1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
|
/*
* copyright (c) 2001 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 libavcodec/mpegaudio.h
* mpeg audio declarations for both encoder and decoder.
*/
#ifndef AVCODEC_MPEGAUDIO_H
#define AVCODEC_MPEGAUDIO_H
#include "avcodec.h"
#include "get_bits.h"
#include "dsputil.h"
#define CONFIG_AUDIO_NONSHORT 0
/* max frame size, in samples */
#define MPA_FRAME_SIZE 1152
/* max compressed frame size */
#define MPA_MAX_CODED_FRAME_SIZE 1792
#define MPA_MAX_CHANNELS 2
#define SBLIMIT 32 /* number of subbands */
#define MPA_STEREO 0
#define MPA_JSTEREO 1
#define MPA_DUAL 2
#define MPA_MONO 3
/* header + layer + bitrate + freq + lsf/mpeg25 */
#define SAME_HEADER_MASK \
(0xffe00000 | (3 << 17) | (0xf << 12) | (3 << 10) | (3 << 19))
#define MP3_MASK 0xFFFE0CCF
#if CONFIG_MPEGAUDIO_HP
#define FRAC_BITS 23 /* fractional bits for sb_samples and dct */
#define WFRAC_BITS 16 /* fractional bits for window */
#else
#define FRAC_BITS 15 /* fractional bits for sb_samples and dct */
#define WFRAC_BITS 14 /* fractional bits for window */
#endif
#define FRAC_ONE (1 << FRAC_BITS)
#define FIX(a) ((int)((a) * FRAC_ONE))
#if CONFIG_MPEGAUDIO_HP && CONFIG_AUDIO_NONSHORT
typedef int32_t OUT_INT;
#define OUT_MAX INT32_MAX
#define OUT_MIN INT32_MIN
#define OUT_SHIFT (WFRAC_BITS + FRAC_BITS - 31)
#define OUT_FMT SAMPLE_FMT_S32
#else
typedef int16_t OUT_INT;
#define OUT_MAX INT16_MAX
#define OUT_MIN INT16_MIN
#define OUT_SHIFT (WFRAC_BITS + FRAC_BITS - 15)
#define OUT_FMT SAMPLE_FMT_S16
#endif
#if FRAC_BITS <= 15
typedef int16_t MPA_INT;
#else
typedef int32_t MPA_INT;
#endif
#define BACKSTEP_SIZE 512
#define EXTRABYTES 24
struct GranuleDef;
#define MPA_DECODE_HEADER \
int frame_size; \
int error_protection; \
int layer; \
int sample_rate; \
int sample_rate_index; /* between 0 and 8 */ \
int bit_rate; \
int nb_channels; \
int mode; \
int mode_ext; \
int lsf;
typedef struct MPADecodeHeader {
MPA_DECODE_HEADER
} MPADecodeHeader;
typedef struct MPADecodeContext {
MPA_DECODE_HEADER
DECLARE_ALIGNED_8(uint8_t, last_buf[2*BACKSTEP_SIZE + EXTRABYTES]);
int last_buf_size;
/* next header (used in free format parsing) */
uint32_t free_format_next_header;
GetBitContext gb;
GetBitContext in_gb;
DECLARE_ALIGNED_16(MPA_INT, synth_buf[MPA_MAX_CHANNELS][512 * 2]);
int synth_buf_offset[MPA_MAX_CHANNELS];
DECLARE_ALIGNED_16(int32_t, sb_samples[MPA_MAX_CHANNELS][36][SBLIMIT]);
int32_t mdct_buf[MPA_MAX_CHANNELS][SBLIMIT * 18]; /* previous samples, for layer 3 MDCT */
#ifdef DEBUG
int frame_count;
#endif
void (*compute_antialias)(struct MPADecodeContext *s, struct GranuleDef *g);
int adu_mode; ///< 0 for standard mp3, 1 for adu formatted mp3
int dither_state;
int error_recognition;
AVCodecContext* avctx;
} MPADecodeContext;
/* layer 3 huffman tables */
typedef struct HuffTable {
int xsize;
const uint8_t *bits;
const uint16_t *codes;
} HuffTable;
int ff_mpa_l2_select_table(int bitrate, int nb_channels, int freq, int lsf);
int ff_mpa_decode_header(AVCodecContext *avctx, uint32_t head, int *sample_rate, int *channels, int *frame_size, int *bitrate);
void ff_mpa_synth_init(MPA_INT *window);
void ff_mpa_synth_filter(MPA_INT *synth_buf_ptr, int *synth_buf_offset,
MPA_INT *window, int *dither_state,
OUT_INT *samples, int incr,
int32_t sb_samples[SBLIMIT]);
/* fast header check for resync */
static inline int ff_mpa_check_header(uint32_t header){
/* header */
if ((header & 0xffe00000) != 0xffe00000)
return -1;
/* layer check */
if ((header & (3<<17)) == 0)
return -1;
/* bit rate */
if ((header & (0xf<<12)) == 0xf<<12)
return -1;
/* frequency */
if ((header & (3<<10)) == 3<<10)
return -1;
return 0;
}
#endif /* AVCODEC_MPEGAUDIO_H */
|
