contrib/src/mmedia/g723_40.cpp

/*
 * 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 "wx/wxprec.h"
#include "wx/mmedia/internal/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.
 */
int
g723_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 = ((short) 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.
 */
int
g723_40_decoder(
    int                i,
    int                out_coding,
    struct g72x_state *state_ptr)
{
    short        sezi, sei, sez, se;    /* ACCUM */
    short        y;                     /* 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);
    }
}
Commit	Line	Data
	1	/*
	2	* This source code is a product of Sun Microsystems, Inc. and is provided
	3	* for unrestricted use. Users may copy or modify this source code without
	4	* charge.
	5	*
	6	* SUN SOURCE CODE IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING
	7	* THE WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
	8	* PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
	9	*
	10	* Sun source code is provided with no support and without any obligation on
	11	* the part of Sun Microsystems, Inc. to assist in its use, correction,
	12	* modification or enhancement.
	13	*
	14	* SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
	15	* INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY THIS SOFTWARE
	16	* OR ANY PART THEREOF.
	17	*
	18	* In no event will Sun Microsystems, Inc. be liable for any lost revenue
	19	* or profits or other special, indirect and consequential damages, even if
	20	* Sun has been advised of the possibility of such damages.
	21	*
	22	* Sun Microsystems, Inc.
	23	* 2550 Garcia Avenue
	24	* Mountain View, California 94043
	25	*/
	26
	27	/*
	28	* g723_40.c
	29	*
	30	* Description:
	31	*
	32	* g723_40_encoder(), g723_40_decoder()
	33	*
	34	* These routines comprise an implementation of the CCITT G.723 40Kbps
	35	* ADPCM coding algorithm. Essentially, this implementation is identical to
	36	* the bit level description except for a few deviations which
	37	* take advantage of workstation attributes, such as hardware 2's
	38	* complement arithmetic.
	39	*
	40	* The deviation from the bit level specification (lookup tables),
	41	* preserves the bit level performance specifications.
	42	*
	43	* As outlined in the G.723 Recommendation, the algorithm is broken
	44	* down into modules. Each section of code below is preceded by
	45	* the name of the module which it is implementing.
	46	*
	47	*/
	48	#include "wx/wxprec.h"
	49	#include "wx/mmedia/internal/g72x.h"
	50
	51	/*
	52	* Maps G.723_40 code word to ructeconstructed scale factor normalized log
	53	* magnitude values.
	54	*/
	55	static short _dqlntab[32] = {-2048, -66, 28, 104, 169, 224, 274, 318,
	56	358, 395, 429, 459, 488, 514, 539, 566,
	57	566, 539, 514, 488, 459, 429, 395, 358,
	58	318, 274, 224, 169, 104, 28, -66, -2048};
	59
	60	/* Maps G.723_40 code word to log of scale factor multiplier. */
	61	static short _witab[32] = {448, 448, 768, 1248, 1280, 1312, 1856, 3200,
	62	4512, 5728, 7008, 8960, 11456, 14080, 16928, 22272,
	63	22272, 16928, 14080, 11456, 8960, 7008, 5728, 4512,
	64	3200, 1856, 1312, 1280, 1248, 768, 448, 448};
	65
	66	/*
	67	* Maps G.723_40 code words to a set of values whose long and short
	68	* term averages are computed and then compared to give an indication
	69	* how stationary (steady state) the signal is.
	70	*/
	71	static short _fitab[32] = {0, 0, 0, 0, 0, 0x200, 0x200, 0x200,
	72	0x200, 0x200, 0x400, 0x600, 0x800, 0xA00, 0xC00, 0xC00,
	73	0xC00, 0xC00, 0xA00, 0x800, 0x600, 0x400, 0x200, 0x200,
	74	0x200, 0x200, 0x200, 0, 0, 0, 0, 0};
	75
	76	static short qtab_723_40[15] = {-122, -16, 68, 139, 198, 250, 298, 339,
	77	378, 413, 445, 475, 502, 528, 553};
	78
	79	/*
	80	* g723_40_encoder()
	81	*
	82	* Encodes a 16-bit linear PCM, A-law or u-law input sample and retuens
	83	* the resulting 5-bit CCITT G.723 40Kbps code.
	84	* Returns -1 if the input coding value is invalid.
	85	*/
	86	int
	87	g723_40_encoder(
	88	int sl,
	89	int in_coding,
	90	struct g72x_state *state_ptr)
	91	{
	92	short sei, sezi, se, sez; /* ACCUM */
	93	short d; /* SUBTA */
	94	short y; /* MIX */
	95	short sr; /* ADDB */
	96	short dqsez; /* ADDC */
	97	short dq, i;
	98
	99	switch (in_coding) { /* linearize input sample to 14-bit PCM */
	100	case AUDIO_ENCODING_ALAW:
	101	sl = alaw2linear(sl) >> 2;
	102	break;
	103	case AUDIO_ENCODING_ULAW:
	104	sl = ulaw2linear(sl) >> 2;
	105	break;
	106	case AUDIO_ENCODING_LINEAR:
	107	sl = ((short) sl) >> 2; /* sl of 14-bit dynamic range */
	108	break;
	109	default:
	110	return (-1);
	111	}
	112
	113	sezi = predictor_zero(state_ptr);
	114	sez = sezi >> 1;
	115	sei = sezi + predictor_pole(state_ptr);
	116	se = sei >> 1; /* se = estimated signal */
	117
	118	d = sl - se; /* d = estimation difference */
	119
	120	/* quantize prediction difference */
	121	y = step_size(state_ptr); /* adaptive quantizer step size */
	122	i = quantize(d, y, qtab_723_40, 15); /* i = ADPCM code */
	123
	124	dq = reconstruct(i & 0x10, _dqlntab[i], y); /* quantized diff */
	125
	126	sr = (dq < 0) ? se - (dq & 0x7FFF) : se + dq; /* reconstructed signal */
	127
	128	dqsez = sr + sez - se; /* dqsez = pole prediction diff. */
	129
	130	update(5, y, _witab[i], _fitab[i], dq, sr, dqsez, state_ptr);
	131
	132	return (i);
	133	}
	134
	135	/*
	136	* g723_40_decoder()
	137	*
	138	* Decodes a 5-bit CCITT G.723 40Kbps code and returns
	139	* the resulting 16-bit linear PCM, A-law or u-law sample value.
	140	* -1 is returned if the output coding is unknown.
	141	*/
	142	int
	143	g723_40_decoder(
	144	int i,
	145	int out_coding,
	146	struct g72x_state *state_ptr)
	147	{
	148	short sezi, sei, sez, se; /* ACCUM */
	149	short y; /* MIX */
	150	short sr; /* ADDB */
	151	short dq;
	152	short dqsez;
	153
	154	i &= 0x1f; /* mask to get proper bits */
	155	sezi = predictor_zero(state_ptr);
	156	sez = sezi >> 1;
	157	sei = sezi + predictor_pole(state_ptr);
	158	se = sei >> 1; /* se = estimated signal */
	159
	160	y = step_size(state_ptr); /* adaptive quantizer step size */
	161	dq = reconstruct(i & 0x10, _dqlntab[i], y); /* estimation diff. */
	162
	163	sr = (dq < 0) ? (se - (dq & 0x7FFF)) : (se + dq); /* reconst. signal */
	164
	165	dqsez = sr - se + sez; /* pole prediction diff. */
	166
	167	update(5, y, _witab[i], _fitab[i], dq, sr, dqsez, state_ptr);
	168
	169	switch (out_coding) {
	170	case AUDIO_ENCODING_ALAW:
	171	return (tandem_adjust_alaw(sr, se, y, i, 0x10, qtab_723_40));
	172	case AUDIO_ENCODING_ULAW:
	173	return (tandem_adjust_ulaw(sr, se, y, i, 0x10, qtab_723_40));
	174	case AUDIO_ENCODING_LINEAR:
	175	return (sr << 2); /* sr was of 14-bit dynamic range */
	176	default:
	177	return (-1);
	178	}
	179	}