1 /* Common routines for G.721 and G.723 conversions.
2 *
3 * (c) SoX Contributors
4 *
5 * This library is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU Lesser General Public License as published by
7 * the Free Software Foundation; either version 2.1 of the License, or (at
8 * your option) any later version.
9 *
10 * This library is distributed in the hope that it will be useful, but
11 * WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU Lesser
13 * General Public License for more details.
14 *
15 * You should have received a copy of the GNU Lesser General Public License
16 * along with this library; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
18 *
19 *
20 * This code is based on code from Sun, which came with the following
21 * copyright notice:
22 * -----------------------------------------------------------------------
23 * This source code is a product of Sun Microsystems, Inc. and is provided
24 * for unrestricted use. Users may copy or modify this source code without
25 * charge.
26 *
27 * SUN SOURCE CODE IS PROVIDED AS IS WITH NO WARRANTIES OF ANY KIND INCLUDING
28 * THE WARRANTIES OF DESIGN, MERCHANTIBILITY AND FITNESS FOR A PARTICULAR
29 * PURPOSE, OR ARISING FROM A COURSE OF DEALING, USAGE OR TRADE PRACTICE.
30 *
31 * Sun source code is provided with no support and without any obligation on
32 * the part of Sun Microsystems, Inc. to assist in its use, correction,
33 * modification or enhancement.
34 *
35 * SUN MICROSYSTEMS, INC. SHALL HAVE NO LIABILITY WITH RESPECT TO THE
36 * INFRINGEMENT OF COPYRIGHTS, TRADE SECRETS OR ANY PATENTS BY THIS SOFTWARE
37 * OR ANY PART THEREOF.
38 *
39 * In no event will Sun Microsystems, Inc. be liable for any lost revenue
40 * or profits or other special, indirect and consequential damages, even if
41 * Sun has been advised of the possibility of such damages.
42 *
43 * Sun Microsystems, Inc.
44 * 2550 Garcia Avenue
45 * Mountain View, California 94043
46 * -----------------------------------------------------------------------
47 */
48
49 #include "sox_i.h"
50 #include "g711.h"
51 #include "g72x.h"
52
53 static const char LogTable256[] =
54 {
55 0, 0, 1, 1, 2, 2, 2, 2, 3, 3, 3, 3, 3, 3, 3, 3,
56 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4, 4,
57 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
58 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5, 5,
59 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
60 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
61 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
62 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6,
63 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
64 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
65 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
66 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
67 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
68 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
69 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7,
70 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7, 7
71 };
72
log2plus1(int val)73 static inline int log2plus1(int val)
74 {
75 /* From http://graphics.stanford.edu/~seander/bithacks.html#IntegerLogLookup */
76 unsigned int v = (unsigned int)val; /* 32-bit word to find the log of */
77 unsigned r; /* r will be lg(v) */
78 register unsigned int t, tt; /* temporaries */
79
80 if ((tt = v >> 16))
81 {
82 r = (t = tt >> 8) ? 24 + LogTable256[t] : 16 + LogTable256[tt];
83 }
84 else
85 {
86 r = (t = v >> 8) ? 8 + LogTable256[t] : LogTable256[v];
87 }
88
89 return r + 1;
90 }
91
92 /*
93 * quan()
94 *
95 * quantizes the input val against the table of size short integers.
96 * It returns i if table[i - 1] <= val < table[i].
97 *
98 * Using linear search for simple coding.
99 */
quan(int val,short const * table,int size)100 static int quan(int val, short const *table, int size)
101 {
102 int i;
103
104 for (i = 0; i < size; i++)
105 if (val < *table++)
106 break;
107 return (i);
108 }
109
110 /*
111 * fmult()
112 *
113 * returns the integer product of the 14-bit integer "an" and
114 * "floating point" representation (4-bit exponent, 6-bit mantessa) "srn".
115 */
fmult(int an,int srn)116 static int fmult(int an, int srn)
117 {
118 short anmag, anexp, anmant;
119 short wanexp, wanmant;
120 short retval;
121
122 anmag = (an > 0) ? an : ((-an) & 0x1FFF);
123 anexp = log2plus1(anmag) - 6;
124 anmant = (anmag == 0) ? 32 :
125 (anexp >= 0) ? anmag >> anexp : anmag << -anexp;
126 wanexp = anexp + ((srn >> 6) & 0xF) - 13;
127
128 wanmant = (anmant * (srn & 077) + 0x30) >> 4;
129 retval = (wanexp >= 0) ? ((wanmant << wanexp) & 0x7FFF) :
130 (wanmant >> -wanexp);
131
132 return (((an ^ srn) < 0) ? -retval : retval);
133 }
134
135 /*
136 * g72x_init_state()
137 *
138 * This routine initializes and/or resets the g72x_state structure
139 * pointed to by 'state_ptr'.
140 * All the initial state values are specified in the CCITT G.721 document.
141 */
g72x_init_state(struct g72x_state * state_ptr)142 void g72x_init_state(struct g72x_state *state_ptr)
143 {
144 int cnta;
145
146 state_ptr->yl = 34816;
147 state_ptr->yu = 544;
148 state_ptr->dms = 0;
149 state_ptr->dml = 0;
150 state_ptr->ap = 0;
151 for (cnta = 0; cnta < 2; cnta++) {
152 state_ptr->a[cnta] = 0;
153 state_ptr->pk[cnta] = 0;
154 state_ptr->sr[cnta] = 32;
155 }
156 for (cnta = 0; cnta < 6; cnta++) {
157 state_ptr->b[cnta] = 0;
158 state_ptr->dq[cnta] = 32;
159 }
160 state_ptr->td = 0;
161 }
162
163 /*
164 * predictor_zero()
165 *
166 * computes the estimated signal from 6-zero predictor.
167 *
168 */
predictor_zero(struct g72x_state * state_ptr)169 int predictor_zero(struct g72x_state *state_ptr)
170 {
171 int i;
172 int sezi;
173
174 sezi = fmult(state_ptr->b[0] >> 2, state_ptr->dq[0]);
175 for (i = 1; i < 6; i++) /* ACCUM */
176 sezi += fmult(state_ptr->b[i] >> 2, state_ptr->dq[i]);
177 return (sezi);
178 }
179 /*
180 * predictor_pole()
181 *
182 * computes the estimated signal from 2-pole predictor.
183 *
184 */
predictor_pole(struct g72x_state * state_ptr)185 int predictor_pole(struct g72x_state *state_ptr)
186 {
187 return (fmult(state_ptr->a[1] >> 2, state_ptr->sr[1]) +
188 fmult(state_ptr->a[0] >> 2, state_ptr->sr[0]));
189 }
190 /*
191 * step_size()
192 *
193 * computes the quantization step size of the adaptive quantizer.
194 *
195 */
step_size(struct g72x_state * state_ptr)196 int step_size(struct g72x_state *state_ptr)
197 {
198 int y;
199 int dif;
200 int al;
201
202 if (state_ptr->ap >= 256)
203 return (state_ptr->yu);
204 else {
205 y = state_ptr->yl >> 6;
206 dif = state_ptr->yu - y;
207 al = state_ptr->ap >> 2;
208 if (dif > 0)
209 y += (dif * al) >> 6;
210 else if (dif < 0)
211 y += (dif * al + 0x3F) >> 6;
212 return (y);
213 }
214 }
215
216 /*
217 * quantize()
218 *
219 * Given a raw sample, 'd', of the difference signal and a
220 * quantization step size scale factor, 'y', this routine returns the
221 * ADPCM codeword to which that sample gets quantized. The step
222 * size scale factor division operation is done in the log base 2 domain
223 * as a subtraction.
224 */
quantize(int d,int y,short const * table,int size)225 int quantize(int d, int y, short const *table, int size)
226 {
227 short dqm; /* Magnitude of 'd' */
228 short exp; /* Integer part of base 2 log of 'd' */
229 short mant; /* Fractional part of base 2 log */
230 short dl; /* Log of magnitude of 'd' */
231 short dln; /* Step size scale factor normalized log */
232 int i;
233
234 /*
235 * LOG
236 *
237 * Compute base 2 log of 'd', and store in 'dl'.
238 */
239 dqm = abs(d);
240 exp = log2plus1(dqm >> 1);
241 mant = ((dqm << 7) >> exp) & 0x7F; /* Fractional portion. */
242 dl = (exp << 7) + mant;
243
244 /*
245 * SUBTB
246 *
247 * "Divide" by step size multiplier.
248 */
249 dln = dl - (y >> 2);
250
251 /*
252 * QUAN
253 *
254 * Obtain codword i for 'd'.
255 */
256 i = quan(dln, table, size);
257 if (d < 0) /* take 1's complement of i */
258 return ((size << 1) + 1 - i);
259 else if (i == 0) /* take 1's complement of 0 */
260 return ((size << 1) + 1); /* new in 1988 */
261 else
262 return (i);
263 }
264 /*
265 * reconstruct()
266 *
267 * Returns reconstructed difference signal 'dq' obtained from
268 * codeword 'i' and quantization step size scale factor 'y'.
269 * Multiplication is performed in log base 2 domain as addition.
270 */
reconstruct(int sign,int dqln,int y)271 int reconstruct(int sign, int dqln, int y)
272 {
273 short dql; /* Log of 'dq' magnitude */
274 short dex; /* Integer part of log */
275 short dqt;
276 short dq; /* Reconstructed difference signal sample */
277
278 dql = dqln + (y >> 2); /* ADDA */
279
280 if (dql < 0) {
281 return ((sign) ? -0x8000 : 0);
282 } else { /* ANTILOG */
283 dex = (dql >> 7) & 15;
284 dqt = 128 + (dql & 127);
285 dq = (dqt << 7) >> (14 - dex);
286 return ((sign) ? (dq - 0x8000) : dq);
287 }
288 }
289
290
291 /*
292 * update()
293 *
294 * updates the state variables for each output code
295 */
update(int code_size,int y,int wi,int fi,int dq,int sr,int dqsez,struct g72x_state * state_ptr)296 void update(int code_size, int y, int wi, int fi, int dq, int sr,
297 int dqsez, struct g72x_state *state_ptr)
298 {
299 int cnt;
300 short mag, exp; /* Adaptive predictor, FLOAT A */
301 short a2p=0; /* LIMC */
302 short a1ul; /* UPA1 */
303 short pks1; /* UPA2 */
304 short fa1;
305 char tr; /* tone/transition detector */
306 short ylint, thr2, dqthr;
307 short ylfrac, thr1;
308 short pk0;
309
310 pk0 = (dqsez < 0) ? 1 : 0; /* needed in updating predictor poles */
311
312 mag = dq & 0x7FFF; /* prediction difference magnitude */
313 /* TRANS */
314 ylint = state_ptr->yl >> 15; /* exponent part of yl */
315 ylfrac = (state_ptr->yl >> 10) & 0x1F; /* fractional part of yl */
316 thr1 = (32 + ylfrac) << ylint; /* threshold */
317 thr2 = (ylint > 9) ? 31 << 10 : thr1; /* limit thr2 to 31 << 10 */
318 dqthr = (thr2 + (thr2 >> 1)) >> 1; /* dqthr = 0.75 * thr2 */
319 if (state_ptr->td == 0) /* signal supposed voice */
320 tr = 0;
321 else if (mag <= dqthr) /* supposed data, but small mag */
322 tr = 0; /* treated as voice */
323 else /* signal is data (modem) */
324 tr = 1;
325
326 /*
327 * Quantizer scale factor adaptation.
328 */
329
330 /* FUNCTW & FILTD & DELAY */
331 /* update non-steady state step size multiplier */
332 state_ptr->yu = y + ((wi - y) >> 5);
333
334 /* LIMB */
335 if (state_ptr->yu < 544) /* 544 <= yu <= 5120 */
336 state_ptr->yu = 544;
337 else if (state_ptr->yu > 5120)
338 state_ptr->yu = 5120;
339
340 /* FILTE & DELAY */
341 /* update steady state step size multiplier */
342 state_ptr->yl += state_ptr->yu + ((-state_ptr->yl) >> 6);
343
344 /*
345 * Adaptive predictor coefficients.
346 */
347 if (tr == 1) { /* reset a's and b's for modem signal */
348 state_ptr->a[0] = 0;
349 state_ptr->a[1] = 0;
350 state_ptr->b[0] = 0;
351 state_ptr->b[1] = 0;
352 state_ptr->b[2] = 0;
353 state_ptr->b[3] = 0;
354 state_ptr->b[4] = 0;
355 state_ptr->b[5] = 0;
356 } else { /* update a's and b's */
357 pks1 = pk0 ^ state_ptr->pk[0]; /* UPA2 */
358
359 /* update predictor pole a[1] */
360 a2p = state_ptr->a[1] - (state_ptr->a[1] >> 7);
361 if (dqsez != 0) {
362 fa1 = (pks1) ? state_ptr->a[0] : -state_ptr->a[0];
363 if (fa1 < -8191) /* a2p = function of fa1 */
364 a2p -= 0x100;
365 else if (fa1 > 8191)
366 a2p += 0xFF;
367 else
368 a2p += fa1 >> 5;
369
370 if (pk0 ^ state_ptr->pk[1])
371 {
372 /* LIMC */
373 if (a2p <= -12160)
374 a2p = -12288;
375 else if (a2p >= 12416)
376 a2p = 12288;
377 else
378 a2p -= 0x80;
379 }
380 else if (a2p <= -12416)
381 a2p = -12288;
382 else if (a2p >= 12160)
383 a2p = 12288;
384 else
385 a2p += 0x80;
386 }
387
388 /* Possible bug: a2p not initialized if dqsez == 0) */
389 /* TRIGB & DELAY */
390 state_ptr->a[1] = a2p;
391
392 /* UPA1 */
393 /* update predictor pole a[0] */
394 state_ptr->a[0] -= state_ptr->a[0] >> 8;
395 if (dqsez != 0)
396 {
397 if (pks1 == 0)
398 state_ptr->a[0] += 192;
399 else
400 state_ptr->a[0] -= 192;
401 }
402 /* LIMD */
403 a1ul = 15360 - a2p;
404 if (state_ptr->a[0] < -a1ul)
405 state_ptr->a[0] = -a1ul;
406 else if (state_ptr->a[0] > a1ul)
407 state_ptr->a[0] = a1ul;
408
409 /* UPB : update predictor zeros b[6] */
410 for (cnt = 0; cnt < 6; cnt++) {
411 if (code_size == 5) /* for 40Kbps G.723 */
412 state_ptr->b[cnt] -= state_ptr->b[cnt] >> 9;
413 else /* for G.721 and 24Kbps G.723 */
414 state_ptr->b[cnt] -= state_ptr->b[cnt] >> 8;
415 if (dq & 0x7FFF) { /* XOR */
416 if ((dq ^ state_ptr->dq[cnt]) >= 0)
417 state_ptr->b[cnt] += 128;
418 else
419 state_ptr->b[cnt] -= 128;
420 }
421 }
422 }
423
424 for (cnt = 5; cnt > 0; cnt--)
425 state_ptr->dq[cnt] = state_ptr->dq[cnt-1];
426 /* FLOAT A : convert dq[0] to 4-bit exp, 6-bit mantissa f.p. */
427 if (mag == 0) {
428 state_ptr->dq[0] = (dq >= 0) ? 0x20 : (short)(unsigned short)0xFC20;
429 } else {
430 exp = log2plus1(mag);
431 state_ptr->dq[0] = (dq >= 0) ?
432 (exp << 6) + ((mag << 6) >> exp) :
433 (exp << 6) + ((mag << 6) >> exp) - 0x400;
434 }
435
436 state_ptr->sr[1] = state_ptr->sr[0];
437 /* FLOAT B : convert sr to 4-bit exp., 6-bit mantissa f.p. */
438 if (sr == 0) {
439 state_ptr->sr[0] = 0x20;
440 } else if (sr > 0) {
441 exp = log2plus1(sr);
442 state_ptr->sr[0] = (exp << 6) + ((sr << 6) >> exp);
443 } else if (sr > -32768) {
444 mag = -sr;
445 exp = log2plus1(mag);
446 state_ptr->sr[0] = (exp << 6) + ((mag << 6) >> exp) - 0x400;
447 } else
448 state_ptr->sr[0] = (short)(unsigned short)0xFC20;
449
450 /* DELAY A */
451 state_ptr->pk[1] = state_ptr->pk[0];
452 state_ptr->pk[0] = pk0;
453
454 /* TONE */
455 if (tr == 1) /* this sample has been treated as data */
456 state_ptr->td = 0; /* next one will be treated as voice */
457 else if (a2p < -11776) /* small sample-to-sample correlation */
458 state_ptr->td = 1; /* signal may be data */
459 else /* signal is voice */
460 state_ptr->td = 0;
461
462 /*
463 * Adaptation speed control.
464 */
465 state_ptr->dms += (fi - state_ptr->dms) >> 5; /* FILTA */
466 state_ptr->dml += (((fi << 2) - state_ptr->dml) >> 7); /* FILTB */
467
468 if (tr == 1)
469 state_ptr->ap = 256;
470 else if (y < 1536) /* SUBTC */
471 state_ptr->ap += (0x200 - state_ptr->ap) >> 4;
472 else if (state_ptr->td == 1)
473 state_ptr->ap += (0x200 - state_ptr->ap) >> 4;
474 else if (abs((state_ptr->dms << 2) - state_ptr->dml) >=
475 (state_ptr->dml >> 3))
476 state_ptr->ap += (0x200 - state_ptr->ap) >> 4;
477 else
478 state_ptr->ap += (-state_ptr->ap) >> 4;
479 }
480
481 /*
482 * tandem_adjust(sr, se, y, i, sign)
483 *
484 * At the end of ADPCM decoding, it simulates an encoder which may be receiving
485 * the output of this decoder as a tandem process. If the output of the
486 * simulated encoder differs from the input to this decoder, the decoder output
487 * is adjusted by one level of A-law or u-law codes.
488 *
489 * Input:
490 * sr decoder output linear PCM sample,
491 * se predictor estimate sample,
492 * y quantizer step size,
493 * i decoder input code,
494 * sign sign bit of code i
495 *
496 * Return:
497 * adjusted A-law or u-law compressed sample.
498 */
tandem_adjust_alaw(int sr,int se,int y,int i,int sign,short const * qtab)499 int tandem_adjust_alaw(int sr, int se, int y, int i, int sign, short const *qtab)
500 {
501 unsigned char sp; /* A-law compressed 8-bit code */
502 short dx; /* prediction error */
503 char id; /* quantized prediction error */
504 int sd; /* adjusted A-law decoded sample value */
505 int im; /* biased magnitude of i */
506 int imx; /* biased magnitude of id */
507
508 if (sr <= -32768)
509 sr = -1;
510 sp = sox_13linear2alaw(((sr >> 1) << 3));/* short to A-law compression */
511 dx = (sox_alaw2linear16(sp) >> 2) - se; /* 16-bit prediction error */
512 id = quantize(dx, y, qtab, sign - 1);
513
514 if (id == i) { /* no adjustment on sp */
515 return (sp);
516 } else { /* sp adjustment needed */
517 /* ADPCM codes : 8, 9, ... F, 0, 1, ... , 6, 7 */
518 im = i ^ sign; /* 2's complement to biased unsigned */
519 imx = id ^ sign;
520
521 if (imx > im) { /* sp adjusted to next lower value */
522 if (sp & 0x80) {
523 sd = (sp == 0xD5) ? 0x55 :
524 ((sp ^ 0x55) - 1) ^ 0x55;
525 } else {
526 sd = (sp == 0x2A) ? 0x2A :
527 ((sp ^ 0x55) + 1) ^ 0x55;
528 }
529 } else { /* sp adjusted to next higher value */
530 if (sp & 0x80)
531 sd = (sp == 0xAA) ? 0xAA :
532 ((sp ^ 0x55) + 1) ^ 0x55;
533 else
534 sd = (sp == 0x55) ? 0xD5 :
535 ((sp ^ 0x55) - 1) ^ 0x55;
536 }
537 return (sd);
538 }
539 }
540
tandem_adjust_ulaw(int sr,int se,int y,int i,int sign,short const * qtab)541 int tandem_adjust_ulaw(int sr, int se, int y, int i, int sign, short const *qtab)
542 {
543 unsigned char sp; /* u-law compressed 8-bit code */
544 short dx; /* prediction error */
545 char id; /* quantized prediction error */
546 int sd; /* adjusted u-law decoded sample value */
547 int im; /* biased magnitude of i */
548 int imx; /* biased magnitude of id */
549
550 if (sr <= -32768)
551 sr = 0;
552 sp = sox_14linear2ulaw((sr << 2));/* short to u-law compression */
553 dx = (sox_ulaw2linear16(sp) >> 2) - se; /* 16-bit prediction error */
554 id = quantize(dx, y, qtab, sign - 1);
555 if (id == i) {
556 return (sp);
557 } else {
558 /* ADPCM codes : 8, 9, ... F, 0, 1, ... , 6, 7 */
559 im = i ^ sign; /* 2's complement to biased unsigned */
560 imx = id ^ sign;
561 if (imx > im) { /* sp adjusted to next lower value */
562 if (sp & 0x80)
563 sd = (sp == 0xFF) ? 0x7E : sp + 1;
564 else
565 sd = (sp == 0) ? 0 : sp - 1;
566
567 } else { /* sp adjusted to next higher value */
568 if (sp & 0x80)
569 sd = (sp == 0x80) ? 0x80 : sp - 1;
570 else
571 sd = (sp == 0x7F) ? 0xFE : sp + 1;
572 }
573 return (sd);
574 }
575 }
576