www.pudn.com > mediator15src.zip > bit_allocate.c
/*
* bit_allocate.c
* Copyright (C) 2000-2002 Michel Lespinasse
* Copyright (C) 1999-2000 Aaron Holtzman
*
* This file is part of a52dec, a free ATSC A-52 stream decoder.
* See http://liba52.sourceforge.net/ for updates.
*
* a52dec is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* a52dec is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include "config.h"
#include "a52.h"
#include "a52_internal.h"
static int hthtab[3][50] = {
{0x730, 0x730, 0x7c0, 0x800, 0x820, 0x840, 0x850, 0x850, 0x860, 0x860,
0x860, 0x860, 0x860, 0x870, 0x870, 0x870, 0x880, 0x880, 0x890, 0x890,
0x8a0, 0x8a0, 0x8b0, 0x8b0, 0x8c0, 0x8c0, 0x8d0, 0x8e0, 0x8f0, 0x900,
0x910, 0x910, 0x910, 0x910, 0x900, 0x8f0, 0x8c0, 0x870, 0x820, 0x7e0,
0x7a0, 0x770, 0x760, 0x7a0, 0x7c0, 0x7c0, 0x6e0, 0x400, 0x3c0, 0x3c0},
{0x710, 0x710, 0x7a0, 0x7f0, 0x820, 0x830, 0x840, 0x850, 0x850, 0x860,
0x860, 0x860, 0x860, 0x860, 0x870, 0x870, 0x870, 0x880, 0x880, 0x880,
0x890, 0x890, 0x8a0, 0x8a0, 0x8b0, 0x8b0, 0x8c0, 0x8c0, 0x8e0, 0x8f0,
0x900, 0x910, 0x910, 0x910, 0x910, 0x900, 0x8e0, 0x8b0, 0x870, 0x820,
0x7e0, 0x7b0, 0x760, 0x770, 0x7a0, 0x7c0, 0x780, 0x5d0, 0x3c0, 0x3c0},
{0x680, 0x680, 0x750, 0x7b0, 0x7e0, 0x810, 0x820, 0x830, 0x840, 0x850,
0x850, 0x850, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860,
0x870, 0x870, 0x870, 0x870, 0x880, 0x880, 0x880, 0x890, 0x8a0, 0x8b0,
0x8c0, 0x8d0, 0x8e0, 0x8f0, 0x900, 0x910, 0x910, 0x910, 0x900, 0x8f0,
0x8d0, 0x8b0, 0x840, 0x7f0, 0x790, 0x760, 0x7a0, 0x7c0, 0x7b0, 0x720}
};
static int8_t baptab[305] = {
16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, /* 93 padding elems */
16, 16, 16, 16, 16, 16, 16, 16, 16, 14, 14, 14, 14, 14, 14, 14,
14, 12, 12, 12, 12, 11, 11, 11, 11, 10, 10, 10, 10, 9, 9, 9,
9, 8, 8, 8, 8, 7, 7, 7, 7, 6, 6, 6, 6, 5, 5, 5,
5, 4, 4, -3, -3, 3, 3, 3, -2, -2, -1, -1, -1, -1, -1, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0 /* 148 padding elems */
};
static int bndtab[30] = {21, 22, 23, 24, 25, 26, 27, 28, 31, 34,
37, 40, 43, 46, 49, 55, 61, 67, 73, 79,
85, 97, 109, 121, 133, 157, 181, 205, 229, 253};
static int8_t latab[256] = {
-64, -63, -62, -61, -60, -59, -58, -57, -56, -55, -54, -53,
-52, -52, -51, -50, -49, -48, -47, -47, -46, -45, -44, -44,
-43, -42, -41, -41, -40, -39, -38, -38, -37, -36, -36, -35,
-35, -34, -33, -33, -32, -32, -31, -30, -30, -29, -29, -28,
-28, -27, -27, -26, -26, -25, -25, -24, -24, -23, -23, -22,
-22, -21, -21, -21, -20, -20, -19, -19, -19, -18, -18, -18,
-17, -17, -17, -16, -16, -16, -15, -15, -15, -14, -14, -14,
-13, -13, -13, -13, -12, -12, -12, -12, -11, -11, -11, -11,
-10, -10, -10, -10, -10, -9, -9, -9, -9, -9, -8, -8,
-8, -8, -8, -8, -7, -7, -7, -7, -7, -7, -6, -6,
-6, -6, -6, -6, -6, -6, -5, -5, -5, -5, -5, -5,
-5, -5, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4,
-4, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3,
-3, -3, -3, -2, -2, -2, -2, -2, -2, -2, -2, -2,
-2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
-1, -1, -1, -1, -1, -1, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
0, 0, 0, 0
};
#define UPDATE_LEAK() \
do { \
fastleak += fdecay; \
if (fastleak > psd + fgain) \
fastleak = psd + fgain; \
slowleak += sdecay; \
if (slowleak > psd + sgain) \
slowleak = psd + sgain; \
} while (0)
#define COMPUTE_MASK() \
do { \
if (psd > dbknee) \
mask -= (psd - dbknee) >> 2; \
if (mask > hth [i >> halfrate]) \
mask = hth [i >> halfrate]; \
mask -= snroffset + 128 * deltba[i]; \
mask = (mask > 0) ? 0 : ((-mask) >> 5); \
mask -= floor; \
} while (0)
void a52_bit_allocate (a52_state_t * state, ba_t * ba, int bndstart,
int start, int end, int fastleak, int slowleak,
expbap_t * expbap)
{
static int slowgain[4] = {0x540, 0x4d8, 0x478, 0x410};
static int dbpbtab[4] = {0xc00, 0x500, 0x300, 0x100};
static int floortab[8] = {0x910, 0x950, 0x990, 0x9d0,
0xa10, 0xa90, 0xb10, 0x1400};
int i, j;
uint8_t * exp;
int8_t * bap;
int fdecay, fgain, sdecay, sgain, dbknee, floor, snroffset;
int psd, mask;
int8_t * deltba;
int * hth;
int halfrate;
halfrate = state->halfrate;
fdecay = (63 + 20 * ((state->bai >> 7) & 3)) >> halfrate; /* fdcycod */
fgain = 128 + 128 * (ba->bai & 7); /* fgaincod */
sdecay = (15 + 2 * (state->bai >> 9)) >> halfrate; /* sdcycod */
sgain = slowgain[(state->bai >> 5) & 3]; /* sgaincod */
dbknee = dbpbtab[(state->bai >> 3) & 3]; /* dbpbcod */
hth = hthtab[state->fscod];
/*
* if there is no delta bit allocation, make deltba point to an area
* known to contain zeroes. baptab+156 here.
*/
deltba = (ba->deltbae == DELTA_BIT_NONE) ? baptab + 156 : ba->deltba;
floor = floortab[state->bai & 7]; /* floorcod */
snroffset = 960 - 64 * state->csnroffst - 4 * (ba->bai >> 3) + floor;
floor >>= 5;
exp = expbap->exp;
bap = expbap->bap;
i = bndstart;
j = start;
if (start == 0) { /* not the coupling channel */
int lowcomp;
lowcomp = 0;
j = end - 1;
do {
if (i < j) {
if (exp[i+1] == exp[i] - 2)
lowcomp = 384;
else if (lowcomp && (exp[i+1] > exp[i]))
lowcomp -= 64;
}
psd = 128 * exp[i];
mask = psd + fgain + lowcomp;
COMPUTE_MASK ();
bap[i] = (baptab+156)[mask + 4 * exp[i]];
i++;
} while ((i < 3) || ((i < 7) && (exp[i] > exp[i-1])));
fastleak = psd + fgain;
slowleak = psd + sgain;
while (i < 7) {
if (i < j) {
if (exp[i+1] == exp[i] - 2)
lowcomp = 384;
else if (lowcomp && (exp[i+1] > exp[i]))
lowcomp -= 64;
}
psd = 128 * exp[i];
UPDATE_LEAK ();
mask = ((fastleak + lowcomp < slowleak) ?
fastleak + lowcomp : slowleak);
COMPUTE_MASK ();
bap[i] = (baptab+156)[mask + 4 * exp[i]];
i++;
}
if (end == 7) /* lfe channel */
return;
do {
if (exp[i+1] == exp[i] - 2)
lowcomp = 320;
else if (lowcomp && (exp[i+1] > exp[i]))
lowcomp -= 64;
psd = 128 * exp[i];
UPDATE_LEAK ();
mask = ((fastleak + lowcomp < slowleak) ?
fastleak + lowcomp : slowleak);
COMPUTE_MASK ();
bap[i] = (baptab+156)[mask + 4 * exp[i]];
i++;
} while (i < 20);
while (lowcomp > 128) { /* two iterations maximum */
lowcomp -= 128;
psd = 128 * exp[i];
UPDATE_LEAK ();
mask = ((fastleak + lowcomp < slowleak) ?
fastleak + lowcomp : slowleak);
COMPUTE_MASK ();
bap[i] = (baptab+156)[mask + 4 * exp[i]];
i++;
}
j = i;
}
do {
int startband, endband;
startband = j;
endband = ((bndtab-20)[i] < end) ? (bndtab-20)[i] : end;
psd = 128 * exp[j++];
while (j < endband) {
int next, delta;
next = 128 * exp[j++];
delta = next - psd;
switch (delta >> 9) {
case -6: case -5: case -4: case -3: case -2:
psd = next;
break;
case -1:
psd = next + latab[(-delta) >> 1];
break;
case 0:
psd += latab[delta >> 1];
break;
}
}
/* minpsd = -289 */
UPDATE_LEAK ();
mask = (fastleak < slowleak) ? fastleak : slowleak;
COMPUTE_MASK ();
i++;
j = startband;
do {
/* max(mask+4*exp)=147=-(minpsd+fgain-deltba-snroffset)>>5+4*exp */
/* min(mask+4*exp)=-156=-(sgain-deltba-snroffset)>>5 */
bap[j] = (baptab+156)[mask + 4 * exp[j]];
} while (++j < endband);
} while (j < end);
}