1 /*
2 * exp golomb vlc stuff
3 * Copyright (c) 2003 Michael Niedermayer <michaelni@gmx.at>
4 * Copyright (c) 2004 Alex Beregszaszi
5 *
6 * This file is part of FFmpeg.
7 *
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
12 *
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
17 *
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
21 */
22
23 /**
24 * @file
25 * @brief
26 * exp golomb vlc stuff
27 * @author Michael Niedermayer <michaelni@gmx.at> and Alex Beregszaszi
28 */
29
30 #ifndef AVCODEC_GOLOMB_H
31 #define AVCODEC_GOLOMB_H
32
33 #include <stdint.h>
34
35 #include "get_bits.h"
36
37 #define INVALID_VLC 0x80000000
38
39 extern const uint8_t ff_golomb_vlc_len[512];
40 extern const uint8_t ff_ue_golomb_vlc_code[512];
41 extern const int8_t ff_se_golomb_vlc_code[512];
42
43 extern const uint8_t ff_interleaved_golomb_vlc_len[256];
44 extern const uint8_t ff_interleaved_ue_golomb_vlc_code[256];
45 extern const int8_t ff_interleaved_se_golomb_vlc_code[256];
46 extern const uint8_t ff_interleaved_dirac_golomb_vlc_code[256];
47
48 /**
49 * Read an unsigned Exp-Golomb code in the range 0 to 8190.
50 *
51 * @returns the read value or a negative error code.
52 */
get_ue_golomb(GetBitContext * gb)53 static inline int get_ue_golomb(GetBitContext *gb)
54 {
55 unsigned int buf;
56
57 #if CACHED_BITSTREAM_READER
58 buf = show_bits_long(gb, 32);
59
60 if (buf >= (1 << 27)) {
61 buf >>= 32 - 9;
62 skip_bits_long(gb, ff_golomb_vlc_len[buf]);
63
64 return ff_ue_golomb_vlc_code[buf];
65 } else {
66 int log = 2 * av_log2(buf) - 31;
67
68 skip_bits_long(gb, 32 - log);
69 if (log < 7)
70 return AVERROR_INVALIDDATA;
71 buf >>= log;
72 buf--;
73
74 return buf;
75 }
76 #else
77 OPEN_READER(re, gb);
78 UPDATE_CACHE(re, gb);
79 buf = GET_CACHE(re, gb);
80
81 if (buf >= (1 << 27)) {
82 buf >>= 32 - 9;
83 LAST_SKIP_BITS(re, gb, ff_golomb_vlc_len[buf]);
84 CLOSE_READER(re, gb);
85
86 return ff_ue_golomb_vlc_code[buf];
87 } else {
88 int log = 2 * av_log2(buf) - 31;
89 LAST_SKIP_BITS(re, gb, 32 - log);
90 CLOSE_READER(re, gb);
91 if (log < 7)
92 return AVERROR_INVALIDDATA;
93 buf >>= log;
94 buf--;
95
96 return buf;
97 }
98 #endif
99 }
100
101 /**
102 * Read an unsigned Exp-Golomb code in the range 0 to UINT32_MAX-1.
103 */
get_ue_golomb_long(GetBitContext * gb)104 static inline unsigned get_ue_golomb_long(GetBitContext *gb)
105 {
106 unsigned buf, log;
107
108 buf = show_bits_long(gb, 32);
109 log = 31 - av_log2(buf);
110 skip_bits_long(gb, log);
111
112 return get_bits_long(gb, log + 1) - 1;
113 }
114
115 /**
116 * read unsigned exp golomb code, constraint to a max of 31.
117 * If the value encountered is not in 0..31, the return value
118 * is outside the range 0..30.
119 */
get_ue_golomb_31(GetBitContext * gb)120 static inline int get_ue_golomb_31(GetBitContext *gb)
121 {
122 unsigned int buf;
123
124 #if CACHED_BITSTREAM_READER
125 buf = show_bits_long(gb, 32);
126
127 buf >>= 32 - 9;
128 skip_bits_long(gb, ff_golomb_vlc_len[buf]);
129 #else
130
131 OPEN_READER(re, gb);
132 UPDATE_CACHE(re, gb);
133 buf = GET_CACHE(re, gb);
134
135 buf >>= 32 - 9;
136 LAST_SKIP_BITS(re, gb, ff_golomb_vlc_len[buf]);
137 CLOSE_READER(re, gb);
138 #endif
139
140 return ff_ue_golomb_vlc_code[buf];
141 }
142
get_interleaved_ue_golomb(GetBitContext * gb)143 static inline unsigned get_interleaved_ue_golomb(GetBitContext *gb)
144 {
145 uint32_t buf;
146
147 #if CACHED_BITSTREAM_READER
148 buf = show_bits_long(gb, 32);
149
150 if (buf & 0xAA800000) {
151 buf >>= 32 - 8;
152 skip_bits_long(gb, ff_interleaved_golomb_vlc_len[buf]);
153
154 return ff_interleaved_ue_golomb_vlc_code[buf];
155 } else {
156 unsigned ret = 1;
157
158 do {
159 buf >>= 32 - 8;
160 skip_bits_long(gb, FFMIN(ff_interleaved_golomb_vlc_len[buf], 8));
161
162 if (ff_interleaved_golomb_vlc_len[buf] != 9) {
163 ret <<= (ff_interleaved_golomb_vlc_len[buf] - 1) >> 1;
164 ret |= ff_interleaved_dirac_golomb_vlc_code[buf];
165 break;
166 }
167 ret = (ret << 4) | ff_interleaved_dirac_golomb_vlc_code[buf];
168 buf = show_bits_long(gb, 32);
169 } while (get_bits_left(gb) > 0);
170
171 return ret - 1;
172 }
173 #else
174 OPEN_READER(re, gb);
175 UPDATE_CACHE(re, gb);
176 buf = GET_CACHE(re, gb);
177
178 if (buf & 0xAA800000) {
179 buf >>= 32 - 8;
180 LAST_SKIP_BITS(re, gb, ff_interleaved_golomb_vlc_len[buf]);
181 CLOSE_READER(re, gb);
182
183 return ff_interleaved_ue_golomb_vlc_code[buf];
184 } else {
185 unsigned ret = 1;
186
187 do {
188 buf >>= 32 - 8;
189 LAST_SKIP_BITS(re, gb,
190 FFMIN(ff_interleaved_golomb_vlc_len[buf], 8));
191
192 if (ff_interleaved_golomb_vlc_len[buf] != 9) {
193 ret <<= (ff_interleaved_golomb_vlc_len[buf] - 1) >> 1;
194 ret |= ff_interleaved_dirac_golomb_vlc_code[buf];
195 break;
196 }
197 ret = (ret << 4) | ff_interleaved_dirac_golomb_vlc_code[buf];
198 UPDATE_CACHE(re, gb);
199 buf = GET_CACHE(re, gb);
200 } while (ret<0x8000000U && BITS_AVAILABLE(re, gb));
201
202 CLOSE_READER(re, gb);
203 return ret - 1;
204 }
205 #endif
206 }
207
208 /**
209 * read unsigned truncated exp golomb code.
210 */
get_te0_golomb(GetBitContext * gb,int range)211 static inline int get_te0_golomb(GetBitContext *gb, int range)
212 {
213 av_assert2(range >= 1);
214
215 if (range == 1)
216 return 0;
217 else if (range == 2)
218 return get_bits1(gb) ^ 1;
219 else
220 return get_ue_golomb(gb);
221 }
222
223 /**
224 * read unsigned truncated exp golomb code.
225 */
get_te_golomb(GetBitContext * gb,int range)226 static inline int get_te_golomb(GetBitContext *gb, int range)
227 {
228 av_assert2(range >= 1);
229
230 if (range == 2)
231 return get_bits1(gb) ^ 1;
232 else
233 return get_ue_golomb(gb);
234 }
235
236 /**
237 * read signed exp golomb code.
238 */
get_se_golomb(GetBitContext * gb)239 static inline int get_se_golomb(GetBitContext *gb)
240 {
241 unsigned int buf;
242
243 #if CACHED_BITSTREAM_READER
244 buf = show_bits_long(gb, 32);
245
246 if (buf >= (1 << 27)) {
247 buf >>= 32 - 9;
248 skip_bits_long(gb, ff_golomb_vlc_len[buf]);
249
250 return ff_se_golomb_vlc_code[buf];
251 } else {
252 int log = 2 * av_log2(buf) - 31;
253 buf >>= log;
254
255 skip_bits_long(gb, 32 - log);
256
257 if (buf & 1)
258 buf = -(buf >> 1);
259 else
260 buf = (buf >> 1);
261
262 return buf;
263 }
264 #else
265 OPEN_READER(re, gb);
266 UPDATE_CACHE(re, gb);
267 buf = GET_CACHE(re, gb);
268
269 if (buf >= (1 << 27)) {
270 buf >>= 32 - 9;
271 LAST_SKIP_BITS(re, gb, ff_golomb_vlc_len[buf]);
272 CLOSE_READER(re, gb);
273
274 return ff_se_golomb_vlc_code[buf];
275 } else {
276 int log = av_log2(buf), sign;
277 LAST_SKIP_BITS(re, gb, 31 - log);
278 UPDATE_CACHE(re, gb);
279 buf = GET_CACHE(re, gb);
280
281 buf >>= log;
282
283 LAST_SKIP_BITS(re, gb, 32 - log);
284 CLOSE_READER(re, gb);
285
286 sign = -(buf & 1);
287 buf = ((buf >> 1) ^ sign) - sign;
288
289 return buf;
290 }
291 #endif
292 }
293
get_se_golomb_long(GetBitContext * gb)294 static inline int get_se_golomb_long(GetBitContext *gb)
295 {
296 unsigned int buf = get_ue_golomb_long(gb);
297 int sign = (buf & 1) - 1;
298 return ((buf >> 1) ^ sign) + 1;
299 }
300
get_interleaved_se_golomb(GetBitContext * gb)301 static inline int get_interleaved_se_golomb(GetBitContext *gb)
302 {
303 unsigned int buf;
304
305 #if CACHED_BITSTREAM_READER
306 buf = show_bits_long(gb, 32);
307
308 if (buf & 0xAA800000) {
309 buf >>= 32 - 8;
310 skip_bits_long(gb, ff_interleaved_golomb_vlc_len[buf]);
311
312 return ff_interleaved_se_golomb_vlc_code[buf];
313 } else {
314 int log;
315 skip_bits(gb, 8);
316 buf |= 1 | show_bits(gb, 24);
317
318 if ((buf & 0xAAAAAAAA) == 0)
319 return INVALID_VLC;
320
321 for (log = 31; (buf & 0x80000000) == 0; log--)
322 buf = (buf << 2) - ((buf << log) >> (log - 1)) + (buf >> 30);
323
324 skip_bits_long(gb, 63 - 2 * log - 8);
325
326 return (signed) (((((buf << log) >> log) - 1) ^ -(buf & 0x1)) + 1) >> 1;
327 }
328 #else
329 OPEN_READER(re, gb);
330 UPDATE_CACHE(re, gb);
331 buf = GET_CACHE(re, gb);
332
333 if (buf & 0xAA800000) {
334 buf >>= 32 - 8;
335 LAST_SKIP_BITS(re, gb, ff_interleaved_golomb_vlc_len[buf]);
336 CLOSE_READER(re, gb);
337
338 return ff_interleaved_se_golomb_vlc_code[buf];
339 } else {
340 int log;
341 LAST_SKIP_BITS(re, gb, 8);
342 UPDATE_CACHE(re, gb);
343 buf |= 1 | (GET_CACHE(re, gb) >> 8);
344
345 if ((buf & 0xAAAAAAAA) == 0)
346 return INVALID_VLC;
347
348 for (log = 31; (buf & 0x80000000) == 0; log--)
349 buf = (buf << 2) - ((buf << log) >> (log - 1)) + (buf >> 30);
350
351 LAST_SKIP_BITS(re, gb, 63 - 2 * log - 8);
352 CLOSE_READER(re, gb);
353
354 return (signed) (((((buf << log) >> log) - 1) ^ -(buf & 0x1)) + 1) >> 1;
355 }
356 #endif
357 }
358
dirac_get_se_golomb(GetBitContext * gb)359 static inline int dirac_get_se_golomb(GetBitContext *gb)
360 {
361 uint32_t ret = get_interleaved_ue_golomb(gb);
362
363 if (ret) {
364 int sign = -get_bits1(gb);
365 ret = (ret ^ sign) - sign;
366 }
367
368 return ret;
369 }
370
371 /**
372 * read unsigned golomb rice code (ffv1).
373 */
get_ur_golomb(GetBitContext * gb,int k,int limit,int esc_len)374 static inline int get_ur_golomb(GetBitContext *gb, int k, int limit,
375 int esc_len)
376 {
377 unsigned int buf;
378 int log;
379
380 #if CACHED_BITSTREAM_READER
381 buf = show_bits_long(gb, 32);
382
383 log = av_log2(buf);
384
385 if (log > 31 - limit) {
386 buf >>= log - k;
387 buf += (30 - log) << k;
388 skip_bits_long(gb, 32 + k - log);
389
390 return buf;
391 } else {
392 skip_bits_long(gb, limit);
393 buf = get_bits_long(gb, esc_len);
394
395 return buf + limit - 1;
396 }
397 #else
398 OPEN_READER(re, gb);
399 UPDATE_CACHE(re, gb);
400 buf = GET_CACHE(re, gb);
401
402 log = av_log2(buf);
403
404 if (log > 31 - limit) {
405 buf >>= log - k;
406 buf += (30U - log) << k;
407 LAST_SKIP_BITS(re, gb, 32 + k - log);
408 CLOSE_READER(re, gb);
409
410 return buf;
411 } else {
412 LAST_SKIP_BITS(re, gb, limit);
413 UPDATE_CACHE(re, gb);
414
415 buf = SHOW_UBITS(re, gb, esc_len);
416
417 LAST_SKIP_BITS(re, gb, esc_len);
418 CLOSE_READER(re, gb);
419
420 return buf + limit - 1;
421 }
422 #endif
423 }
424
425 /**
426 * read unsigned golomb rice code (jpegls).
427 */
get_ur_golomb_jpegls(GetBitContext * gb,int k,int limit,int esc_len)428 static inline int get_ur_golomb_jpegls(GetBitContext *gb, int k, int limit,
429 int esc_len)
430 {
431 unsigned int buf;
432 int log;
433
434 #if CACHED_BITSTREAM_READER
435 buf = show_bits_long(gb, 32);
436
437 log = av_log2(buf);
438
439 if (log - k >= 1 && 32 - log < limit) {
440 buf >>= log - k;
441 buf += (30 - log) << k;
442 skip_bits_long(gb, 32 + k - log);
443
444 return buf;
445 } else {
446 int i;
447 for (i = 0;
448 i < limit && get_bits1(gb) == 0 && get_bits_left(gb) > 0;
449 i++);
450
451 if (i < limit - 1) {
452 buf = get_bits_long(gb, k);
453
454 return buf + (i << k);
455 } else if (i == limit - 1) {
456 buf = get_bits_long(gb, esc_len);
457
458 return buf + 1;
459 } else
460 return -1;
461 }
462 #else
463 OPEN_READER(re, gb);
464 UPDATE_CACHE(re, gb);
465 buf = GET_CACHE(re, gb);
466
467 log = av_log2(buf);
468
469 av_assert2(k <= 31);
470
471 if (log - k >= 32 - MIN_CACHE_BITS + (MIN_CACHE_BITS == 32) &&
472 32 - log < limit) {
473 buf >>= log - k;
474 buf += (30U - log) << k;
475 LAST_SKIP_BITS(re, gb, 32 + k - log);
476 CLOSE_READER(re, gb);
477
478 return buf;
479 } else {
480 int i;
481 for (i = 0; i + MIN_CACHE_BITS <= limit && SHOW_UBITS(re, gb, MIN_CACHE_BITS) == 0; i += MIN_CACHE_BITS) {
482 if (gb->size_in_bits <= re_index) {
483 CLOSE_READER(re, gb);
484 return -1;
485 }
486 LAST_SKIP_BITS(re, gb, MIN_CACHE_BITS);
487 UPDATE_CACHE(re, gb);
488 }
489 for (; i < limit && SHOW_UBITS(re, gb, 1) == 0; i++) {
490 SKIP_BITS(re, gb, 1);
491 }
492 LAST_SKIP_BITS(re, gb, 1);
493 UPDATE_CACHE(re, gb);
494
495 if (i < limit - 1) {
496 if (k) {
497 if (k > MIN_CACHE_BITS - 1) {
498 buf = SHOW_UBITS(re, gb, 16) << (k-16);
499 LAST_SKIP_BITS(re, gb, 16);
500 UPDATE_CACHE(re, gb);
501 buf |= SHOW_UBITS(re, gb, k-16);
502 LAST_SKIP_BITS(re, gb, k-16);
503 } else {
504 buf = SHOW_UBITS(re, gb, k);
505 LAST_SKIP_BITS(re, gb, k);
506 }
507 } else {
508 buf = 0;
509 }
510
511 buf += ((SUINT)i << k);
512 } else if (i == limit - 1) {
513 buf = SHOW_UBITS(re, gb, esc_len);
514 LAST_SKIP_BITS(re, gb, esc_len);
515
516 buf ++;
517 } else {
518 buf = -1;
519 }
520 CLOSE_READER(re, gb);
521 return buf;
522 }
523 #endif
524 }
525
526 /**
527 * read signed golomb rice code (ffv1).
528 */
get_sr_golomb(GetBitContext * gb,int k,int limit,int esc_len)529 static inline int get_sr_golomb(GetBitContext *gb, int k, int limit,
530 int esc_len)
531 {
532 unsigned v = get_ur_golomb(gb, k, limit, esc_len);
533 return (v >> 1) ^ -(v & 1);
534 }
535
536 /**
537 * read signed golomb rice code (flac).
538 */
get_sr_golomb_flac(GetBitContext * gb,int k,int limit,int esc_len)539 static inline int get_sr_golomb_flac(GetBitContext *gb, int k, int limit,
540 int esc_len)
541 {
542 unsigned v = get_ur_golomb_jpegls(gb, k, limit, esc_len);
543 return (v >> 1) ^ -(v & 1);
544 }
545
546 /**
547 * read unsigned golomb rice code (shorten).
548 */
get_ur_golomb_shorten(GetBitContext * gb,int k)549 static inline unsigned int get_ur_golomb_shorten(GetBitContext *gb, int k)
550 {
551 return get_ur_golomb_jpegls(gb, k, INT_MAX, 0);
552 }
553
554 /**
555 * read signed golomb rice code (shorten).
556 */
get_sr_golomb_shorten(GetBitContext * gb,int k)557 static inline int get_sr_golomb_shorten(GetBitContext *gb, int k)
558 {
559 int uvar = get_ur_golomb_jpegls(gb, k + 1, INT_MAX, 0);
560 return (uvar >> 1) ^ -(uvar & 1);
561 }
562
563 #ifdef TRACE
564
get_ue(GetBitContext * s,const char * file,const char * func,int line)565 static inline int get_ue(GetBitContext *s, const char *file, const char *func,
566 int line)
567 {
568 int show = show_bits(s, 24);
569 int pos = get_bits_count(s);
570 int i = get_ue_golomb(s);
571 int len = get_bits_count(s) - pos;
572 int bits = show >> (24 - len);
573
574 av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d ue @%5d in %s %s:%d\n",
575 bits, len, i, pos, file, func, line);
576
577 return i;
578 }
579
get_se(GetBitContext * s,const char * file,const char * func,int line)580 static inline int get_se(GetBitContext *s, const char *file, const char *func,
581 int line)
582 {
583 int show = show_bits(s, 24);
584 int pos = get_bits_count(s);
585 int i = get_se_golomb(s);
586 int len = get_bits_count(s) - pos;
587 int bits = show >> (24 - len);
588
589 av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d se @%5d in %s %s:%d\n",
590 bits, len, i, pos, file, func, line);
591
592 return i;
593 }
594
get_te(GetBitContext * s,int r,char * file,const char * func,int line)595 static inline int get_te(GetBitContext *s, int r, char *file, const char *func,
596 int line)
597 {
598 int show = show_bits(s, 24);
599 int pos = get_bits_count(s);
600 int i = get_te0_golomb(s, r);
601 int len = get_bits_count(s) - pos;
602 int bits = show >> (24 - len);
603
604 av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d te @%5d in %s %s:%d\n",
605 bits, len, i, pos, file, func, line);
606
607 return i;
608 }
609
610 #define get_ue_golomb(a) get_ue(a, __FILE__, __func__, __LINE__)
611 #define get_se_golomb(a) get_se(a, __FILE__, __func__, __LINE__)
612 #define get_te_golomb(a, r) get_te(a, r, __FILE__, __func__, __LINE__)
613 #define get_te0_golomb(a, r) get_te(a, r, __FILE__, __func__, __LINE__)
614
615 #endif /* TRACE */
616 #endif /* AVCODEC_GOLOMB_H */
617