ref: 19b480838af1721b833f6cd7575e994a5d55071d
dir: /sys/src/cmd/audio/mp3dec/frame.h/
/*
* 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 "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) */
};
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