cog/Frameworks/libcelt_0061/celt-0.6.1/libcelt/rate.h

/* (C) 2007-2008 Jean-Marc Valin, CSIRO
*/
/*
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   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.
   
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   notice, this list of conditions and the following disclaimer in the
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   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,
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   SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#ifndef RATE_H
#define RATE_H

#define MAX_PULSES 128
#define LOG_MAX_PULSES 7

#define BITRES 4
#define BITROUND 8
#define BITOVERFLOW 30000

#include "cwrs.h"

static inline int bits2pulses(const CELTMode *m, const celt_int16_t *cache, int N, int bits)
{
   int i;
   int lo, hi;
   lo = 0;
   hi = MAX_PULSES-1;
   
#if 0 /* Disabled until we can make that useful */
   /* Use of more than MAX_PULSES is disabled until we are able to cwrs that decently */
   if (bits > cache[MAX_PULSES-1] && N<=4)
   {
      /*int pulses;
      pulses = 127;
      while (16 + log2_frac(2*(pulses+1)*(pulses+1) + 1, 4) <= bits && pulses < 32767)
         pulses++;*/
      lo = 127;
      switch (N)
      {
         case 3:
            hi = 1024;
            for (i=0;i<10;i++)
            {
               int pulses = (lo+hi)>>1;
               if (log2_frac(((UMUL16_16(pulses,pulses)>>1)+1)>>1, 4) > bits)
                  hi = pulses;
               else
                  lo = pulses;
            }
            break;
         case 4:
            hi = 1024;
            for (i=0;i<10;i++)
            {
               int pulses = (lo+hi)>>1;
               if (log2_frac((UMUL32(UMUL16_16(pulses,pulses)+2,pulses))/3<<3, 4) > bits)
                  hi = pulses;
               else
                  lo = pulses;
            }
            break;
      }
      return lo;
   }
#endif
   /* Instead of using the "bisection condition" we use a fixed number of 
   iterations because it should be faster */
   /*while (hi-lo != 1)*/
   for (i=0;i<LOG_MAX_PULSES;i++)
   {
      int mid = (lo+hi)>>1;
      /* OPT: Make sure this is implemented with a conditional move */
      if (cache[mid] >= bits)
         hi = mid;
      else
         lo = mid;
   }
   if (bits-cache[lo] <= cache[hi]-bits)
      return lo;
   else
      return hi;
}


static inline int pulses2bits(const celt_int16_t *cache, int N, int pulses)
{
#if 0 /* Use of more than MAX_PULSES is disabled until we are able to cwrs that decently */
   if (pulses > 127)
   {
      int bits;
      switch (N)
      {
         case 3:
            bits = log2_frac(((UMUL16_16(pulses,pulses)>>1)+1)>>1, 4);
            break;
         case 4:
            bits = log2_frac((UMUL32(UMUL16_16(pulses,pulses)+2,pulses))/3<<3, 4);
            break;
      }
      /*printf ("%d <- %d\n", bits, pulses);*/
      return bits;
   }
#endif
   return cache[pulses];
}

/** Computes a cache of the pulses->bits mapping in each band */
celt_int16_t **compute_alloc_cache(CELTMode *m, int C);

/** Compute the pulse allocation, i.e. how many pulses will go in each
  * band. 
 @param m mode
 @param offsets Requested increase or decrease in the number of bits for
                each band
 @param total Number of bands
 @param pulses Number of pulses per band (returned)
 @return Total number of bits allocated
*/
void compute_allocation(const CELTMode *m, int *offsets, int total, int *pulses, int *ebits, int *fine_priority);


#endif