contrib/src/mmedia/g711.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>

/*
 * g711.c
 *
 * u-law, A-law and linear PCM conversions.
 */
#define	SIGN_BIT	(0x80)		/* Sign bit for a A-law byte. */
#define	QUANT_MASK	(0xf)		/* Quantization field mask. */
#define	NSEGS		(8)		/* Number of A-law segments. */
#define	SEG_SHIFT	(4)		/* Left shift for segment number. */
#define	SEG_MASK	(0x70)		/* Segment field mask. */

static short seg_end[8] = {0xFF, 0x1FF, 0x3FF, 0x7FF,
			    0xFFF, 0x1FFF, 0x3FFF, 0x7FFF};

/* copy from CCITT G.711 specifications */
unsigned char _u2a[128] = {			/* u- to A-law conversions */
	1,	1,	2,	2,	3,	3,	4,	4,
	5,	5,	6,	6,	7,	7,	8,	8,
	9,	10,	11,	12,	13,	14,	15,	16,
	17,	18,	19,	20,	21,	22,	23,	24,
	25,	27,	29,	31,	33,	34,	35,	36,
	37,	38,	39,	40,	41,	42,	43,	44,
	46,	48,	49,	50,	51,	52,	53,	54,
	55,	56,	57,	58,	59,	60,	61,	62,
	64,	65,	66,	67,	68,	69,	70,	71,
	72,	73,	74,	75,	76,	77,	78,	79,
	81,	82,	83,	84,	85,	86,	87,	88,
	89,	90,	91,	92,	93,	94,	95,	96,
	97,	98,	99,	100,	101,	102,	103,	104,
	105,	106,	107,	108,	109,	110,	111,	112,
	113,	114,	115,	116,	117,	118,	119,	120,
	121,	122,	123,	124,	125,	126,	127,	128};

unsigned char _a2u[128] = {			/* A- to u-law conversions */
	1,	3,	5,	7,	9,	11,	13,	15,
	16,	17,	18,	19,	20,	21,	22,	23,
	24,	25,	26,	27,	28,	29,	30,	31,
	32,	32,	33,	33,	34,	34,	35,	35,
	36,	37,	38,	39,	40,	41,	42,	43,
	44,	45,	46,	47,	48,	48,	49,	49,
	50,	51,	52,	53,	54,	55,	56,	57,
	58,	59,	60,	61,	62,	63,	64,	64,
	65,	66,	67,	68,	69,	70,	71,	72,
	73,	74,	75,	76,	77,	78,	79,	79,
	80,	81,	82,	83,	84,	85,	86,	87,
	88,	89,	90,	91,	92,	93,	94,	95,
	96,	97,	98,	99,	100,	101,	102,	103,
	104,	105,	106,	107,	108,	109,	110,	111,
	112,	113,	114,	115,	116,	117,	118,	119,
	120,	121,	122,	123,	124,	125,	126,	127};

static int
search(
	int		val,
	short		*table,
	int		size)
{
	int		i;

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

/*
 * linear2alaw() - Convert a 16-bit linear PCM value to 8-bit A-law
 *
 * linear2alaw() accepts an 16-bit integer and encodes it as A-law data.
 *
 *		Linear Input Code	Compressed Code
 *	------------------------	---------------
 *	0000000wxyza			000wxyz
 *	0000001wxyza			001wxyz
 *	000001wxyzab			010wxyz
 *	00001wxyzabc			011wxyz
 *	0001wxyzabcd			100wxyz
 *	001wxyzabcde			101wxyz
 *	01wxyzabcdef			110wxyz
 *	1wxyzabcdefg			111wxyz
 *
 * For further information see John C. Bellamy's Digital Telephony, 1982,
 * John Wiley & Sons, pps 98-111 and 472-476.
 */
unsigned char
linear2alaw(
	int		pcm_val)	/* 2's complement (16-bit range) */
{
	int		mask;
	int		seg;
	unsigned char	aval;

	if (pcm_val >= 0) {
		mask = 0xD5;		/* sign (7th) bit = 1 */
	} else {
		mask = 0x55;		/* sign bit = 0 */
		pcm_val = -pcm_val - 8;
	}

	/* Convert the scaled magnitude to segment number. */
	seg = search(pcm_val, seg_end, 8);

	/* Combine the sign, segment, and quantization bits. */

	if (seg >= 8)		/* out of range, return maximum value. */
		return (0x7F ^ mask);
	else {
		aval = seg << SEG_SHIFT;
		if (seg < 2)
			aval |= (pcm_val >> 4) & QUANT_MASK;
		else
			aval |= (pcm_val >> (seg + 3)) & QUANT_MASK;
		return (aval ^ mask);
	}
}

/*
 * alaw2linear() - Convert an A-law value to 16-bit linear PCM
 *
 */
int
alaw2linear(
	unsigned char	a_val)
{
	int		t;
	int		seg;

	a_val ^= 0x55;

	t = (a_val & QUANT_MASK) << 4;
	seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT;
	switch (seg) {
	case 0:
		t += 8;
		break;
	case 1:
		t += 0x108;
		break;
	default:
		t += 0x108;
		t <<= seg - 1;
	}
	return ((a_val & SIGN_BIT) ? t : -t);
}

#define	BIAS		(0x84)		/* Bias for linear code. */

/*
 * linear2ulaw() - Convert a linear PCM value to u-law
 *
 * In order to simplify the encoding process, the original linear magnitude
 * is biased by adding 33 which shifts the encoding range from (0 - 8158) to
 * (33 - 8191). The result can be seen in the following encoding table:
 *
 *	Biased Linear Input Code	Compressed Code
 *	------------------------	---------------
 *	00000001wxyza			000wxyz
 *	0000001wxyzab			001wxyz
 *	000001wxyzabc			010wxyz
 *	00001wxyzabcd			011wxyz
 *	0001wxyzabcde			100wxyz
 *	001wxyzabcdef			101wxyz
 *	01wxyzabcdefg			110wxyz
 *	1wxyzabcdefgh			111wxyz
 *
 * Each biased linear code has a leading 1 which identifies the segment
 * number. The value of the segment number is equal to 7 minus the number
 * of leading 0's. The quantization interval is directly available as the
 * four bits wxyz.  * The trailing bits (a - h) are ignored.
 *
 * Ordinarily the complement of the resulting code word is used for
 * transmission, and so the code word is complemented before it is returned.
 *
 * For further information see John C. Bellamy's Digital Telephony, 1982,
 * John Wiley & Sons, pps 98-111 and 472-476.
 */
unsigned char
linear2ulaw(
	int		pcm_val)	/* 2's complement (16-bit range) */
{
	int		mask;
	int		seg;
	unsigned char	uval;

	/* Get the sign and the magnitude of the value. */
	if (pcm_val < 0) {
		pcm_val = BIAS - pcm_val;
		mask = 0x7F;
	} else {
		pcm_val += BIAS;
		mask = 0xFF;
	}

	/* Convert the scaled magnitude to segment number. */
	seg = search(pcm_val, seg_end, 8);

	/*
	 * Combine the sign, segment, quantization bits;
	 * and complement the code word.
	 */
	if (seg >= 8)		/* out of range, return maximum value. */
		return (0x7F ^ mask);
	else {
		uval = (seg << 4) | ((pcm_val >> (seg + 3)) & 0xF);
		return (uval ^ mask);
	}

}

/*
 * ulaw2linear() - Convert a u-law value to 16-bit linear PCM
 *
 * First, a biased linear code is derived from the code word. An unbiased
 * output can then be obtained by subtracting 33 from the biased code.
 *
 * Note that this function expects to be passed the complement of the
 * original code word. This is in keeping with ISDN conventions.
 */
int
ulaw2linear(
	unsigned char	u_val)
{
	int		t;

	/* Complement to obtain normal u-law value. */
	u_val = ~u_val;

	/*
	 * Extract and bias the quantization bits. Then
	 * shift up by the segment number and subtract out the bias.
	 */
	t = ((u_val & QUANT_MASK) << 3) + BIAS;
	t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT;

	return ((u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS));
}

/* A-law to u-law conversion */
unsigned char
alaw2ulaw(
	unsigned char	aval)
{
	aval &= 0xff;
	return ((aval & 0x80) ? (0xFF ^ _a2u[aval ^ 0xD5]) :
	    (0x7F ^ _a2u[aval ^ 0x55]));
}

/* u-law to A-law conversion */
unsigned char
ulaw2alaw(
	unsigned char	uval)
{
	uval &= 0xff;
	return ((uval & 0x80) ? (0xD5 ^ (_u2a[0xFF ^ uval] - 1)) :
	    (0x55 ^ (_u2a[0x7F ^ uval] - 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	* g711.c
	31	*
	32	* u-law, A-law and linear PCM conversions.
	33	*/
	34	#define SIGN_BIT (0x80) /* Sign bit for a A-law byte. */
	35	#define QUANT_MASK (0xf) /* Quantization field mask. */
	36	#define NSEGS (8) /* Number of A-law segments. */
	37	#define SEG_SHIFT (4) /* Left shift for segment number. */
	38	#define SEG_MASK (0x70) /* Segment field mask. */
	39
	40	static short seg_end[8] = {0xFF, 0x1FF, 0x3FF, 0x7FF,
	41	0xFFF, 0x1FFF, 0x3FFF, 0x7FFF};
	42
	43	/* copy from CCITT G.711 specifications */
	44	unsigned char _u2a[128] = { /* u- to A-law conversions */
	45	1, 1, 2, 2, 3, 3, 4, 4,
	46	5, 5, 6, 6, 7, 7, 8, 8,
	47	9, 10, 11, 12, 13, 14, 15, 16,
	48	17, 18, 19, 20, 21, 22, 23, 24,
	49	25, 27, 29, 31, 33, 34, 35, 36,
	50	37, 38, 39, 40, 41, 42, 43, 44,
	51	46, 48, 49, 50, 51, 52, 53, 54,
	52	55, 56, 57, 58, 59, 60, 61, 62,
	53	64, 65, 66, 67, 68, 69, 70, 71,
	54	72, 73, 74, 75, 76, 77, 78, 79,
	55	81, 82, 83, 84, 85, 86, 87, 88,
	56	89, 90, 91, 92, 93, 94, 95, 96,
	57	97, 98, 99, 100, 101, 102, 103, 104,
	58	105, 106, 107, 108, 109, 110, 111, 112,
	59	113, 114, 115, 116, 117, 118, 119, 120,
	60	121, 122, 123, 124, 125, 126, 127, 128};
	61
	62	unsigned char _a2u[128] = { /* A- to u-law conversions */
	63	1, 3, 5, 7, 9, 11, 13, 15,
	64	16, 17, 18, 19, 20, 21, 22, 23,
	65	24, 25, 26, 27, 28, 29, 30, 31,
	66	32, 32, 33, 33, 34, 34, 35, 35,
	67	36, 37, 38, 39, 40, 41, 42, 43,
	68	44, 45, 46, 47, 48, 48, 49, 49,
	69	50, 51, 52, 53, 54, 55, 56, 57,
	70	58, 59, 60, 61, 62, 63, 64, 64,
	71	65, 66, 67, 68, 69, 70, 71, 72,
	72	73, 74, 75, 76, 77, 78, 79, 79,
	73	80, 81, 82, 83, 84, 85, 86, 87,
	74	88, 89, 90, 91, 92, 93, 94, 95,
	75	96, 97, 98, 99, 100, 101, 102, 103,
	76	104, 105, 106, 107, 108, 109, 110, 111,
	77	112, 113, 114, 115, 116, 117, 118, 119,
	78	120, 121, 122, 123, 124, 125, 126, 127};
	79
	80	static int
	81	search(
	82	int val,
	83	short *table,
	84	int size)
	85	{
	86	int i;
	87
	88	for (i = 0; i < size; i++) {
	89	if (val <= *table++)
	90	return (i);
	91	}
	92	return (size);
	93	}
	94
	95	/*
	96	* linear2alaw() - Convert a 16-bit linear PCM value to 8-bit A-law
	97	*
	98	* linear2alaw() accepts an 16-bit integer and encodes it as A-law data.
	99	*
	100	* Linear Input Code Compressed Code
	101	* ------------------------ ---------------
	102	* 0000000wxyza 000wxyz
	103	* 0000001wxyza 001wxyz
	104	* 000001wxyzab 010wxyz
	105	* 00001wxyzabc 011wxyz
	106	* 0001wxyzabcd 100wxyz
	107	* 001wxyzabcde 101wxyz
	108	* 01wxyzabcdef 110wxyz
	109	* 1wxyzabcdefg 111wxyz
	110	*
	111	* For further information see John C. Bellamy's Digital Telephony, 1982,
	112	* John Wiley & Sons, pps 98-111 and 472-476.
	113	*/
	114	unsigned char
	115	linear2alaw(
	116	int pcm_val) /* 2's complement (16-bit range) */
	117	{
	118	int mask;
	119	int seg;
	120	unsigned char aval;
	121
	122	if (pcm_val >= 0) {
	123	mask = 0xD5; /* sign (7th) bit = 1 */
	124	} else {
	125	mask = 0x55; /* sign bit = 0 */
	126	pcm_val = -pcm_val - 8;
	127	}
	128
	129	/* Convert the scaled magnitude to segment number. */
	130	seg = search(pcm_val, seg_end, 8);
	131
	132	/* Combine the sign, segment, and quantization bits. */
	133
	134	if (seg >= 8) /* out of range, return maximum value. */
	135	return (0x7F ^ mask);
	136	else {
	137	aval = seg << SEG_SHIFT;
	138	if (seg < 2)
	139	aval \|= (pcm_val >> 4) & QUANT_MASK;
	140	else
	141	aval \|= (pcm_val >> (seg + 3)) & QUANT_MASK;
	142	return (aval ^ mask);
	143	}
	144	}
	145
	146	/*
	147	* alaw2linear() - Convert an A-law value to 16-bit linear PCM
	148	*
	149	*/
	150	int
	151	alaw2linear(
	152	unsigned char a_val)
	153	{
	154	int t;
	155	int seg;
	156
	157	a_val ^= 0x55;
	158
	159	t = (a_val & QUANT_MASK) << 4;
	160	seg = ((unsigned)a_val & SEG_MASK) >> SEG_SHIFT;
	161	switch (seg) {
	162	case 0:
	163	t += 8;
	164	break;
	165	case 1:
	166	t += 0x108;
	167	break;
	168	default:
	169	t += 0x108;
	170	t <<= seg - 1;
	171	}
	172	return ((a_val & SIGN_BIT) ? t : -t);
	173	}
	174
	175	#define BIAS (0x84) /* Bias for linear code. */
	176
	177	/*
	178	* linear2ulaw() - Convert a linear PCM value to u-law
	179	*
	180	* In order to simplify the encoding process, the original linear magnitude
	181	* is biased by adding 33 which shifts the encoding range from (0 - 8158) to
	182	* (33 - 8191). The result can be seen in the following encoding table:
	183	*
	184	* Biased Linear Input Code Compressed Code
	185	* ------------------------ ---------------
	186	* 00000001wxyza 000wxyz
	187	* 0000001wxyzab 001wxyz
	188	* 000001wxyzabc 010wxyz
	189	* 00001wxyzabcd 011wxyz
	190	* 0001wxyzabcde 100wxyz
	191	* 001wxyzabcdef 101wxyz
	192	* 01wxyzabcdefg 110wxyz
	193	* 1wxyzabcdefgh 111wxyz
	194	*
	195	* Each biased linear code has a leading 1 which identifies the segment
	196	* number. The value of the segment number is equal to 7 minus the number
	197	* of leading 0's. The quantization interval is directly available as the
	198	* four bits wxyz. * The trailing bits (a - h) are ignored.
	199	*
	200	* Ordinarily the complement of the resulting code word is used for
	201	* transmission, and so the code word is complemented before it is returned.
	202	*
	203	* For further information see John C. Bellamy's Digital Telephony, 1982,
	204	* John Wiley & Sons, pps 98-111 and 472-476.
	205	*/
	206	unsigned char
	207	linear2ulaw(
	208	int pcm_val) /* 2's complement (16-bit range) */
	209	{
	210	int mask;
	211	int seg;
	212	unsigned char uval;
	213
	214	/* Get the sign and the magnitude of the value. */
	215	if (pcm_val < 0) {
	216	pcm_val = BIAS - pcm_val;
	217	mask = 0x7F;
	218	} else {
	219	pcm_val += BIAS;
	220	mask = 0xFF;
	221	}
	222
	223	/* Convert the scaled magnitude to segment number. */
	224	seg = search(pcm_val, seg_end, 8);
	225
	226	/*
	227	* Combine the sign, segment, quantization bits;
	228	* and complement the code word.
	229	*/
	230	if (seg >= 8) /* out of range, return maximum value. */
	231	return (0x7F ^ mask);
	232	else {
	233	uval = (seg << 4) \| ((pcm_val >> (seg + 3)) & 0xF);
	234	return (uval ^ mask);
	235	}
	236
	237	}
	238
	239	/*
	240	* ulaw2linear() - Convert a u-law value to 16-bit linear PCM
	241	*
	242	* First, a biased linear code is derived from the code word. An unbiased
	243	* output can then be obtained by subtracting 33 from the biased code.
	244	*
	245	* Note that this function expects to be passed the complement of the
	246	* original code word. This is in keeping with ISDN conventions.
	247	*/
	248	int
	249	ulaw2linear(
	250	unsigned char u_val)
	251	{
	252	int t;
	253
	254	/* Complement to obtain normal u-law value. */
	255	u_val = ~u_val;
	256
	257	/*
	258	* Extract and bias the quantization bits. Then
	259	* shift up by the segment number and subtract out the bias.
	260	*/
	261	t = ((u_val & QUANT_MASK) << 3) + BIAS;
	262	t <<= ((unsigned)u_val & SEG_MASK) >> SEG_SHIFT;
	263
	264	return ((u_val & SIGN_BIT) ? (BIAS - t) : (t - BIAS));
	265	}
	266
	267	/* A-law to u-law conversion */
	268	unsigned char
	269	alaw2ulaw(
	270	unsigned char aval)
	271	{
	272	aval &= 0xff;
	273	return ((aval & 0x80) ? (0xFF ^ _a2u[aval ^ 0xD5]) :
	274	(0x7F ^ _a2u[aval ^ 0x55]));
	275	}
	276
	277	/* u-law to A-law conversion */
	278	unsigned char
	279	ulaw2alaw(
	280	unsigned char uval)
	281	{
	282	uval &= 0xff;
	283	return ((uval & 0x80) ? (0xD5 ^ (_u2a[0xFF ^ uval] - 1)) :
	284	(0x55 ^ (_u2a[0x7F ^ uval] - 1)));
	285	}