ref: 7a7c42a7166bba35084f44436b1f43078b806c8c
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"
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++)
{
float score;
if (xcorr[i]>0)
{
celt_word16 num;
celt_word32 xcorr16;
xcorr16 = EXTRACT16(VSHR32(xcorr[i], xshift));
num = MULT16_16_Q15(xcorr16,xcorr16);
score = num*1./Syy;
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);
}
}
void find_temporal_pitch(const CELTMode *m, const celt_sig * restrict x, celt_word16 * restrict y, int len, int max_pitch, int *pitch, int _C, celt_sig *xmem)
{
int i, j;
const int C = CHANNELS(_C);
const int lag = MAX_PERIOD;
const int N = FRAMESIZE(m);
int best_pitch[2]={0};
VARDECL(celt_word16, x_lp);
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;
ALLOC(x_lp, len>>1, celt_word16);
ALLOC(x_lp4, len>>2, celt_word16);
ALLOC(y_lp4, len>>2, celt_word16);
ALLOC(xcorr, max_pitch>>1, celt_word32);
/* Down-sample by two and downmix to mono */
for (i=1;i<len>>1;i++)
x_lp[i] = SHR32(HALF32(HALF32(x[(2*i-1)*C]+x[(2*i+1)*C])+x[2*i*C]), SIG_SHIFT);
x_lp[0] = SHR32(HALF32(HALF32(*xmem+x[C])+x[0]), SIG_SHIFT);
*xmem = x[N-C];
if (C==2)
{
for (i=1;i<len>>1;i++)
x_lp[i] = SHR32(HALF32(HALF32(x[(2*i-1)*C+1]+x[(2*i+1)*C+1])+x[2*i*C+1]), SIG_SHIFT);
x_lp[0] += SHR32(HALF32(HALF32(x[C+1])+x[1]), SIG_SHIFT);
*xmem += x[N-C+1];
}
/* 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(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;
CELT_MOVE(y, y+(N>>1), (lag-N)>>1);
CELT_COPY(y+((lag-N)>>1), x_lp, N>>1);
RESTORE_STACK;
/*printf ("%d\n", *pitch);*/
}