ref: 283a9b606dcbbf03e651c257009e02201b8cc714
dir: /libcelt/rate.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 <math.h>
#include "modes.h"
#include "cwrs.h"
#include "arch.h"
#include "os_support.h"
#include "entcode.h"
#include "rate.h"
#ifndef STATIC_MODES
/*Determines if V(N,K) fits in a 32-bit unsigned integer.
N and K are themselves limited to 15 bits.*/
static int fits_in32(int _n, int _k)
{
static const celt_int16 maxN[15] = {
32767, 32767, 32767, 1476, 283, 109, 60, 40,
29, 24, 20, 18, 16, 14, 13};
static const celt_int16 maxK[15] = {
32767, 32767, 32767, 32767, 1172, 238, 95, 53,
36, 27, 22, 18, 16, 15, 13};
if (_n>=14)
{
if (_k>=14)
return 0;
else
return _n <= maxN[_k];
} else {
return _k <= maxK[_n];
}
}
void compute_pulse_cache(CELTMode *m, int LM)
{
int i;
int curr=0;
int nbEntries=0;
int entryN[100], entryK[100], entryI[100];
const celt_int16 *eBands = m->eBands;
PulseCache *cache = &m->cache;
celt_int16 *cindex;
unsigned char *bits;
cindex = celt_alloc(sizeof(cache->index[0])*m->nbEBands*(LM+2));
cache->index = cindex;
/* Scan for all unique band sizes */
for (i=0;i<=LM+1;i++)
{
int j;
for (j=0;j<m->nbEBands;j++)
{
int k;
int N = (eBands[j+1]-eBands[j])<<i>>1;
cindex[i*m->nbEBands+j] = -1;
/* Find other bands that have the same size */
for (k=0;k<=i;k++)
{
int n;
for (n=0;n<m->nbEBands && (k!=i || n<j);n++)
{
if (N == (eBands[n+1]-eBands[n])<<k>>1)
{
cindex[i*m->nbEBands+j] = cindex[k*m->nbEBands+n];
break;
}
}
}
if (cache->index[i*m->nbEBands+j] == -1 && N!=0)
{
int K;
entryN[nbEntries] = N;
K = 0;
while (fits_in32(N,get_pulses(K+1)) && K<MAX_PSEUDO)
K++;
entryK[nbEntries] = K;
cindex[i*m->nbEBands+j] = curr;
entryI[nbEntries] = curr;
curr += K+1;
nbEntries++;
}
}
}
bits = celt_alloc(sizeof(unsigned char)*curr);
cache->bits = bits;
cache->size = curr;
/* Compute the cache for all unique sizes */
for (i=0;i<nbEntries;i++)
{
int j;
unsigned char *ptr = bits+entryI[i];
celt_int16 tmp[MAX_PULSES+1];
get_required_bits(tmp, entryN[i], get_pulses(entryK[i]), BITRES);
for (j=1;j<=entryK[i];j++)
ptr[j] = tmp[get_pulses(j)]-1;
ptr[0] = entryK[i];
}
}
#endif /* !STATIC_MODES */
#define ALLOC_STEPS 6
static inline int interp_bits2pulses(const CELTMode *m, int start, int end,
int *bits1, int *bits2, const int *thresh, int total, int *bits,
int *ebits, int *fine_priority, int len, int _C, int LM, void *ec, int encode, int prev)
{
int psum;
int lo, hi;
int i, j;
int logM;
const int C = CHANNELS(_C);
int codedBands=-1;
int alloc_floor;
int left, percoeff;
int done;
SAVE_STACK;
alloc_floor = C<<BITRES;
logM = LM<<BITRES;
lo = 0;
hi = 1<<ALLOC_STEPS;
for (i=0;i<ALLOC_STEPS;i++)
{
int mid = (lo+hi)>>1;
psum = 0;
done = 0;
for (j=start;j<end;j++)
{
int tmp = bits1[j] + (mid*bits2[j]>>ALLOC_STEPS);
/* Don't allocate more than we can actually use */
if (tmp >= thresh[j] && !done)
{
psum += tmp;
} else {
done = 1;
if (tmp >= alloc_floor)
psum += alloc_floor;
}
}
if (psum > (total<<BITRES))
hi = mid;
else
lo = mid;
}
psum = 0;
/*printf ("interp bisection gave %d\n", lo);*/
done = 0;
for (j=start;j<end;j++)
{
int tmp = bits1[j] + (lo*bits2[j]>>ALLOC_STEPS);
if (tmp < thresh[j] || done)
{
done = 1;
if (tmp >= alloc_floor)
tmp = alloc_floor;
else
tmp = 0;
}
/* Don't allocate more than we can actually use */
tmp = IMIN(tmp, 64*C<<BITRES<<LM);
bits[j] = tmp;
psum += tmp;
}
/*Decide which bands to skip, working backwards from the end.
The loop condition stops before the first band, which we never skip: we'd
be coding a bit to signal that we're going to waste all the other bits.*/
codedBands=end;
for (j=end;--j>start;)
{
int band_width;
int band_bits;
int rem;
/*Figure out how many left-over bits we would be adding to this band.
This can include bits we've stolen back from higher, skipped bands.*/
left = (total<<BITRES)-psum;
percoeff = left/(m->eBands[codedBands]-m->eBands[start]);
left -= (m->eBands[codedBands]-m->eBands[start])*percoeff;
rem = IMAX(left-m->eBands[j],0);
band_width = m->eBands[codedBands]-m->eBands[j];
band_bits = bits[j] + percoeff*band_width + rem;
/*Only code a skip decision if we're above the threshold for this band.
Otherwise it is force-skipped.
This ensures that a) we have enough bits to code the skip flag and b)
there are actually some bits to redistribute.*/
if (band_bits >= IMAX(thresh[j], alloc_floor+(1<<BITRES)+1))
{
if (encode)
{
/*This if() block is the only part of the allocation function that
is not a mandatory part of the bitstream: any bands we choose to
skip here must be explicitly signaled.*/
/*Choose a threshold with some hysteresis to keep bands from
fluctuating in and out.*/
if (band_bits > ((j<prev?7:9)*band_width<<LM<<BITRES)>>4)
{
ec_enc_bit_prob((ec_enc *)ec, 1, 32768);
break;
}
ec_enc_bit_prob((ec_enc *)ec, 0, 32768);
} else if (ec_dec_bit_prob((ec_dec *)ec, 32768)) {
break;
}
/*We used a bit to skip this band.*/
psum += 1<<BITRES;
band_bits -= 1<<BITRES;
}
/*Reclaim the bits originally allocated to this band.*/
psum -= bits[j];
if (band_bits >= alloc_floor)
{
/*If we have enough for a fine energy bit per channel, use it.*/
psum += alloc_floor;
bits[j] = alloc_floor;
} else {
/*Otherwise this band gets nothing at all.*/
bits[j] = 0;
}
codedBands--;
}
/* Allocate the remaining bits */
if (codedBands>start) {
for (j=start;j<codedBands;j++)
bits[j] += percoeff*(m->eBands[j+1]-m->eBands[j]);
for (j=start;j<codedBands;j++)
{
int tmp = IMIN(left, m->eBands[j+1]-m->eBands[j]);
bits[j] += tmp;
left -= tmp;
}
}
/*for (j=0;j<end;j++)printf("%d ", bits[j]);printf("\n");*/
for (j=start;j<end;j++)
{
int N0, N, den;
int offset;
int NClogN;
celt_assert(bits[j] >= 0);
N0 = m->eBands[j+1]-m->eBands[j];
N=N0<<LM;
NClogN = N*C*(m->logN[j] + logM);
/* Compensate for the extra DoF in stereo */
den=(C*N+ ((C==2 && N>2) ? 1 : 0));
/* Offset for the number of fine bits by log2(N)/2 + FINE_OFFSET
compared to their "fair share" of total/N */
offset = (NClogN>>1)-N*C*FINE_OFFSET;
/* N=2 is the only point that doesn't match the curve */
if (N==2)
offset += N*C<<BITRES>>2;
/* Changing the offset for allocating the second and third fine energy bit */
if (bits[j] + offset < den*2<<BITRES)
offset += NClogN>>2;
else if (bits[j] + offset < den*3<<BITRES)
offset += NClogN>>3;
/* Divide with rounding */
ebits[j] = IMAX(0, (bits[j] + offset + (den<<(BITRES-1))) / (den<<BITRES));
/* If we rounded down, make it a candidate for final fine energy pass */
fine_priority[j] = ebits[j]*(den<<BITRES) >= bits[j]+offset;
/* For N=1, all bits go to fine energy except for a single sign bit */
if (N==1)
{
ebits[j] = IMAX(0,(bits[j]/C >> BITRES)-1);
fine_priority[j] = (ebits[j]+1)*C<<BITRES >= bits[j];
}
/* Make sure not to bust */
if (C*ebits[j] > (bits[j]>>BITRES))
ebits[j] = bits[j]/C >> BITRES;
/* More than that is useless because that's about as far as PVQ can go */
if (ebits[j]>7)
ebits[j]=7;
/* The other bits are assigned to PVQ */
bits[j] -= C*ebits[j]<<BITRES;
celt_assert(bits[j] >= 0);
celt_assert(ebits[j] >= 0);
}
RESTORE_STACK;
return codedBands;
}
int compute_allocation(const CELTMode *m, int start, int end, int *offsets, int alloc_trim,
int total, int *pulses, int *ebits, int *fine_priority, int _C, int LM, void *ec, int encode, int prev)
{
int lo, hi, len, j;
const int C = CHANNELS(_C);
int codedBands;
VARDECL(int, bits1);
VARDECL(int, bits2);
VARDECL(int, thresh);
VARDECL(int, trim_offset);
SAVE_STACK;
total = IMAX(total, 0);
len = m->nbEBands;
ALLOC(bits1, len, int);
ALLOC(bits2, len, int);
ALLOC(thresh, len, int);
ALLOC(trim_offset, len, int);
/* Below this threshold, we're sure not to allocate any PVQ bits */
for (j=start;j<end;j++)
thresh[j] = IMAX((C)<<BITRES, (3*(m->eBands[j+1]-m->eBands[j])<<LM<<BITRES)>>4);
/* Tilt of the allocation curve */
for (j=start;j<end;j++)
trim_offset[j] = C*(m->eBands[j+1]-m->eBands[j])*(alloc_trim-5-LM)*(m->nbEBands-j-1)
<<(LM+BITRES)>>6;
lo = 0;
hi = m->nbAllocVectors - 1;
while (hi-lo != 1)
{
int psum = 0;
int mid = (lo+hi) >> 1;
for (j=start;j<end;j++)
{
int N = m->eBands[j+1]-m->eBands[j];
bits1[j] = C*N*m->allocVectors[mid*len+j]<<LM>>2;
if (bits1[j] > 0)
bits1[j] += trim_offset[j];
if (bits1[j] < 0)
bits1[j] = 0;
bits1[j] += offsets[j];
if (bits1[j] >= thresh[j])
psum += bits1[j];
else if (bits1[j] >= C<<BITRES)
psum += C<<BITRES;
/*printf ("%d ", bits[j]);*/
}
/*printf ("\n");*/
if (psum > (total<<BITRES))
hi = mid;
else
lo = mid;
/*printf ("lo = %d, hi = %d\n", lo, hi);*/
}
/*printf ("interp between %d and %d\n", lo, hi);*/
for (j=start;j<end;j++)
{
int N = m->eBands[j+1]-m->eBands[j];
bits1[j] = (C*N*m->allocVectors[lo*len+j]<<LM>>2);
bits2[j] = (C*N*m->allocVectors[hi*len+j]<<LM>>2) - bits1[j];
if (bits1[j] > 0)
bits1[j] += trim_offset[j];
if (bits1[j] < 0)
bits1[j] = 0;
bits1[j] += offsets[j];
}
codedBands = interp_bits2pulses(m, start, end, bits1, bits2, thresh,
total, pulses, ebits, fine_priority, len, C, LM, ec, encode, prev);
RESTORE_STACK;
return codedBands;
}