| /* |
| Copyright 1992, 1993, 1994 by Jutta Degener and Carsten Bormann, |
| Technische Universitaet Berlin |
| |
| Any use of this software is permitted provided that this notice is not |
| removed and that neither the authors nor the Technische Universitaet Berlin |
| are deemed to have made any representations as to the suitability of this |
| software for any purpose nor are held responsible for any defects of |
| this software. THERE IS ABSOLUTELY NO WARRANTY FOR THIS SOFTWARE. |
| |
| As a matter of courtesy, the authors request to be informed about uses |
| this software has found, about bugs in this software, and about any |
| improvements that may be of general interest. |
| |
| Berlin, 28.11.1994 |
| Jutta Degener |
| Carsten Bormann |
| |
| |
| Code modified by Jean-Marc Valin |
| |
| Speex License: |
| |
| Redistribution and use in source and binary forms, with or without |
| modification, are permitted provided that the following conditions |
| are met: |
| |
| - Redistributions of source code must retain the above copyright |
| notice, this list of conditions and the following disclaimer. |
| |
| - Redistributions in binary form must reproduce the above copyright |
| notice, this list of conditions and the following disclaimer in the |
| documentation and/or other materials provided with the distribution. |
| |
| - Neither the name of the Xiph.org Foundation nor the names of its |
| contributors may be used to endorse or promote products derived from |
| this software without specific prior written permission. |
| |
| THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
| ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
| LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
| A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR |
| CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
| EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
| PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
| PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
| LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
| NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
| SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #ifdef HAVE_CONFIG_H |
| #include "config.h" |
| #endif |
| |
| #include "lpc.h" |
| |
| #ifdef BFIN_ASM |
| #include "lpc_bfin.h" |
| #endif |
| |
| /* LPC analysis |
| * |
| * The next two functions calculate linear prediction coefficients |
| * and/or the related reflection coefficients from the first P_MAX+1 |
| * values of the autocorrelation function. |
| */ |
| |
| /* Invented by N. Levinson in 1947, modified by J. Durbin in 1959. |
| */ |
| |
| /* returns minimum mean square error */ |
| spx_word32_t _spx_lpc( |
| spx_coef_t *lpc, /* out: [0...p-1] LPC coefficients */ |
| const spx_word16_t *ac, /* in: [0...p] autocorrelation values */ |
| int p |
| ) |
| { |
| int i, j; |
| spx_word16_t r; |
| spx_word16_t error = ac[0]; |
| |
| if (ac[0] == 0) |
| { |
| for (i = 0; i < p; i++) |
| lpc[i] = 0; |
| return 0; |
| } |
| |
| for (i = 0; i < p; i++) { |
| |
| /* Sum up this iteration's reflection coefficient */ |
| spx_word32_t rr = NEG32(SHL32(EXTEND32(ac[i + 1]),13)); |
| for (j = 0; j < i; j++) |
| rr = SUB32(rr,MULT16_16(lpc[j],ac[i - j])); |
| #ifdef FIXED_POINT |
| r = DIV32_16(rr+PSHR32(error,1),ADD16(error,8)); |
| #else |
| r = rr/(error+.003*ac[0]); |
| #endif |
| /* Update LPC coefficients and total error */ |
| lpc[i] = r; |
| for (j = 0; j < i>>1; j++) |
| { |
| spx_word16_t tmp = lpc[j]; |
| lpc[j] = MAC16_16_P13(lpc[j],r,lpc[i-1-j]); |
| lpc[i-1-j] = MAC16_16_P13(lpc[i-1-j],r,tmp); |
| } |
| if (i & 1) |
| lpc[j] = MAC16_16_P13(lpc[j],lpc[j],r); |
| |
| error = SUB16(error,MULT16_16_Q13(r,MULT16_16_Q13(error,r))); |
| } |
| return error; |
| } |
| |
| |
| #ifdef FIXED_POINT |
| |
| /* Compute the autocorrelation |
| * ,--, |
| * ac(i) = > x(n) * x(n-i) for all n |
| * `--' |
| * for lags between 0 and lag-1, and x == 0 outside 0...n-1 |
| */ |
| |
| #ifndef OVERRIDE_SPEEX_AUTOCORR |
| void _spx_autocorr( |
| const spx_word16_t *x, /* in: [0...n-1] samples x */ |
| spx_word16_t *ac, /* out: [0...lag-1] ac values */ |
| int lag, |
| int n |
| ) |
| { |
| spx_word32_t d; |
| int i, j; |
| spx_word32_t ac0=1; |
| int shift, ac_shift; |
| |
| for (j=0;j<n;j++) |
| ac0 = ADD32(ac0,SHR32(MULT16_16(x[j],x[j]),8)); |
| ac0 = ADD32(ac0,n); |
| shift = 8; |
| while (shift && ac0<0x40000000) |
| { |
| shift--; |
| ac0 <<= 1; |
| } |
| ac_shift = 18; |
| while (ac_shift && ac0<0x40000000) |
| { |
| ac_shift--; |
| ac0 <<= 1; |
| } |
| |
| |
| for (i=0;i<lag;i++) |
| { |
| d=0; |
| for (j=i;j<n;j++) |
| { |
| d = ADD32(d,SHR32(MULT16_16(x[j],x[j-i]), shift)); |
| } |
| |
| ac[i] = SHR32(d, ac_shift); |
| } |
| } |
| #endif |
| |
| |
| #else |
| |
| |
| |
| /* Compute the autocorrelation |
| * ,--, |
| * ac(i) = > x(n) * x(n-i) for all n |
| * `--' |
| * for lags between 0 and lag-1, and x == 0 outside 0...n-1 |
| */ |
| void _spx_autocorr( |
| const spx_word16_t *x, /* in: [0...n-1] samples x */ |
| float *ac, /* out: [0...lag-1] ac values */ |
| int lag, |
| int n |
| ) |
| { |
| float d; |
| int i; |
| while (lag--) |
| { |
| for (i = lag, d = 0; i < n; i++) |
| d += x[i] * x[i-lag]; |
| ac[lag] = d; |
| } |
| ac[0] += 10; |
| } |
| |
| #endif |
| |
| |