mp3common.h

来自「An complete pmp solution for mattel juic」· C头文件 代码 · 共 125 行

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/**************************************************************************************
 * Fixed-point MP3 decoder
 * Jon Recker ([e-mail]), Ken Cooke ([e-mail])
 * June 2003
 *
 * mp3common.h - implementation-independent API's, datatypes, and definitions
 **************************************************************************************/

#ifndef _MP3COMMON_H
#define _MP3COMMON_H

#include "mp3dec.h"
#include "statname.h"	/* do name-mangling for static linking */

#define MAX_SCFBD		4		/* max scalefactor bands per channel */
#define NGRANS_MPEG1	2
#define NGRANS_MPEG2	1

/* 11-bit syncword if MPEG 2.5 extensions are enabled */
/*
#define	SYNCWORDH		0xff
#define	SYNCWORDL		0xe0
*/

/* 12-bit syncword if MPEG 1,2 only are supported */
#define	SYNCWORDH		0xff
#define	SYNCWORDL		0xf0

typedef struct _MP3DecInfo {
	/* pointers to platform-specific data structures */
	void *FrameHeaderPS;
	void *SideInfoPS;
	void *ScaleFactorInfoPS;
	void *HuffmanInfoPS;
	void *DequantInfoPS;
	void *IMDCTInfoPS;
	void *SubbandInfoPS;

	/* buffer which must be large enough to hold largest possible main_data section */
	u08 mainBuf[MAINBUF_SIZE];

	/* special info for "free" bitrate files */
	i32 freeBitrateFlag;
	i32 freeBitrateSlots;

	/* user-accessible info */
	i32 bitrate;
	i32 nChans;
	i32 samprate;
	i32 nGrans;				/* granules per frame */
	i32 nGranSamps;			/* samples per granule */
	i32 nSlots;
	i32 layer;
	MPEGVersion version;

	i32 mainDataBegin;
	i32 mainDataBytes;

	i32 part23Length[MAX_NGRAN][MAX_NCHAN];

} MP3DecInfo;

typedef struct _SFBandTable {
	i16 l[23];
	i16 s[14];
} SFBandTable;

/* decoder functions which must be implemented for each platform */
MP3DecInfo *AllocateBuffers(void);
void FreeBuffers(MP3DecInfo *mp3DecInfo);
i32 CheckPadBit(MP3DecInfo *mp3DecInfo);
i32 UnpackFrameHeader(MP3DecInfo *mp3DecInfo, u08 *buf);
i32 UnpackSideInfo(MP3DecInfo *mp3DecInfo, u08 *buf);
i32 DecodeHuffman(MP3DecInfo *mp3DecInfo, u08 *buf, i32 *bitOffset, i32 huffBlockBits, i32 gr, i32 ch);
i32 Dequantize(MP3DecInfo *mp3DecInfo, i32 gr);
i32 IMDCT(MP3DecInfo *mp3DecInfo, i32 gr, i32 ch);
i32 UnpackScaleFactors(MP3DecInfo *mp3DecInfo, u08 *buf, i32 *bitOffset, i32 bitsAvail, i32 gr, i32 ch);
i32 Subband(MP3DecInfo *mp3DecInfo, i16 *pcmBuf);

/* mp3tabs.c - global ROM tables */
extern const i32 samplerateTab[3][3];
extern const i16 bitrateTab[3][3][15];
extern const i16 samplesPerFrameTab[3][3];
extern const i16 bitsPerSlotTab[3];
extern const i16 sideBytesTab[3][2];
extern const i16 slotTab[3][3][15];
extern const SFBandTable sfBandTable[3][3];

#endif	/* _MP3COMMON_H */