g726private.h

g.726源码

/**
 *
 * $Log: private.h,v $
 * Revision 1.4  2002/11/20 04:29:13  robertj
 * Included optimisations for G.711 and G.726 codecs, thanks Ted Szoczei
 *
 * Revision 1.1  2002/02/11 23:24:23  robertj
 * Updated to openH323 v1.8.0
 *
 * Revision 1.2  2002/02/10 21:14:54  dereks
 * Add cvs log history to head of the file.
 * Ensure file is terminated by a newline.
 *
 *
 *
 */
typedef struct g726_state_s {
	long yl;	/* Locked or steady state step size multiplier. */
	int yu;		/* Unlocked or non-steady state step size multiplier. */
	int dms;	/* Short term energy estimate. */
	int dml;	/* Long term energy estimate. */
	int ap;		/* Linear weighting coefficient of 'yl' and 'yu'. */

	int a[2];	/* Coefficients of pole portion of prediction filter. */
	int b[6];	/* Coefficients of zero portion of prediction filter. */
	int pk[2];	/* Signs of previous two samples of a partially
				 * reconstructed signal. */
	short dq[6];/* int here fails in newupdate on encode!
				 * Previous 6 samples of the quantized difference
				 * signal represented in an internal floating point
				 * format.
				 */
	int sr[2];	/* Previous 2 samples of the quantized difference
				 * signal represented in an internal floating point
				 * format. */
	int td;		/* delayed tone detect, new in 1988 version */
} g726_state;
static int fmult(int an, int srn);
int predictor_zero(	g726_state *state_ptr);
int predictor_pole(	g726_state *state_ptr);
int step_size(	g726_state *state_ptr);
int quantize(	int		d,	/* Raw difference signal sample */
	int		y,	/* Step size multiplier */
	int *	table,	/* quantization table */
	int		size);	/* table size of short integers */
int reconstruct(	int		sign,	/* 0 for non-negative value */
	int		dqln,	/* G.72x codeword */
	int		y);	/* Step size multiplier */
void update(	
	int		y,		/* quantizer step size */
	int		wi,		/* scale factor multiplier */
	int		fi,		/* for long/short term energies */
	int		dq,		/* quantized prediction difference */
	int		sr,		/* reconstructed signal */
	int		dqsez,		/* difference from 2-pole predictor */
	g726_state *state_ptr);	/* coder state pointer */

void g726_init_state( g726_state *);

int g726_32encoder(
        int sample,
         g726_state *state_ptr);
int g726_32decoder(
        int code,
         g726_state *state_ptr);