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7f00235804
git-svn-id: https://svn.code.sf.net/p/fteqw/code/trunk@16 fc73d0e0-1445-4013-8a0c-d673dee63da5
118 lines
3.9 KiB
C
118 lines
3.9 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 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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//see the function bodies for a description
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unsigned char linear2alaw(int pcm_val);
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unsigned char linear2ulaw(int pcm_val);
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int ulaw2linear(unsigned char u_val);
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int alaw2linear(unsigned char a_val);
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int predictor_zero(struct g72x_state *state_ptr);
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int predictor_pole(struct g72x_state *state_ptr);
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int step_size(struct g72x_state *state_ptr);
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int quantize(int d, int y, short *table, int size);
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int reconstruct(int sign, int dqln, int y);
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void update(int code_size, int y, int wi, int fi, int dq, int sr, int dqsez, struct g72x_state *state_ptr);
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int tandem_adjust_ulaw(int sr, int se, int y, int i, int sign, short *qtab);
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int tandem_adjust_alaw(int sr, int se, int y, int i, int sign, short *qtab);
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#endif /* !_G72X_H */
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