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
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 "get_bits.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
91/* layer 3 "granule" */
92typedef struct GranuleDef {
93    uint8_t scfsi;
94    int part2_3_length;
95    int big_values;
96    int global_gain;
97    int scalefac_compress;
98    uint8_t block_type;
99    uint8_t switch_point;
100    int table_select[3];
101    int subblock_gain[3];
102    uint8_t scalefac_scale;
103    uint8_t count1table_select;
104    int region_size[3]; /* number of huffman codes in each region */
105    int preflag;
106    int short_start, long_end; /* long/short band indexes */
107    uint8_t scale_factors[40];
108    int32_t sb_hybrid[SBLIMIT * 18]; /* 576 samples */
109} GranuleDef;
110
111#define MPA_DECODE_HEADER \
112    int frame_size; \
113    int error_protection; \
114    int layer; \
115    int sample_rate; \
116    int sample_rate_index; /* between 0 and 8 */ \
117    int bit_rate; \
118    int nb_channels; \
119    int mode; \
120    int mode_ext; \
121    int lsf;
122
123typedef struct MPADecodeHeader {
124  MPA_DECODE_HEADER
125} MPADecodeHeader;
126
127typedef struct MPADecodeContext {
128    MPA_DECODE_HEADER
129    uint8_t last_buf[2*BACKSTEP_SIZE + EXTRABYTES];
130    int last_buf_size;
131    /* next header (used in free format parsing) */
132    uint32_t free_format_next_header;
133    GetBitContext gb;
134    GetBitContext in_gb;
135    DECLARE_ALIGNED(16, MPA_INT, synth_buf)[MPA_MAX_CHANNELS][512 * 2];
136    int synth_buf_offset[MPA_MAX_CHANNELS];
137    DECLARE_ALIGNED(16, int32_t, sb_samples)[MPA_MAX_CHANNELS][36][SBLIMIT];
138    int32_t mdct_buf[MPA_MAX_CHANNELS][SBLIMIT * 18]; /* previous samples, for layer 3 MDCT */
139    GranuleDef granules[2][2]; /* Used in Layer 3 */
140#ifdef DEBUG
141    int frame_count;
142#endif
143    void (*compute_antialias)(struct MPADecodeContext *s, struct GranuleDef *g);
144    int adu_mode; ///< 0 for standard mp3, 1 for adu formatted mp3
145    int dither_state;
146    int error_recognition;
147    AVCodecContext* avctx;
148} MPADecodeContext;
149
150/* layer 3 huffman tables */
151typedef struct HuffTable {
152    int xsize;
153    const uint8_t *bits;
154    const uint16_t *codes;
155} HuffTable;
156
157int ff_mpa_l2_select_table(int bitrate, int nb_channels, int freq, int lsf);
158int ff_mpa_decode_header(AVCodecContext *avctx, uint32_t head, int *sample_rate, int *channels, int *frame_size, int *bitrate);
159extern MPA_INT ff_mpa_synth_window[];
160void ff_mpa_synth_init(MPA_INT *window);
161void ff_mpa_synth_filter(MPA_INT *synth_buf_ptr, int *synth_buf_offset,
162                         MPA_INT *window, int *dither_state,
163                         OUT_INT *samples, int incr,
164                         int32_t sb_samples[SBLIMIT]);
165
166/* fast header check for resync */
167static inline int ff_mpa_check_header(uint32_t header){
168    /* header */
169    if ((header & 0xffe00000) != 0xffe00000)
170        return -1;
171    /* layer check */
172    if ((header & (3<<17)) == 0)
173        return -1;
174    /* bit rate */
175    if ((header & (0xf<<12)) == 0xf<<12)
176        return -1;
177    /* frequency */
178    if ((header & (3<<10)) == 3<<10)
179        return -1;
180    return 0;
181}
182
183#endif /* AVCODEC_MPEGAUDIO_H */
184