Tristan Matthews | 0a329cc | 2013-07-17 13:20:14 -0400 | [diff] [blame] | 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 | |