Line data Source code
1 : /*
2 : * SpanDSP - a series of DSP components for telephony
3 : *
4 : * g711.c - A-law and u-law transcoding routines
5 : *
6 : * Written by Steve Underwood <steveu@coppice.org>
7 : *
8 : * Copyright (C) 2006 Steve Underwood
9 : *
10 : * Despite my general liking of the GPL, I place this code in the
11 : * public domain for the benefit of all mankind - even the slimy
12 : * ones who might try to proprietize my work and use it to my
13 : * detriment.
14 : *
15 : * $Id: g711.c,v 1.1 2006/06/07 15:46:39 steveu Exp $
16 : *
17 : * Modifications for WebRtc, 2011/04/28, by tlegrand:
18 : * -Removed unused include files
19 : * -Changed to use WebRtc types
20 : * -Added option to run encoder bitexact with ITU-T reference implementation
21 : */
22 :
23 : #include "g711.h"
24 : #include "webrtc/typedefs.h"
25 :
26 : /* Copied from the CCITT G.711 specification */
27 : static const uint8_t ulaw_to_alaw_table[256] = {
28 : 42, 43, 40, 41, 46, 47, 44, 45, 34, 35, 32, 33, 38, 39, 36,
29 : 37, 58, 59, 56, 57, 62, 63, 60, 61, 50, 51, 48, 49, 54, 55,
30 : 52, 53, 10, 11, 8, 9, 14, 15, 12, 13, 2, 3, 0, 1, 6,
31 : 7, 4, 26, 27, 24, 25, 30, 31, 28, 29, 18, 19, 16, 17, 22,
32 : 23, 20, 21, 106, 104, 105, 110, 111, 108, 109, 98, 99, 96, 97, 102,
33 : 103, 100, 101, 122, 120, 126, 127, 124, 125, 114, 115, 112, 113, 118, 119,
34 : 116, 117, 75, 73, 79, 77, 66, 67, 64, 65, 70, 71, 68, 69, 90,
35 : 91, 88, 89, 94, 95, 92, 93, 82, 82, 83, 83, 80, 80, 81, 81,
36 : 86, 86, 87, 87, 84, 84, 85, 85, 170, 171, 168, 169, 174, 175, 172,
37 : 173, 162, 163, 160, 161, 166, 167, 164, 165, 186, 187, 184, 185, 190, 191,
38 : 188, 189, 178, 179, 176, 177, 182, 183, 180, 181, 138, 139, 136, 137, 142,
39 : 143, 140, 141, 130, 131, 128, 129, 134, 135, 132, 154, 155, 152, 153, 158,
40 : 159, 156, 157, 146, 147, 144, 145, 150, 151, 148, 149, 234, 232, 233, 238,
41 : 239, 236, 237, 226, 227, 224, 225, 230, 231, 228, 229, 250, 248, 254, 255,
42 : 252, 253, 242, 243, 240, 241, 246, 247, 244, 245, 203, 201, 207, 205, 194,
43 : 195, 192, 193, 198, 199, 196, 197, 218, 219, 216, 217, 222, 223, 220, 221,
44 : 210, 210, 211, 211, 208, 208, 209, 209, 214, 214, 215, 215, 212, 212, 213,
45 : 213
46 : };
47 :
48 : /* These transcoding tables are copied from the CCITT G.711 specification. To
49 : achieve optimal results, do not change them. */
50 : static const uint8_t alaw_to_ulaw_table[256] = {
51 : 42, 43, 40, 41, 46, 47, 44, 45, 34, 35, 32, 33, 38, 39, 36,
52 : 37, 57, 58, 55, 56, 61, 62, 59, 60, 49, 50, 47, 48, 53, 54,
53 : 51, 52, 10, 11, 8, 9, 14, 15, 12, 13, 2, 3, 0, 1, 6,
54 : 7, 4, 5, 26, 27, 24, 25, 30, 31, 28, 29, 18, 19, 16, 17,
55 : 22, 23, 20, 21, 98, 99, 96, 97, 102, 103, 100, 101, 93, 93, 92,
56 : 92, 95, 95, 94, 94, 116, 118, 112, 114, 124, 126, 120, 122, 106, 107,
57 : 104, 105, 110, 111, 108, 109, 72, 73, 70, 71, 76, 77, 74, 75, 64,
58 : 65, 63, 63, 68, 69, 66, 67, 86, 87, 84, 85, 90, 91, 88, 89,
59 : 79, 79, 78, 78, 82, 83, 80, 81, 170, 171, 168, 169, 174, 175, 172,
60 : 173, 162, 163, 160, 161, 166, 167, 164, 165, 185, 186, 183, 184, 189, 190,
61 : 187, 188, 177, 178, 175, 176, 181, 182, 179, 180, 138, 139, 136, 137, 142,
62 : 143, 140, 141, 130, 131, 128, 129, 134, 135, 132, 133, 154, 155, 152, 153,
63 : 158, 159, 156, 157, 146, 147, 144, 145, 150, 151, 148, 149, 226, 227, 224,
64 : 225, 230, 231, 228, 229, 221, 221, 220, 220, 223, 223, 222, 222, 244, 246,
65 : 240, 242, 252, 254, 248, 250, 234, 235, 232, 233, 238, 239, 236, 237, 200,
66 : 201, 198, 199, 204, 205, 202, 203, 192, 193, 191, 191, 196, 197, 194, 195,
67 : 214, 215, 212, 213, 218, 219, 216, 217, 207, 207, 206, 206, 210, 211, 208,
68 : 209
69 : };
70 :
71 0 : uint8_t alaw_to_ulaw(uint8_t alaw) { return alaw_to_ulaw_table[alaw]; }
72 :
73 0 : uint8_t ulaw_to_alaw(uint8_t ulaw) { return ulaw_to_alaw_table[ulaw]; }
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