2 * Common code between AC3 encoder and decoder
3 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard.
5 * This library is free software; you can redistribute it and/or
6 * modify it under the terms of the GNU Lesser General Public
7 * License as published by the Free Software Foundation; either
8 * version 2 of the License, or (at your option) any later version.
10 * This library is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 * Lesser General Public License for more details.
15 * You should have received a copy of the GNU Lesser General Public
16 * License along with this library; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
20 #define AC3_MAX_CODED_FRAME_SIZE 3840 /* in bytes */
21 #define AC3_MAX_CHANNELS 6 /* including LFE channel */
23 #define NB_BLOCKS 6 /* number of PCM blocks inside an AC3 frame */
24 #define AC3_FRAME_SIZE (NB_BLOCKS * 256)
26 /* exponent encoding strategy */
34 typedef struct AC3BitAllocParameters {
35 int fscod; /* frequency */
37 int sgain, sdecay, fdecay, dbknee, floor;
38 int cplfleak, cplsleak;
39 } AC3BitAllocParameters;
41 extern const UINT16 ac3_freqs[3];
42 extern const UINT16 ac3_bitratetab[19];
43 extern const INT16 ac3_window[256];
44 extern const UINT8 sdecaytab[4];
45 extern const UINT8 fdecaytab[4];
46 extern const UINT16 sgaintab[4];
47 extern const UINT16 dbkneetab[4];
48 extern const UINT16 floortab[8];
49 extern const UINT16 fgaintab[8];
51 void ac3_common_init(void);
52 void ac3_parametric_bit_allocation(AC3BitAllocParameters *s, UINT8 *bap,
53 INT8 *exp, int start, int end,
54 int snroffset, int fgain, int is_lfe,
55 int deltbae,int deltnseg,
56 UINT8 *deltoffst, UINT8 *deltlen, UINT8 *deltba);