g72x.c

sloedgy open sip stack source code

/*
 * 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
 */

/*
 * $Log: g72x.c,v $
 * Revision 1.2  2007/03/04 03:00:43  joegenbaclor
 * Removed Linux compile warnings
 *
 * Revision 1.1  2006/06/26 03:02:36  joegenbaclor
 * I have decided to include the latest development realease  of OPAL tagged Deimos Devel 1 (June 8 2006) as inegrated classes to opensipstack to avoid future version conflicts due to the fast pace in OPAL development.   This move is also aimed to reduce the size of projects using OPAL componets such as the soon to be relased OpenSIPPhone.
 *
 * Revision 1.2  2002/11/20 04:53:16  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.
 *
 *
 *
 * Common routines for G.721 and G.723 conversions.
 */

#include "g72x.h"
#include "private.h"

static int power2[15] = {1, 2, 4, 8, 0x10, 0x20, 0x40, 0x80,
			0x100, 0x200, 0x400, 0x800, 0x1000, 0x2000, 0x4000};

int abs(int _X);
/*
 * quan()
 *
 * quantizes the input val against the table of size short integers.
 * It returns i if table[i - 1] <= val < table[i].
 *
 * Using linear search for simple coding.
 */
static int
quan(
	int		val,
	int *	table,
	int		size)
{
	int		i;

	for (i = 0; i < size; i++)
		if (val < *table++)
			break;
	return (i);
}

/*
 * fmult()
 *
 * returns the integer product of the 14-bit integer "an" and
 * "floating point" representation (4-bit exponent, 6-bit mantessa) "srn".
 */
static int
fmult(
	int		an,
	int		srn)
{
	int anmag;
	int anexp;
	int anmant;
	int wanexp;
	int wanmant;
	int retval;

	anmag = (an > 0) ? an : ((-an) & 0x1FFF);
	anexp = quan(anmag, power2, 15) - 6;
	anmant = (anmag == 0) ? 32 :
	    (anexp >= 0) ? anmag >> anexp : anmag << -anexp;
	wanexp = anexp + ((srn >> 6) & 0xF) - 13;

	wanmant = (anmant * (srn & 077) + 0x30) >> 4;
	retval = (wanexp >= 0) ? ((wanmant << wanexp) & 0x7FFF) :
	    (wanmant >> -wanexp);

	return (((an ^ srn) < 0) ? -retval : retval);
}

/*
 * g72x_init_state()
 *
 * This routine initializes and/or resets the g72x_state structure
 * pointed to by 'state_ptr'.
 * All the initial state values are specified in the CCITT G.721 document.
 */
void
g726_init_state(
	g726_state *state_ptr)
{
	int		cnta;

	state_ptr->yl = 34816;
	state_ptr->yu = 544;
	state_ptr->dms = 0;
	state_ptr->dml = 0;
	state_ptr->ap = 0;
	for (cnta = 0; cnta < 2; cnta++) {
		state_ptr->a[cnta] = 0;
		state_ptr->pk[cnta] = 0;
		state_ptr->sr[cnta] = 32;
	}
	for (cnta = 0; cnta < 6; cnta++) {
		state_ptr->b[cnta] = 0;
		state_ptr->dq[cnta] = 32;
	}
	state_ptr->td = 0;
}

/*
 * predictor_zero()
 *
 * computes the estimated signal from 6-zero predictor.
 *
 */
int
predictor_zero(
	g726_state *state_ptr)
{
	int		i;
	int		sezi;

	sezi = fmult(state_ptr->b[0] >> 2, state_ptr->dq[0]);
	for (i = 1; i < 6; i++)			/* ACCUM */
		sezi += fmult(state_ptr->b[i] >> 2, state_ptr->dq[i]);
	return (sezi);
}
/*
 * predictor_pole()
 *
 * computes the estimated signal from 2-pole predictor.
 *
 */
int
predictor_pole(
	g726_state *state_ptr)
{
	return (fmult(state_ptr->a[1] >> 2, state_ptr->sr[1]) +
	    fmult(state_ptr->a[0] >> 2, state_ptr->sr[0]));
}
/*
 * step_size()
 *
 * computes the quantization step size of the adaptive quantizer.
 *
 */
int
step_size(
	g726_state *state_ptr)
{
	int		y;
	int		dif;
	int		al;

	if (state_ptr->ap >= 256)
		return (state_ptr->yu);
	else {
		y = state_ptr->yl >> 6;
		dif = state_ptr->yu - y;
		al = state_ptr->ap >> 2;
		if (dif > 0)
			y += (dif * al) >> 6;
		else if (dif < 0)
			y += (dif * al + 0x3F) >> 6;
		return (y);
	}
}

/*
 * quantize()
 *
 * Given a raw sample, 'd', of the difference signal and a
 * quantization step size scale factor, 'y', this routine returns the
 * ADPCM codeword to which that sample gets quantized.  The step
 * size scale factor division operation is done in the log base 2 domain
 * as a subtraction.
 */
int
quantize(
	int		d,	/* Raw difference signal sample */
	int		y,	/* Step size multiplier */
	int	*	table,	/* quantization table */
	int		size)	/* table size of integers */
{
	int		dqm;	/* Magnitude of 'd' */
	int		exp;	/* Integer part of base 2 log of 'd' */
	int		mant;	/* Fractional part of base 2 log */
	int		dl;	/* Log of magnitude of 'd' */
	int		dln;	/* Step size scale factor normalized log */
	int		i;

	/*
	 * LOG
	 *
	 * Compute base 2 log of 'd', and store in 'dl'.
	 */
	dqm = abs(d);
	exp = quan(dqm >> 1, power2, 15);
	mant = ((dqm << 7) >> exp) & 0x7F;	/* Fractional portion. */
	dl = (exp << 7) + mant;

	/*
	 * SUBTB
	 *
	 * "Divide" by step size multiplier.
	 */
	dln = dl - (y >> 2);

	/*
	 * QUAN
	 *
	 * Obtain codword i for 'd'.
	 */
	i = quan(dln, table, size);
	if (d < 0)			/* take 1's complement of i */
		return ((size << 1) + 1 - i);
	else if (i == 0)		/* take 1's complement of 0 */
		return ((size << 1) + 1); /* new in 1988 */
	else
		return (i);
}
/*
 * reconstruct()
 *
 * Returns reconstructed difference signal 'dq' obtained from
 * codeword 'i' and quantization step size scale factor 'y'.
 * Multiplication is performed in log base 2 domain as addition.
 */
int
reconstruct(
	int		sign,	/* 0 for non-negative value */
	int		dqln,	/* G.72x codeword */
	int		y)		/* Step size multiplier */
{
	int		dql;	/* Log of 'dq' magnitude */
	int		dex;	/* Integer part of log */
	int		dqt;
	int		dq;		/* Reconstructed difference signal sample */

	dql = dqln + (y >> 2);	/* ADDA */

	if (dql < 0) {
		return ((sign) ? -0x8000 : 0);
	} else {		/* ANTILOG */
		dex = (dql >> 7) & 15;
		dqt = 128 + (dql & 127);
		dq = (short)((dqt << 7) >> (14 - dex));
		return ((sign) ? (dq - 0x8000) : dq);
	}
}


/*
 * update()
 *
 * updates the state variables for each output code
 */
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 */
	g726_state *state_ptr)	/* coder state pointer */
{