Отправлено SM 03 декабря 2002 г. 10:57 В ответ на: Ответ: у меня С6201 отправлено Valery2 03 декабря 2002 г. 09:50

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

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);
}
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));
}

• спасибо :) — Valery2   (03.12.2002 11:16, пустое)