blob: e8f53bf0ce8ce2c9ec4f292a5635bef4602857d1
1 | /* |
2 | * libmad - MPEG audio decoder library |
3 | * Copyright (C) 2000-2004 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 | * $Id: frame.h,v 1.20 2004/01/23 09:41:32 rob Exp $ |
20 | */ |
21 | |
22 | # ifndef LIBMAD_FRAME_H |
23 | # define LIBMAD_FRAME_H |
24 | |
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 | int mode_extension; /* additional mode info */ |
53 | enum mad_emphasis emphasis; /* de-emphasis to use (see above) */ |
54 | |
55 | unsigned long bitrate; /* stream bitrate (bps) */ |
56 | unsigned int samplerate; /* sampling frequency (Hz) */ |
57 | |
58 | unsigned short crc_check; /* frame CRC accumulator */ |
59 | unsigned short crc_target; /* final target CRC checksum */ |
60 | |
61 | int flags; /* flags (see below) */ |
62 | int 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 | int 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 | int 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 | int mad_frame_decode(struct mad_frame *, struct mad_stream *); |
115 | |
116 | void mad_frame_mute(struct mad_frame *); |
117 | |
118 | # endif |
119 |