112 lines
3.4 KiB
C
112 lines
3.4 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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#include "math.h"
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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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typedef struct g726_state_s {
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long yl; /* Locked or steady state step size multiplier. */
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int yu; /* Unlocked or non-steady state step size multiplier. */
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int dms; /* Short term energy estimate. */
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int dml; /* Long term energy estimate. */
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int ap; /* Linear weighting coefficient of 'yl' and 'yu'. */
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int a[2]; /* Coefficients of pole portion of prediction filter. */
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int b[6]; /* Coefficients of zero portion of prediction filter. */
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int pk[2]; /* Signs of previous two samples of a partially
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* reconstructed signal. */
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short dq[6];/* int here fails in newupdate on encode!
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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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int sr[2]; /* 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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int td; /* delayed tone detect, new in 1988 version */
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} g726_state;
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/* External function definitions. */
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void g726_init_state( g726_state *);
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int g726_32_encoder(
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int sample,
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int in_coding,
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g726_state *state_ptr);
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int g726_32_decoder(
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int code,
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int out_coding,
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g726_state *state_ptr);
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int g726_16_encoder(
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int sample,
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int in_coding,
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g726_state *state_ptr);
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int g726_16_decoder(
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int code,
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int out_coding,
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g726_state *state_ptr);
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int g726_24_encoder(
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int sample,
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int in_coding,
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g726_state *state_ptr);
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int g726_24_decoder(
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int code,
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int out_coding,
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g726_state *state_ptr);
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int g726_40_encoder(
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int sample,
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int in_coding,
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g726_state *state_ptr);
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int g726_40_decoder(
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int code,
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int out_coding,
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g726_state *state_ptr);
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#endif /* !_G72X_H */
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