mp3coder.h

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/* ***** BEGIN LICENSE BLOCK ***** 
 * Version: RCSL 1.0/RPSL 1.0 
 *  
 * Portions Copyright (c) 1995-2002 RealNetworks, Inc. All Rights Reserved. 
 *      
 * The contents of this file, and the files included with this file, are 
 * subject to the current version of the RealNetworks Public Source License 
 * Version 1.0 (the "RPSL") available at 
 * http://www.helixcommunity.org/content/rpsl unless you have licensed 
 * the file under the RealNetworks Community Source License Version 1.0 
 * (the "RCSL") available at http://www.helixcommunity.org/content/rcsl, 
 * in which case the RCSL will apply. You may also obtain the license terms 
 * directly from RealNetworks.  You may not use this file except in 
 * compliance with the RPSL or, if you have a valid RCSL with RealNetworks 
 * applicable to this file, the RCSL.  Please see the applicable RPSL or 
 * RCSL for the rights, obligations and limitations governing use of the 
 * contents of the file.  
 *  
 * This file is part of the Helix DNA Technology. RealNetworks is the 
 * developer of the Original Code and owns the copyrights in the portions 
 * it created. 
 *  
 * This file, and the files included with this file, is distributed and made 
 * available on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER 
 * EXPRESS OR IMPLIED, AND REALNETWORKS HEREBY DISCLAIMS ALL SUCH WARRANTIES, 
 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY, FITNESS 
 * FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT. 
 * 
 * Technology Compatibility Kit Test Suite(s) Location: 
 *    http://www.helixcommunity.org/content/tck 
 * 
 * Contributor(s): 
 *  
 * ***** END LICENSE BLOCK ***** */ 

/**************************************************************************************
 * Fixed-point MP3 decoder
 * Jon Recker (jrecker@real.com), Ken Cooke (kenc@real.com)
 * June 2003
 *
 * mp3coder.h - private, implementation-specific header file
 **************************************************************************************/

#ifndef _CODER_H
#define _CODER_H

#include "mp3common.h"

#if defined(ASSERT)
#undef ASSERT
#endif
#if defined(_WIN32) && defined(_M_IX86) && (defined (_DEBUG) || defined (REL_ENABLE_ASSERTS))
#define ASSERT(x) if (!(x)) __asm int 3;
#else
#define ASSERT(x) /* do nothing */
#endif

#ifndef MAX
#define MAX(a,b)    ((a) > (b) ? (a) : (b))
#endif

#ifndef MIN
#define MIN(a,b)    ((a) < (b) ? (a) : (b))
#endif

/* clip to range [-2^n, 2^n - 1] */
#define CLIP_2N(y, n) { \
    int sign = (y) >> 31;  \
    if (sign != (y) >> (n))  { \
        (y) = sign ^ ((1 << (n)) - 1); \
    } \
}

#define SIBYTES_MPEG1_MONO      17
#define SIBYTES_MPEG1_STEREO    32
#define SIBYTES_MPEG2_MONO       9
#define SIBYTES_MPEG2_STEREO    17

/* number of fraction bits for pow43Tab (see comments there) */
#define POW43_FRACBITS_LOW      22
#define POW43_FRACBITS_HIGH     12

#define DQ_FRACBITS_OUT         25  /* number of fraction bits in output of dequant */
#define IMDCT_SCALE             2   /* additional scaling (by sqrt(2)) for fast IMDCT36 */

#define HUFF_PAIRTABS           32
#define BLOCK_SIZE              18
#define NBANDS                  32
#define MAX_REORDER_SAMPS       ((192-126)*3)       /* largest critical band for short blocks (see sfBandTable) */
#define VBUF_LENGTH             (17 * 2 * NBANDS)   /* for double-sized vbuf FIFO */

/* additional external symbols to name-mangle for static linking */
#define SetBitstreamPointer STATNAME(SetBitstreamPointer)
#define GetBits             STATNAME(GetBits)
#define CalcBitsUsed        STATNAME(CalcBitsUsed)
#define DequantChannel      STATNAME(DequantChannel)
#define MidSideProc         STATNAME(MidSideProc)
#define IntensityProcMPEG1  STATNAME(IntensityProcMPEG1)
#define IntensityProcMPEG2  STATNAME(IntensityProcMPEG2)
//#define PolyphaseMono     STATNAME(PolyphaseMono)
//#define PolyphaseStereo       STATNAME(PolyphaseStereo)
#define FDCT32              STATNAME(FDCT32)

#define ISFMpeg1            STATNAME(ISFMpeg1)
#define ISFMpeg2            STATNAME(ISFMpeg2)
#define ISFIIP              STATNAME(ISFIIP)
#define uniqueIDTab         STATNAME(uniqueIDTab)
#define coef32              STATNAME(coef32)
#define polyCoef            STATNAME(polyCoef)
#define csa                 STATNAME(csa)
#define imdctWin            STATNAME(imdctWin)

#define huffTable_0         STATNAME(huffTable_0)
#define huffTable_1         STATNAME(huffTable_1)
#define huffTable_2         STATNAME(huffTable_2)
#define huffTabOffset       STATNAME(huffTabOffset)
#define huffTabLookup       STATNAME(huffTabLookup)
#define quadTable           STATNAME(quadTable)
#define quadTabOffset       STATNAME(quadTabOffset)
#define quadTabMaxBits      STATNAME(quadTabMaxBits)

/* map these to the corresponding 2-bit values in the frame header */
typedef enum {
    Stereo = 0x00,  /* two independent channels, but L and R frames might have different # of bits */
    Joint = 0x01,   /* coupled channels - layer III: mix of M-S and intensity, Layers I/II: intensity and direct coding only */
    Dual = 0x02,    /* two independent channels, L and R always have exactly 1/2 the total bitrate */
    Mono = 0x03     /* one channel */
} StereoMode;

typedef struct _BitStreamInfo {
    unsigned char *bytePtr;
    unsigned int iCache;
    int cachedBits;
    int nBytes;
} BitStreamInfo;

typedef struct _FrameHeader {
    MPEGVersion ver;    /* version ID */
    int layer;          /* layer index (1, 2, or 3) */
    int crc;            /* CRC flag: 0 = disabled, 1 = enabled */
    int brIdx;          /* bitrate index (0 - 15) */
    int srIdx;          /* sample rate index (0 - 2) */
    int paddingBit;     /* padding flag: 0 = no padding, 1 = single pad byte */
    int privateBit;     /* unused */
    StereoMode sMode;   /* mono/stereo mode */
    int modeExt;        /* used to decipher joint stereo mode */
    int copyFlag;       /* copyright flag: 0 = no, 1 = yes */
    int origFlag;       /* original flag: 0 = copy, 1 = original */
    int emphasis;       /* deemphasis mode */
    int CRCWord;        /* CRC word (16 bits, 0 if crc not enabled) */

    const SFBandTable *sfBand;
} FrameHeader;

typedef struct _SideInfoSub {
    int part23Length;       /* number of bits in main data */ 
    int nBigvals;           /* 2x this = first set of Huffman cw's (maximum amplitude can be > 1) */
    int globalGain;         /* overall gain for dequantizer */
    int sfCompress;         /* unpacked to figure out number of bits in scale factors */
    int winSwitchFlag;      /* window switching flag */
    int blockType;          /* block type */
    int mixedBlock;         /* 0 = regular block (all short or long), 1 = mixed block */
    int tableSelect[3];     /* index of Huffman tables for the big values regions */
    int subBlockGain[3];    /* subblock gain offset, relative to global gain */
    int region0Count;       /* 1+region0Count = num scale factor bands in first region of bigvals */
    int region1Count;       /* 1+region1Count = num scale factor bands in second region of bigvals */
    int preFlag;            /* for optional high frequency boost */
    int sfactScale;         /* scaling of the scalefactors */
    int count1TableSelect;  /* index of Huffman table for quad codewords */
} SideInfoSub;

typedef struct _SideInfo {
    int mainDataBegin;
    int privateBits;
    int scfsi[MAX_NCHAN][MAX_SCFBD];                /* 4 scalefactor bands per channel */
    
    SideInfoSub sis[MAX_NGRAN][MAX_NCHAN];
} SideInfo;

typedef struct {
    int cbType;     /* pure long = 0, pure short = 1, mixed = 2 */
    int cbEndS[3];  /* number nonzero short cb's, per subbblock */
    int cbEndSMax;  /* max of cbEndS[] */
    int cbEndL;     /* number nonzero long cb's  */
} CriticalBandInfo;

typedef struct _DequantInfo {
    int workBuf[MAX_REORDER_SAMPS];     /* workbuf for reordering short blocks */
    CriticalBandInfo cbi[MAX_NCHAN];    /* filled in dequantizer, used in joint stereo reconstruction */
} DequantInfo;

typedef struct _HuffmanInfo {
    int huffDecBuf[MAX_NCHAN][MAX_NSAMP];       /* used both for decoded Huffman values and dequantized coefficients */
    int nonZeroBound[MAX_NCHAN];                /* number of coeffs in huffDecBuf[ch] which can be > 0 */
    int gb[MAX_NCHAN];                          /* minimum number of guard bits in huffDecBuf[ch] */
} HuffmanInfo;

typedef enum _HuffTabType {
    noBits,
    oneShot,
    loopNoLinbits,
    loopLinbits,
    quadA,
    quadB,
    invalidTab
} HuffTabType;

typedef struct _HuffTabLookup {
    int linBits;
    HuffTabType tabType;
} HuffTabLookup;

typedef struct _IMDCTInfo {
    int outBuf[MAX_NCHAN][BLOCK_SIZE][NBANDS];  /* output of IMDCT */   
    int overBuf[MAX_NCHAN][MAX_NSAMP / 2];      /* overlap-add buffer (by symmetry, only need 1/2 size) */
    int numPrevIMDCT[MAX_NCHAN];                /* how many IMDCT's calculated in this channel on prev. granule */
    int prevType[MAX_NCHAN];
    int prevWinSwitch[MAX_NCHAN];
    int gb[MAX_NCHAN];
} IMDCTInfo;

typedef struct _BlockCount {
    int nBlocksLong;
    int nBlocksTotal;
    int nBlocksPrev; 
    int prevType;
    int prevWinSwitch;
    int currWinSwitch;
    int gbIn;
    int gbOut;
} BlockCount;

/* max bits in scalefactors = 5, so use char's to save space */
typedef struct _ScaleFactorInfoSub {
    char l[23];            /* [band] */
    char s[13][3];         /* [band][window] */
} ScaleFactorInfoSub;  

/* used in MPEG 2, 2.5 intensity (joint) stereo only */
typedef struct _ScaleFactorJS {
    int intensityScale;     
    int slen[4];
    int nr[4];
} ScaleFactorJS;

typedef struct _ScaleFactorInfo {
    ScaleFactorInfoSub sfis[MAX_NGRAN][MAX_NCHAN];
    ScaleFactorJS sfjs;
} ScaleFactorInfo;

/* NOTE - could get by with smaller vbuf if memory is more important than speed
 *  (in Subband, instead of replicating each block in FDCT32 you would do a memmove on the
 *   last 15 blocks to shift them down one, a hardware style FIFO)
 */ 
typedef struct _SubbandInfo {
    int vbuf[MAX_NCHAN * VBUF_LENGTH];      /* vbuf for fast DCT-based synthesis PQMF - double size for speed (no modulo indexing) */
    int vindex;                             /* internal index for tracking position in vbuf */
} SubbandInfo;

/* mp3bitstream.c */
void SetBitstreamPointer(BitStreamInfo *bsi, int nBytes, unsigned char *buf);
unsigned int GetBits(BitStreamInfo *bsi, int nBits);
int CalcBitsUsed(BitStreamInfo *bsi, unsigned char *startBuf, int startOffset);

/* mp3dequant.c, mp3dqchan.c, mp3stproc.c */
int DequantChannel(int *sampleBuf, int *workBuf, int *nonZeroBound, FrameHeader *fh, SideInfoSub *sis, 
                    ScaleFactorInfoSub *sfis, CriticalBandInfo *cbi);
void MidSideProc(int x[MAX_NCHAN][MAX_NSAMP], int nSamps, int mOut[2]);
void IntensityProcMPEG1(int x[MAX_NCHAN][MAX_NSAMP], int nSamps, FrameHeader *fh, ScaleFactorInfoSub *sfis, 
                        CriticalBandInfo *cbi, int midSideFlag, int mixFlag, int mOut[2]);
void IntensityProcMPEG2(int x[MAX_NCHAN][MAX_NSAMP], int nSamps, FrameHeader *fh, ScaleFactorInfoSub *sfis, 
                        CriticalBandInfo *cbi, ScaleFactorJS *sfjs, int midSideFlag, int mixFlag, int mOut[2]);

/* mp3dct32.c */
void FDCT32(int *x, int *d, int offset, int oddBlock, int gb);

#ifdef USE_OUTSIDE_MP3_TABLE
/* mp3hufftabs.c */
extern HuffTabLookup * huffTabLookup;
extern int * huffTabOffset;
extern unsigned short * huffTable_0;
extern unsigned short * huffTable_1;
extern unsigned short * huffTable_2;
extern unsigned char * quadTable;
extern int * quadTabOffset;
extern int * quadTabMaxBits;
#else
/* mp3hufftabs.c */
extern const HuffTabLookup huffTabLookup[HUFF_PAIRTABS];
extern const int huffTabOffset[HUFF_PAIRTABS];
extern const unsigned short huffTable_0[];
extern const unsigned short huffTable_1[];
extern const unsigned short huffTable_2[];
extern const unsigned char quadTable[64+16];
extern const int quadTabOffset[2];
extern const int quadTabMaxBits[2];
#endif  /* USE_OUTSIDE_MP3_TABLE */

/* mp3polyphase.c (or asmpoly.s)
 * some platforms require a C++ compile of all source files,
 * so if we're compiling C as C++ and using native assembly
 * for these functions we need to prevent C++ name mangling.
 */
#ifdef __cplusplus
extern "C" {
#endif
void PolyphaseMono(short *pcm, int *vbuf, const int *coefBase);
void PolyphaseStereo(short *pcm, int *vbuf, const int *coefBase);
#ifdef __cplusplus
}
#endif

#ifdef USE_OUTSIDE_MP3_TABLE
/* mp3trigtabs.c */
extern int (* imdctWin)[36];
extern int (* ISFMpeg1)[7];
extern int (* ISFMpeg2)[2][16];
extern int (* ISFIIP)[2];
extern unsigned char * uniqueIDTab;
extern int (* csa)[2];
extern int * coef32;
extern int * polyCoef;
#else
/* mp3trigtabs.c */
extern const int imdctWin[4][36];
extern const int ISFMpeg1[2][7];
extern const int ISFMpeg2[2][2][16];
extern const int ISFIIP[2][2];
extern const int csa[8][2];
extern const int coef32[31];
extern const int polyCoef[264];
#endif  /* USE_OUTSIDE_MP3_TABLE */

#endif  /* _CODER_H */