, 0x00, 0x00, 0x00, 0x77, 0x6d, 54 0xb6, 0xdd, 0xdb, 0x6d, 0xb7, 0x76, 0xdb, 0x6d, 0xdd, 0xb6, 0xdb, 0x77, 0x6d, 55 0xb6, 0xdd, 0xdb, 0x6d, 0xb7, 0x76, 0xdb, 0x6d, 0xdd, 0xb6, 0xdb, 0x77, 0x6d, 56 0xb6, 0xdd, 0xdb, 0x6d, 0xb7, 0x76, 0xdb, 0x6d, 0xdd, 0xb6, 0xdb, 0x77, 0x6d, 57 0xb6, 0xdd, 0xdb, 0x6d, 0xb7, 0x76, 0xdb, 0x6c}; 58 59 /* Raised COSine table for OLA */ 60 static float rcos[SBC_OLAL] = { 61 0.99148655f,0.96623611f,0.92510857f,0.86950446f, 62 0.80131732f,0.72286918f,0.63683150f,0.54613418f, 63 0.45386582f,0.36316850f,0.27713082f,0.19868268f, 64 0.13049554f,0.07489143f,0.03376389f,0.00851345f}; 65 66 static float CrossCorrelation(int16_t *x, int16_t *y){ 67 float num = 0; 68 float den = 0; 69 float x2 = 0; 70 float y2 = 0; 71 int m; 72 for (m=0;m<SBC_M;m++){ 73 num+=((float)x[m])*y[m]; 74 x2+=((float)x[m])*x[m]; 75 y2+=((float)y[m])*y[m]; 76 } 77 den = (float)sqrt(x2*y2); 78 return num/den; 79 } 80 81 static int PatternMatch(int16_t *y){ 82 float maxCn = -999999.0; /* large negative number */ 83 int bestmatch = 0; 84 float Cn; 85 int n; 86 for (n=0;n<SBC_N;n++){ 87 Cn = CrossCorrelation(&y[SBC_LHIST-SBC_M] /* x */, &y[n]); 88 if (Cn>maxCn){ 89 bestmatch=n; 90 maxCn = Cn; 91 } 92 } 93 return bestmatch; 94 } 95 96 97 static float AmplitudeMatch(int16_t *y, int16_t bestmatch) { 98 int i; 99 float sumx = 0; 100 float sumy = 0.000001f; 101 float sf; 102 103 for (i=0;i<SBC_FS;i++){ 104 sumx += abs(y[SBC_LHIST-SBC_FS+i]); 105 sumy += abs(y[bestmatch+i]); 106 } 107 sf = sumx/sumy; 108 /* This is not in the paper, but limit the scaling factor to something reasonable to avoid creating artifacts */ 109 if (sf<0.75f) sf=0.75f; 110 if (sf>1.2f) sf=1.2f; 111 return sf; 112 } 113 114 static int16_t crop_to_int16(float val){ 115 float croped_val = val; 116 if (croped_val > 32767.0) croped_val= 32767.0; 117 if (croped_val < -32768.0) croped_val=-32768.0; 118 return (int16_t) croped_val; 119 } 120 121 uint8_t * btstack_sbc_plc_zero_signal_frame(void){ 122 return (uint8_t *)&indices0; 123 } 124 125 void btstack_sbc_plc_init(btstack_sbc_plc_state_t *plc_state){ 126 plc_state->nbf=0; 127 plc_state->bestlag=0; 128 memset(plc_state->hist,0,sizeof(plc_state->hist)); 129 } 130 131 void btstack_sbc_plc_bad_frame(btstack_sbc_plc_state_t *plc_state, int16_t *ZIRbuf, int16_t *out){ 132 float val; 133 int i = 0; 134 float sf = 1; 135 136 plc_state->nbf++; 137 138 if (plc_state->nbf==1){ 139 /* Perform pattern matching to find where to replicate */ 140 plc_state->bestlag = PatternMatch(plc_state->hist); 141 /* the replication begins after the template match */ 142 plc_state->bestlag += SBC_M; 143 144 /* Compute Scale Factor to Match Amplitude of Substitution Packet to that of Preceding Packet */ 145 sf = AmplitudeMatch(plc_state->hist, plc_state->bestlag); 146 for (i=0;i<SBC_OLAL;i++){ 147 float left = ZIRbuf[i]; 148 float right = sf*plc_state->hist[plc_state->bestlag+i]; 149 val = left*rcos[i] + right*rcos[SBC_OLAL-1-i]; 150 plc_state->hist[SBC_LHIST+i] = crop_to_int16(val); 151 } 152 153 for (;i<SBC_FS;i++){ 154 val = sf*plc_state->hist[plc_state->bestlag+i]; 155 plc_state->hist[SBC_LHIST+i] = crop_to_int16(val); 156 } 157 158 for (;i<SBC_FS+SBC_OLAL;i++){ 159 float left = sf*plc_state->hist[plc_state->bestlag+i]; 160 float right = plc_state->hist[plc_state->bestlag+i]; 161 val = left*rcos[i-SBC_FS]+right*rcos[SBC_FS+SBC_OLAL-1-i]; 162 plc_state->hist[SBC_LHIST+i] = crop_to_int16(val); 163 } 164 165 for (;i<SBC_FS+SBC_RT+SBC_OLAL;i++){ 166 plc_state->hist[SBC_LHIST+i] = plc_state->hist[plc_state->bestlag+i]; 167 } 168 169 } else { 170 for (i=0;i<SBC_FS+SBC_RT+SBC_OLAL;i++){ 171 plc_state->hist[SBC_LHIST+i] = plc_state->hist[plc_state->bestlag+i]; 172 } 173 } 174 for (i=0;i<SBC_FS;i++){ 175 out[i] = plc_state->hist[SBC_LHIST+i]; 176 } 177 178 /* shift the history buffer */ 179 for (i=0;i<SBC_LHIST+SBC_RT+SBC_OLAL;i++){ 180 plc_state->hist[i] = plc_state->hist[i+SBC_FS]; 181 } 182 183 } 184 185 void btstack_sbc_plc_good_frame(btstack_sbc_plc_state_t *plc_state, int16_t *in, int16_t *out){ 186 float val; 187 int i = 0; 188 if (plc_state->nbf>0){ 189 for (i=0;i<SBC_RT;i++){ 190 out[i] = plc_state->hist[SBC_LHIST+i]; 191 } 192 193 for (;i<SBC_RT+SBC_OLAL;i++){ 194 float left = plc_state->hist[SBC_LHIST+i]; 195 float right = in[i]; 196 val = left*rcos[i-SBC_RT] + right*rcos[SBC_OLAL-1-i+SBC_RT]; 197 out[i] = (int16_t)val; 198 } 199 } 200 for (;i<SBC_FS;i++){ 201 out[i] = in[i]; 202 } 203 204 /*Copy the output to the history buffer */ 205 for (i=0;i<SBC_FS;i++){ 206 plc_state->hist[SBC_LHIST+i] = out[i]; 207 } 208 /* shift the history buffer */ 209 for (i=0;i<SBC_LHIST;i++){ 210 plc_state->hist[i] = plc_state->hist[i+SBC_FS]; 211 } 212 213 plc_state->nbf=0; 214 } 215