chromium/third_party/opus/src/celt/modes.c

/* Copyright (c) 2007-2008 CSIRO
   Copyright (c) 2007-2009 Xiph.Org Foundation
   Copyright (c) 2008 Gregory Maxwell
   Written by Jean-Marc Valin and Gregory Maxwell */
/*
   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 "celt.h"
#include "modes.h"
#include "rate.h"
#include "os_support.h"
#include "stack_alloc.h"
#include "quant_bands.h"
#include "cpu_support.h"

static const opus_int16 eband5ms[] = …;

/* Alternate tuning (partially derived from Vorbis) */
#define BITALLOC_SIZE …
/* Bit allocation table in units of 1/32 bit/sample (0.1875 dB SNR) */
static const unsigned char band_allocation[] = …;

#ifndef CUSTOM_MODES_ONLY
 #ifdef FIXED_POINT
  #include "static_modes_fixed.h"
 #else
  #include "static_modes_float.h"
 #endif
#endif /* CUSTOM_MODES_ONLY */

#ifndef M_PI
#define M_PI …
#endif

#ifdef CUSTOM_MODES

/* Defining 25 critical bands for the full 0-20 kHz audio bandwidth
   Taken from http://ccrma.stanford.edu/~jos/bbt/Bark_Frequency_Scale.html */
#define BARK_BANDS …
static const opus_int16 bark_freq[BARK_BANDS+1] = {
      0,   100,   200,   300,   400,
    510,   630,   770,   920,  1080,
   1270,  1480,  1720,  2000,  2320,
   2700,  3150,  3700,  4400,  5300,
   6400,  7700,  9500, 12000, 15500,
  20000};

static opus_int16 *compute_ebands(opus_int32 Fs, int frame_size, int res, int *nbEBands)
{
   opus_int16 *eBands;
   int i, j, lin, low, high, nBark, offset=0;

   /* All modes that have 2.5 ms short blocks use the same definition */
   if (Fs == 400*(opus_int32)frame_size)
   {
      *nbEBands = sizeof(eband5ms)/sizeof(eband5ms[0])-1;
      eBands = opus_alloc(sizeof(opus_int16)*(*nbEBands+1));
      for (i=0;i<*nbEBands+1;i++)
         eBands[i] = eband5ms[i];
      return eBands;
   }
   /* Find the number of critical bands supported by our sampling rate */
   for (nBark=1;nBark<BARK_BANDS;nBark++)
    if (bark_freq[nBark+1]*2 >= Fs)
       break;

   /* Find where the linear part ends (i.e. where the spacing is more than min_width */
   for (lin=0;lin<nBark;lin++)
      if (bark_freq[lin+1]-bark_freq[lin] >= res)
         break;

   low = (bark_freq[lin]+res/2)/res;
   high = nBark-lin;
   *nbEBands = low+high;
   eBands = opus_alloc(sizeof(opus_int16)*(*nbEBands+2));

   if (eBands==NULL)
      return NULL;

   /* Linear spacing (min_width) */
   for (i=0;i<low;i++)
      eBands[i] = i;
   if (low>0)
      offset = eBands[low-1]*res - bark_freq[lin-1];
   /* Spacing follows critical bands */
   for (i=0;i<high;i++)
   {
      int target = bark_freq[lin+i];
      /* Round to an even value */
      eBands[i+low] = (target+offset/2+res)/(2*res)*2;
      offset = eBands[i+low]*res - target;
   }
   /* Enforce the minimum spacing at the boundary */
   for (i=0;i<*nbEBands;i++)
      if (eBands[i] < i)
         eBands[i] = i;
   /* Round to an even value */
   eBands[*nbEBands] = (bark_freq[nBark]+res)/(2*res)*2;
   if (eBands[*nbEBands] > frame_size)
      eBands[*nbEBands] = frame_size;
   for (i=1;i<*nbEBands-1;i++)
   {
      if (eBands[i+1]-eBands[i] < eBands[i]-eBands[i-1])
      {
         eBands[i] -= (2*eBands[i]-eBands[i-1]-eBands[i+1])/2;
      }
   }
   /* Remove any empty bands. */
   for (i=j=0;i<*nbEBands;i++)
      if(eBands[i+1]>eBands[j])
         eBands[++j]=eBands[i+1];
   *nbEBands=j;

   for (i=1;i<*nbEBands;i++)
   {
      /* Every band must be smaller than the last band. */
      celt_assert(eBands[i]-eBands[i-1]<=eBands[*nbEBands]-eBands[*nbEBands-1]);
      /* Each band must be no larger than twice the size of the previous one. */
      celt_assert(eBands[i+1]-eBands[i]<=2*(eBands[i]-eBands[i-1]));
   }

   return eBands;
}

static void compute_allocation_table(CELTMode *mode)
{
   int i, j;
   unsigned char *allocVectors;
   int maxBands = sizeof(eband5ms)/sizeof(eband5ms[0])-1;

   mode->nbAllocVectors = BITALLOC_SIZE;
   allocVectors = opus_alloc(sizeof(unsigned char)*(BITALLOC_SIZE*mode->nbEBands));
   if (allocVectors==NULL)
   {
      mode->allocVectors = NULL;
      return;
   }

   /* Check for standard mode */
   if (mode->Fs == 400*(opus_int32)mode->shortMdctSize)
   {
      for (i=0;i<BITALLOC_SIZE*mode->nbEBands;i++)
         allocVectors[i] = band_allocation[i];
      mode->allocVectors = allocVectors;
      return;
   }
   /* If not the standard mode, interpolate */
   /* Compute per-codec-band allocation from per-critical-band matrix */
   for (i=0;i<BITALLOC_SIZE;i++)
   {
      for (j=0;j<mode->nbEBands;j++)
      {
         int k;
         for (k=0;k<maxBands;k++)
         {
            if (400*(opus_int32)eband5ms[k] > mode->eBands[j]*(opus_int32)mode->Fs/mode->shortMdctSize)
               break;
         }
         if (k>maxBands-1)
            allocVectors[i*mode->nbEBands+j] = band_allocation[i*maxBands + maxBands-1];
         else {
            opus_int32 a0, a1;
            a1 = mode->eBands[j]*(opus_int32)mode->Fs/mode->shortMdctSize - 400*(opus_int32)eband5ms[k-1];
            a0 = 400*(opus_int32)eband5ms[k] - mode->eBands[j]*(opus_int32)mode->Fs/mode->shortMdctSize;
            allocVectors[i*mode->nbEBands+j] = (a0*band_allocation[i*maxBands+k-1]
                                             + a1*band_allocation[i*maxBands+k])/(a0+a1);
         }
      }
   }

   /*printf ("\n");
   for (i=0;i<BITALLOC_SIZE;i++)
   {
      for (j=0;j<mode->nbEBands;j++)
         printf ("%d ", allocVectors[i*mode->nbEBands+j]);
      printf ("\n");
   }
   exit(0);*/

   mode->allocVectors = allocVectors;
}

#endif /* CUSTOM_MODES */

CELTMode *opus_custom_mode_create(opus_int32 Fs, int frame_size, int *error)
{ … }

#ifdef CUSTOM_MODES
void opus_custom_mode_destroy(CELTMode *mode)
{
   int arch = opus_select_arch();

   if (mode == NULL)
      return;
#ifndef CUSTOM_MODES_ONLY
   {
     int i;
     for (i=0;i<TOTAL_MODES;i++)
     {
        if (mode == static_mode_list[i])
        {
           return;
        }
     }
   }
#endif /* CUSTOM_MODES_ONLY */
   opus_free((opus_int16*)mode->eBands);
   opus_free((unsigned char*)mode->allocVectors);

   opus_free((opus_val16*)mode->window);
   opus_free((opus_int16*)mode->logN);

   opus_free((opus_int16*)mode->cache.index);
   opus_free((unsigned char*)mode->cache.bits);
   opus_free((unsigned char*)mode->cache.caps);
   clt_mdct_clear(&mode->mdct, arch);

   opus_free((CELTMode *)mode);
}
#endif