contrib/src/mmedia/g721.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
 */

#include "wx/wxprec.h"

/*
 * g721.c
 *
 * Description:
 *
 * g721_encoder(), g721_decoder()
 *
 * These routines comprise an implementation of the CCITT G.721 ADPCM
 * coding algorithm.  Essentially, this implementation is identical to
 * the bit level description except for a few deviations which
 * take advantage of work station attributes, such as hardware 2's
 * complement arithmetic and large memory.  Specifically, certain time
 * consuming operations such as multiplications are replaced
 * with lookup tables and software 2's complement operations are
 * replaced with hardware 2's complement.
 *
 * The deviation from the bit level specification (lookup tables)
 * preserves the bit level performance specifications.
 *
 * As outlined in the G.721 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/mmedia/internal/g72x.h"

static short qtab_721[7] = {-124, 80, 178, 246, 300, 349, 400};
/*
 * Maps G.721 code word to reconstructed scale factor normalized log
 * magnitude values.
 */
static short _dqlntab[16] = {-2048, 4, 135, 213, 273, 323, 373, 425,
                425, 373, 323, 273, 213, 135, 4, -2048};

/* Maps G.721 code word to log of scale factor multiplier. */
static short _witab[16] = {-12, 18, 41, 64, 112, 198, 355, 1122,
                1122, 355, 198, 112, 64, 41, 18, -12};
/*
 * Maps G.721 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[16] = {0, 0, 0, 0x200, 0x200, 0x200, 0x600, 0xE00,
                0xE00, 0x600, 0x200, 0x200, 0x200, 0, 0, 0};

/*
 * g721_encoder()
 *
 * Encodes the input vale of linear PCM, A-law or u-law data sl and returns
 * the resulting code. -1 is returned for unknown input coding value.
 */
int
g721_encoder(
    int                sl,
    int                in_coding,
    struct g72x_state *state_ptr)
{
    short        sezi, se, sez;        /* ACCUM */
    short        d;                    /* SUBTA */
    short        sr;                   /* ADDB */
    short        y;                    /* MIX */
    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;        /* 14-bit dynamic range */
        break;
    default:
        return (-1);
    }

    sezi = predictor_zero(state_ptr);
    sez = sezi >> 1;
    se = (sezi + predictor_pole(state_ptr)) >> 1;    /* estimated signal */

    d = sl - se;                /* estimation difference */

    /* quantize the prediction difference */
    y = step_size(state_ptr);        /* quantizer step size */
    i = quantize(d, y, qtab_721, 7);    /* i = ADPCM code */

    dq = reconstruct(i & 8, _dqlntab[i], y);    /* quantized est diff */

    sr = (dq < 0) ? se - (dq & 0x3FFF) : se + dq;    /* reconst. signal */

    dqsez = sr + sez - se;            /* pole prediction diff. */

    update(4, y, _witab[i] << 5, _fitab[i], dq, sr, dqsez, state_ptr);

    return (i);
}

/*
 * g721_decoder()
 *
 * Description:
 *
 * Decodes a 4-bit code of G.721 encoded data of i and
 * returns the resulting linear PCM, A-law or u-law value.
 * return -1 for unknown out_coding value.
 */
int
g721_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 &= 0x0f;            /* 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);    /* dynamic quantizer step size */

    dq = reconstruct(i & 0x08, _dqlntab[i], y); /* quantized diff. */

    sr = (dq < 0) ? (se - (dq & 0x3FFF)) : se + dq;    /* reconst. signal */

    dqsez = sr - se + sez;            /* pole prediction diff. */

    update(4, y, _witab[i] << 5, _fitab[i], dq, sr, dqsez, state_ptr);

    switch (out_coding) {
    case AUDIO_ENCODING_ALAW:
        return (tandem_adjust_alaw(sr, se, y, i, 8, qtab_721));
    case AUDIO_ENCODING_ULAW:
        return (tandem_adjust_ulaw(sr, se, y, i, 8, qtab_721));
    case AUDIO_ENCODING_LINEAR:
        return (sr << 2);    /* sr was 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	#include "wx/wxprec.h"
	28
	29	/*
	30	* g721.c
	31	*
	32	* Description:
	33	*
	34	* g721_encoder(), g721_decoder()
	35	*
	36	* These routines comprise an implementation of the CCITT G.721 ADPCM
	37	* coding algorithm. Essentially, this implementation is identical to
	38	* the bit level description except for a few deviations which
	39	* take advantage of work station attributes, such as hardware 2's
	40	* complement arithmetic and large memory. Specifically, certain time
	41	* consuming operations such as multiplications are replaced
	42	* with lookup tables and software 2's complement operations are
	43	* replaced with hardware 2's complement.
	44	*
	45	* The deviation from the bit level specification (lookup tables)
	46	* preserves the bit level performance specifications.
	47	*
	48	* As outlined in the G.721 Recommendation, the algorithm is broken
	49	* down into modules. Each section of code below is preceded by
	50	* the name of the module which it is implementing.
	51	*
	52	*/
	53	#include "wx/mmedia/internal/g72x.h"
	54
	55	static short qtab_721[7] = {-124, 80, 178, 246, 300, 349, 400};
	56	/*
	57	* Maps G.721 code word to reconstructed scale factor normalized log
	58	* magnitude values.
	59	*/
	60	static short _dqlntab[16] = {-2048, 4, 135, 213, 273, 323, 373, 425,
	61	425, 373, 323, 273, 213, 135, 4, -2048};
	62
	63	/* Maps G.721 code word to log of scale factor multiplier. */
	64	static short _witab[16] = {-12, 18, 41, 64, 112, 198, 355, 1122,
	65	1122, 355, 198, 112, 64, 41, 18, -12};
	66	/*
	67	* Maps G.721 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[16] = {0, 0, 0, 0x200, 0x200, 0x200, 0x600, 0xE00,
	72	0xE00, 0x600, 0x200, 0x200, 0x200, 0, 0, 0};
	73
	74	/*
	75	* g721_encoder()
	76	*
	77	* Encodes the input vale of linear PCM, A-law or u-law data sl and returns
	78	* the resulting code. -1 is returned for unknown input coding value.
	79	*/
	80	int
	81	g721_encoder(
	82	int sl,
	83	int in_coding,
	84	struct g72x_state *state_ptr)
	85	{
	86	short sezi, se, sez; /* ACCUM */
	87	short d; /* SUBTA */
	88	short sr; /* ADDB */
	89	short y; /* MIX */
	90	short dqsez; /* ADDC */
	91	short dq, i;
	92
	93	switch (in_coding) { /* linearize input sample to 14-bit PCM */
	94	case AUDIO_ENCODING_ALAW:
	95	sl = alaw2linear(sl) >> 2;
	96	break;
	97	case AUDIO_ENCODING_ULAW:
	98	sl = ulaw2linear(sl) >> 2;
	99	break;
	100	case AUDIO_ENCODING_LINEAR:
	101	sl = ((short)sl) >> 2; /* 14-bit dynamic range */
	102	break;
	103	default:
	104	return (-1);
	105	}
	106
	107	sezi = predictor_zero(state_ptr);
	108	sez = sezi >> 1;
	109	se = (sezi + predictor_pole(state_ptr)) >> 1; /* estimated signal */
	110
	111	d = sl - se; /* estimation difference */
	112
	113	/* quantize the prediction difference */
	114	y = step_size(state_ptr); /* quantizer step size */
	115	i = quantize(d, y, qtab_721, 7); /* i = ADPCM code */
	116
	117	dq = reconstruct(i & 8, _dqlntab[i], y); /* quantized est diff */
	118
	119	sr = (dq < 0) ? se - (dq & 0x3FFF) : se + dq; /* reconst. signal */
	120
	121	dqsez = sr + sez - se; /* pole prediction diff. */
	122
	123	update(4, y, _witab[i] << 5, _fitab[i], dq, sr, dqsez, state_ptr);
	124
	125	return (i);
	126	}
	127
	128	/*
	129	* g721_decoder()
	130	*
	131	* Description:
	132	*
	133	* Decodes a 4-bit code of G.721 encoded data of i and
	134	* returns the resulting linear PCM, A-law or u-law value.
	135	* return -1 for unknown out_coding value.
	136	*/
	137	int
	138	g721_decoder(
	139	int i,
	140	int out_coding,
	141	struct g72x_state *state_ptr)
	142	{
	143	short sezi, sei, sez, se; /* ACCUM */
	144	short y; /* MIX */
	145	short sr; /* ADDB */
	146	short dq;
	147	short dqsez;
	148
	149	i &= 0x0f; /* mask to get proper bits */
	150	sezi = predictor_zero(state_ptr);
	151	sez = sezi >> 1;
	152	sei = sezi + predictor_pole(state_ptr);
	153	se = sei >> 1; /* se = estimated signal */
	154
	155	y = step_size(state_ptr); /* dynamic quantizer step size */
	156
	157	dq = reconstruct(i & 0x08, _dqlntab[i], y); /* quantized diff. */
	158
	159	sr = (dq < 0) ? (se - (dq & 0x3FFF)) : se + dq; /* reconst. signal */
	160
	161	dqsez = sr - se + sez; /* pole prediction diff. */
	162
	163	update(4, y, _witab[i] << 5, _fitab[i], dq, sr, dqsez, state_ptr);
	164
	165	switch (out_coding) {
	166	case AUDIO_ENCODING_ALAW:
	167	return (tandem_adjust_alaw(sr, se, y, i, 8, qtab_721));
	168	case AUDIO_ENCODING_ULAW:
	169	return (tandem_adjust_ulaw(sr, se, y, i, 8, qtab_721));
	170	case AUDIO_ENCODING_LINEAR:
	171	return (sr << 2); /* sr was 14-bit dynamic range */
	172	default:
	173	return (-1);
	174	}
	175	}