/ src / coder.h
coder.h
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 35  
 36  /**************************************************************************************
 37   * Fixed-point MP3 decoder
 38   * Jon Recker (jrecker@real.com), Ken Cooke (kenc@real.com)
 39   * June 2003
 40   *
 41   * coder.h - private, implementation-specific header file
 42   **************************************************************************************/
 43  
 44  #ifndef _CODER_H
 45  #define _CODER_H
 46  
 47  #include "mp3common.h"
 48  
 49  #if defined(ASSERT)
 50  #undef ASSERT
 51  #endif
 52  #if defined(_WIN32) && defined(_M_IX86) && (defined (_DEBUG) || defined (REL_ENABLE_ASSERTS))
 53  #define ASSERT(x) if (!(x)) __asm int 3;
 54  #else
 55  #define ASSERT(x) /* do nothing */
 56  #endif
 57  
 58  #ifndef MAX
 59  #define MAX(a,b)	((a) > (b) ? (a) : (b))
 60  #endif
 61  
 62  #ifndef MIN
 63  #define MIN(a,b)	((a) < (b) ? (a) : (b))
 64  #endif
 65  
 66  /* clip to range [-2^n, 2^n - 1] */
 67  #define CLIP_2N(y, n) { \
 68  	int sign = (y) >> 31;  \
 69  	if (sign != (y) >> (n))  { \
 70  		(y) = sign ^ ((1 << (n)) - 1); \
 71  	} \
 72  }
 73  
 74  #define SIBYTES_MPEG1_MONO		17
 75  #define SIBYTES_MPEG1_STEREO	32
 76  #define SIBYTES_MPEG2_MONO		 9
 77  #define SIBYTES_MPEG2_STEREO	17
 78  
 79  /* number of fraction bits for pow43Tab (see comments there) */
 80  #define POW43_FRACBITS_LOW		22
 81  #define POW43_FRACBITS_HIGH		12
 82  
 83  #define DQ_FRACBITS_OUT			25	/* number of fraction bits in output of dequant */
 84  #define	IMDCT_SCALE				2	/* additional scaling (by sqrt(2)) for fast IMDCT36 */
 85  
 86  #define	HUFF_PAIRTABS			32
 87  #define BLOCK_SIZE				18
 88  #define	NBANDS					32
 89  #define MAX_REORDER_SAMPS		((192-126)*3)		/* largest critical band for short blocks (see sfBandTable) */
 90  #define VBUF_LENGTH				(17 * 2 * NBANDS)	/* for double-sized vbuf FIFO */
 91  
 92  /* additional external symbols to name-mangle for static linking */
 93  #define	SetBitstreamPointer	STATNAME(SetBitstreamPointer)
 94  #define	GetBits				STATNAME(GetBits)
 95  #define	CalcBitsUsed		STATNAME(CalcBitsUsed)
 96  #define	DequantChannel		STATNAME(DequantChannel)
 97  #define	MidSideProc			STATNAME(MidSideProc)
 98  #define	IntensityProcMPEG1	STATNAME(IntensityProcMPEG1)
 99  #define	IntensityProcMPEG2	STATNAME(IntensityProcMPEG2)
100  #define PolyphaseMono		STATNAME(PolyphaseMono)
101  #define PolyphaseStereo		STATNAME(PolyphaseStereo)
102  #define FDCT32				STATNAME(FDCT32)
103  
104  #define	ISFMpeg1			STATNAME(ISFMpeg1)
105  #define	ISFMpeg2			STATNAME(ISFMpeg2)
106  #define	ISFIIP				STATNAME(ISFIIP)
107  #define uniqueIDTab			STATNAME(uniqueIDTab)
108  #define	coef32				STATNAME(coef32)
109  #define	polyCoef			STATNAME(polyCoef)
110  #define	csa					STATNAME(csa)
111  #define	imdctWin			STATNAME(imdctWin)
112  
113  #define	huffTable			STATNAME(huffTable)
114  #define	huffTabOffset		STATNAME(huffTabOffset)
115  #define	huffTabLookup		STATNAME(huffTabLookup)
116  #define	quadTable			STATNAME(quadTable)
117  #define	quadTabOffset		STATNAME(quadTabOffset)
118  #define	quadTabMaxBits		STATNAME(quadTabMaxBits)
119  
120  /* map these to the corresponding 2-bit values in the frame header */
121  typedef enum {
122  	Stereo = 0x00,	/* two independent channels, but L and R frames might have different # of bits */
123  	Joint = 0x01,	/* coupled channels - layer III: mix of M-S and intensity, Layers I/II: intensity and direct coding only */
124  	Dual = 0x02,	/* two independent channels, L and R always have exactly 1/2 the total bitrate */
125  	Mono = 0x03		/* one channel */
126  } StereoMode;
127  
128  typedef struct _BitStreamInfo {
129  	unsigned char *bytePtr;
130  	unsigned int iCache;
131  	int cachedBits;
132  	int nBytes;
133  } BitStreamInfo;
134  
135  typedef struct _FrameHeader {
136      MPEGVersion ver;	/* version ID */
137      int layer;			/* layer index (1, 2, or 3) */
138      int crc;			/* CRC flag: 0 = disabled, 1 = enabled */
139      int brIdx;			/* bitrate index (0 - 15) */
140      int srIdx;			/* sample rate index (0 - 2) */
141      int paddingBit;		/* padding flag: 0 = no padding, 1 = single pad byte */
142      int privateBit;		/* unused */
143      StereoMode sMode;	/* mono/stereo mode */
144      int modeExt;		/* used to decipher joint stereo mode */
145      int copyFlag;		/* copyright flag: 0 = no, 1 = yes */
146      int origFlag;		/* original flag: 0 = copy, 1 = original */
147      int emphasis;		/* deemphasis mode */
148      int CRCWord;		/* CRC word (16 bits, 0 if crc not enabled) */
149  
150  	const SFBandTable *sfBand;
151  } FrameHeader;
152  
153  typedef struct _SideInfoSub {
154      int part23Length;		/* number of bits in main data */ 
155      int nBigvals;			/* 2x this = first set of Huffman cw's (maximum amplitude can be > 1) */
156      int globalGain;			/* overall gain for dequantizer */
157      int sfCompress;			/* unpacked to figure out number of bits in scale factors */
158      int winSwitchFlag;		/* window switching flag */
159      int blockType;			/* block type */
160      int mixedBlock;			/* 0 = regular block (all short or long), 1 = mixed block */
161      int tableSelect[3];		/* index of Huffman tables for the big values regions */
162      int subBlockGain[3];	/* subblock gain offset, relative to global gain */
163      int region0Count;		/* 1+region0Count = num scale factor bands in first region of bigvals */
164      int region1Count;		/* 1+region1Count = num scale factor bands in second region of bigvals */
165      int preFlag;			/* for optional high frequency boost */
166      int sfactScale;			/* scaling of the scalefactors */
167      int count1TableSelect;	/* index of Huffman table for quad codewords */
168  } SideInfoSub;
169  
170  typedef struct _SideInfo {
171  	int mainDataBegin;
172  	int privateBits;
173  	int scfsi[MAX_NCHAN][MAX_SCFBD];				/* 4 scalefactor bands per channel */
174  	
175  	SideInfoSub	sis[MAX_NGRAN][MAX_NCHAN];
176  } SideInfo;
177  
178  typedef struct {
179      int cbType;		/* pure long = 0, pure short = 1, mixed = 2 */
180      int cbEndS[3];	/* number nonzero short cb's, per subbblock */
181  	int cbEndSMax;	/* max of cbEndS[] */
182      int cbEndL;		/* number nonzero long cb's  */
183  } CriticalBandInfo;
184  
185  typedef struct _DequantInfo {
186  	int workBuf[MAX_REORDER_SAMPS];		/* workbuf for reordering short blocks */
187  	CriticalBandInfo cbi[MAX_NCHAN];	/* filled in dequantizer, used in joint stereo reconstruction */
188  } DequantInfo;
189  
190  typedef struct _HuffmanInfo {
191  	int huffDecBuf[MAX_NCHAN][MAX_NSAMP];		/* used both for decoded Huffman values and dequantized coefficients */
192  	int nonZeroBound[MAX_NCHAN];				/* number of coeffs in huffDecBuf[ch] which can be > 0 */
193  	int gb[MAX_NCHAN];							/* minimum number of guard bits in huffDecBuf[ch] */
194  } HuffmanInfo;
195  
196  typedef enum _HuffTabType {
197  	noBits,
198  	oneShot,
199  	loopNoLinbits,
200  	loopLinbits,
201  	quadA,
202  	quadB,
203  	invalidTab
204  } HuffTabType;
205  
206  typedef struct _HuffTabLookup {
207  	int	linBits;
208  	HuffTabType tabType;
209  } HuffTabLookup;
210  
211  typedef struct _IMDCTInfo {
212  	int outBuf[MAX_NCHAN][BLOCK_SIZE][NBANDS];	/* output of IMDCT */	
213  	int overBuf[MAX_NCHAN][MAX_NSAMP / 2];		/* overlap-add buffer (by symmetry, only need 1/2 size) */
214  	int numPrevIMDCT[MAX_NCHAN];				/* how many IMDCT's calculated in this channel on prev. granule */
215  	int prevType[MAX_NCHAN];
216  	int prevWinSwitch[MAX_NCHAN];
217  	int gb[MAX_NCHAN];
218  } IMDCTInfo;
219  
220  typedef struct _BlockCount {
221  	int nBlocksLong;
222  	int nBlocksTotal;
223  	int nBlocksPrev; 
224  	int prevType;
225  	int prevWinSwitch;
226  	int currWinSwitch;
227  	int gbIn;
228  	int gbOut;
229  } BlockCount;
230  
231  /* max bits in scalefactors = 5, so use char's to save space */
232  typedef struct _ScaleFactorInfoSub {
233  	char l[23];            /* [band] */
234  	char s[13][3];         /* [band][window] */
235  } ScaleFactorInfoSub;  
236  
237  /* used in MPEG 2, 2.5 intensity (joint) stereo only */
238  typedef struct _ScaleFactorJS {
239  	int intensityScale;		
240  	int	slen[4];
241  	int	nr[4];
242  } ScaleFactorJS;
243  
244  typedef struct _ScaleFactorInfo {
245  	ScaleFactorInfoSub sfis[MAX_NGRAN][MAX_NCHAN];
246  	ScaleFactorJS sfjs;
247  } ScaleFactorInfo;
248  
249  /* NOTE - could get by with smaller vbuf if memory is more important than speed
250   *  (in Subband, instead of replicating each block in FDCT32 you would do a memmove on the
251   *   last 15 blocks to shift them down one, a hardware style FIFO)
252   */ 
253  typedef struct _SubbandInfo {
254  	int vbuf[MAX_NCHAN * VBUF_LENGTH];		/* vbuf for fast DCT-based synthesis PQMF - double size for speed (no modulo indexing) */
255  	int vindex;								/* internal index for tracking position in vbuf */
256  } SubbandInfo;
257  
258  /* bitstream.c */
259  void SetBitstreamPointer(BitStreamInfo *bsi, int nBytes, unsigned char *buf);
260  unsigned int GetBits(BitStreamInfo *bsi, int nBits);
261  int CalcBitsUsed(BitStreamInfo *bsi, unsigned char *startBuf, int startOffset);
262  
263  /* dequant.c, dqchan.c, stproc.c */
264  int DequantChannel(int *sampleBuf, int *workBuf, int *nonZeroBound, FrameHeader *fh, SideInfoSub *sis, 
265  					ScaleFactorInfoSub *sfis, CriticalBandInfo *cbi);
266  void MidSideProc(int x[MAX_NCHAN][MAX_NSAMP], int nSamps, int mOut[2]);
267  void IntensityProcMPEG1(int x[MAX_NCHAN][MAX_NSAMP], int nSamps, FrameHeader *fh, ScaleFactorInfoSub *sfis, 
268  						CriticalBandInfo *cbi, int midSideFlag, int mixFlag, int mOut[2]);
269  void IntensityProcMPEG2(int x[MAX_NCHAN][MAX_NSAMP], int nSamps, FrameHeader *fh, ScaleFactorInfoSub *sfis, 
270  						CriticalBandInfo *cbi, ScaleFactorJS *sfjs, int midSideFlag, int mixFlag, int mOut[2]);
271  
272  /* dct32.c */
273  // about 1 ms faster in RAM, but very large
274  void FDCT32(int *x, int *d, int offset, int oddBlock, int gb);// __attribute__ ((section (".data")));
275  
276  /* hufftabs.c */
277  extern const HuffTabLookup huffTabLookup[HUFF_PAIRTABS];
278  extern const int huffTabOffset[HUFF_PAIRTABS];
279  extern const unsigned short huffTable[];
280  extern const unsigned char quadTable[64+16];
281  extern const int quadTabOffset[2];
282  extern const int quadTabMaxBits[2];
283  
284  /* polyphase.c (or asmpoly.s)
285   * some platforms require a C++ compile of all source files,
286   * so if we're compiling C as C++ and using native assembly
287   * for these functions we need to prevent C++ name mangling.
288   */
289  #ifdef __cplusplus
290  extern "C" {
291  #endif
292  void PolyphaseMono(short *pcm, int *vbuf, const int *coefBase);
293  void PolyphaseStereo(short *pcm, int *vbuf, const int *coefBase);
294  #ifdef __cplusplus
295  }
296  #endif
297  
298  /* trigtabs.c */
299  extern const int imdctWin[4][36];
300  extern const int ISFMpeg1[2][7];
301  extern const int ISFMpeg2[2][2][16];
302  extern const int ISFIIP[2][2];
303  extern const int csa[8][2];
304  extern const int coef32[31];
305  extern const int polyCoef[264];
306  
307  #endif	/* _CODER_H */