ref: a404d4e9d528cf240c806ab51cae2ef5172b8a04
dir: /celt/plc.c/
/* Copyright (c) 2009-2010 Xiph.Org Foundation Written by Jean-Marc Valin */ /* 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. 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 "plc.h" #include "stack_alloc.h" #include "mathops.h" void _celt_lpc( opus_val16 *_lpc, /* out: [0...p-1] LPC coefficients */ const opus_val32 *ac, /* in: [0...p] autocorrelation values */ int p ) { int i, j; opus_val32 r; opus_val32 error = ac[0]; #ifdef FIXED_POINT opus_val32 lpc[LPC_ORDER]; #else float *lpc = _lpc; #endif for (i = 0; i < p; i++) lpc[i] = 0; if (ac[0] != 0) { for (i = 0; i < p; i++) { /* Sum up this iteration's reflection coefficient */ opus_val32 rr = 0; for (j = 0; j < i; j++) rr += MULT32_32_Q31(lpc[j],ac[i - j]); rr += SHR32(ac[i + 1],3); r = -frac_div32(SHL32(rr,3), error); /* Update LPC coefficients and total error */ lpc[i] = SHR32(r,3); for (j = 0; j < (i+1)>>1; j++) { opus_val32 tmp1, tmp2; tmp1 = lpc[j]; tmp2 = lpc[i-1-j]; lpc[j] = tmp1 + MULT32_32_Q31(r,tmp2); lpc[i-1-j] = tmp2 + MULT32_32_Q31(r,tmp1); } error = error - MULT32_32_Q31(MULT32_32_Q31(r,r),error); /* Bail out once we get 30 dB gain */ #ifdef FIXED_POINT if (error<SHR32(ac[0],10)) break; #else if (error<.001f*ac[0]) break; #endif } } #ifdef FIXED_POINT for (i=0;i<p;i++) _lpc[i] = ROUND16(lpc[i],16); #endif } void celt_fir(const opus_val16 *x, const opus_val16 *num, opus_val16 *y, int N, int ord, opus_val16 *mem) { int i,j; for (i=0;i<N;i++) { opus_val32 sum = SHL32(EXTEND32(x[i]), SIG_SHIFT); for (j=0;j<ord;j++) { sum += MULT16_16(num[j],mem[j]); } for (j=ord-1;j>=1;j--) { mem[j]=mem[j-1]; } mem[0] = x[i]; y[i] = ROUND16(sum, SIG_SHIFT); } } void celt_iir(const opus_val32 *x, const opus_val16 *den, opus_val32 *y, int N, int ord, opus_val16 *mem) { int i,j; for (i=0;i<N;i++) { opus_val32 sum = x[i]; for (j=0;j<ord;j++) { sum -= MULT16_16(den[j],mem[j]); } for (j=ord-1;j>=1;j--) { mem[j]=mem[j-1]; } mem[0] = ROUND16(sum,SIG_SHIFT); y[i] = sum; } } void _celt_autocorr( const opus_val16 *x, /* in: [0...n-1] samples x */ opus_val32 *ac, /* out: [0...lag-1] ac values */ const opus_val16 *window, int overlap, int lag, int n ) { opus_val32 d; int i; VARDECL(opus_val16, xx); SAVE_STACK; ALLOC(xx, n, opus_val16); for (i=0;i<n;i++) xx[i] = x[i]; for (i=0;i<overlap;i++) { xx[i] = MULT16_16_Q15(x[i],window[i]); xx[n-i-1] = MULT16_16_Q15(x[n-i-1],window[i]); } #ifdef FIXED_POINT { opus_val32 ac0=0; int shift; for(i=0;i<n;i++) ac0 += SHR32(MULT16_16(xx[i],xx[i]),8); ac0 += 1+n; shift = celt_ilog2(ac0)-30+9; shift = (shift+1)/2; for(i=0;i<n;i++) xx[i] = VSHR32(xx[i], shift); } #endif while (lag>=0) { for (i = lag, d = 0; i < n; i++) d += xx[i] * xx[i-lag]; ac[lag] = d; /*printf ("%f ", ac[lag]);*/ lag--; } /*printf ("\n");*/ ac[0] += 10; RESTORE_STACK; }