mpegaud.h

mp3解码源代码

/****************************************************************************/

/*
 *	mpegaud.h -- MPEG Audio defintions
 *
 *	Author  :   St閜hane TAVENARD
 *
 *	(C) Copyright 1997-1999 St閜hane TAVENARD
 *	    All Rights Reserved
 *	
 *	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., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

/****************************************************************************/
#ifndef MPEGAUD_H
#define MPEGAUD_H
/****************************************************************************/

#include "bitstr.h"
#include "huff.h"

/*
 *	Integer only decode.
 */
//#define MPEGAUD_INT


/*
 *	ID
 */
#define MPA_ID_1	1
#define MPA_ID_2	0

/*
 *	Sampling Frequencies
 */
#define MPA_SAMP_44100		0
#define MPA_SAMP_48000		1
#define MPA_SAMP_32000		2

/*
 *	Modes
 */
#define MPA_MAX_CHANNELS	2

#define MPA_MODE_STEREO		0
#define MPA_MODE_JOINT_STEREO	1
#define MPA_MODE_DUAL_CHANNEL	2
#define MPA_MODE_MONO		3

#define MPA_SSLIMIT		18
#define MPA_SBLIMIT		32

#define MPA_GRANULE_SIZE	576  // MPA_SSLIMIT*MPA_SBLIMIT

#define MPA_SCALE_BLOCK		12
#define MPA_HANNING_SIZE	512
#define MPA_SCALE_RANGE		64
#define MPA_SCALE		32768
#define MPA_PCM_SIZE		1152

/*
 *	Layer II
 */
#define MPA_GROUPS		3

/*
 *	Layer III
 */
#define MPA_MAX_GRANULES	2
#define MPA_MAX_WINDOWS		3

typedef struct {
	INT16	ID;
	INT16	layer;
	INT16	protection_bit;
	INT16	bitrate_index;
	INT16	sampling_frequency;
	BOOL	padding_bit;
	BOOL	private_bit;
	INT16	mode;
	INT16	mode_extension;
	BOOL	copyright;
	BOOL	original;
	INT16	emphasis;
	INT16	crc_check;
	BOOL	half_freq; // MPEG 2.5 ext.
	INT32	header_pos;
} MPA_HEADER;

/*
 *	Layer III granule info
 */
typedef struct {
	UINT16	part2_3_length;        // 12 uimsbf
	UINT16	big_values;            // 9  uimsbf
	UINT16	global_gain;           // 8  uimsbf
	UINT16	scalefac_compress;     // 4  bslbf MPEG1, 9 bslbf MPEG2
	BOOL	window_switching_flag;
	UINT16	block_type;            // 2  bslbf
	BOOL	mixed_block_flag;
	UINT16	table_select[ 3 ];     // 5  bslbf
	UINT16	subblock_gain[ 3 ];    // 3  bslbf
	UINT16	region0_count;         // 4  bslbf
	UINT16	region1_count;         // 3  bslbf
	BOOL	preflag;
	BOOL	scalefac_scale;        // 1 bslbf
	UINT16	count1table_select;    // 1 bslbf
} MPA_GRANULE_INFO;

/*
 *	Layer III side info
 */
typedef struct {
	UINT16	main_data_begin;       // 9  uimsbf MPEG1, 8 uimsbf MPEG2
	UINT16	private_bits;          // 5/3 bslbf MPEG1, 1/2 bslbf MPEG2
	struct {
		BOOL scfsi[4];
		MPA_GRANULE_INFO gr[MPA_MAX_GRANULES];
	} ch[MPA_MAX_CHANNELS];
} MPA_SIDE_INFO;

/*
 *	Layer III scale factors
 *	Note : swap  s[MPA_MAX_WINDOWS][13] to s[13][MPA_MAX_WINDOWS]
 *	       to optimize time access ?
 */
typedef struct {
   UINT16	l[23];
   UINT16	s[MPA_MAX_WINDOWS][13];
} MPA_SCALE_FAC3;


#ifdef MPEGAUD_INT
#define MPEGAUD_SCALE_TYPE INT32
#define MPEGAUD_SCALE_BITS 30
#define MPEGAUD_FRACT_TYPE INT16
#define MPEGAUD_FRACT_BITS 14
#else
#define MPEGAUD_SCALE_TYPE REAL
#define MPEGAUD_FRACT_TYPE REAL
#endif

#include "mpegsub.h"
#include "mpegimdc.h" // #4

/*
 *	Warning: assume 32-bit alignement
 */

typedef struct {
	const UINT8	(*alloc)[16]; // MPEG-II alloc table
	INT16		bit_alloc[MPA_MAX_CHANNELS][MPA_SBLIMIT];
	MPEGAUD_SCALE_TYPE scale[MPA_MAX_CHANNELS][MPA_GROUPS][MPA_SBLIMIT];
	UINT16		sample[MPA_MAX_CHANNELS][MPA_GROUPS][MPA_SBLIMIT];
	MPEGAUD_FRACT_TYPE fraction[MPA_MAX_CHANNELS][MPA_GROUPS][MPA_SBLIMIT];

	INT16		is[MPA_GRANULE_SIZE];
	MPEGAUD_FRACT_TYPE xr[MPA_MAX_CHANNELS][MPA_GRANULE_SIZE];
	MPEGAUD_FRACT_TYPE lr[MPA_MAX_CHANNELS][MPA_GRANULE_SIZE];

	INT16		*pcm[MPA_MAX_CHANNELS];
	INT16		scfsi[MPA_MAX_CHANNELS][MPA_SBLIMIT];
	MPA_SCALE_FAC3	scale_fac3[MPA_MAX_CHANNELS];

	BITSTREAM	*bitstream;
	HUFFMAN		*huffman;
	MPEGSUB		*mpegsub;
	MPEGIMDCT	*mpegimdct;

	MPA_HEADER	header;
	MPA_SIDE_INFO	side_info;
	BOOL		stereo;
	INT16		channels;
	UINT16		sfreq;
	UINT32		stream_size;
	INT16		bitrate;
	INT16		jsbound;
	INT16		sblimit;
	INT16		current_table;
	UINT32		frame;

	INT16		freq_div;
	INT16		quality;
	INT16		sb_max;
	BOOL		force_mono;

	INT16		sfb_nul_l[MPA_MAX_CHANNELS];
	INT16		sfb_nul_s[MPA_MAX_WINDOWS][MPA_MAX_CHANNELS];

	// For MPEG2-III is_pos illegal is not 7 but is_max[sfb]
	INT16		is_max_l[21];
	INT16		is_max_s[MPA_MAX_WINDOWS][12];

	BOOL		need_sync;
	INT16		imdct_max[MPA_MAX_CHANNELS];
	INT16		sfb_nul_s_top[MPA_MAX_WINDOWS];

	INT32		bitstream_start_pos;
	void		*keyp;
} MPA_STREAM;

/****************************************************************************/
#endif /* MPEGAUD_H */