The Tor Browser: media/libopus/celt/pitch.c@ac0c01689b40 (annotated)

media/libopus/celt/pitch.c@ac0c01689b40 (annotated)

media/libopus/celt/pitch.c

Thu, 15 Jan 2015 15:59:08 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 15 Jan 2015 15:59:08 +0100
branch: TOR_BUG_9701
changeset 10: ac0c01689b40
permissions: -rw-r--r--

Implement a real Private Browsing Mode condition by changing the API/ABI;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /* 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(const opus_val16 *x,
          const opus_val16 *num,
          opus_val16 *y,
          int N,
          opus_val16 *mem)
 {
    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=mem[0];
    mem1=mem[1];
    mem2=mem[2];
    mem3=mem[3];
    mem4=mem[4];
    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];
       y[i] = ROUND16(sum, SIG_SHIFT);
    }
    mem[0]=mem0;
    mem[1]=mem1;
    mem[2]=mem2;
    mem[3]=mem3;
    mem[4]=mem4;
 }
 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], mem[5]={0,0,0,0,0};
    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,
 , 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, x_lp, len>>1, mem);
 }
 #if 0 /* This is a simple version of the pitch correlation that should work
          well on DSPs like Blackfin and TI C5x/C6x */
 #ifdef FIXED_POINT
 opus_val32
 #else
 void
 #endif
 celt_pitch_xcorr(opus_val16 *x, opus_val16 *y, opus_val32 *xcorr, int len, int max_pitch)
 {
    int i, j;
 #ifdef FIXED_POINT
    opus_val32 maxcorr=1;
 #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 */
 #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 i,j;
    /*The EDSP version requires that max_pitch is at least 1, and that _x is
 -bit aligned.
      Since it's hard to put asserts in assembly, put them here.*/
    celt_assert(max_pitch>0);
    celt_assert((((unsigned char *)_x-(unsigned char *)NULL)&3)==0);
 #ifdef FIXED_POINT
    opus_val32 maxcorr=1;
 #endif
    for (i=0;i<max_pitch-3;i+=4)
    {
       opus_val32 sum[4]={0,0,0,0};
       xcorr_kernel(_x, _y+i, sum, len);
       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 = 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
 }
 #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=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);
 #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;
 }
 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 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);
    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;
 #ifdef FIXED_POINT
       {
          opus_val32 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/celt_sqrt(1+xx*yy);
 #endif
    /* 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 = (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);
       }
       dual_inner_prod(x, &x[-T1], &x[-T1b], N, &xy, &xy2);
       xy += xy2;
       yy = yy_lookup[T1] + yy_lookup[T1b];
 #ifdef FIXED_POINT
       {
          opus_val32 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/celt_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;
       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++)
    {
       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;
    RESTORE_STACK;
    return pg;
 }

The Tor Browser / annotate

media/libopus/celt/pitch.c@ac0c01689b40 (annotated)

media/libopus/celt/pitch.c