libavcodec/mpegaudio.h

   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 "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
  69 typedef 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
  75 typedef 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
  83 typedef int16_t MPA_INT;
  84 #else
  85 typedef int32_t MPA_INT;
  86 #endif
  87
  88 #define BACKSTEP_SIZE 512
  89 #define EXTRABYTES 24
  90
  91 /* layer 3 "granule" */
  92 typedef 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
 123 typedef struct MPADecodeHeader {
 124   MPA_DECODE_HEADER
 125 } MPADecodeHeader;
 126
 127 typedef 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 */
 151 typedef struct HuffTable {
 152     int xsize;
 153     const uint8_t *bits;
 154     const uint16_t *codes;
 155 } HuffTable;
 156
 157 int ff_mpa_l2_select_table(int bitrate, int nb_channels, int freq, int lsf);
 158 int ff_mpa_decode_header(AVCodecContext *avctx, uint32_t head, int *sample_rate, int *channels, int *frame_size, int *bitrate);
 159 extern MPA_INT ff_mpa_synth_window[];
 160 void ff_mpa_synth_init(MPA_INT *window);
 161 void 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 */
 167 static 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 */