libcelt/vq.c

/* Copyright (c) 2007-2008 CSIRO
   Copyright (c) 2007-2009 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.
   
   - 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 "mathops.h"
#include "cwrs.h"
#include "vq.h"
#include "arch.h"
#include "os_support.h"
#include "rate.h"

#ifndef M_PI
#define M_PI 3.141592653
#endif

static celt_uint32 lcg_rand(celt_uint32 seed)
{
   return 1664525 * seed + 1013904223;
}

static void exp_rotation1(celt_norm *X, int len, int stride, celt_word16 c, celt_word16 s)
{
   int i;
   celt_norm *Xptr;
   Xptr = X;
   for (i=0;i<len-stride;i++)
   {
      celt_norm x1, x2;
      x1 = Xptr[0];
      x2 = Xptr[stride];
      Xptr[stride] = EXTRACT16(SHR32(MULT16_16(c,x2) + MULT16_16(s,x1), 15));
      *Xptr++      = EXTRACT16(SHR32(MULT16_16(c,x1) - MULT16_16(s,x2), 15));
   }
   Xptr = &X[len-2*stride-1];
   for (i=len-2*stride-1;i>=0;i--)
   {
      celt_norm x1, x2;
      x1 = Xptr[0];
      x2 = Xptr[stride];
      Xptr[stride] = EXTRACT16(SHR32(MULT16_16(c,x2) + MULT16_16(s,x1), 15));
      *Xptr--      = EXTRACT16(SHR32(MULT16_16(c,x1) - MULT16_16(s,x2), 15));
   }
}

static void exp_rotation(celt_norm *X, int len, int dir, int stride, int K, int spread)
{
   int i;
   celt_word16 c, s;
   celt_word16 gain, theta;
   int stride2=0;
   int factor;
   /*int i;
   if (len>=30)
   {
      for (i=0;i<len;i++)
         X[i] = 0;
      X[14] = 1;
      K=5;
   }*/
   if (2*K>=len || spread==0)
      return;
   if (spread==1)
      factor=10;
   else if (spread==2)
      factor=5;
   else
      factor=15;

   gain = celt_div((celt_word32)MULT16_16(Q15_ONE,len),(celt_word32)(len+factor*K));
   /* FIXME: Make that HALF16 instead of HALF32 */
   theta = HALF32(MULT16_16_Q15(gain,gain));

   c = celt_cos_norm(EXTEND32(theta));
   s = celt_cos_norm(EXTEND32(SUB16(Q15ONE,theta))); /*  sin(theta) */

   if (len>=8*stride)
   {
      stride2 = 1;
      /* This is just a simple way of computing sqrt(len/stride) with rounding.
         It's basically incrementing long as (stride2+0.5)^2 < len/stride.
         I _think_ it is bit-exact */
      while ((stride2*stride2+stride2)*stride + (stride>>2) < len)
         stride2++;
   }
   len /= stride;
   for (i=0;i<stride;i++)
   {
      if (dir < 0)
      {
         if (stride2)
            exp_rotation1(X+i*len, len, stride2, s, c);
         exp_rotation1(X+i*len, len, 1, c, s);
      } else {
         exp_rotation1(X+i*len, len, 1, c, -s);
         if (stride2)
            exp_rotation1(X+i*len, len, stride2, s, -c);
      }
   }
   /*if (len>=30)
   {
      for (i=0;i<len;i++)
         printf ("%f ", X[i]);
      printf ("\n");
      exit(0);
   }*/
}

/** Takes the pitch vector and the decoded residual vector, computes the gain
    that will give ||p+g*y||=1 and mixes the residual with the pitch. */
static void normalise_residual(int * restrict iy, celt_norm * restrict X,
      int N, int K, celt_word32 Ryy, celt_word16 gain)
{
   int i;
#ifdef FIXED_POINT
   int k;
#endif
   celt_word32 t;
   celt_word16 g;

#ifdef FIXED_POINT
   k = celt_ilog2(Ryy)>>1;
#endif
   t = VSHR32(Ryy, (k-7)<<1);
   g = MULT16_16_P15(celt_rsqrt_norm(t),gain);

   i=0;
   do
      X[i] = EXTRACT16(PSHR32(MULT16_16(g, iy[i]), k+1));
   while (++i < N);
}

void alg_quant(celt_norm *X, int N, int K, int spread, int B, celt_norm *lowband,
      int resynth, ec_enc *enc, celt_int32 *seed, celt_word16 gain)
{
   VARDECL(celt_norm, y);
   VARDECL(int, iy);
   VARDECL(celt_word16, signx);
   int j, is;
   celt_word16 s;
   int pulsesLeft;
   celt_word32 sum;
   celt_word32 xy, yy;
   int N_1; /* Inverse of N, in Q14 format (even for float) */
#ifdef FIXED_POINT
   int yshift;
#endif
   SAVE_STACK;

   /* When there's no pulse, fill with noise or folded spectrum */
   if (K==0)
   {
      if (lowband != NULL && resynth)
      {
         for (j=0;j<N;j++)
            X[j] = lowband[j];
      } else {
         /* This is important for encoding the side in stereo mode */
         for (j=0;j<N;j++)
         {
            *seed = lcg_rand(*seed);
            X[j] = (int)(*seed)>>20;
         }
      }
      renormalise_vector(X, N, gain);
      return;
   }
   K = get_pulses(K);
#ifdef FIXED_POINT
   yshift = 13-celt_ilog2(K);
#endif

   ALLOC(y, N, celt_norm);
   ALLOC(iy, N, int);
   ALLOC(signx, N, celt_word16);
   N_1 = 512/N;
   
   exp_rotation(X, N, 1, B, K, spread);

   /* Get rid of the sign */
   sum = 0;
   j=0; do {
      if (X[j]>0)
         signx[j]=1;
      else {
         signx[j]=-1;
         X[j]=-X[j];
      }
      iy[j] = 0;
      y[j] = 0;
   } while (++j<N);

   xy = yy = 0;

   pulsesLeft = K;

   /* Do a pre-search by projecting on the pyramid */
   if (K > (N>>1))
   {
      celt_word16 rcp;
      j=0; do {
         sum += X[j];
      }  while (++j<N);

      /* If X is too small, just replace it with a pulse at 0 */
#ifdef FIXED_POINT
      if (sum <= K)
#else
      if (sum <= EPSILON)
#endif
      {
         X[0] = QCONST16(1.f,14);
         j=1; do
            X[j]=0;
         while (++j<N);
         sum = QCONST16(1.f,14);
      }
      /* Do we have sufficient accuracy here? */
      rcp = EXTRACT16(MULT16_32_Q16(K-1, celt_rcp(sum)));
      j=0; do {
#ifdef FIXED_POINT
         /* It's really important to round *towards zero* here */
         iy[j] = MULT16_16_Q15(X[j],rcp);
#else
         iy[j] = (int)floor(rcp*X[j]);
#endif
         y[j] = SHL16(iy[j],yshift);
         yy = MAC16_16(yy, y[j],y[j]);
         xy = MAC16_16(xy, X[j],y[j]);
         y[j] *= 2;
         pulsesLeft -= iy[j];
      }  while (++j<N);
   }
   celt_assert2(pulsesLeft>=1, "Allocated too many pulses in the quick pass");

   while (pulsesLeft > 0)
   {
      int pulsesAtOnce=1;
      int best_id;
      celt_word16 magnitude;
      celt_word32 best_num = -VERY_LARGE16;
      celt_word16 best_den = 0;
#ifdef FIXED_POINT
      int rshift;
#endif
      /* Decide on how many pulses to find at once */
      pulsesAtOnce = (pulsesLeft*N_1)>>9; /* pulsesLeft/N */
      if (pulsesAtOnce<1)
         pulsesAtOnce = 1;
#ifdef FIXED_POINT
      rshift = yshift+1+celt_ilog2(K-pulsesLeft+pulsesAtOnce);
#endif
      magnitude = SHL16(pulsesAtOnce, yshift);

      best_id = 0;
      /* The squared magnitude term gets added anyway, so we might as well 
         add it outside the loop */
      yy = MAC16_16(yy, magnitude,magnitude);
      /* Choose between fast and accurate strategy depending on where we are in the search */
         /* This should ensure that anything we can process will have a better score */
      j=0;
      do {
         celt_word16 Rxy, Ryy;
         /* Select sign based on X[j] alone */
         s = magnitude;
         /* Temporary sums of the new pulse(s) */
         Rxy = EXTRACT16(SHR32(MAC16_16(xy, s,X[j]),rshift));
         /* We're multiplying y[j] by two so we don't have to do it here */
         Ryy = EXTRACT16(SHR32(MAC16_16(yy, s,y[j]),rshift));
            
         /* Approximate score: we maximise Rxy/sqrt(Ryy) (we're guaranteed that
            Rxy is positive because the sign is pre-computed) */
         Rxy = MULT16_16_Q15(Rxy,Rxy);
         /* The idea is to check for num/den >= best_num/best_den, but that way
            we can do it without any division */
         /* OPT: Make sure to use conditional moves here */
         if (MULT16_16(best_den, Rxy) > MULT16_16(Ryy, best_num))
         {
            best_den = Ryy;
            best_num = Rxy;
            best_id = j;
         }
      } while (++j<N);
      
      j = best_id;
      is = pulsesAtOnce;
      s = SHL16(is, yshift);

      /* Updating the sums of the new pulse(s) */
      xy = xy + MULT16_16(s,X[j]);
      /* We're multiplying y[j] by two so we don't have to do it here */
      yy = yy + MULT16_16(s,y[j]);

      /* Only now that we've made the final choice, update y/iy */
      /* Multiplying y[j] by 2 so we don't have to do it everywhere else */
      y[j] += 2*s;
      iy[j] += is;
      pulsesLeft -= pulsesAtOnce;
   }

   /* Put the original sign back */
   j=0;
   do {
      X[j] = MULT16_16(signx[j],X[j]);
      if (signx[j] < 0)
         iy[j] = -iy[j];
   } while (++j<N);
   encode_pulses(iy, N, K, enc);
   
   if (resynth)
   {
      normalise_residual(iy, X, N, K, EXTRACT16(SHR32(yy,2*yshift)), gain);
      exp_rotation(X, N, -1, B, K, spread);
   }
   RESTORE_STACK;
}


/** Decode pulse vector and combine the result with the pitch vector to produce
    the final normalised signal in the current band. */
void alg_unquant(celt_norm *X, int N, int K, int spread, int B,
      celt_norm *lowband, ec_dec *dec, celt_int32 *seed, celt_word16 gain)
{
   int i;
   celt_word32 Ryy;
   VARDECL(int, iy);
   SAVE_STACK;

   if (K==0)
   {
      if (lowband != NULL)
      {
         for (i=0;i<N;i++)
            X[i] = lowband[i];
      } else {
         /* This is important for encoding the side in stereo mode */
         for (i=0;i<N;i++)
         {
            *seed = lcg_rand(*seed);
            X[i] = (int)(*seed)>>20;
         }
      }
      renormalise_vector(X, N, gain);
      return;
   }
   K = get_pulses(K);
   ALLOC(iy, N, int);
   decode_pulses(iy, N, K, dec);
   Ryy = 0;
   i=0;
   do {
      Ryy = MAC16_16(Ryy, iy[i], iy[i]);
   } while (++i < N);
   normalise_residual(iy, X, N, K, Ryy, gain);
   exp_rotation(X, N, -1, B, K, spread);
   RESTORE_STACK;
}

celt_word16 vector_norm(const celt_norm *X, int N)
{
   int i;
   celt_word32 E = EPSILON;
   const celt_norm *xptr = X;
   for (i=0;i<N;i++)
   {
      E = MAC16_16(E, *xptr, *xptr);
      xptr++;
   }
   return celt_sqrt(E);
}

void renormalise_vector(celt_norm *X, int N, celt_word16 gain)
{
   int i;
#ifdef FIXED_POINT
   int k;
#endif
   celt_word32 E = EPSILON;
   celt_word16 g;
   celt_word32 t;
   celt_norm *xptr = X;
   for (i=0;i<N;i++)
   {
      E = MAC16_16(E, *xptr, *xptr);
      xptr++;
   }
#ifdef FIXED_POINT
   k = celt_ilog2(E)>>1;
#endif
   t = VSHR32(E, (k-7)<<1);
   g = MULT16_16_P15(celt_rsqrt_norm(t),gain);

   xptr = X;
   for (i=0;i<N;i++)
   {
      *xptr = EXTRACT16(PSHR32(MULT16_16(g, *xptr), k+1));
      xptr++;
   }
   /*return celt_sqrt(E);*/
}