1/*
2 * copyright (c) 2001 Fabrice Bellard
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21/**
22 * @file libavcodec/mpegaudio.h
23 * mpeg audio declarations for both encoder and decoder.
24 */
25
26#ifndef AVCODEC_MPEGAUDIO_H
27#define AVCODEC_MPEGAUDIO_H
28
29#include "avcodec.h"
30#include "bitstream.h"
31#include "dsputil.h"
32
33#define CONFIG_AUDIO_NONSHORT 0
34
35/* max frame size, in samples */
36#define MPA_FRAME_SIZE 1152
37
38/* max compressed frame size */
39#define MPA_MAX_CODED_FRAME_SIZE 1792
40
41#define MPA_MAX_CHANNELS 2
42
43#define SBLIMIT 32 /* number of subbands */
44
45#define MPA_STEREO  0
46#define MPA_JSTEREO 1
47#define MPA_DUAL    2
48#define MPA_MONO    3
49
50/* header + layer + bitrate + freq + lsf/mpeg25 */
51#define SAME_HEADER_MASK \
52   (0xffe00000 | (3 << 17) | (0xf << 12) | (3 << 10) | (3 << 19))
53
54#define MP3_MASK 0xFFFE0CCF
55
56#if CONFIG_MPEGAUDIO_HP
57#define FRAC_BITS   23   /* fractional bits for sb_samples and dct */
58#define WFRAC_BITS  16   /* fractional bits for window */
59#else
60#define FRAC_BITS   15   /* fractional bits for sb_samples and dct */
61#define WFRAC_BITS  14   /* fractional bits for window */
62#endif
63
64#define FRAC_ONE    (1 << FRAC_BITS)
65
66#define FIX(a)   ((int)((a) * FRAC_ONE))
67
68#if CONFIG_MPEGAUDIO_HP && CONFIG_AUDIO_NONSHORT
69typedef int32_t OUT_INT;
70#define OUT_MAX INT32_MAX
71#define OUT_MIN INT32_MIN
72#define OUT_SHIFT (WFRAC_BITS + FRAC_BITS - 31)
73#define OUT_FMT SAMPLE_FMT_S32
74#else
75typedef int16_t OUT_INT;
76#define OUT_MAX INT16_MAX
77#define OUT_MIN INT16_MIN
78#define OUT_SHIFT (WFRAC_BITS + FRAC_BITS - 15)
79#define OUT_FMT SAMPLE_FMT_S16
80#endif
81
82#if FRAC_BITS <= 15
83typedef int16_t MPA_INT;
84#else
85typedef int32_t MPA_INT;
86#endif
87
88#define BACKSTEP_SIZE 512
89#define EXTRABYTES 24
90
91struct GranuleDef;
92
93#define MPA_DECODE_HEADER \
94    int frame_size; \
95    int error_protection; \
96    int layer; \
97    int sample_rate; \
98    int sample_rate_index; /* between 0 and 8 */ \
99    int bit_rate; \
100    int nb_channels; \
101    int mode; \
102    int mode_ext; \
103    int lsf;
104
105typedef struct MPADecodeHeader {
106  MPA_DECODE_HEADER
107} MPADecodeHeader;
108
109typedef struct MPADecodeContext {
110    MPA_DECODE_HEADER
111    DECLARE_ALIGNED_8(uint8_t, last_buf[2*BACKSTEP_SIZE + EXTRABYTES]);
112    int last_buf_size;
113    /* next header (used in free format parsing) */
114    uint32_t free_format_next_header;
115    GetBitContext gb;
116    GetBitContext in_gb;
117    DECLARE_ALIGNED_16(MPA_INT, synth_buf[MPA_MAX_CHANNELS][512 * 2]);
118    int synth_buf_offset[MPA_MAX_CHANNELS];
119    DECLARE_ALIGNED_16(int32_t, sb_samples[MPA_MAX_CHANNELS][36][SBLIMIT]);
120    int32_t mdct_buf[MPA_MAX_CHANNELS][SBLIMIT * 18]; /* previous samples, for layer 3 MDCT */
121#ifdef DEBUG
122    int frame_count;
123#endif
124    void (*compute_antialias)(struct MPADecodeContext *s, struct GranuleDef *g);
125    int adu_mode; ///< 0 for standard mp3, 1 for adu formatted mp3
126    int dither_state;
127    int error_recognition;
128    AVCodecContext* avctx;
129} MPADecodeContext;
130
131/* layer 3 huffman tables */
132typedef struct HuffTable {
133    int xsize;
134    const uint8_t *bits;
135    const uint16_t *codes;
136} HuffTable;
137
138int ff_mpa_l2_select_table(int bitrate, int nb_channels, int freq, int lsf);
139int ff_mpa_decode_header(AVCodecContext *avctx, uint32_t head, int *sample_rate, int *channels, int *frame_size, int *bitrate);
140void ff_mpa_synth_init(MPA_INT *window);
141void ff_mpa_synth_filter(MPA_INT *synth_buf_ptr, int *synth_buf_offset,
142                         MPA_INT *window, int *dither_state,
143                         OUT_INT *samples, int incr,
144                         int32_t sb_samples[SBLIMIT]);
145
146/* fast header check for resync */
147static inline int ff_mpa_check_header(uint32_t header){
148    /* header */
149    if ((header & 0xffe00000) != 0xffe00000)
150        return -1;
151    /* layer check */
152    if ((header & (3<<17)) == 0)
153        return -1;
154    /* bit rate */
155    if ((header & (0xf<<12)) == 0xf<<12)
156        return -1;
157    /* frequency */
158    if ((header & (3<<10)) == 3<<10)
159        return -1;
160    return 0;
161}
162
163#endif /* AVCODEC_MPEGAUDIO_H */
164