3 * Copyright (C) 2000-2003 Michel Lespinasse <walken@zoy.org>
4 * Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
6 * This file is part of a52dec, a free ATSC A-52 stream decoder.
7 * See http://liba52.sourceforge.net/ for updates.
9 * a52dec is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License as published by
11 * the Free Software Foundation; either version 2 of the License, or
12 * (at your option) any later version.
14 * a52dec is distributed in the hope that it will be useful,
15 * but WITHOUT ANY WARRANTY; without even the implied warranty of
16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
17 * GNU General Public License for more details.
19 * You should have received a copy of the GNU General Public License
20 * along with this program; if not, write to the Free Software
21 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
24 #include "a52_internal.h"
26 static int hthtab[3][50] = {
27 {0x730, 0x730, 0x7c0, 0x800, 0x820, 0x840, 0x850, 0x850, 0x860, 0x860,
28 0x860, 0x860, 0x860, 0x870, 0x870, 0x870, 0x880, 0x880, 0x890, 0x890,
29 0x8a0, 0x8a0, 0x8b0, 0x8b0, 0x8c0, 0x8c0, 0x8d0, 0x8e0, 0x8f0, 0x900,
30 0x910, 0x910, 0x910, 0x910, 0x900, 0x8f0, 0x8c0, 0x870, 0x820, 0x7e0,
31 0x7a0, 0x770, 0x760, 0x7a0, 0x7c0, 0x7c0, 0x6e0, 0x400, 0x3c0, 0x3c0},
32 {0x710, 0x710, 0x7a0, 0x7f0, 0x820, 0x830, 0x840, 0x850, 0x850, 0x860,
33 0x860, 0x860, 0x860, 0x860, 0x870, 0x870, 0x870, 0x880, 0x880, 0x880,
34 0x890, 0x890, 0x8a0, 0x8a0, 0x8b0, 0x8b0, 0x8c0, 0x8c0, 0x8e0, 0x8f0,
35 0x900, 0x910, 0x910, 0x910, 0x910, 0x900, 0x8e0, 0x8b0, 0x870, 0x820,
36 0x7e0, 0x7b0, 0x760, 0x770, 0x7a0, 0x7c0, 0x780, 0x5d0, 0x3c0, 0x3c0},
37 {0x680, 0x680, 0x750, 0x7b0, 0x7e0, 0x810, 0x820, 0x830, 0x840, 0x850,
38 0x850, 0x850, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860,
39 0x870, 0x870, 0x870, 0x870, 0x880, 0x880, 0x880, 0x890, 0x8a0, 0x8b0,
40 0x8c0, 0x8d0, 0x8e0, 0x8f0, 0x900, 0x910, 0x910, 0x910, 0x900, 0x8f0,
41 0x8d0, 0x8b0, 0x840, 0x7f0, 0x790, 0x760, 0x7a0, 0x7c0, 0x7b0, 0x720}
44 static int8_t baptab[305] = {
45 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
46 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
47 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
48 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
49 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
50 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, /* 93 padding elems */
52 16, 16, 16, 16, 16, 16, 16, 16, 16, 14, 14, 14, 14, 14, 14, 14,
53 14, 12, 12, 12, 12, 11, 11, 11, 11, 10, 10, 10, 10, 9, 9, 9,
54 9, 8, 8, 8, 8, 7, 7, 7, 7, 6, 6, 6, 6, 5, 5, 5,
55 5, 4, 4, -3, -3, 3, 3, 3, -2, -2, -1, -1, -1, -1, -1, 0,
57 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
58 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
59 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
60 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
61 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
62 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
63 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
64 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
65 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
66 0, 0, 0, 0 /* 148 padding elems */
69 static int bndtab[30] = {21, 22, 23, 24, 25, 26, 27, 28, 31, 34,
70 37, 40, 43, 46, 49, 55, 61, 67, 73, 79,
71 85, 97, 109, 121, 133, 157, 181, 205, 229, 253};
73 static int8_t latab[256] = {
74 -64, -63, -62, -61, -60, -59, -58, -57, -56, -55, -54, -53,
75 -52, -52, -51, -50, -49, -48, -47, -47, -46, -45, -44, -44,
76 -43, -42, -41, -41, -40, -39, -38, -38, -37, -36, -36, -35,
77 -35, -34, -33, -33, -32, -32, -31, -30, -30, -29, -29, -28,
78 -28, -27, -27, -26, -26, -25, -25, -24, -24, -23, -23, -22,
79 -22, -21, -21, -21, -20, -20, -19, -19, -19, -18, -18, -18,
80 -17, -17, -17, -16, -16, -16, -15, -15, -15, -14, -14, -14,
81 -13, -13, -13, -13, -12, -12, -12, -12, -11, -11, -11, -11,
82 -10, -10, -10, -10, -10, -9, -9, -9, -9, -9, -8, -8,
83 -8, -8, -8, -8, -7, -7, -7, -7, -7, -7, -6, -6,
84 -6, -6, -6, -6, -6, -6, -5, -5, -5, -5, -5, -5,
85 -5, -5, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4,
86 -4, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3,
87 -3, -3, -3, -2, -2, -2, -2, -2, -2, -2, -2, -2,
88 -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -1, -1,
89 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
90 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
91 -1, -1, -1, -1, -1, -1, 0, 0, 0, 0, 0, 0,
92 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
93 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
94 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
98 #define UPDATE_LEAK() \
100 fastleak += fdecay; \
101 if (fastleak > psd + fgain) \
102 fastleak = psd + fgain; \
103 slowleak += sdecay; \
104 if (slowleak > psd + sgain) \
105 slowleak = psd + sgain; \
108 #define COMPUTE_MASK() \
111 mask -= (psd - dbknee) >> 2; \
112 if (mask > hth [i >> halfrate]) \
113 mask = hth [i >> halfrate]; \
114 mask -= snroffset + 128 * deltba[i]; \
115 mask = (mask > 0) ? 0 : ((-mask) >> 5); \
119 void a52_bit_allocate (a52_state_t * state, ba_t * ba, int bndstart,
120 int start, int end, int fastleak, int slowleak,
123 static int slowgain[4] = {0x540, 0x4d8, 0x478, 0x410};
124 static int dbpbtab[4] = {0xc00, 0x500, 0x300, 0x100};
125 static int floortab[8] = {0x910, 0x950, 0x990, 0x9d0,
126 0xa10, 0xa90, 0xb10, 0x1400};
131 int fdecay, fgain, sdecay, sgain, dbknee, floor, snroffset;
137 halfrate = state->halfrate;
138 fdecay = (63 + 20 * ((state->bai >> 7) & 3)) >> halfrate; /* fdcycod */
139 fgain = 128 + 128 * (ba->bai & 7); /* fgaincod */
140 sdecay = (15 + 2 * (state->bai >> 9)) >> halfrate; /* sdcycod */
141 sgain = slowgain[(state->bai >> 5) & 3]; /* sgaincod */
142 dbknee = dbpbtab[(state->bai >> 3) & 3]; /* dbpbcod */
143 hth = hthtab[state->fscod];
145 * if there is no delta bit allocation, make deltba point to an area
146 * known to contain zeroes. baptab+156 here.
148 deltba = (ba->deltbae == DELTA_BIT_NONE) ? baptab + 156 : ba->deltba;
149 floor = floortab[state->bai & 7]; /* floorcod */
150 snroffset = 960 - 64 * state->csnroffst - 4 * (ba->bai >> 3) + floor;
158 if (start == 0) { /* not the coupling channel */
165 if (exp[i+1] == exp[i] - 2)
167 else if (lowcomp && (exp[i+1] > exp[i]))
171 mask = psd + fgain + lowcomp;
173 bap[i] = (baptab+156)[mask + 4 * exp[i]];
175 } while ((i < 3) || ((i < 7) && (exp[i] > exp[i-1])));
176 fastleak = psd + fgain;
177 slowleak = psd + sgain;
181 if (exp[i+1] == exp[i] - 2)
183 else if (lowcomp && (exp[i+1] > exp[i]))
188 mask = ((fastleak + lowcomp < slowleak) ?
189 fastleak + lowcomp : slowleak);
191 bap[i] = (baptab+156)[mask + 4 * exp[i]];
195 if (end == 7) /* lfe channel */
199 if (exp[i+1] == exp[i] - 2)
201 else if (lowcomp && (exp[i+1] > exp[i]))
205 mask = ((fastleak + lowcomp < slowleak) ?
206 fastleak + lowcomp : slowleak);
208 bap[i] = (baptab+156)[mask + 4 * exp[i]];
212 while (lowcomp > 128) { /* two iterations maximum */
216 mask = ((fastleak + lowcomp < slowleak) ?
217 fastleak + lowcomp : slowleak);
219 bap[i] = (baptab+156)[mask + 4 * exp[i]];
226 int startband, endband;
229 endband = (bndtab[i-20] < end) ? bndtab[i-20] : end;
230 psd = 128 * exp[j++];
231 while (j < endband) {
234 next = 128 * exp[j++];
236 switch (delta >> 9) {
237 case -6: case -5: case -4: case -3: case -2:
241 psd = next + latab[(-delta) >> 1];
244 psd += latab[delta >> 1];
250 mask = (fastleak < slowleak) ? fastleak : slowleak;
255 /* max(mask+4*exp)=147=-(minpsd+fgain-deltba-snroffset)>>5+4*exp */
256 /* min(mask+4*exp)=-156=-(sgain-deltba-snroffset)>>5 */
257 bap[j] = (baptab+156)[mask + 4 * exp[j]];
258 } while (++j < endband);