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 struct 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
 105 typedef struct MPADecodeHeader {
 106   MPA_DECODE_HEADER
 107 } MPADecodeHeader;
 108
 109 typedef struct MPADecodeContext {
 110     MPA_DECODE_HEADER
 111     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 */
 132 typedef struct HuffTable {
 133     int xsize;
 134     const uint8_t *bits;
 135     const uint16_t *codes;
 136 } HuffTable;
 137
 138 int ff_mpa_l2_select_table(int bitrate, int nb_channels, int freq, int lsf);
 139 int ff_mpa_decode_header(AVCodecContext *avctx, uint32_t head, int *sample_rate, int *channels, int *frame_size, int *bitrate);
 140 void ff_mpa_synth_init(MPA_INT *window);
 141 void 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 */
 147 static 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 */