git-svn-id: svn://10.65.10.50/branches/R_10_00@23289 c028cbd2-c16b-5b4b-a496-9718f37d4682
		
			
				
	
	
		
			124 lines
		
	
	
		
			4.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			124 lines
		
	
	
		
			4.2 KiB
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * This source code is a product of Sun Microsystems, Inc. and is provided
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 * for unrestricted use.  Users may copy or modify this source code without
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 * charge.
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 *
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 * SUN SOURCE CODE IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING
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 * THE WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
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 * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
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 *
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 * Sun source code is provided with no support and without any obligation on
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 * the part of Sun Microsystems, Inc. to assist in its use, correction,
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 * modification or enhancement.
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 *
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 * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
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 * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY THIS SOFTWARE
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 * OR ANY PART THEREOF.
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 *
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 * In no event will Sun Microsystems, Inc. be liable for any lost revenue
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 * or profits or other special, indirect and consequential damages, even if
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 * Sun has been advised of the possibility of such damages.
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 *
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 * Sun Microsystems, Inc.
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 * 2550 Garcia Avenue
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 * Mountain View, California  94043
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 */
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/*
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 * g72x.h
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 *
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 * Header file for CCITT conversion routines.
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 *
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 */
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#ifndef _G72X_H
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#define	_G72X_H
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#define	AUDIO_ENCODING_ULAW	(1)	/* ISDN u-law */
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#define	AUDIO_ENCODING_ALAW	(2)	/* ISDN A-law */
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#define	AUDIO_ENCODING_LINEAR	(3)	/* PCM 2's-complement (0-center) */
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/*
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 * The following is the definition of the state structure
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 * used by the G.721/G.723 encoder and decoder to preserve their internal
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 * state between successive calls.  The meanings of the majority
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 * of the state structure fields are explained in detail in the
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 * CCITT Recommendation G.721.  The field names are essentially indentical
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 * to variable names in the bit level description of the coding algorithm
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 * included in this Recommendation.
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 */
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struct g72x_state {
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	long yl;	/* Locked or steady state step size multiplier. */
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	short yu;	/* Unlocked or non-steady state step size multiplier. */
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	short dms;	/* Short term energy estimate. */
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	short dml;	/* Long term energy estimate. */
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	short ap;	/* Linear weighting coefficient of 'yl' and 'yu'. */
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	short a[2];	/* Coefficients of pole portion of prediction filter. */
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	short b[6];	/* Coefficients of zero portion of prediction filter. */
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	short pk[2];	/*
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			 * Signs of previous two samples of a partially
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			 * reconstructed signal.
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			 */
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	short dq[6];	/*
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			 * Previous 6 samples of the quantized difference
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			 * signal represented in an internal floating point
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			 * format.
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			 */
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	short sr[2];	/*
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			 * Previous 2 samples of the quantized difference
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			 * signal represented in an internal floating point
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			 * format.
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			 */
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	char td;	/* delayed tone detect, new in 1988 version */
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};
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/* External function definitions. */
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extern unsigned char linear2alaw (int pcm_val);	/* 2's complement (16-bit range) */
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extern int alaw2linear (unsigned char a_val);
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extern unsigned char linear2ulaw (int pcm_val);	/* 2's complement (16-bit range) */
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extern int ulaw2linear (unsigned char u_val);
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extern int predictor_zero (struct g72x_state *state_ptr);
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extern int predictor_pole (struct g72x_state *state_ptr);
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extern int step_size (struct g72x_state *state_ptr);
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extern int quantize (int d, int y, short *table, int size);
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extern int reconstruct (int sign, int dqln, int y);
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extern void update
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    ( int code_size, int y, int wi, int fi, int dq
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	, int sr, int dqsez, struct g72x_state *state_ptr);
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int tandem_adjust_alaw
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    (int sr, int se, int y, int i, int sign, short *qtab);
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int tandem_adjust_ulaw
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    (int sr, int se, int y, int i, int sign, short *qtab);
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extern void g72x_init_state (struct g72x_state *);
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extern int g721_encoder(
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		int sample,
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		int in_coding,
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		struct g72x_state *state_ptr);
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extern int g721_decoder(
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		int code,
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		int out_coding,
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		struct g72x_state *state_ptr);
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extern int g723_24_encoder(
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		int sample,
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		int in_coding,
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		struct g72x_state *state_ptr);
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extern int g723_24_decoder(
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		int code,
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		int out_coding,
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		struct g72x_state *state_ptr);
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extern int g723_40_encoder(
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		int sample,
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		int in_coding,
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		struct g72x_state *state_ptr);
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extern int g723_40_decoder(
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		int code,
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		int out_coding,
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		struct g72x_state *state_ptr);
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#endif /* !_G72X_H */
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