/* * 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 *//* * g723_40.c * * Description: * * g723_40_encoder(), g723_40_decoder() * * These routines comprise an implementation of the CCITT G.723 40Kbps * ADPCM coding algorithm.  Essentially, this implementation is identical to * the bit level description except for a few deviations which * take advantage of workstation attributes, such as hardware 2's * complement arithmetic. * * The deviation from the bit level specification (lookup tables), * preserves the bit level performance specifications. * * As outlined in the G.723 Recommendation, the algorithm is broken * down into modules.  Each section of code below is preceded by * the name of the module which it is implementing. * */#include "g72x.h"/* * Maps G.723_40 code word to ructeconstructed scale factor normalized log * magnitude values. */static short	_dqlntab[32] = {-2048, -66, 28, 104, 169, 224, 274, 318,				358, 395, 429, 459, 488, 514, 539, 566,				566, 539, 514, 488, 459, 429, 395, 358,				318, 274, 224, 169, 104, 28, -66, -2048};/* Maps G.723_40 code word to log of scale factor multiplier. */static short	_witab[32] = {448, 448, 768, 1248, 1280, 1312, 1856, 3200,			4512, 5728, 7008, 8960, 11456, 14080, 16928, 22272,			22272, 16928, 14080, 11456, 8960, 7008, 5728, 4512,			3200, 1856, 1312, 1280, 1248, 768, 448, 448};/* * Maps G.723_40 code words to a set of values whose long and short * term averages are computed and then compared to give an indication * how stationary (steady state) the signal is. */static short	_fitab[32] = {0, 0, 0, 0, 0, 0x200, 0x200, 0x200,			0x200, 0x200, 0x400, 0x600, 0x800, 0xA00, 0xC00, 0xC00,			0xC00, 0xC00, 0xA00, 0x800, 0x600, 0x400, 0x200, 0x200,			0x200, 0x200, 0x200, 0, 0, 0, 0, 0};static short qtab_723_40[15] = {-122, -16, 68, 139, 198, 250, 298, 339,				378, 413, 445, 475, 502, 528, 553};/* * g723_40_encoder() * * Encodes a 16-bit linear PCM, A-law or u-law input sample and retuens * the resulting 5-bit CCITT G.723 40Kbps code. * Returns -1 if the input coding value is invalid. */intg723_40_encoder(	int		sl,	int		in_coding,	struct g72x_state *state_ptr){	short		sei, sezi, se, sez;	/* ACCUM */	short		d;			/* SUBTA */	short		y;			/* MIX */	short		sr;			/* ADDB */	short		dqsez;			/* ADDC */	short		dq, i;	switch (in_coding) {	/* linearize input sample to 14-bit PCM */	case AUDIO_ENCODING_ALAW:		sl = alaw2linear(sl) >> 2;		break;	case AUDIO_ENCODING_ULAW:		sl = ulaw2linear(sl) >> 2;		break;	case AUDIO_ENCODING_LINEAR:		sl >>= 2;		/* sl of 14-bit dynamic range */		break;	default:		return (-1);	}	sezi = predictor_zero(state_ptr);	sez = sezi >> 1;	sei = sezi + predictor_pole(state_ptr);	se = sei >> 1;			/* se = estimated signal */	d = sl - se;			/* d = estimation difference */	/* quantize prediction difference */	y = step_size(state_ptr);	/* adaptive quantizer step size */	i = quantize(d, y, qtab_723_40, 15);	/* i = ADPCM code */	dq = reconstruct(i & 0x10, _dqlntab[i], y);	/* quantized diff */	sr = (dq < 0) ? se - (dq & 0x7FFF) : se + dq; /* reconstructed signal */	dqsez = sr + sez - se;		/* dqsez = pole prediction diff. */	update(5, y, _witab[i], _fitab[i], dq, sr, dqsez, state_ptr);	return (i);}/* * g723_40_decoder() * * Decodes a 5-bit CCITT G.723 40Kbps code and returns * the resulting 16-bit linear PCM, A-law or u-law sample value. * -1 is returned if the output coding is unknown. */intg723_40_decoder(	int		i,	int		out_coding,	struct g72x_state *state_ptr){	short		sezi, sei, sez, se;	/* ACCUM */	short		y, dif;			/* MIX */	short		sr;			/* ADDB */	short		dq;	short		dqsez;	i &= 0x1f;			/* mask to get proper bits */	sezi = predictor_zero(state_ptr);	sez = sezi >> 1;	sei = sezi + predictor_pole(state_ptr);	se = sei >> 1;			/* se = estimated signal */	y = step_size(state_ptr);	/* adaptive quantizer step size */	dq = reconstruct(i & 0x10, _dqlntab[i], y);	/* estimation diff. */	sr = (dq < 0) ? (se - (dq & 0x7FFF)) : (se + dq); /* reconst. signal */	dqsez = sr - se + sez;		/* pole prediction diff. */	update(5, y, _witab[i], _fitab[i], dq, sr, dqsez, state_ptr);	switch (out_coding) {	case AUDIO_ENCODING_ALAW:		return (tandem_adjust_alaw(sr, se, y, i, 0x10, qtab_723_40));	case AUDIO_ENCODING_ULAW:		return (tandem_adjust_ulaw(sr, se, y, i, 0x10, qtab_723_40));	case AUDIO_ENCODING_LINEAR:		return (sr << 2);	/* sr was of 14-bit dynamic range */	default:		return (-1);	}}