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 "mad_fixed.h" 26 # include "mad_timer.h" 27 # include "mad_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 /* Erez Volk 2007-05-30: */ 67 unsigned long offset; /* Offset of frame in stream */ 68 }; 69 70 struct mad_frame { 71 struct mad_header header; /* MPEG audio header */ 72 73 int options; /* decoding options (from stream) */ 74 75 mad_fixed_t sbsample[2][36][32]; /* synthesis subband filter samples */ 76 mad_fixed_t (*overlap)[2][32][18]; /* Layer III block overlap data */ 77 }; 78 79 # define MAD_NCHANNELS(header) ((header)->mode ? 2 : 1) 80 # define MAD_NSBSAMPLES(header) \ 81 ((header)->layer == MAD_LAYER_I ? 12 : \ 82 (((header)->layer == MAD_LAYER_III && \ 83 ((header)->flags & MAD_FLAG_LSF_EXT)) ? 18 : 36)) 84 85 enum { 86 MAD_FLAG_NPRIVATE_III = 0x0007, /* number of Layer III private bits */ 87 MAD_FLAG_INCOMPLETE = 0x0008, /* header but not data is decoded */ 88 89 MAD_FLAG_PROTECTION = 0x0010, /* frame has CRC protection */ 90 MAD_FLAG_COPYRIGHT = 0x0020, /* frame is copyright */ 91 MAD_FLAG_ORIGINAL = 0x0040, /* frame is original (else copy) */ 92 MAD_FLAG_PADDING = 0x0080, /* frame has additional slot */ 93 94 MAD_FLAG_I_STEREO = 0x0100, /* uses intensity joint stereo */ 95 MAD_FLAG_MS_STEREO = 0x0200, /* uses middle/side joint stereo */ 96 MAD_FLAG_FREEFORMAT = 0x0400, /* uses free format bitrate */ 97 98 MAD_FLAG_LSF_EXT = 0x1000, /* lower sampling freq. extension */ 99 MAD_FLAG_MC_EXT = 0x2000, /* multichannel audio extension */ 100 MAD_FLAG_MPEG_2_5_EXT = 0x4000 /* MPEG 2.5 (unofficial) extension */ 101 }; 102 103 enum { 104 MAD_PRIVATE_HEADER = 0x0100, /* header private bit */ 105 MAD_PRIVATE_III = 0x001f /* Layer III private bits (up to 5) */ 106 }; 107 108 void mad_header_init(struct mad_header *); 109 110 # define mad_header_finish(header) /* nothing */ 111 112 int mad_header_decode(struct mad_header *, struct mad_stream *); 113 114 void mad_frame_init(struct mad_frame *); 115 void mad_frame_finish(struct mad_frame *); 116 117 int mad_frame_decode(struct mad_frame *, struct mad_stream *); 118 119 void mad_frame_mute(struct mad_frame *); 120 121 # endif 122