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1 /*
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2 * libmad - MPEG audio decoder library
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3 * Copyright (C) 2000-2004 Underbit Technologies, Inc.
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4 *
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5 * This program is free software; you can redistribute it and/or modify
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6 * it under the terms of the GNU General Public License as published by
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7 * the Free Software Foundation; either version 2 of the License, or
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8 * (at your option) any later version.
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9 *
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10 * This program is distributed in the hope that it will be useful,
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11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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13 * GNU General Public License for more details.
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14 *
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15 * You should have received a copy of the GNU General Public License
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16 * along with this program; if not, write to the Free Software
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17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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18 *
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19 * $Id: frame.h,v 1.20 2004/01/23 09:41:32 rob Exp $
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20 */
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21
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22 # ifndef LIBMAD_FRAME_H
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23 # define LIBMAD_FRAME_H
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24
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25 # include "fixed.h"
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26 # include "timer.h"
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27 # include "stream.h"
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28
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29 enum mad_layer {
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30 MAD_LAYER_I = 1, /* Layer I */
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31 MAD_LAYER_II = 2, /* Layer II */
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32 MAD_LAYER_III = 3 /* Layer III */
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33 };
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34
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35 enum mad_mode {
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36 MAD_MODE_SINGLE_CHANNEL = 0, /* single channel */
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37 MAD_MODE_DUAL_CHANNEL = 1, /* dual channel */
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38 MAD_MODE_JOINT_STEREO = 2, /* joint (MS/intensity) stereo */
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39 MAD_MODE_STEREO = 3 /* normal LR stereo */
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40 };
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41
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42 enum mad_emphasis {
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43 MAD_EMPHASIS_NONE = 0, /* no emphasis */
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44 MAD_EMPHASIS_50_15_US = 1, /* 50/15 microseconds emphasis */
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45 MAD_EMPHASIS_CCITT_J_17 = 3, /* CCITT J.17 emphasis */
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46 MAD_EMPHASIS_RESERVED = 2 /* unknown emphasis */
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47 };
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48
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49 struct mad_header {
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50 enum mad_layer layer; /* audio layer (1, 2, or 3) */
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51 enum mad_mode mode; /* channel mode (see above) */
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52 int mode_extension; /* additional mode info */
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53 enum mad_emphasis emphasis; /* de-emphasis to use (see above) */
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54
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55 unsigned long bitrate; /* stream bitrate (bps) */
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56 unsigned int samplerate; /* sampling frequency (Hz) */
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57
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58 unsigned short crc_check; /* frame CRC accumulator */
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59 unsigned short crc_target; /* final target CRC checksum */
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60
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61 int flags; /* flags (see below) */
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62 int private_bits; /* private bits (see below) */
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63
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64 mad_timer_t duration; /* audio playing time of frame */
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65 };
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66
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67 struct mad_frame {
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68 struct mad_header header; /* MPEG audio header */
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69
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70 int options; /* decoding options (from stream) */
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71
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72 mad_fixed_t sbsample[2][36][32]; /* synthesis subband filter samples */
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73 mad_fixed_t (*overlap)[2][32][18]; /* Layer III block overlap data */
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74 };
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75
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76 # define MAD_NCHANNELS(header) ((header)->mode ? 2 : 1)
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77 # define MAD_NSBSAMPLES(header) \
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78 ((header)->layer == MAD_LAYER_I ? 12 : \
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79 (((header)->layer == MAD_LAYER_III && \
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80 ((header)->flags & MAD_FLAG_LSF_EXT)) ? 18 : 36))
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81
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82 enum {
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83 MAD_FLAG_NPRIVATE_III = 0x0007, /* number of Layer III private bits */
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84 MAD_FLAG_INCOMPLETE = 0x0008, /* header but not data is decoded */
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85
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86 MAD_FLAG_PROTECTION = 0x0010, /* frame has CRC protection */
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87 MAD_FLAG_COPYRIGHT = 0x0020, /* frame is copyright */
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88 MAD_FLAG_ORIGINAL = 0x0040, /* frame is original (else copy) */
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89 MAD_FLAG_PADDING = 0x0080, /* frame has additional slot */
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90
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91 MAD_FLAG_I_STEREO = 0x0100, /* uses intensity joint stereo */
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92 MAD_FLAG_MS_STEREO = 0x0200, /* uses middle/side joint stereo */
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93 MAD_FLAG_FREEFORMAT = 0x0400, /* uses free format bitrate */
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94
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95 MAD_FLAG_LSF_EXT = 0x1000, /* lower sampling freq. extension */
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96 MAD_FLAG_MC_EXT = 0x2000, /* multichannel audio extension */
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97 MAD_FLAG_MPEG_2_5_EXT = 0x4000 /* MPEG 2.5 (unofficial) extension */
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98 };
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99
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100 enum {
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101 MAD_PRIVATE_HEADER = 0x0100, /* header private bit */
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102 MAD_PRIVATE_III = 0x001f /* Layer III private bits (up to 5) */
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103 };
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104
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105 void mad_header_init(struct mad_header *);
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106
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107 # define mad_header_finish(header) /* nothing */
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108
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109 int mad_header_decode(struct mad_header *, struct mad_stream *);
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110
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111 void mad_frame_init(struct mad_frame *);
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112 void mad_frame_finish(struct mad_frame *);
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113
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114 int mad_frame_decode(struct mad_frame *, struct mad_stream *);
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115
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116 void mad_frame_mute(struct mad_frame *);
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117
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118 # endif
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