1 /*
2 * bit_allocate.c
3 * Copyright (C) 2000-2002 Michel Lespinasse <walken@zoy.org>
4 * Copyright (C) 1999-2000 Aaron Holtzman <aholtzma@ess.engr.uvic.ca>
5 *
6 * This file is part of a52dec, a free ATSC A-52 stream decoder.
7 * See http://liba52.sourceforge.net/ for updates.
8 *
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.
13 *
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.
18 *
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
22 */
23
24 #include "config.h"
25
26 #include <inttypes.h>
27
28 #include "a52.h"
29 #include "a52_internal.h"
30
31 static const uint16_t hthtab[3][50] = {
32 {0x730, 0x730, 0x7c0, 0x800, 0x820, 0x840, 0x850, 0x850, 0x860, 0x860,
33 0x860, 0x860, 0x860, 0x870, 0x870, 0x870, 0x880, 0x880, 0x890, 0x890,
34 0x8a0, 0x8a0, 0x8b0, 0x8b0, 0x8c0, 0x8c0, 0x8d0, 0x8e0, 0x8f0, 0x900,
35 0x910, 0x910, 0x910, 0x910, 0x900, 0x8f0, 0x8c0, 0x870, 0x820, 0x7e0,
36 0x7a0, 0x770, 0x760, 0x7a0, 0x7c0, 0x7c0, 0x6e0, 0x400, 0x3c0, 0x3c0},
37 {0x710, 0x710, 0x7a0, 0x7f0, 0x820, 0x830, 0x840, 0x850, 0x850, 0x860,
38 0x860, 0x860, 0x860, 0x860, 0x870, 0x870, 0x870, 0x880, 0x880, 0x880,
39 0x890, 0x890, 0x8a0, 0x8a0, 0x8b0, 0x8b0, 0x8c0, 0x8c0, 0x8e0, 0x8f0,
40 0x900, 0x910, 0x910, 0x910, 0x910, 0x900, 0x8e0, 0x8b0, 0x870, 0x820,
41 0x7e0, 0x7b0, 0x760, 0x770, 0x7a0, 0x7c0, 0x780, 0x5d0, 0x3c0, 0x3c0},
42 {0x680, 0x680, 0x750, 0x7b0, 0x7e0, 0x810, 0x820, 0x830, 0x840, 0x850,
43 0x850, 0x850, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860, 0x860,
44 0x870, 0x870, 0x870, 0x870, 0x880, 0x880, 0x880, 0x890, 0x8a0, 0x8b0,
45 0x8c0, 0x8d0, 0x8e0, 0x8f0, 0x900, 0x910, 0x910, 0x910, 0x900, 0x8f0,
46 0x8d0, 0x8b0, 0x840, 0x7f0, 0x790, 0x760, 0x7a0, 0x7c0, 0x7b0, 0x720}
47 };
48
49 static const int8_t baptab[305] = {
50 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
51 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
52 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
53 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
54 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16,
55 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, 16, /* 93 padding elems */
56
57 16, 16, 16, 16, 16, 16, 16, 16, 16, 14, 14, 14, 14, 14, 14, 14,
58 14, 12, 12, 12, 12, 11, 11, 11, 11, 10, 10, 10, 10, 9, 9, 9,
59 9, 8, 8, 8, 8, 7, 7, 7, 7, 6, 6, 6, 6, 5, 5, 5,
60 5, 4, 4, -3, -3, 3, 3, 3, -2, -2, -1, -1, -1, -1, -1, 0,
61
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, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
67 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
68 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
69 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
70 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
71 0, 0, 0, 0 /* 148 padding elems */
72 };
73
74 static const uint8_t bndtab[30] = {
75 21, 22, 23, 24, 25, 26, 27, 28, 31, 34,
76 37, 40, 43, 46, 49, 55, 61, 67, 73, 79,
77 85, 97, 109, 121, 133, 157, 181, 205, 229, 253
78 };
79
80 static const int8_t latab[256] = {
81 -64, -63, -62, -61, -60, -59, -58, -57, -56, -55, -54, -53,
82 -52, -52, -51, -50, -49, -48, -47, -47, -46, -45, -44, -44,
83 -43, -42, -41, -41, -40, -39, -38, -38, -37, -36, -36, -35,
84 -35, -34, -33, -33, -32, -32, -31, -30, -30, -29, -29, -28,
85 -28, -27, -27, -26, -26, -25, -25, -24, -24, -23, -23, -22,
86 -22, -21, -21, -21, -20, -20, -19, -19, -19, -18, -18, -18,
87 -17, -17, -17, -16, -16, -16, -15, -15, -15, -14, -14, -14,
88 -13, -13, -13, -13, -12, -12, -12, -12, -11, -11, -11, -11,
89 -10, -10, -10, -10, -10, -9, -9, -9, -9, -9, -8, -8,
90 -8, -8, -8, -8, -7, -7, -7, -7, -7, -7, -6, -6,
91 -6, -6, -6, -6, -6, -6, -5, -5, -5, -5, -5, -5,
92 -5, -5, -4, -4, -4, -4, -4, -4, -4, -4, -4, -4,
93 -4, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3, -3,
94 -3, -3, -3, -2, -2, -2, -2, -2, -2, -2, -2, -2,
95 -2, -2, -2, -2, -2, -2, -2, -2, -2, -2, -1, -1,
96 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
97 -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1, -1,
98 -1, -1, -1, -1, -1, -1, 0, 0, 0, 0, 0, 0,
99 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
100 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
101 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0,
102 0, 0, 0, 0
103 };
104
105 #define UPDATE_LEAK() \
106 do { \
107 fastleak += fdecay; \
108 if (fastleak > psd + fgain) \
109 fastleak = psd + fgain; \
110 slowleak += sdecay; \
111 if (slowleak > psd + sgain) \
112 slowleak = psd + sgain; \
113 } while (0)
114
115 #define COMPUTE_MASK() \
116 do { \
117 if (psd > dbknee) \
118 mask -= (psd - dbknee) >> 2; \
119 if (mask > hth [i >> halfrate]) \
120 mask = hth [i >> halfrate]; \
121 mask -= snroffset + 128 * deltba[i]; \
122 mask = (mask > 0) ? 0 : ((-mask) >> 5); \
123 mask -= floor; \
124 } while (0)
125
a52_bit_allocate(a52_state_t * state,ba_t * ba,int bndstart,int start,int end,int fastleak,int slowleak,expbap_t * expbap)126 void a52_bit_allocate (a52_state_t * state, ba_t * ba, int bndstart,
127 int start, int end, int fastleak, int slowleak,
128 expbap_t * expbap)
129 {
130 static const uint16_t slowgain[4] = {0x540, 0x4d8, 0x478, 0x410};
131 static const uint16_t dbpbtab[4] = {0xc00, 0x500, 0x300, 0x100};
132 static const uint16_t floortab[8] = {0x910, 0x950, 0x990, 0x9d0,
133 0xa10, 0xa90, 0xb10, 0x1400};
134
135 int i, j;
136 uint8_t * exp;
137 int8_t * bap;
138 int fdecay, fgain, sdecay, sgain, dbknee, floor, snroffset;
139 int psd, mask;
140 const int8_t * deltba;
141 const uint16_t * hth;
142 int halfrate;
143
144 halfrate = state->halfrate;
145 fdecay = (63 + 20 * ((state->bai >> 7) & 3)) >> halfrate; /* fdcycod */
146 fgain = 128 + 128 * (ba->bai & 7); /* fgaincod */
147 sdecay = (15 + 2 * (state->bai >> 9)) >> halfrate; /* sdcycod */
148 sgain = slowgain[(state->bai >> 5) & 3]; /* sgaincod */
149 dbknee = dbpbtab[(state->bai >> 3) & 3]; /* dbpbcod */
150 hth = hthtab[state->fscod];
151 /*
152 * if there is no delta bit allocation, make deltba point to an area
153 * known to contain zeroes. baptab+156 here.
154 */
155 deltba = (ba->deltbae == DELTA_BIT_NONE) ? baptab + 156 : ba->deltba;
156 floor = floortab[state->bai & 7]; /* floorcod */
157 snroffset = 960 - 64 * state->csnroffst - 4 * (ba->bai >> 3) + floor;
158 floor >>= 5;
159
160 exp = expbap->exp;
161 bap = expbap->bap;
162
163 i = bndstart;
164 j = start;
165 if (start == 0) { /* not the coupling channel */
166 int lowcomp;
167
168 lowcomp = 0;
169 j = end - 1;
170 do {
171 if (i < j) {
172 if (exp[i+1] == exp[i] - 2)
173 lowcomp = 384;
174 else if (lowcomp && (exp[i+1] > exp[i]))
175 lowcomp -= 64;
176 }
177 psd = 128 * exp[i];
178 mask = psd + fgain + lowcomp;
179 COMPUTE_MASK ();
180 bap[i] = (baptab+156)[mask + 4 * exp[i]];
181 i++;
182 } while ((i < 3) || ((i < 7) && (exp[i] > exp[i-1])));
183 fastleak = psd + fgain;
184 slowleak = psd + sgain;
185
186 while (i < 7) {
187 if (i < j) {
188 if (exp[i+1] == exp[i] - 2)
189 lowcomp = 384;
190 else if (lowcomp && (exp[i+1] > exp[i]))
191 lowcomp -= 64;
192 }
193 psd = 128 * exp[i];
194 UPDATE_LEAK ();
195 mask = ((fastleak + lowcomp < slowleak) ?
196 fastleak + lowcomp : slowleak);
197 COMPUTE_MASK ();
198 bap[i] = (baptab+156)[mask + 4 * exp[i]];
199 i++;
200 }
201
202 if (end == 7) /* lfe channel */
203 return;
204
205 do {
206 if (exp[i+1] == exp[i] - 2)
207 lowcomp = 320;
208 else if (lowcomp && (exp[i+1] > exp[i]))
209 lowcomp -= 64;
210 psd = 128 * exp[i];
211 UPDATE_LEAK ();
212 mask = ((fastleak + lowcomp < slowleak) ?
213 fastleak + lowcomp : slowleak);
214 COMPUTE_MASK ();
215 bap[i] = (baptab+156)[mask + 4 * exp[i]];
216 i++;
217 } while (i < 20);
218
219 while (lowcomp > 128) { /* two iterations maximum */
220 lowcomp -= 128;
221 psd = 128 * exp[i];
222 UPDATE_LEAK ();
223 mask = ((fastleak + lowcomp < slowleak) ?
224 fastleak + lowcomp : slowleak);
225 COMPUTE_MASK ();
226 bap[i] = (baptab+156)[mask + 4 * exp[i]];
227 i++;
228 }
229 j = i;
230 }
231
232 do {
233 int startband, endband;
234
235 startband = j;
236 endband = ((bndtab-20)[i] < end) ? (bndtab-20)[i] : end;
237 psd = 128 * exp[j++];
238 while (j < endband) {
239 int next, delta;
240
241 next = 128 * exp[j++];
242 delta = next - psd;
243 switch (delta >> 9) {
244 case -6: case -5: case -4: case -3: case -2:
245 psd = next;
246 break;
247 case -1:
248 psd = next + latab[(-delta) >> 1];
249 break;
250 case 0:
251 psd += latab[delta >> 1];
252 break;
253 }
254 }
255 /* minpsd = -289 */
256 UPDATE_LEAK ();
257 mask = (fastleak < slowleak) ? fastleak : slowleak;
258 COMPUTE_MASK ();
259 i++;
260 j = startband;
261 do {
262 /* max(mask+4*exp)=147=-(minpsd+fgain-deltba-snroffset)>>5+4*exp */
263 /* min(mask+4*exp)=-156=-(sgain-deltba-snroffset)>>5 */
264 bap[j] = (baptab+156)[mask + 4 * exp[j]];
265 } while (++j < endband);
266 } while (j < end);
267 }
268
269