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 #define __BTSTACK_FILE__ "btstack_sbc_plc.c" 39 40 /* 41 * btstack_sbc_plc.c 42 * 43 */ 44 45 #include <stdint.h> 46 #include <stdio.h> 47 #include <stdlib.h> 48 #include <string.h> 49 50 #include "btstack_sbc_plc.h" 51 #include "btstack_debug.h" 52 53 #define SAMPLE_FORMAT int16_t 54 55 static uint8_t indices0[] = { 0xad, 0x00, 0x00, 0xc5, 0x00, 0x00, 0x00, 0x00, 0x77, 0x6d, 56 0xb6, 0xdd, 0xdb, 0x6d, 0xb7, 0x76, 0xdb, 0x6d, 0xdd, 0xb6, 0xdb, 0x77, 0x6d, 57 0xb6, 0xdd, 0xdb, 0x6d, 0xb7, 0x76, 0xdb, 0x6d, 0xdd, 0xb6, 0xdb, 0x77, 0x6d, 58 0xb6, 0xdd, 0xdb, 0x6d, 0xb7, 0x76, 0xdb, 0x6d, 0xdd, 0xb6, 0xdb, 0x77, 0x6d, 59 0xb6, 0xdd, 0xdb, 0x6d, 0xb7, 0x76, 0xdb, 0x6c}; 60 61 /* Raised COSine table for OLA */ 62 static float rcos[SBC_OLAL] = { 63 0.99148655f,0.96623611f,0.92510857f,0.86950446f, 64 0.80131732f,0.72286918f,0.63683150f,0.54613418f, 65 0.45386582f,0.36316850f,0.27713082f,0.19868268f, 66 0.13049554f,0.07489143f,0.03376389f,0.00851345f}; 67 68 // taken from http://www.codeproject.com/Articles/69941/Best-Square-Root-Method-Algorithm-Function-Precisi 69 // Algorithm: Babylonian Method + some manipulations on IEEE 32 bit floating point representation 70 static float sqrt3(const float x){ 71 union { 72 int i; 73 float x; 74 } u; 75 u.x = x; 76 u.i = (1<<29) + (u.i >> 1) - (1<<22); 77 78 // Two Babylonian Steps (simplified from:) 79 // u.x = 0.5f * (u.x + x/u.x); 80 // u.x = 0.5f * (u.x + x/u.x); 81 u.x = u.x + x/u.x; 82 u.x = 0.25f*u.x + x/u.x; 83 84 return u.x; 85 } 86 87 static float absolute(float x){ 88 if (x < 0) x = -x; 89 return x; 90 } 91 92 static float CrossCorrelation(SAMPLE_FORMAT *x, SAMPLE_FORMAT *y){ 93 float num = 0; 94 float den = 0; 95 float x2 = 0; 96 float y2 = 0; 97 int m; 98 for (m=0;m<SBC_M;m++){ 99 num+=((float)x[m])*y[m]; 100 x2+=((float)x[m])*x[m]; 101 y2+=((float)y[m])*y[m]; 102 } 103 den = (float)sqrt3(x2*y2); 104 return num/den; 105 } 106 107 static int PatternMatch(SAMPLE_FORMAT *y){ 108 float maxCn = -999999.0; // large negative number 109 int bestmatch = 0; 110 float Cn; 111 int n; 112 for (n=0;n<SBC_N;n++){ 113 Cn = CrossCorrelation(&y[SBC_LHIST-SBC_M], &y[n]); 114 if (Cn>maxCn){ 115 bestmatch=n; 116 maxCn = Cn; 117 } 118 } 119 return bestmatch; 120 } 121 122 static float AmplitudeMatch(SAMPLE_FORMAT *y, SAMPLE_FORMAT bestmatch) { 123 int i; 124 float sumx = 0; 125 float sumy = 0.000001f; 126 float sf; 127 128 for (i=0;i<SBC_FS;i++){ 129 sumx += absolute(y[SBC_LHIST-SBC_FS+i]); 130 sumy += absolute(y[bestmatch+i]); 131 } 132 sf = sumx/sumy; 133 // This is not in the paper, but limit the scaling factor to something reasonable to avoid creating artifacts 134 if (sf<0.75f) sf=0.75f; 135 if (sf>1.2f) sf=1.2f; 136 return sf; 137 } 138 139 static SAMPLE_FORMAT crop_sample(float val){ 140 float croped_val = val; 141 if (croped_val > 32767.0) croped_val= 32767.0; 142 if (croped_val < -32768.0) croped_val=-32768.0; 143 return (SAMPLE_FORMAT) croped_val; 144 } 145 146 uint8_t * btstack_sbc_plc_zero_signal_frame(void){ 147 return (uint8_t *)&indices0; 148 } 149 150 void btstack_sbc_plc_init(btstack_sbc_plc_state_t *plc_state){ 151 plc_state->nbf=0; 152 plc_state->bestlag=0; 153 memset(plc_state->hist,0,sizeof(plc_state->hist)); 154 } 155 156 void btstack_sbc_plc_bad_frame(btstack_sbc_plc_state_t *plc_state, SAMPLE_FORMAT *ZIRbuf, SAMPLE_FORMAT *out){ 157 float val; 158 int i = 0; 159 float sf = 1; 160 plc_state->nbf++; 161 162 plc_state->bad_frames_nr++; 163 plc_state->frame_count++; 164 if (plc_state->max_consecutive_bad_frames_nr < plc_state->nbf){ 165 plc_state->max_consecutive_bad_frames_nr = plc_state->nbf; 166 } 167 168 if (plc_state->nbf==1){ 169 // Perform pattern matching to find where to replicate 170 plc_state->bestlag = PatternMatch(plc_state->hist); 171 // the replication begins after the template match 172 plc_state->bestlag += SBC_M; 173 174 // Compute Scale Factor to Match Amplitude of Substitution Packet to that of Preceding Packet 175 sf = AmplitudeMatch(plc_state->hist, plc_state->bestlag); 176 for (i=0;i<SBC_OLAL;i++){ 177 float left = ZIRbuf[i]; 178 float right = sf*plc_state->hist[plc_state->bestlag+i]; 179 val = left*rcos[i] + right*rcos[SBC_OLAL-1-i]; 180 plc_state->hist[SBC_LHIST+i] = crop_sample(val); 181 } 182 183 for (;i<SBC_FS;i++){ 184 val = sf*plc_state->hist[plc_state->bestlag+i]; 185 plc_state->hist[SBC_LHIST+i] = crop_sample(val); 186 } 187 188 for (;i<SBC_FS+SBC_OLAL;i++){ 189 float left = sf*plc_state->hist[plc_state->bestlag+i]; 190 float right = plc_state->hist[plc_state->bestlag+i]; 191 val = left*rcos[i-SBC_FS]+right*rcos[SBC_OLAL-1-i+SBC_FS]; 192 plc_state->hist[SBC_LHIST+i] = crop_sample(val); 193 } 194 195 for (;i<SBC_FS+SBC_RT+SBC_OLAL;i++){ 196 plc_state->hist[SBC_LHIST+i] = plc_state->hist[plc_state->bestlag+i]; 197 } 198 } else { 199 for (;i<SBC_FS+SBC_RT+SBC_OLAL;i++){ 200 plc_state->hist[SBC_LHIST+i] = plc_state->hist[plc_state->bestlag+i]; 201 } 202 } 203 for (i=0;i<SBC_FS;i++){ 204 out[i] = plc_state->hist[SBC_LHIST+i]; 205 } 206 207 // shift the history buffer 208 for (i=0;i<SBC_LHIST+SBC_RT+SBC_OLAL;i++){ 209 plc_state->hist[i] = plc_state->hist[i+SBC_FS]; 210 } 211 } 212 213 void btstack_sbc_plc_good_frame(btstack_sbc_plc_state_t *plc_state, SAMPLE_FORMAT *in, SAMPLE_FORMAT *out){ 214 float val; 215 int i = 0; 216 plc_state->good_frames_nr++; 217 plc_state->frame_count++; 218 219 if (plc_state->nbf>0){ 220 for (i=0;i<SBC_RT;i++){ 221 out[i] = plc_state->hist[SBC_LHIST+i]; 222 } 223 224 for (i = SBC_RT;i<SBC_RT+SBC_OLAL;i++){ 225 float left = plc_state->hist[SBC_LHIST+i]; 226 float right = in[i]; 227 val = left*rcos[i-SBC_RT] + right*rcos[SBC_OLAL+SBC_RT-1-i]; 228 out[i] = (SAMPLE_FORMAT)val; 229 } 230 } 231 232 for (;i<SBC_FS;i++){ 233 out[i] = in[i]; 234 } 235 // Copy the output to the history buffer 236 for (i=0;i<SBC_FS;i++){ 237 plc_state->hist[SBC_LHIST+i] = out[i]; 238 } 239 // shift the history buffer 240 for (i=0;i<SBC_LHIST;i++){ 241 plc_state->hist[i] = plc_state->hist[i+SBC_FS]; 242 } 243 244 plc_state->nbf=0; 245 } 246 247 void btstack_sbc_dump_statistics(btstack_sbc_plc_state_t * state){ 248 log_info("Good frames: %d\n", state->good_frames_nr); 249 log_info("Bad frames: %d\n", state->bad_frames_nr); 250 log_info("Max Consecutive bad frames: %d\n", state->max_consecutive_bad_frames_nr); 251 } 252