audiostuff: spandsp-0.0.6pre17/src/spandsp/g711.h annotate

author	Peter Meerwald <pmeerw@cosy.sbg.ac.at>
date	Fri, 25 Jun 2010 15:50:58 +0200
parents
children

rev	line source
4 26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	1 /*
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	2 * SpanDSP - a series of DSP components for telephony
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	3 *
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	4 * g711.h - In line A-law and u-law conversion routines
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	5 *
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	6 * Written by Steve Underwood <steveu@coppice.org>
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	7 *
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	8 * Copyright (C) 2001 Steve Underwood
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	9 *
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	10 * All rights reserved.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	11 *
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	12 * This program is free software; you can redistribute it and/or modify
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	13 * it under the terms of the GNU Lesser General Public License version 2.1,
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	14 * as published by the Free Software Foundation.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	15 *
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	16 * This program is distributed in the hope that it will be useful,
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	19 * GNU Lesser General Public License for more details.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	20 *
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	21 * You should have received a copy of the GNU Lesser General Public
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	22 * License along with this program; if not, write to the Free Software
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	23 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	24 *
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	25 * $Id: g711.h,v 1.19 2009/04/12 09:12:10 steveu Exp $
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	26 */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	27
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	28 /! \file /
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	29
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	30 /*! \page g711_page A-law and mu-law handling
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	31 Lookup tables for A-law and u-law look attractive, until you consider the impact
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	32 on the CPU cache. If it causes a substantial area of your processor cache to get
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	33 hit too often, cache sloshing will severely slow things down. The main reason
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	34 these routines are slow in C, is the lack of direct access to the CPU's "find
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	35 the first 1" instruction. A little in-line assembler fixes that, and the
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	36 conversion routines can be faster than lookup tables, in most real world usage.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	37 A "find the first 1" instruction is available on most modern CPUs, and is a
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	38 much underused feature.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	39
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	40 If an assembly language method of bit searching is not available, these routines
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	41 revert to a method that can be a little slow, so the cache thrashing might not
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	42 seem so bad :(
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	43
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	44 Feel free to submit patches to add fast "find the first 1" support for your own
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	45 favourite processor.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	46
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	47 Look up tables are used for transcoding between A-law and u-law, since it is
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	48 difficult to achieve the precise transcoding procedure laid down in the G.711
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	49 specification by other means.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	50 */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	51
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	52 #if !defined(_SPANDSP_G711_H_)
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	53 #define _SPANDSP_G711_H_
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	54
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	55 /* The usual values to use on idle channels, to emulate silence */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	56 /! Idle value for A-law channels /
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	57 #define G711_ALAW_IDLE_OCTET 0x5D
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	58 /! Idle value for u-law channels /
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	59 #define G711_ULAW_IDLE_OCTET 0xFF
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	60
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	61 enum
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	62 {
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	63 G711_ALAW = 0,
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	64 G711_ULAW
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	65 };
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	66
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	67 /*!
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	68 G.711 state
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	69 */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	70 typedef struct g711_state_s g711_state_t;
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	71
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	72 #if defined(__cplusplus)
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	73 extern "C"
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	74 {
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	75 #endif
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	76
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	77 /* N.B. It is tempting to use look-up tables for A-law and u-law conversion.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	78 * However, you should consider the cache footprint.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	79 *
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	80 * A 64K byte table for linear to x-law and a 512 byte table for x-law to
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	81 * linear sound like peanuts these days, and shouldn't an array lookup be
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	82 * real fast? No! When the cache sloshes as badly as this one will, a tight
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	83 * calculation may be better. The messiest part is normally finding the
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	84 * segment, but a little inline assembly can fix that on an i386, x86_64 and
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	85 * many other modern processors.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	86 */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	87
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	88 /*
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	89 * Mu-law is basically as follows:
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	90 *
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	91 * Biased Linear Input Code Compressed Code
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	92 * ------------------------ ---------------
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	93 * 00000001wxyza 000wxyz
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	94 * 0000001wxyzab 001wxyz
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	95 * 000001wxyzabc 010wxyz
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	96 * 00001wxyzabcd 011wxyz
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	97 * 0001wxyzabcde 100wxyz
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	98 * 001wxyzabcdef 101wxyz
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	99 * 01wxyzabcdefg 110wxyz
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	100 * 1wxyzabcdefgh 111wxyz
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	101 *
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	102 * Each biased linear code has a leading 1 which identifies the segment
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	103 * number. The value of the segment number is equal to 7 minus the number
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	104 * of leading 0's. The quantization interval is directly available as the
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	105 * four bits wxyz. * The trailing bits (a - h) are ignored.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	106 *
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	107 * Ordinarily the complement of the resulting code word is used for
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	108 * transmission, and so the code word is complemented before it is returned.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	109 *
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	110 * For further information see John C. Bellamy's Digital Telephony, 1982,
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	111 * John Wiley & Sons, pps 98-111 and 472-476.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	112 */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	113
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	114 /* Enable the trap as per the MIL-STD */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	115 //#define ULAW_ZEROTRAP
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	116 /! Bias for u-law encoding from linear. /
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	117 #define ULAW_BIAS 0x84
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	118
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	119 /*! \brief Encode a linear sample to u-law
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	120 \param linear The sample to encode.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	121 \return The u-law value.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	122 */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	123 static __inline__ uint8_t linear_to_ulaw(int linear)
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	124 {
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	125 uint8_t u_val;
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	126 int mask;
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	127 int seg;
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	128
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	129 /* Get the sign and the magnitude of the value. */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	130 if (linear >= 0)
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	131 {
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	132 linear = ULAW_BIAS + linear;
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	133 mask = 0xFF;
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	134 }
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	135 else
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	136 {
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	137 linear = ULAW_BIAS - linear;
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	138 mask = 0x7F;
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	139 }
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	140
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	141 seg = top_bit(linear \| 0xFF) - 7;
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	142
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	143 /*
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	144 * Combine the sign, segment, quantization bits,
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	145 * and complement the code word.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	146 */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	147 if (seg >= 8)
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	148 u_val = (uint8_t) (0x7F ^ mask);
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	149 else
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	150 u_val = (uint8_t) (((seg << 4) \| ((linear >> (seg + 3)) & 0xF)) ^ mask);
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	151 #ifdef ULAW_ZEROTRAP
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	152 /* Optional ITU trap */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	153 if (u_val == 0)
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	154 u_val = 0x02;
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	155 #endif
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	156 return u_val;
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	157 }
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	158 /- End of function --------------------------------------------------------/
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	159
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	160 /*! \brief Decode an u-law sample to a linear value.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	161 \param ulaw The u-law sample to decode.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	162 \return The linear value.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	163 */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	164 static __inline__ int16_t ulaw_to_linear(uint8_t ulaw)
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	165 {
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	166 int t;
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	167
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	168 /* Complement to obtain normal u-law value. */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	169 ulaw = ~ulaw;
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	170 /*
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	171 * Extract and bias the quantization bits. Then
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	172 * shift up by the segment number and subtract out the bias.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	173 */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	174 t = (((ulaw & 0x0F) << 3) + ULAW_BIAS) << (((int) ulaw & 0x70) >> 4);
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	175 return (int16_t) ((ulaw & 0x80) ? (ULAW_BIAS - t) : (t - ULAW_BIAS));
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	176 }
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	177 /- End of function --------------------------------------------------------/
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	178
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	179 /*
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	180 * A-law is basically as follows:
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	181 *
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	182 * Linear Input Code Compressed Code
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	183 * ----------------- ---------------
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	184 * 0000000wxyza 000wxyz
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	185 * 0000001wxyza 001wxyz
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	186 * 000001wxyzab 010wxyz
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	187 * 00001wxyzabc 011wxyz
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	188 * 0001wxyzabcd 100wxyz
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	189 * 001wxyzabcde 101wxyz
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	190 * 01wxyzabcdef 110wxyz
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	191 * 1wxyzabcdefg 111wxyz
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	192 *
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	193 * For further information see John C. Bellamy's Digital Telephony, 1982,
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	194 * John Wiley & Sons, pps 98-111 and 472-476.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	195 */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	196
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	197 /! The A-law alternate mark inversion mask /
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	198 #define ALAW_AMI_MASK 0x55
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	199
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	200 /*! \brief Encode a linear sample to A-law
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	201 \param linear The sample to encode.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	202 \return The A-law value.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	203 */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	204 static __inline__ uint8_t linear_to_alaw(int linear)
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	205 {
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	206 int mask;
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	207 int seg;
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	208
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	209 if (linear >= 0)
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	210 {
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	211 /* Sign (bit 7) bit = 1 */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	212 mask = ALAW_AMI_MASK \| 0x80;
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	213 }
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	214 else
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	215 {
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	216 /* Sign (bit 7) bit = 0 */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	217 mask = ALAW_AMI_MASK;
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	218 linear = -linear - 1;
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	219 }
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	220
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	221 /* Convert the scaled magnitude to segment number. */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	222 seg = top_bit(linear \| 0xFF) - 7;
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	223 if (seg >= 8)
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	224 {
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	225 if (linear >= 0)
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	226 {
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	227 /* Out of range. Return maximum value. */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	228 return (uint8_t) (0x7F ^ mask);
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	229 }
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	230 /* We must be just a tiny step below zero */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	231 return (uint8_t) (0x00 ^ mask);
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	232 }
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	233 /* Combine the sign, segment, and quantization bits. */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	234 return (uint8_t) (((seg << 4) \| ((linear >> ((seg) ? (seg + 3) : 4)) & 0x0F)) ^ mask);
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	235 }
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	236 /- End of function --------------------------------------------------------/
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	237
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	238 /*! \brief Decode an A-law sample to a linear value.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	239 \param alaw The A-law sample to decode.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	240 \return The linear value.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	241 */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	242 static __inline__ int16_t alaw_to_linear(uint8_t alaw)
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	243 {
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	244 int i;
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	245 int seg;
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	246
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	247 alaw ^= ALAW_AMI_MASK;
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	248 i = ((alaw & 0x0F) << 4);
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	249 seg = (((int) alaw & 0x70) >> 4);
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	250 if (seg)
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	251 i = (i + 0x108) << (seg - 1);
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	252 else
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	253 i += 8;
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	254 return (int16_t) ((alaw & 0x80) ? i : -i);
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	255 }
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	256 /- End of function --------------------------------------------------------/
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	257
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	258 /*! \brief Transcode from A-law to u-law, using the procedure defined in G.711.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	259 \param alaw The A-law sample to transcode.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	260 \return The best matching u-law value.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	261 */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	262 SPAN_DECLARE(uint8_t) alaw_to_ulaw(uint8_t alaw);
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	263
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	264 /*! \brief Transcode from u-law to A-law, using the procedure defined in G.711.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	265 \param ulaw The u-law sample to transcode.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	266 \return The best matching A-law value.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	267 */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	268 SPAN_DECLARE(uint8_t) ulaw_to_alaw(uint8_t ulaw);
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	269
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	270 /*! \brief Decode from u-law or A-law to linear.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	271 \param s The G.711 context.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	272 \param amp The linear audio buffer.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	273 \param g711_data The G.711 data.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	274 \param g711_bytes The number of G.711 samples to decode.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	275 \return The number of samples of linear audio produced.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	276 */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	277 SPAN_DECLARE(int) g711_decode(g711_state_t *s,
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	278 int16_t amp[],
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	279 const uint8_t g711_data[],
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	280 int g711_bytes);
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	281
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	282 /*! \brief Encode from linear to u-law or A-law.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	283 \param s The G.711 context.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	284 \param g711_data The G.711 data.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	285 \param amp The linear audio buffer.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	286 \param len The number of samples to encode.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	287 \return The number of G.711 samples produced.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	288 */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	289 SPAN_DECLARE(int) g711_encode(g711_state_t *s,
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	290 uint8_t g711_data[],
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	291 const int16_t amp[],
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	292 int len);
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	293
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	294 /*! \brief Transcode between u-law and A-law.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	295 \param s The G.711 context.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	296 \param g711_out The resulting G.711 data.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	297 \param g711_in The original G.711 data.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	298 \param g711_bytes The number of G.711 samples to transcode.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	299 \return The number of G.711 samples produced.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	300 */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	301 SPAN_DECLARE(int) g711_transcode(g711_state_t *s,
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	302 uint8_t g711_out[],
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	303 const uint8_t g711_in[],
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	304 int g711_bytes);
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	305
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	306 /*! Initialise a G.711 encode or decode context.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	307 \param s The G.711 context.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	308 \param mode The G.711 mode.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	309 \return A pointer to the G.711 context, or NULL for error. */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	310 SPAN_DECLARE(g711_state_t ) g711_init(g711_state_t s, int mode);
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	311
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	312 /*! Release a G.711 encode or decode context.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	313 \param s The G.711 context.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	314 \return 0 for OK. */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	315 SPAN_DECLARE(int) g711_release(g711_state_t *s);
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	316
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	317 /*! Free a G.711 encode or decode context.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	318 \param s The G.711 context.
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	319 \return 0 for OK. */
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	320 SPAN_DECLARE(int) g711_free(g711_state_t *s);
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	321
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	322 #if defined(__cplusplus)
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	323 }
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	324 #endif
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	325
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	326 #endif
26cd8f1ef0b1 import spandsp-0.0.6pre17 Peter Meerwald <pmeerw@cosy.sbg.ac.at> parents: diff changeset	327 /- End of file ------------------------------------------------------------/

4

26cd8f1ef0b1 import spandsp-0.0.6pre17