538 lines
		
	
	
		
			14 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
		
		
			
		
	
	
			538 lines
		
	
	
		
			14 KiB
		
	
	
	
		
			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. | ||
|  | 
 | ||
|  |    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 COPYRIGHT OWNER | ||
|  |    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"
 | ||
|  | #include "celt_lpc.h"
 | ||
|  | 
 | ||
|  | static void find_best_pitch(opus_val32 *xcorr, opus_val16 *y, int len, | ||
|  |                             int max_pitch, int *best_pitch | ||
|  | #ifdef FIXED_POINT
 | ||
|  |                             , int yshift, opus_val32 maxcorr | ||
|  | #endif
 | ||
|  |                             ) | ||
|  | { | ||
|  |    int i, j; | ||
|  |    opus_val32 Syy=1; | ||
|  |    opus_val16 best_num[2]; | ||
|  |    opus_val32 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 = ADD32(Syy, SHR32(MULT16_16(y[j],y[j]), yshift)); | ||
|  |    for (i=0;i<max_pitch;i++) | ||
|  |    { | ||
|  |       if (xcorr[i]>0) | ||
|  |       { | ||
|  |          opus_val16 num; | ||
|  |          opus_val32 xcorr16; | ||
|  |          xcorr16 = EXTRACT16(VSHR32(xcorr[i], xshift)); | ||
|  | #ifndef FIXED_POINT
 | ||
|  |          /* Considering the range of xcorr16, this should avoid both underflows
 | ||
|  |             and overflows (inf) when squaring xcorr16 */ | ||
|  |          xcorr16 *= 1e-12f; | ||
|  | #endif
 | ||
|  |          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); | ||
|  |    } | ||
|  | } | ||
|  | 
 | ||
|  | static void celt_fir5(opus_val16 *x, | ||
|  |          const opus_val16 *num, | ||
|  |          int N) | ||
|  | { | ||
|  |    int i; | ||
|  |    opus_val16 num0, num1, num2, num3, num4; | ||
|  |    opus_val32 mem0, mem1, mem2, mem3, mem4; | ||
|  |    num0=num[0]; | ||
|  |    num1=num[1]; | ||
|  |    num2=num[2]; | ||
|  |    num3=num[3]; | ||
|  |    num4=num[4]; | ||
|  |    mem0=0; | ||
|  |    mem1=0; | ||
|  |    mem2=0; | ||
|  |    mem3=0; | ||
|  |    mem4=0; | ||
|  |    for (i=0;i<N;i++) | ||
|  |    { | ||
|  |       opus_val32 sum = SHL32(EXTEND32(x[i]), SIG_SHIFT); | ||
|  |       sum = MAC16_16(sum,num0,mem0); | ||
|  |       sum = MAC16_16(sum,num1,mem1); | ||
|  |       sum = MAC16_16(sum,num2,mem2); | ||
|  |       sum = MAC16_16(sum,num3,mem3); | ||
|  |       sum = MAC16_16(sum,num4,mem4); | ||
|  |       mem4 = mem3; | ||
|  |       mem3 = mem2; | ||
|  |       mem2 = mem1; | ||
|  |       mem1 = mem0; | ||
|  |       mem0 = x[i]; | ||
|  |       x[i] = ROUND16(sum, SIG_SHIFT); | ||
|  |    } | ||
|  | } | ||
|  | 
 | ||
|  | 
 | ||
|  | void pitch_downsample(celt_sig * OPUS_RESTRICT x[], opus_val16 * OPUS_RESTRICT x_lp, | ||
|  |       int len, int C, int arch) | ||
|  | { | ||
|  |    int i; | ||
|  |    opus_val32 ac[5]; | ||
|  |    opus_val16 tmp=Q15ONE; | ||
|  |    opus_val16 lpc[4]; | ||
|  |    opus_val16 lpc2[5]; | ||
|  |    opus_val16 c1 = QCONST16(.8f,15); | ||
|  | #ifdef FIXED_POINT
 | ||
|  |    int shift; | ||
|  |    opus_val32 maxabs = celt_maxabs32(x[0], len); | ||
|  |    if (C==2) | ||
|  |    { | ||
|  |       opus_val32 maxabs_1 = celt_maxabs32(x[1], len); | ||
|  |       maxabs = MAX32(maxabs, maxabs_1); | ||
|  |    } | ||
|  |    if (maxabs<1) | ||
|  |       maxabs=1; | ||
|  |    shift = celt_ilog2(maxabs)-10; | ||
|  |    if (shift<0) | ||
|  |       shift=0; | ||
|  |    if (C==2) | ||
|  |       shift++; | ||
|  | #endif
 | ||
|  |    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]), shift); | ||
|  |    x_lp[0] = SHR32(HALF32(HALF32(x[0][1])+x[0][0]), shift); | ||
|  |    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]), shift); | ||
|  |       x_lp[0] += SHR32(HALF32(HALF32(x[1][1])+x[1][0]), shift); | ||
|  |    } | ||
|  | 
 | ||
|  |    _celt_autocorr(x_lp, ac, NULL, 0, | ||
|  |                   4, len>>1, arch); | ||
|  | 
 | ||
|  |    /* 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); | ||
|  |    } | ||
|  |    /* Add a zero */ | ||
|  |    lpc2[0] = lpc[0] + QCONST16(.8f,SIG_SHIFT); | ||
|  |    lpc2[1] = lpc[1] + MULT16_16_Q15(c1,lpc[0]); | ||
|  |    lpc2[2] = lpc[2] + MULT16_16_Q15(c1,lpc[1]); | ||
|  |    lpc2[3] = lpc[3] + MULT16_16_Q15(c1,lpc[2]); | ||
|  |    lpc2[4] = MULT16_16_Q15(c1,lpc[3]); | ||
|  |    celt_fir5(x_lp, lpc2, len>>1); | ||
|  | } | ||
|  | 
 | ||
|  | /* Pure C implementation. */ | ||
|  | #ifdef FIXED_POINT
 | ||
|  | opus_val32 | ||
|  | #else
 | ||
|  | void | ||
|  | #endif
 | ||
|  | celt_pitch_xcorr_c(const opus_val16 *_x, const opus_val16 *_y, | ||
|  |       opus_val32 *xcorr, int len, int max_pitch, int arch) | ||
|  | { | ||
|  | 
 | ||
|  | #if 0 /* This is a simple version of the pitch correlation that should work
 | ||
|  |          well on DSPs like Blackfin and TI C5x/C6x */ | ||
|  |    int i, j; | ||
|  | #ifdef FIXED_POINT
 | ||
|  |    opus_val32 maxcorr=1; | ||
|  | #endif
 | ||
|  | #if !defined(OVERRIDE_PITCH_XCORR)
 | ||
|  |    (void)arch; | ||
|  | #endif
 | ||
|  |    for (i=0;i<max_pitch;i++) | ||
|  |    { | ||
|  |       opus_val32 sum = 0; | ||
|  |       for (j=0;j<len;j++) | ||
|  |          sum = MAC16_16(sum, _x[j], _y[i+j]); | ||
|  |       xcorr[i] = sum; | ||
|  | #ifdef FIXED_POINT
 | ||
|  |       maxcorr = MAX32(maxcorr, sum); | ||
|  | #endif
 | ||
|  |    } | ||
|  | #ifdef FIXED_POINT
 | ||
|  |    return maxcorr; | ||
|  | #endif
 | ||
|  | 
 | ||
|  | #else /* Unrolled version of the pitch correlation -- runs faster on x86 and ARM */
 | ||
|  |    int i; | ||
|  |    /*The EDSP version requires that max_pitch is at least 1, and that _x is
 | ||
|  |       32-bit aligned. | ||
|  |      Since it's hard to put asserts in assembly, put them here.*/ | ||
|  | #ifdef FIXED_POINT
 | ||
|  |    opus_val32 maxcorr=1; | ||
|  | #endif
 | ||
|  |    celt_assert(max_pitch>0); | ||
|  |    celt_sig_assert((((unsigned char *)_x-(unsigned char *)NULL)&3)==0); | ||
|  |    for (i=0;i<max_pitch-3;i+=4) | ||
|  |    { | ||
|  |       opus_val32 sum[4]={0,0,0,0}; | ||
|  |       xcorr_kernel(_x, _y+i, sum, len, arch); | ||
|  |       xcorr[i]=sum[0]; | ||
|  |       xcorr[i+1]=sum[1]; | ||
|  |       xcorr[i+2]=sum[2]; | ||
|  |       xcorr[i+3]=sum[3]; | ||
|  | #ifdef FIXED_POINT
 | ||
|  |       sum[0] = MAX32(sum[0], sum[1]); | ||
|  |       sum[2] = MAX32(sum[2], sum[3]); | ||
|  |       sum[0] = MAX32(sum[0], sum[2]); | ||
|  |       maxcorr = MAX32(maxcorr, sum[0]); | ||
|  | #endif
 | ||
|  |    } | ||
|  |    /* In case max_pitch isn't a multiple of 4, do non-unrolled version. */ | ||
|  |    for (;i<max_pitch;i++) | ||
|  |    { | ||
|  |       opus_val32 sum; | ||
|  |       sum = celt_inner_prod(_x, _y+i, len, arch); | ||
|  |       xcorr[i] = sum; | ||
|  | #ifdef FIXED_POINT
 | ||
|  |       maxcorr = MAX32(maxcorr, sum); | ||
|  | #endif
 | ||
|  |    } | ||
|  | #ifdef FIXED_POINT
 | ||
|  |    return maxcorr; | ||
|  | #endif
 | ||
|  | #endif
 | ||
|  | } | ||
|  | 
 | ||
|  | void pitch_search(const opus_val16 * OPUS_RESTRICT x_lp, opus_val16 * OPUS_RESTRICT y, | ||
|  |                   int len, int max_pitch, int *pitch, int arch) | ||
|  | { | ||
|  |    int i, j; | ||
|  |    int lag; | ||
|  |    int best_pitch[2]={0,0}; | ||
|  |    VARDECL(opus_val16, x_lp4); | ||
|  |    VARDECL(opus_val16, y_lp4); | ||
|  |    VARDECL(opus_val32, xcorr); | ||
|  | #ifdef FIXED_POINT
 | ||
|  |    opus_val32 maxcorr; | ||
|  |    opus_val32 xmax, ymax; | ||
|  |    int shift=0; | ||
|  | #endif
 | ||
|  |    int offset; | ||
|  | 
 | ||
|  |    SAVE_STACK; | ||
|  | 
 | ||
|  |    celt_assert(len>0); | ||
|  |    celt_assert(max_pitch>0); | ||
|  |    lag = len+max_pitch; | ||
|  | 
 | ||
|  |    ALLOC(x_lp4, len>>2, opus_val16); | ||
|  |    ALLOC(y_lp4, lag>>2, opus_val16); | ||
|  |    ALLOC(xcorr, max_pitch>>1, opus_val32); | ||
|  | 
 | ||
|  |    /* 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
 | ||
|  |    xmax = celt_maxabs16(x_lp4, len>>2); | ||
|  |    ymax = celt_maxabs16(y_lp4, lag>>2); | ||
|  |    shift = celt_ilog2(MAX32(1, MAX32(xmax, ymax)))-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 */ | ||
|  | 
 | ||
|  | #ifdef FIXED_POINT
 | ||
|  |    maxcorr = | ||
|  | #endif
 | ||
|  |    celt_pitch_xcorr(x_lp4, y_lp4, xcorr, len>>2, max_pitch>>2, arch); | ||
|  | 
 | ||
|  |    find_best_pitch(xcorr, y_lp4, len>>2, max_pitch>>2, best_pitch | ||
|  | #ifdef FIXED_POINT
 | ||
|  |                    , 0, maxcorr | ||
|  | #endif
 | ||
|  |                    ); | ||
|  | 
 | ||
|  |    /* Finer search with 2x decimation */ | ||
|  | #ifdef FIXED_POINT
 | ||
|  |    maxcorr=1; | ||
|  | #endif
 | ||
|  |    for (i=0;i<max_pitch>>1;i++) | ||
|  |    { | ||
|  |       opus_val32 sum; | ||
|  |       xcorr[i] = 0; | ||
|  |       if (abs(i-2*best_pitch[0])>2 && abs(i-2*best_pitch[1])>2) | ||
|  |          continue; | ||
|  | #ifdef FIXED_POINT
 | ||
|  |       sum = 0; | ||
|  |       for (j=0;j<len>>1;j++) | ||
|  |          sum += SHR32(MULT16_16(x_lp[j],y[i+j]), shift); | ||
|  | #else
 | ||
|  |       sum = celt_inner_prod(x_lp, y+i, len>>1, arch); | ||
|  | #endif
 | ||
|  |       xcorr[i] = MAX32(-1, sum); | ||
|  | #ifdef FIXED_POINT
 | ||
|  |       maxcorr = MAX32(maxcorr, sum); | ||
|  | #endif
 | ||
|  |    } | ||
|  |    find_best_pitch(xcorr, y, len>>1, max_pitch>>1, best_pitch | ||
|  | #ifdef FIXED_POINT
 | ||
|  |                    , shift+1, maxcorr | ||
|  | #endif
 | ||
|  |                    ); | ||
|  | 
 | ||
|  |    /* Refine by pseudo-interpolation */ | ||
|  |    if (best_pitch[0]>0 && best_pitch[0]<(max_pitch>>1)-1) | ||
|  |    { | ||
|  |       opus_val32 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 FIXED_POINT
 | ||
|  | static opus_val16 compute_pitch_gain(opus_val32 xy, opus_val32 xx, opus_val32 yy) | ||
|  | { | ||
|  |    opus_val32 x2y2; | ||
|  |    int sx, sy, shift; | ||
|  |    opus_val32 g; | ||
|  |    opus_val16 den; | ||
|  |    if (xy == 0 || xx == 0 || yy == 0) | ||
|  |       return 0; | ||
|  |    sx = celt_ilog2(xx)-14; | ||
|  |    sy = celt_ilog2(yy)-14; | ||
|  |    shift = sx + sy; | ||
|  |    x2y2 = SHR32(MULT16_16(VSHR32(xx, sx), VSHR32(yy, sy)), 14); | ||
|  |    if (shift & 1) { | ||
|  |       if (x2y2 < 32768) | ||
|  |       { | ||
|  |          x2y2 <<= 1; | ||
|  |          shift--; | ||
|  |       } else { | ||
|  |          x2y2 >>= 1; | ||
|  |          shift++; | ||
|  |       } | ||
|  |    } | ||
|  |    den = celt_rsqrt_norm(x2y2); | ||
|  |    g = MULT16_32_Q15(den, xy); | ||
|  |    g = VSHR32(g, (shift>>1)-1); | ||
|  |    return EXTRACT16(MIN32(g, Q15ONE)); | ||
|  | } | ||
|  | #else
 | ||
|  | static opus_val16 compute_pitch_gain(opus_val32 xy, opus_val32 xx, opus_val32 yy) | ||
|  | { | ||
|  |    return xy/celt_sqrt(1+xx*yy); | ||
|  | } | ||
|  | #endif
 | ||
|  | 
 | ||
|  | static const int second_check[16] = {0, 0, 3, 2, 3, 2, 5, 2, 3, 2, 3, 2, 5, 2, 3, 2}; | ||
|  | opus_val16 remove_doubling(opus_val16 *x, int maxperiod, int minperiod, | ||
|  |       int N, int *T0_, int prev_period, opus_val16 prev_gain, int arch) | ||
|  | { | ||
|  |    int k, i, T, T0; | ||
|  |    opus_val16 g, g0; | ||
|  |    opus_val16 pg; | ||
|  |    opus_val32 xy,xx,yy,xy2; | ||
|  |    opus_val32 xcorr[3]; | ||
|  |    opus_val32 best_xy, best_yy; | ||
|  |    int offset; | ||
|  |    int minperiod0; | ||
|  |    VARDECL(opus_val32, yy_lookup); | ||
|  |    SAVE_STACK; | ||
|  | 
 | ||
|  |    minperiod0 = minperiod; | ||
|  |    maxperiod /= 2; | ||
|  |    minperiod /= 2; | ||
|  |    *T0_ /= 2; | ||
|  |    prev_period /= 2; | ||
|  |    N /= 2; | ||
|  |    x += maxperiod; | ||
|  |    if (*T0_>=maxperiod) | ||
|  |       *T0_=maxperiod-1; | ||
|  | 
 | ||
|  |    T = T0 = *T0_; | ||
|  |    ALLOC(yy_lookup, maxperiod+1, opus_val32); | ||
|  |    dual_inner_prod(x, x, x-T0, N, &xx, &xy, arch); | ||
|  |    yy_lookup[0] = xx; | ||
|  |    yy=xx; | ||
|  |    for (i=1;i<=maxperiod;i++) | ||
|  |    { | ||
|  |       yy = yy+MULT16_16(x[-i],x[-i])-MULT16_16(x[N-i],x[N-i]); | ||
|  |       yy_lookup[i] = MAX32(0, yy); | ||
|  |    } | ||
|  |    yy = yy_lookup[T0]; | ||
|  |    best_xy = xy; | ||
|  |    best_yy = yy; | ||
|  |    g = g0 = compute_pitch_gain(xy, xx, yy); | ||
|  |    /* Look for any pitch at T/k */ | ||
|  |    for (k=2;k<=15;k++) | ||
|  |    { | ||
|  |       int T1, T1b; | ||
|  |       opus_val16 g1; | ||
|  |       opus_val16 cont=0; | ||
|  |       opus_val16 thresh; | ||
|  |       T1 = celt_udiv(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 = celt_udiv(2*second_check[k]*T0+k, 2*k); | ||
|  |       } | ||
|  |       dual_inner_prod(x, &x[-T1], &x[-T1b], N, &xy, &xy2, arch); | ||
|  |       xy = HALF32(xy + xy2); | ||
|  |       yy = HALF32(yy_lookup[T1] + yy_lookup[T1b]); | ||
|  |       g1 = compute_pitch_gain(xy, xx, yy); | ||
|  |       if (abs(T1-prev_period)<=1) | ||
|  |          cont = prev_gain; | ||
|  |       else if (abs(T1-prev_period)<=2 && 5*k*k < T0) | ||
|  |          cont = HALF16(prev_gain); | ||
|  |       else | ||
|  |          cont = 0; | ||
|  |       thresh = MAX16(QCONST16(.3f,15), MULT16_16_Q15(QCONST16(.7f,15),g0)-cont); | ||
|  |       /* Bias against very high pitch (very short period) to avoid false-positives
 | ||
|  |          due to short-term correlation */ | ||
|  |       if (T1<3*minperiod) | ||
|  |          thresh = MAX16(QCONST16(.4f,15), MULT16_16_Q15(QCONST16(.85f,15),g0)-cont); | ||
|  |       else if (T1<2*minperiod) | ||
|  |          thresh = MAX16(QCONST16(.5f,15), MULT16_16_Q15(QCONST16(.9f,15),g0)-cont); | ||
|  |       if (g1 > thresh) | ||
|  |       { | ||
|  |          best_xy = xy; | ||
|  |          best_yy = yy; | ||
|  |          T = T1; | ||
|  |          g = g1; | ||
|  |       } | ||
|  |    } | ||
|  |    best_xy = MAX32(0, best_xy); | ||
|  |    if (best_yy <= best_xy) | ||
|  |       pg = Q15ONE; | ||
|  |    else | ||
|  |       pg = SHR32(frac_div32(best_xy,best_yy+1),16); | ||
|  | 
 | ||
|  |    for (k=0;k<3;k++) | ||
|  |       xcorr[k] = celt_inner_prod(x, x-(T+k-1), N, arch); | ||
|  |    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; | ||
|  |    RESTORE_STACK; | ||
|  |    return pg; | ||
|  | } |