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/*
* 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.
*
*/
#ifndef _G72X_H
#define _G72X_H
#define AUDIO_ENCODING_ULAW (1) /* ISDN u-law */
#define AUDIO_ENCODING_ALAW (2) /* ISDN A-law */
#define AUDIO_ENCODING_LINEAR (3) /* PCM 2's-complement (0-center) */
/*
* 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 {
long yl; /* Locked or steady state step size multiplier. */
short yu; /* Unlocked or non-steady state step size multiplier. */
short dms; /* Short term energy estimate. */
short dml; /* Long term energy estimate. */
short ap; /* Linear weighting coefficient of 'yl' and 'yu'. */
short a[2]; /* Coefficients of pole portion of prediction filter. */
short b[6]; /* Coefficients of zero portion of prediction filter. */
short 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.
*/
short sr[2]; /*
* Previous 2 samples of the quantized difference
* signal represented in an internal floating point
* format.
*/
char td; /* delayed tone detect, new in 1988 version */
};
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, /* Raw difference signal sample */
int y, /* Step size multiplier */
short *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 code_size, /* distinguish 723_40 with others */
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 */
struct g72x_state *state_ptr);
int tandem_adjust_alaw(
int sr, /* decoder output linear PCM sample */
int se, /* predictor estimate sample */
int y, /* quantizer step size */
int i, /* decoder input code */
int sign,
short *qtab);
int
tandem_adjust_ulaw(
int sr, /* decoder output linear PCM sample */
int se, /* predictor estimate sample */
int y, /* quantizer step size */
int i, /* decoder input code */
int sign,
short *qtab);
void g72x_init_state(struct g72x_state *);
int g721_encoder(
int sample,
int in_coding,
struct g72x_state *state_ptr);
int g721_decoder(
int code,
int out_coding,
struct g72x_state *state_ptr);
int g723_16_encoder(
int sample,
int in_coding,
struct g72x_state *state_ptr);
int g723_16_decoder(
int code,
int out_coding,
struct g72x_state *state_ptr);
int g723_24_encoder(
int sample,
int in_coding,
struct g72x_state *state_ptr);
int g723_24_decoder(
int code,
int out_coding,
struct g72x_state *state_ptr);
int g723_40_encoder(
int sample,
int in_coding,
struct g72x_state *state_ptr);
int g723_40_decoder(
int code,
int out_coding,
struct g72x_state *state_ptr);
#endif /* !_G72X_H */
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