mirror of
https://git.ffmpeg.org/ffmpeg.git
synced 2024-12-22 15:23:11 +00:00
66 lines
2.2 KiB
C
66 lines
2.2 KiB
C
/*
|
|
* Common code between AC3 encoder and decoder
|
|
* Copyright (c) 2000, 2001, 2002 Fabrice Bellard.
|
|
*
|
|
* This file is part of FFmpeg.
|
|
*
|
|
* FFmpeg is free software; you can redistribute it and/or
|
|
* modify it under the terms of the GNU Lesser General Public
|
|
* License as published by the Free Software Foundation; either
|
|
* version 2.1 of the License, or (at your option) any later version.
|
|
*
|
|
* FFmpeg 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
|
|
* Lesser General Public License for more details.
|
|
*
|
|
* You should have received a copy of the GNU Lesser General Public
|
|
* License along with FFmpeg; if not, write to the Free Software
|
|
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
/**
|
|
* @file ac3.h
|
|
* Common code between AC3 encoder and decoder.
|
|
*/
|
|
|
|
#define AC3_MAX_CODED_FRAME_SIZE 3840 /* in bytes */
|
|
#define AC3_MAX_CHANNELS 6 /* including LFE channel */
|
|
|
|
#define NB_BLOCKS 6 /* number of PCM blocks inside an AC3 frame */
|
|
#define AC3_FRAME_SIZE (NB_BLOCKS * 256)
|
|
|
|
/* exponent encoding strategy */
|
|
#define EXP_REUSE 0
|
|
#define EXP_NEW 1
|
|
|
|
#define EXP_D15 1
|
|
#define EXP_D25 2
|
|
#define EXP_D45 3
|
|
|
|
typedef struct AC3BitAllocParameters {
|
|
int fscod; /* frequency */
|
|
int halfratecod;
|
|
int sgain, sdecay, fdecay, dbknee, floor;
|
|
int cplfleak, cplsleak;
|
|
} AC3BitAllocParameters;
|
|
|
|
#if 0
|
|
extern const uint16_t ac3_freqs[3];
|
|
extern const uint16_t ac3_bitratetab[19];
|
|
extern const int16_t ac3_window[256];
|
|
extern const uint8_t sdecaytab[4];
|
|
extern const uint8_t fdecaytab[4];
|
|
extern const uint16_t sgaintab[4];
|
|
extern const uint16_t dbkneetab[4];
|
|
extern const uint16_t floortab[8];
|
|
extern const uint16_t fgaintab[8];
|
|
#endif
|
|
|
|
void ac3_common_init(void);
|
|
void ac3_parametric_bit_allocation(AC3BitAllocParameters *s, uint8_t *bap,
|
|
int8_t *exp, int start, int end,
|
|
int snroffset, int fgain, int is_lfe,
|
|
int deltbae,int deltnseg,
|
|
uint8_t *deltoffst, uint8_t *deltlen, uint8_t *deltba);
|