g72x.h

zigbee 飞思卡尔 音频传输 基于ucos的所有源码

/*
 * This source code is a product of Sun Microsystems, Inc. and is provided
 * for unrestricted use.  Users may copy or modify this source code without
 * charge.
 *
 * SUN SOURCE CODE IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING
 * THE WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
 *
 * Sun source code is provided with no support and without any obligation on
 * the part of Sun Microsystems, Inc. to assist in its use, correction,
 * modification or enhancement.
 *
 * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
 * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY THIS SOFTWARE
 * OR ANY PART THEREOF.
 *
 * In no event will Sun Microsystems, Inc. be liable for any lost revenue
 * or profits or other special, indirect and consequential damages, even if
 * Sun has been advised of the possibility of such damages.
 *
 * Sun Microsystems, Inc.
 * 2550 Garcia Avenue
 * Mountain View, California  94043
 */

/*
 * g72x.h
 *
 * Header file for CCITT conversion routines.
 *
 */

/*
 * The following is the definition of the state structure
 * used by the G.721/G.723 encoder and decoder to preserve their internal
 * state between successive calls.  The meanings of the majority
 * of the state structure fields are explained in detail in the
 * CCITT Recommendation G.721.  The field names are essentially indentical
 * to variable names in the bit level description of the coding algorithm
 * included in this Recommendation.
 */
struct g72x_state {
	int 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];	/*
			 * 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 */
};

/* External function definitions. */

int predictor_zero(struct g72x_state* state_ptr);
int predictor_pole( struct g72x_state* state_ptr );
int step_size(struct g72x_state *state_ptr);
int quantize( int d, int y, int* table, int size );
int reconstruct(int sign, int dqln, int y);
void update(int y, int wi, int fi, int dq, int sr, int dqsez, struct g72x_state* state_ptr);

int g721_encoder(int sample,struct g72x_state *state_ptr);

int g721_decoder(int i,struct g72x_state* state_ptr);

void g72x_init_state(struct g72x_state* state_ptr);