libmad/frame.h

   1 /*
   2  * libmad - MPEG audio decoder library
   3  * Copyright (C) 2000-2003 Underbit Technologies, Inc.
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License as published by
   7  * the Free Software Foundation; either version 2 of the License, or
   8  * (at your option) any later version.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  *
  19  */
  20
  21 # ifndef LIBMAD_FRAME_H
  22 # define LIBMAD_FRAME_H
  23
  24 # include <gctypes.h>
  25 # include "fixed.h"
  26 # include "timer.h"
  27 # include "stream.h"
  28
  29 enum mad_layer {
  30   MAD_LAYER_I   = 1,                    /* Layer I */
  31   MAD_LAYER_II  = 2,                    /* Layer II */
  32   MAD_LAYER_III = 3                     /* Layer III */
  33 };
  34
  35 enum mad_mode {
  36   MAD_MODE_SINGLE_CHANNEL = 0,          /* single channel */
  37   MAD_MODE_DUAL_CHANNEL   = 1,          /* dual channel */
  38   MAD_MODE_JOINT_STEREO   = 2,          /* joint (MS/intensity) stereo */
  39   MAD_MODE_STEREO         = 3           /* normal LR stereo */
  40 };
  41
  42 enum mad_emphasis {
  43   MAD_EMPHASIS_NONE       = 0,          /* no emphasis */
  44   MAD_EMPHASIS_50_15_US   = 1,          /* 50/15 microseconds emphasis */
  45   MAD_EMPHASIS_CCITT_J_17 = 3,          /* CCITT J.17 emphasis */
  46   MAD_EMPHASIS_RESERVED   = 2           /* unknown emphasis */
  47 };
  48
  49 struct mad_header {
  50   enum mad_layer layer;                 /* audio layer (1, 2, or 3) */
  51   enum mad_mode mode;                   /* channel mode (see above) */
  52   s32 mode_extension;                   /* additional mode info */
  53   enum mad_emphasis emphasis;           /* de-emphasis to use (see above) */
  54
  55   u32 bitrate;          /* stream bitrate (bps) */
  56   u32 samplerate;               /* sampling frequency (Hz) */
  57
  58   u16 crc_check;                /* frame CRC accumulator */
  59   u16 crc_target;               /* final target CRC checksum */
  60
  61   s32 flags;                            /* flags (see below) */
  62   s32 private_bits;                     /* private bits (see below) */
  63
  64   mad_timer_t duration;                 /* audio playing time of frame */
  65 };
  66
  67 struct mad_frame {
  68   struct mad_header header;             /* MPEG audio header */
  69
  70   s32 options;                          /* decoding options (from stream) */
  71
  72   mad_fixed_t sbsample[2][36][32];      /* synthesis subband filter samples */
  73   mad_fixed_t (*overlap)[2][32][18];    /* Layer III block overlap data */
  74 };
  75
  76 # define MAD_NCHANNELS(header)          ((header)->mode ? 2 : 1)
  77 # define MAD_NSBSAMPLES(header)  \
  78   ((header)->layer == MAD_LAYER_I ? 12 :  \
  79    (((header)->layer == MAD_LAYER_III &&  \
  80      ((header)->flags & MAD_FLAG_LSF_EXT)) ? 18 : 36))
  81
  82 enum {
  83   MAD_FLAG_NPRIVATE_III = 0x0007,       /* number of Layer III private bits */
  84   MAD_FLAG_INCOMPLETE   = 0x0008,       /* header but not data is decoded */
  85
  86   MAD_FLAG_PROTECTION   = 0x0010,       /* frame has CRC protection */
  87   MAD_FLAG_COPYRIGHT    = 0x0020,       /* frame is copyright */
  88   MAD_FLAG_ORIGINAL     = 0x0040,       /* frame is original (else copy) */
  89   MAD_FLAG_PADDING      = 0x0080,       /* frame has additional slot */
  90
  91   MAD_FLAG_I_STEREO     = 0x0100,       /* uses intensity joint stereo */
  92   MAD_FLAG_MS_STEREO    = 0x0200,       /* uses middle/side joint stereo */
  93   MAD_FLAG_FREEFORMAT   = 0x0400,       /* uses free format bitrate */
  94
  95   MAD_FLAG_LSF_EXT      = 0x1000,       /* lower sampling freq. extension */
  96   MAD_FLAG_MC_EXT       = 0x2000,       /* multichannel audio extension */
  97   MAD_FLAG_MPEG_2_5_EXT = 0x4000        /* MPEG 2.5 (unofficial) extension */
  98 };
  99
 100 enum {
 101   MAD_PRIVATE_HEADER    = 0x0100,       /* header private bit */
 102   MAD_PRIVATE_III       = 0x001f        /* Layer III private bits (up to 5) */
 103 };
 104
 105 void mad_header_init(struct mad_header *);
 106
 107 # define mad_header_finish(header)  /* nothing */
 108
 109 s32 mad_header_decode(struct mad_header *, struct mad_stream *);
 110
 111 void mad_frame_init(struct mad_frame *);
 112 void mad_frame_finish(struct mad_frame *);
 113
 114 s32 mad_frame_decode(struct mad_frame *, struct mad_stream *);
 115
 116 void mad_frame_mute(struct mad_frame *);
 117
 118 # endif