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Diffstat (limited to 'libmad/src/frame.h')
| -rw-r--r-- | libmad/src/frame.h | 118 |
1 files changed, 118 insertions, 0 deletions
diff --git a/libmad/src/frame.h b/libmad/src/frame.h new file mode 100644 index 0000000..3f5bf37 --- /dev/null +++ b/libmad/src/frame.h @@ -0,0 +1,118 @@ +/* + * libmad - MPEG audio decoder library + * Copyright (C) 2000-2004 Underbit Technologies, Inc. + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + * + * $Id: frame.h,v 1.20 2004/01/23 09:41:32 rob Exp $ + */ + +# ifndef LIBMAD_FRAME_H +# define LIBMAD_FRAME_H + +# include "fixed.h" +# include "timer.h" +# include "stream.h" + +enum mad_layer { + MAD_LAYER_I = 1, /* Layer I */ + MAD_LAYER_II = 2, /* Layer II */ + MAD_LAYER_III = 3 /* Layer III */ +}; + +enum mad_mode { + MAD_MODE_SINGLE_CHANNEL = 0, /* single channel */ + MAD_MODE_DUAL_CHANNEL = 1, /* dual channel */ + MAD_MODE_JOINT_STEREO = 2, /* joint (MS/intensity) stereo */ + MAD_MODE_STEREO = 3 /* normal LR stereo */ +}; + +enum mad_emphasis { + MAD_EMPHASIS_NONE = 0, /* no emphasis */ + MAD_EMPHASIS_50_15_US = 1, /* 50/15 microseconds emphasis */ + MAD_EMPHASIS_CCITT_J_17 = 3, /* CCITT J.17 emphasis */ + MAD_EMPHASIS_RESERVED = 2 /* unknown emphasis */ +}; + +struct mad_header { + enum mad_layer layer; /* audio layer (1, 2, or 3) */ + enum mad_mode mode; /* channel mode (see above) */ + int mode_extension; /* additional mode info */ + enum mad_emphasis emphasis; /* de-emphasis to use (see above) */ + + unsigned long bitrate; /* stream bitrate (bps) */ + unsigned int samplerate; /* sampling frequency (Hz) */ + + unsigned short crc_check; /* frame CRC accumulator */ + unsigned short crc_target; /* final target CRC checksum */ + + int flags; /* flags (see below) */ + int private_bits; /* private bits (see below) */ + + mad_timer_t duration; /* audio playing time of frame */ +}; + +struct mad_frame { + struct mad_header header; /* MPEG audio header */ + + int options; /* decoding options (from stream) */ + + mad_fixed_t sbsample[2][36][32]; /* synthesis subband filter samples */ + mad_fixed_t (*overlap)[2][32][18]; /* Layer III block overlap data */ +}; + +# define MAD_NCHANNELS(header) ((header)->mode ? 2 : 1) +# define MAD_NSBSAMPLES(header) \ + ((header)->layer == MAD_LAYER_I ? 12 : \ + (((header)->layer == MAD_LAYER_III && \ + ((header)->flags & MAD_FLAG_LSF_EXT)) ? 18 : 36)) + +enum { + MAD_FLAG_NPRIVATE_III = 0x0007, /* number of Layer III private bits */ + MAD_FLAG_INCOMPLETE = 0x0008, /* header but not data is decoded */ + + MAD_FLAG_PROTECTION = 0x0010, /* frame has CRC protection */ + MAD_FLAG_COPYRIGHT = 0x0020, /* frame is copyright */ + MAD_FLAG_ORIGINAL = 0x0040, /* frame is original (else copy) */ + MAD_FLAG_PADDING = 0x0080, /* frame has additional slot */ + + MAD_FLAG_I_STEREO = 0x0100, /* uses intensity joint stereo */ + MAD_FLAG_MS_STEREO = 0x0200, /* uses middle/side joint stereo */ + MAD_FLAG_FREEFORMAT = 0x0400, /* uses free format bitrate */ + + MAD_FLAG_LSF_EXT = 0x1000, /* lower sampling freq. extension */ + MAD_FLAG_MC_EXT = 0x2000, /* multichannel audio extension */ + MAD_FLAG_MPEG_2_5_EXT = 0x4000 /* MPEG 2.5 (unofficial) extension */ +}; + +enum { + MAD_PRIVATE_HEADER = 0x0100, /* header private bit */ + MAD_PRIVATE_III = 0x001f /* Layer III private bits (up to 5) */ +}; + +void mad_header_init(struct mad_header *); + +# define mad_header_finish(header) /* nothing */ + +int mad_header_decode(struct mad_header *, struct mad_stream *); + +void mad_frame_init(struct mad_frame *); +void mad_frame_finish(struct mad_frame *); + +int mad_frame_decode(struct mad_frame *, struct mad_stream *); + +void mad_frame_mute(struct mad_frame *); + +# endif |