ref: 00a98f5debf8ccd3ec64732f0c2592bb5cf42a2c
dir: /libcelt/pitch.c/
/* Copyright (c) 2007-2008 CSIRO Copyright (c) 2007-2009 Xiph.Org Foundation Written by Jean-Marc Valin */ /** @file pitch.c @brief Pitch analysis */ /* 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 "pitch.h" #include "os_support.h" #include "modes.h" #include "stack_alloc.h" #include "mathops.h" static void find_best_pitch(celt_word32 *xcorr, celt_word32 maxcorr, celt_word16 *y, int yshift, int len, int max_pitch, int best_pitch[2]) { int i, j; celt_word32 Syy=1; celt_word16 best_num[2]; celt_word32 best_den[2]; #ifdef FIXED_POINT int xshift; xshift = celt_ilog2(maxcorr)-14; #endif best_num[0] = -1; best_num[1] = -1; best_den[0] = 0; best_den[1] = 0; best_pitch[0] = 0; best_pitch[1] = 1; for (j=0;j<len;j++) Syy = MAC16_16(Syy, y[j],y[j]); for (i=0;i<max_pitch;i++) { if (xcorr[i]>0) { celt_word16 num; celt_word32 xcorr16; xcorr16 = EXTRACT16(VSHR32(xcorr[i], xshift)); num = MULT16_16_Q15(xcorr16,xcorr16); if (MULT16_32_Q15(num,best_den[1]) > MULT16_32_Q15(best_num[1],Syy)) { if (MULT16_32_Q15(num,best_den[0]) > MULT16_32_Q15(best_num[0],Syy)) { best_num[1] = best_num[0]; best_den[1] = best_den[0]; best_pitch[1] = best_pitch[0]; best_num[0] = num; best_den[0] = Syy; best_pitch[0] = i; } else { best_num[1] = num; best_den[1] = Syy; best_pitch[1] = i; } } } Syy += SHR32(MULT16_16(y[i+len],y[i+len]),yshift) - SHR32(MULT16_16(y[i],y[i]),yshift); Syy = MAX32(1, Syy); } } #include "plc.h" void pitch_downsample(celt_sig * restrict x[], celt_word16 * restrict x_lp, int len, int _C) { int i; celt_word32 ac[5]; celt_word16 tmp=Q15ONE; celt_word16 lpc[4], mem[4]={0,0,0,0}; const int C = CHANNELS(_C); for (i=1;i<len>>1;i++) x_lp[i] = SHR32(HALF32(HALF32(x[0][(2*i-1)]+x[0][(2*i+1)])+x[0][2*i]), SIG_SHIFT+3); x_lp[0] = SHR32(HALF32(HALF32(x[0][1])+x[0][0]), SIG_SHIFT+3); if (C==2) { for (i=1;i<len>>1;i++) x_lp[i] += SHR32(HALF32(HALF32(x[1][(2*i-1)]+x[1][(2*i+1)])+x[1][2*i]), SIG_SHIFT+3); x_lp[0] += SHR32(HALF32(HALF32(x[1][1])+x[1][0]), SIG_SHIFT+3); } _celt_autocorr(x_lp, ac, NULL, 0, 4, len>>1); /* Noise floor -40 dB */ #ifdef FIXED_POINT ac[0] += SHR32(ac[0],13); #else ac[0] *= 1.0001f; #endif /* Lag windowing */ for (i=1;i<=4;i++) { /*ac[i] *= exp(-.5*(2*M_PI*.002*i)*(2*M_PI*.002*i));*/ #ifdef FIXED_POINT ac[i] -= MULT16_32_Q15(2*i*i, ac[i]); #else ac[i] -= ac[i]*(.008f*i)*(.008f*i); #endif } _celt_lpc(lpc, ac, 4); for (i=0;i<4;i++) { tmp = MULT16_16_Q15(QCONST16(.9f,15), tmp); lpc[i] = MULT16_16_Q15(lpc[i], tmp); } fir(x_lp, lpc, x_lp, len>>1, 4, mem); mem[0]=0; lpc[0]=QCONST16(.8f,12); fir(x_lp, lpc, x_lp, len>>1, 1, mem); } void pitch_search(const celt_word16 * restrict x_lp, celt_word16 * restrict y, int len, int max_pitch, int *pitch) { int i, j; int lag; int best_pitch[2]={0}; VARDECL(celt_word16, x_lp4); VARDECL(celt_word16, y_lp4); VARDECL(celt_word32, xcorr); celt_word32 maxcorr=1; int offset; int shift=0; SAVE_STACK; lag = len+max_pitch; ALLOC(x_lp4, len>>2, celt_word16); ALLOC(y_lp4, lag>>2, celt_word16); ALLOC(xcorr, max_pitch>>1, celt_word32); /* Downsample by 2 again */ for (j=0;j<len>>2;j++) x_lp4[j] = x_lp[2*j]; for (j=0;j<lag>>2;j++) y_lp4[j] = y[2*j]; #ifdef FIXED_POINT shift = celt_ilog2(MAX16(1, MAX16(celt_maxabs16(x_lp4, len>>2), celt_maxabs16(y_lp4, lag>>2))))-11; if (shift>0) { for (j=0;j<len>>2;j++) x_lp4[j] = SHR16(x_lp4[j], shift); for (j=0;j<lag>>2;j++) y_lp4[j] = SHR16(y_lp4[j], shift); /* Use double the shift for a MAC */ shift *= 2; } else { shift = 0; } #endif /* Coarse search with 4x decimation */ for (i=0;i<max_pitch>>2;i++) { celt_word32 sum = 0; for (j=0;j<len>>2;j++) sum = MAC16_16(sum, x_lp4[j],y_lp4[i+j]); xcorr[i] = MAX32(-1, sum); maxcorr = MAX32(maxcorr, sum); } find_best_pitch(xcorr, maxcorr, y_lp4, 0, len>>2, max_pitch>>2, best_pitch); /* Finer search with 2x decimation */ maxcorr=1; for (i=0;i<max_pitch>>1;i++) { celt_word32 sum=0; xcorr[i] = 0; if (abs(i-2*best_pitch[0])>2 && abs(i-2*best_pitch[1])>2) continue; for (j=0;j<len>>1;j++) sum += SHR32(MULT16_16(x_lp[j],y[i+j]), shift); xcorr[i] = MAX32(-1, sum); maxcorr = MAX32(maxcorr, sum); } find_best_pitch(xcorr, maxcorr, y, shift, len>>1, max_pitch>>1, best_pitch); /* Refine by pseudo-interpolation */ if (best_pitch[0]>0 && best_pitch[0]<(max_pitch>>1)-1) { celt_word32 a, b, c; a = xcorr[best_pitch[0]-1]; b = xcorr[best_pitch[0]]; c = xcorr[best_pitch[0]+1]; if ((c-a) > MULT16_32_Q15(QCONST16(.7f,15),b-a)) offset = 1; else if ((a-c) > MULT16_32_Q15(QCONST16(.7f,15),b-c)) offset = -1; else offset = 0; } else { offset = 0; } *pitch = 2*best_pitch[0]-offset; RESTORE_STACK; } #ifdef ENABLE_POSTFILTER static const int second_check[16] = {0, 0, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2}; celt_word16 remove_doubling(celt_word16 *x, int maxperiod, int minperiod, int N, int *_T0, int prev_period, celt_word16 prev_gain) { int k, i, T, T0, k0; celt_word16 g, g0; celt_word16 pg; celt_word32 xy,xx,yy; celt_word32 xcorr[3]; celt_word32 best_xy, best_yy; int offset; int minperiod0; minperiod0 = minperiod; maxperiod /= 2; minperiod /= 2; *_T0 /= 2; prev_period /= 2; N /= 2; x += maxperiod; if (*_T0>=maxperiod) *_T0=maxperiod-1; T = T0 = *_T0; xx=xy=yy=0; for (i=0;i<N;i++) { xy = MAC16_16(xy, x[i], x[i-T0]); xx = MAC16_16(xx, x[i], x[i]); yy = MAC16_16(yy, x[i-T0],x[i-T0]); } best_xy = xy; best_yy = yy; #ifdef FIXED_POINT { celt_word32 x2y2; int sh, t; x2y2 = 1+HALF32(MULT32_32_Q31(xx,yy)); sh = celt_ilog2(x2y2)>>1; t = VSHR32(x2y2, 2*(sh-7)); g = g0 = VSHR32(MULT16_32_Q15(celt_rsqrt_norm(t), xy),sh+1); } #else g = g0 = xy/sqrt(1+xx*yy); #endif k0 = 1; /* Look for any pitch at T/k */ for (k=2;k<=15;k++) { int T1, T1b; celt_word16 g1; celt_word16 cont=0; T1 = (2*T0+k)/(2*k); if (T1 < minperiod) break; /* Look for another strong correlation at T1b */ if (k==2) { if (T1+T0>maxperiod) T1b = T0; else T1b = T0+T1; } else { T1b = (2*second_check[k]*T0+k)/(2*k); } xy=yy=0; for (i=0;i<N;i++) { xy = MAC16_16(xy, x[i], x[i-T1]); yy = MAC16_16(yy, x[i-T1], x[i-T1]); xy = MAC16_16(xy, x[i], x[i-T1b]); yy = MAC16_16(yy, x[i-T1b], x[i-T1b]); } #ifdef FIXED_POINT { celt_word32 x2y2; int sh, t; x2y2 = 1+MULT32_32_Q31(xx,yy); sh = celt_ilog2(x2y2)>>1; t = VSHR32(x2y2, 2*(sh-7)); g1 = VSHR32(MULT16_32_Q15(celt_rsqrt_norm(t), xy),sh+1); } #else g1 = xy/sqrt(1+2.f*xx*1.f*yy); #endif if (abs(T1-prev_period)<=1) cont = prev_gain; else if (abs(T1-prev_period)<=2 && 5*k*k < T0) cont = HALF32(prev_gain); else cont = 0; if (g1 > QCONST16(.3f,15) + MULT16_16_Q15(QCONST16(.4f,15),g0)-cont) { best_xy = xy; best_yy = yy; T = T1; g = g1; } } if (best_yy <= best_xy) pg = Q15ONE; else pg = SHR32(frac_div32(best_xy,best_yy+1),16); for (k=0;k<3;k++) { int T1 = T+k-1; xy = 0; for (i=0;i<N;i++) xy = MAC16_16(xy, x[i], x[i-T1]); xcorr[k] = xy; } if ((xcorr[2]-xcorr[0]) > MULT16_32_Q15(QCONST16(.7f,15),xcorr[1]-xcorr[0])) offset = 1; else if ((xcorr[0]-xcorr[2]) > MULT16_32_Q15(QCONST16(.7f,15),xcorr[1]-xcorr[2])) offset = -1; else offset = 0; if (pg > g) pg = g; *_T0 = 2*T+offset; if (*_T0<minperiod0) *_T0=minperiod0; return pg; } #endif /* ENABLE_POSTFILTER */