Statistics
| Branch: | Revision:

ffmpeg / libavcodec / ac3.h @ 6107fa87

History | View | Annotate | Download (2.04 KB)

1
/*
2
 * Common code between AC3 encoder and decoder
3
 * Copyright (c) 2000, 2001, 2002 Fabrice Bellard.
4
 *
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.
9
 *
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.
14
 *
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
18
 */
19

    
20
#define AC3_MAX_CODED_FRAME_SIZE 3840 /* in bytes */
21
#define AC3_MAX_CHANNELS 6 /* including LFE channel */
22

    
23
#define NB_BLOCKS 6 /* number of PCM blocks inside an AC3 frame */
24
#define AC3_FRAME_SIZE (NB_BLOCKS * 256)
25

    
26
/* exponent encoding strategy */
27
#define EXP_REUSE 0
28
#define EXP_NEW   1
29

    
30
#define EXP_D15   1
31
#define EXP_D25   2
32
#define EXP_D45   3
33

    
34
typedef struct AC3BitAllocParameters {
35
    int fscod; /* frequency */
36
    int halfratecod;
37
    int sgain, sdecay, fdecay, dbknee, floor;
38
    int cplfleak, cplsleak;
39
} AC3BitAllocParameters;
40

    
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];
50

    
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);