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| 1 /* |
| 2 Copyright 1992, 1993, 1994 by Jutta Degener and Carsten Bormann, |
| 3 Technische Universitaet Berlin |
| 4 |
| 5 Any use of this software is permitted provided that this notice is not |
| 6 removed and that neither the authors nor the Technische Universitaet Berlin |
| 7 are deemed to have made any representations as to the suitability of this |
| 8 software for any purpose nor are held responsible for any defects of |
| 9 this software. THERE IS ABSOLUTELY NO WARRANTY FOR THIS SOFTWARE. |
| 10 |
| 11 As a matter of courtesy, the authors request to be informed about uses |
| 12 this software has found, about bugs in this software, and about any |
| 13 improvements that may be of general interest. |
| 14 |
| 15 Berlin, 28.11.1994 |
| 16 Jutta Degener |
| 17 Carsten Bormann |
| 18 |
| 19 |
| 20 Code modified by Jean-Marc Valin |
| 21 |
| 22 Speex License: |
| 23 |
| 24 Redistribution and use in source and binary forms, with or without |
| 25 modification, are permitted provided that the following conditions |
| 26 are met: |
| 27 |
| 28 - Redistributions of source code must retain the above copyright |
| 29 notice, this list of conditions and the following disclaimer. |
| 30 |
| 31 - Redistributions in binary form must reproduce the above copyright |
| 32 notice, this list of conditions and the following disclaimer in the |
| 33 documentation and/or other materials provided with the distribution. |
| 34 |
| 35 - Neither the name of the Xiph.org Foundation nor the names of its |
| 36 contributors may be used to endorse or promote products derived from |
| 37 this software without specific prior written permission. |
| 38 |
| 39 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| 40 ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| 41 LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| 42 A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR |
| 43 CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| 44 EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| 45 PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| 46 PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
| 47 LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| 48 NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| 49 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| 50 */ |
| 51 |
| 52 #ifdef HAVE_CONFIG_H |
| 53 #include "config.h" |
| 54 #endif |
| 55 |
| 56 #include "lpc.h" |
| 57 |
| 58 #ifdef BFIN_ASM |
| 59 #include "lpc_bfin.h" |
| 60 #endif |
| 61 |
| 62 /* LPC analysis |
| 63 * |
| 64 * The next two functions calculate linear prediction coefficients |
| 65 * and/or the related reflection coefficients from the first P_MAX+1 |
| 66 * values of the autocorrelation function. |
| 67 */ |
| 68 |
| 69 /* Invented by N. Levinson in 1947, modified by J. Durbin in 1959. |
| 70 */ |
| 71 |
| 72 /* returns minimum mean square error */ |
| 73 spx_word32_t _spx_lpc( |
| 74 spx_coef_t *lpc, /* out: [0...p-1] LPC coefficients */ |
| 75 const spx_word16_t *ac, /* in: [0...p] autocorrelation values */ |
| 76 int p |
| 77 ) |
| 78 { |
| 79 int i, j; |
| 80 spx_word16_t r; |
| 81 spx_word16_t error = ac[0]; |
| 82 |
| 83 if (ac[0] == 0) |
| 84 { |
| 85 for (i = 0; i < p; i++) |
| 86 lpc[i] = 0; |
| 87 return 0; |
| 88 } |
| 89 |
| 90 for (i = 0; i < p; i++) { |
| 91 |
| 92 /* Sum up this iteration's reflection coefficient */ |
| 93 spx_word32_t rr = NEG32(SHL32(EXTEND32(ac[i + 1]),13)); |
| 94 for (j = 0; j < i; j++) |
| 95 rr = SUB32(rr,MULT16_16(lpc[j],ac[i - j])); |
| 96 #ifdef FIXED_POINT |
| 97 r = DIV32_16(rr+PSHR32(error,1),ADD16(error,8)); |
| 98 #else |
| 99 r = rr/(error+.003*ac[0]); |
| 100 #endif |
| 101 /* Update LPC coefficients and total error */ |
| 102 lpc[i] = r; |
| 103 for (j = 0; j < i>>1; j++) |
| 104 { |
| 105 spx_word16_t tmp = lpc[j]; |
| 106 lpc[j] = MAC16_16_P13(lpc[j],r,lpc[i-1-j]); |
| 107 lpc[i-1-j] = MAC16_16_P13(lpc[i-1-j],r,tmp); |
| 108 } |
| 109 if (i & 1) |
| 110 lpc[j] = MAC16_16_P13(lpc[j],lpc[j],r); |
| 111 |
| 112 error = SUB16(error,MULT16_16_Q13(r,MULT16_16_Q13(error,r))); |
| 113 } |
| 114 return error; |
| 115 } |
| 116 |
| 117 |
| 118 #ifdef FIXED_POINT |
| 119 |
| 120 /* Compute the autocorrelation |
| 121 * ,--, |
| 122 * ac(i) = > x(n) * x(n-i) for all n |
| 123 * `--' |
| 124 * for lags between 0 and lag-1, and x == 0 outside 0...n-1 |
| 125 */ |
| 126 |
| 127 #ifndef OVERRIDE_SPEEX_AUTOCORR |
| 128 void _spx_autocorr( |
| 129 const spx_word16_t *x, /* in: [0...n-1] samples x */ |
| 130 spx_word16_t *ac, /* out: [0...lag-1] ac values */ |
| 131 int lag, |
| 132 int n |
| 133 ) |
| 134 { |
| 135 spx_word32_t d; |
| 136 int i, j; |
| 137 spx_word32_t ac0=1; |
| 138 int shift, ac_shift; |
| 139 |
| 140 for (j=0;j<n;j++) |
| 141 ac0 = ADD32(ac0,SHR32(MULT16_16(x[j],x[j]),8)); |
| 142 ac0 = ADD32(ac0,n); |
| 143 shift = 8; |
| 144 while (shift && ac0<0x40000000) |
| 145 { |
| 146 shift--; |
| 147 ac0 <<= 1; |
| 148 } |
| 149 ac_shift = 18; |
| 150 while (ac_shift && ac0<0x40000000) |
| 151 { |
| 152 ac_shift--; |
| 153 ac0 <<= 1; |
| 154 } |
| 155 |
| 156 |
| 157 for (i=0;i<lag;i++) |
| 158 { |
| 159 d=0; |
| 160 for (j=i;j<n;j++) |
| 161 { |
| 162 d = ADD32(d,SHR32(MULT16_16(x[j],x[j-i]), shift)); |
| 163 } |
| 164 |
| 165 ac[i] = SHR32(d, ac_shift); |
| 166 } |
| 167 } |
| 168 #endif |
| 169 |
| 170 |
| 171 #else |
| 172 |
| 173 |
| 174 |
| 175 /* Compute the autocorrelation |
| 176 * ,--, |
| 177 * ac(i) = > x(n) * x(n-i) for all n |
| 178 * `--' |
| 179 * for lags between 0 and lag-1, and x == 0 outside 0...n-1 |
| 180 */ |
| 181 void _spx_autocorr( |
| 182 const spx_word16_t *x, /* in: [0...n-1] samples x */ |
| 183 float *ac, /* out: [0...lag-1] ac values */ |
| 184 int lag, |
| 185 int n |
| 186 ) |
| 187 { |
| 188 float d; |
| 189 int i; |
| 190 while (lag--) |
| 191 { |
| 192 for (i = lag, d = 0; i < n; i++) |
| 193 d += x[i] * x[i-lag]; |
| 194 ac[lag] = d; |
| 195 } |
| 196 ac[0] += 10; |
| 197 } |
| 198 |
| 199 #endif |
| 200 |
| 201 |
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