1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
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
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
|
/*
* l1oip_codec.c generic codec using lookup table
* -> conversion from a-Law to u-Law
* -> conversion from u-Law to a-Law
* -> compression by reducing the number of sample resolution to 4
*
* NOTE: It is not compatible with any standard codec like ADPCM.
*
* Author Andreas Eversberg (jolly@eversberg.eu)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2, or (at your option)
* any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*/
/*
How the codec works:
--------------------
The volume is increased to increase the dynamic range of the audio signal.
Each sample is converted to a-LAW with only 16 steps of level resolution.
A pair of two samples are stored in one byte.
The first byte is stored in the upper bits, the second byte is stored in the
lower bits.
To speed up compression and decompression, two lookup tables are formed:
- 16 bits index for two samples (law encoded) with 8 bit compressed result.
- 8 bits index for one compressed data with 16 bits decompressed result.
NOTE: The bytes are handled as they are law-encoded.
*/
#include <linux/vmalloc.h>
#include <linux/mISDNif.h>
#include <linux/in.h>
#include "core.h"
#include "l1oip.h"
/* definitions of codec. don't use calculations, code may run slower. */
static u8 *table_com;
static u16 *table_dec;
/* alaw -> ulaw */
static u8 alaw_to_ulaw[256] =
{
0xab, 0x2b, 0xe3, 0x63, 0x8b, 0x0b, 0xc9, 0x49,
0xba, 0x3a, 0xf6, 0x76, 0x9b, 0x1b, 0xd7, 0x57,
0xa3, 0x23, 0xdd, 0x5d, 0x83, 0x03, 0xc1, 0x41,
0xb2, 0x32, 0xeb, 0x6b, 0x93, 0x13, 0xcf, 0x4f,
0xaf, 0x2f, 0xe7, 0x67, 0x8f, 0x0f, 0xcd, 0x4d,
0xbe, 0x3e, 0xfe, 0x7e, 0x9f, 0x1f, 0xdb, 0x5b,
0xa7, 0x27, 0xdf, 0x5f, 0x87, 0x07, 0xc5, 0x45,
0xb6, 0x36, 0xef, 0x6f, 0x97, 0x17, 0xd3, 0x53,
0xa9, 0x29, 0xe1, 0x61, 0x89, 0x09, 0xc7, 0x47,
0xb8, 0x38, 0xf2, 0x72, 0x99, 0x19, 0xd5, 0x55,
0xa1, 0x21, 0xdc, 0x5c, 0x81, 0x01, 0xbf, 0x3f,
0xb0, 0x30, 0xe9, 0x69, 0x91, 0x11, 0xce, 0x4e,
0xad, 0x2d, 0xe5, 0x65, 0x8d, 0x0d, 0xcb, 0x4b,
0xbc, 0x3c, 0xfa, 0x7a, 0x9d, 0x1d, 0xd9, 0x59,
0xa5, 0x25, 0xde, 0x5e, 0x85, 0x05, 0xc3, 0x43,
0xb4, 0x34, 0xed, 0x6d, 0x95, 0x15, 0xd1, 0x51,
0xac, 0x2c, 0xe4, 0x64, 0x8c, 0x0c, 0xca, 0x4a,
0xbb, 0x3b, 0xf8, 0x78, 0x9c, 0x1c, 0xd8, 0x58,
0xa4, 0x24, 0xde, 0x5e, 0x84, 0x04, 0xc2, 0x42,
0xb3, 0x33, 0xec, 0x6c, 0x94, 0x14, 0xd0, 0x50,
0xb0, 0x30, 0xe8, 0x68, 0x90, 0x10, 0xce, 0x4e,
0xbf, 0x3f, 0xfe, 0x7e, 0xa0, 0x20, 0xdc, 0x5c,
0xa8, 0x28, 0xe0, 0x60, 0x88, 0x08, 0xc6, 0x46,
0xb7, 0x37, 0xf0, 0x70, 0x98, 0x18, 0xd4, 0x54,
0xaa, 0x2a, 0xe2, 0x62, 0x8a, 0x0a, 0xc8, 0x48,
0xb9, 0x39, 0xf4, 0x74, 0x9a, 0x1a, 0xd6, 0x56,
0xa2, 0x22, 0xdd, 0x5d, 0x82, 0x02, 0xc0, 0x40,
0xb1, 0x31, 0xea, 0x6a, 0x92, 0x12, 0xcf, 0x4f,
0xae, 0x2e, 0xe6, 0x66, 0x8e, 0x0e, 0xcc, 0x4c,
0xbd, 0x3d, 0xfc, 0x7c, 0x9e, 0x1e, 0xda, 0x5a,
0xa6, 0x26, 0xdf, 0x5f, 0x86, 0x06, 0xc4, 0x44,
0xb5, 0x35, 0xee, 0x6e, 0x96, 0x16, 0xd2, 0x52
};
/* ulaw -> alaw */
static u8 ulaw_to_alaw[256] =
{
0xab, 0x55, 0xd5, 0x15, 0x95, 0x75, 0xf5, 0x35,
0xb5, 0x45, 0xc5, 0x05, 0x85, 0x65, 0xe5, 0x25,
0xa5, 0x5d, 0xdd, 0x1d, 0x9d, 0x7d, 0xfd, 0x3d,
0xbd, 0x4d, 0xcd, 0x0d, 0x8d, 0x6d, 0xed, 0x2d,
0xad, 0x51, 0xd1, 0x11, 0x91, 0x71, 0xf1, 0x31,
0xb1, 0x41, 0xc1, 0x01, 0x81, 0x61, 0xe1, 0x21,
0x59, 0xd9, 0x19, 0x99, 0x79, 0xf9, 0x39, 0xb9,
0x49, 0xc9, 0x09, 0x89, 0x69, 0xe9, 0x29, 0xa9,
0xd7, 0x17, 0x97, 0x77, 0xf7, 0x37, 0xb7, 0x47,
0xc7, 0x07, 0x87, 0x67, 0xe7, 0x27, 0xa7, 0xdf,
0x9f, 0x7f, 0xff, 0x3f, 0xbf, 0x4f, 0xcf, 0x0f,
0x8f, 0x6f, 0xef, 0x2f, 0x53, 0x13, 0x73, 0x33,
0xb3, 0x43, 0xc3, 0x03, 0x83, 0x63, 0xe3, 0x23,
0xa3, 0x5b, 0xdb, 0x1b, 0x9b, 0x7b, 0xfb, 0x3b,
0xbb, 0xbb, 0x4b, 0x4b, 0xcb, 0xcb, 0x0b, 0x0b,
0x8b, 0x8b, 0x6b, 0x6b, 0xeb, 0xeb, 0x2b, 0x2b,
0xab, 0x54, 0xd4, 0x14, 0x94, 0x74, 0xf4, 0x34,
0xb4, 0x44, 0xc4, 0x04, 0x84, 0x64, 0xe4, 0x24,
0xa4, 0x5c, 0xdc, 0x1c, 0x9c, 0x7c, 0xfc, 0x3c,
0xbc, 0x4c, 0xcc, 0x0c, 0x8c, 0x6c, 0xec, 0x2c,
0xac, 0x50, 0xd0, 0x10, 0x90, 0x70, 0xf0, 0x30,
0xb0, 0x40, 0xc0, 0x00, 0x80, 0x60, 0xe0, 0x20,
0x58, 0xd8, 0x18, 0x98, 0x78, 0xf8, 0x38, 0xb8,
0x48, 0xc8, 0x08, 0x88, 0x68, 0xe8, 0x28, 0xa8,
0xd6, 0x16, 0x96, 0x76, 0xf6, 0x36, 0xb6, 0x46,
0xc6, 0x06, 0x86, 0x66, 0xe6, 0x26, 0xa6, 0xde,
0x9e, 0x7e, 0xfe, 0x3e, 0xbe, 0x4e, 0xce, 0x0e,
0x8e, 0x6e, 0xee, 0x2e, 0x52, 0x12, 0x72, 0x32,
0xb2, 0x42, 0xc2, 0x02, 0x82, 0x62, 0xe2, 0x22,
0xa2, 0x5a, 0xda, 0x1a, 0x9a, 0x7a, 0xfa, 0x3a,
0xba, 0xba, 0x4a, 0x4a, 0xca, 0xca, 0x0a, 0x0a,
0x8a, 0x8a, 0x6a, 0x6a, 0xea, 0xea, 0x2a, 0x2a
};
/* alaw -> 4bit compression */
static u8 alaw_to_4bit[256] = {
0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04,
0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04,
0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04,
0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04,
0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04,
0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0d, 0x02,
0x0e, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04,
0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04,
0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04,
0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04,
0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04,
0x0e, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04,
0x0d, 0x02, 0x08, 0x07, 0x0f, 0x01, 0x0a, 0x05,
0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
0x0d, 0x02, 0x09, 0x07, 0x0f, 0x00, 0x0b, 0x04,
0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04,
0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04,
0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
0x0d, 0x02, 0x08, 0x07, 0x0f, 0x00, 0x0b, 0x04,
0x0e, 0x01, 0x0a, 0x05, 0x0f, 0x00, 0x0c, 0x03,
0x0d, 0x02, 0x09, 0x06, 0x0f, 0x00, 0x0b, 0x04,
};
/* 4bit -> alaw decompression */
static u8 _4bit_to_alaw[16] = {
0x5d, 0x51, 0xd9, 0xd7, 0x5f, 0x53, 0xa3, 0x4b,
0x2a, 0x3a, 0x22, 0x2e, 0x26, 0x56, 0x20, 0x2c,
};
/* ulaw -> 4bit compression */
static u8 ulaw_to_4bit[256] = {
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02, 0x02,
0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x03,
0x03, 0x03, 0x03, 0x03, 0x03, 0x03, 0x04, 0x04,
0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04, 0x04,
0x04, 0x04, 0x04, 0x04, 0x05, 0x05, 0x05, 0x05,
0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05, 0x05,
0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06, 0x06,
0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07,
0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x07, 0x08,
0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f,
0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f,
0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f,
0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f, 0x0f,
0x0f, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e,
0x0e, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e, 0x0e,
0x0e, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d,
0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d, 0x0d,
0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c,
0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0c, 0x0b, 0x0b,
0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b, 0x0b,
0x0b, 0x0b, 0x0b, 0x0b, 0x0a, 0x0a, 0x0a, 0x0a,
0x0a, 0x0a, 0x0a, 0x0a, 0x0a, 0x0a, 0x0a, 0x0a,
0x09, 0x09, 0x09, 0x09, 0x09, 0x09, 0x09, 0x09,
0x09, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08,
0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08, 0x08,
};
/* 4bit -> ulaw decompression */
static u8 _4bit_to_ulaw[16] = {
0x11, 0x21, 0x31, 0x40, 0x4e, 0x5c, 0x68, 0x71,
0xfe, 0xef, 0xe7, 0xdb, 0xcd, 0xbf, 0xaf, 0x9f,
};
/*
* Compresses data to the result buffer
* The result size must be at least half of the input buffer.
* The number of samples also must be even!
*/
int
l1oip_law_to_4bit(u8 *data, int len, u8 *result, u32 *state)
{
int ii, i = 0, o = 0;
if (!len)
return 0;
/* send saved byte and first input byte */
if (*state) {
*result++ = table_com[(((*state)<<8)&0xff00) | (*data++)];
len--;
o++;
}
ii = len >> 1;
while (i < ii) {
*result++ = table_com[(data[0]<<8) | (data[1])];
data += 2;
i++;
o++;
}
/* if len has an odd number, we save byte for next call */
if (len & 1)
*state = 0x100 + *data;
else
*state = 0;
return o;
}
/* Decompress data to the result buffer
* The result size must be the number of sample in packet. (2 * input data)
* The number of samples in the result are even!
*/
int
l1oip_4bit_to_law(u8 *data, int len, u8 *result)
{
int i = 0;
u16 r;
while (i < len) {
r = table_dec[*data++];
*result++ = r>>8;
*result++ = r;
i++;
}
return len << 1;
}
/*
* law conversion
*/
int
l1oip_alaw_to_ulaw(u8 *data, int len, u8 *result)
{
int i = 0;
while (i < len) {
*result++ = alaw_to_ulaw[*data++];
i++;
}
return len;
}
int
l1oip_ulaw_to_alaw(u8 *data, int len, u8 *result)
{
int i = 0;
while (i < len) {
*result++ = ulaw_to_alaw[*data++];
i++;
}
return len;
}
/*
* generate/free compression and decompression table
*/
void
l1oip_4bit_free(void)
{
if (table_dec)
vfree(table_dec);
if (table_com)
vfree(table_com);
table_com = NULL;
table_dec = NULL;
}
int
l1oip_4bit_alloc(int ulaw)
{
int i1, i2, c, sample;
/* in case, it is called again */
if (table_dec)
return 0;
/* alloc conversion tables */
table_com = vmalloc(65536);
table_dec = vmalloc(512);
if (!table_com || !table_dec) {
l1oip_4bit_free();
return -ENOMEM;
}
memset(table_com, 0, 65536);
memset(table_dec, 0, 512);
/* generate compression table */
i1 = 0;
while (i1 < 256) {
if (ulaw)
c = ulaw_to_4bit[i1];
else
c = alaw_to_4bit[i1];
i2 = 0;
while (i2 < 256) {
table_com[(i1<<8) | i2] |= (c<<4);
table_com[(i2<<8) | i1] |= c;
i2++;
}
i1++;
}
/* generate decompression table */
i1 = 0;
while (i1 < 16) {
if (ulaw)
sample = _4bit_to_ulaw[i1];
else
sample = _4bit_to_alaw[i1];
i2 = 0;
while (i2 < 16) {
table_dec[(i1<<4) | i2] |= (sample<<8);
table_dec[(i2<<4) | i1] |= sample;
i2++;
}
i1++;
}
return 0;
}
|
