Index: speex/libspeex/lpc.c |
=================================================================== |
--- speex/libspeex/lpc.c (revision 0) |
+++ speex/libspeex/lpc.c (revision 0) |
@@ -0,0 +1,201 @@ |
+/* |
+ 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 |
+ |
+ |
Property changes on: speex/libspeex/lpc.c |
___________________________________________________________________ |
Name: svn:executable |
+ * |