libavcodec/golomb.h

   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 Libav.
   7  *
   8  * Libav 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  * Libav 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 Libav; 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 #include "get_bits.h"
  35 #include "put_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 extern const uint8_t ff_ue_golomb_len[256];
  43
  44 extern const uint8_t ff_interleaved_golomb_vlc_len[256];
  45 extern const uint8_t ff_interleaved_ue_golomb_vlc_code[256];
  46 extern const  int8_t ff_interleaved_se_golomb_vlc_code[256];
  47 extern const uint8_t ff_interleaved_dirac_golomb_vlc_code[256];
  48
  49
  50  /**
  51  * read unsigned exp golomb code.
  52  */
  53 static inline int get_ue_golomb(GetBitContext *gb){
  54     unsigned int buf;
  55     int log;
  56
  57     OPEN_READER(re, gb);
  58     UPDATE_CACHE(re, gb);
  59     buf=GET_CACHE(re, gb);
  60
  61     if(buf >= (1<<27)){
  62         buf >>= 32 - 9;
  63         LAST_SKIP_BITS(re, gb, ff_golomb_vlc_len[buf]);
  64         CLOSE_READER(re, gb);
  65
  66         return ff_ue_golomb_vlc_code[buf];
  67     }else{
  68         log= 2*av_log2(buf) - 31;
  69         buf>>= log;
  70         buf--;
  71         LAST_SKIP_BITS(re, gb, 32 - log);
  72         CLOSE_READER(re, gb);
  73
  74         return buf;
  75     }
  76 }
  77
  78 /**
  79  * Read an unsigned Exp-Golomb code in the range 0 to UINT32_MAX-1.
  80  */
  81 static inline unsigned get_ue_golomb_long(GetBitContext *gb)
  82 {
  83     unsigned buf, log;
  84
  85     buf = show_bits_long(gb, 32);
  86     log = 31 - av_log2(buf);
  87     skip_bits_long(gb, log);
  88
  89     return get_bits_long(gb, log + 1) - 1;
  90 }
  91
  92  /**
  93  * read unsigned exp golomb code, constraint to a max of 31.
  94  * the return value is undefined if the stored value exceeds 31.
  95  */
  96 static inline int get_ue_golomb_31(GetBitContext *gb){
  97     unsigned int buf;
  98
  99     OPEN_READER(re, gb);
 100     UPDATE_CACHE(re, gb);
 101     buf=GET_CACHE(re, gb);
 102
 103     buf >>= 32 - 9;
 104     LAST_SKIP_BITS(re, gb, ff_golomb_vlc_len[buf]);
 105     CLOSE_READER(re, gb);
 106
 107     return ff_ue_golomb_vlc_code[buf];
 108 }
 109
 110 static inline unsigned svq3_get_ue_golomb(GetBitContext *gb)
 111 {
 112     uint32_t buf;
 113
 114     OPEN_READER(re, gb);
 115     UPDATE_CACHE(re, gb);
 116     buf=GET_CACHE(re, gb);
 117
 118     if(buf&0xAA800000){
 119         buf >>= 32 - 8;
 120         LAST_SKIP_BITS(re, gb, ff_interleaved_golomb_vlc_len[buf]);
 121         CLOSE_READER(re, gb);
 122
 123         return ff_interleaved_ue_golomb_vlc_code[buf];
 124     }else{
 125         unsigned ret = 1;
 126
 127         do {
 128             buf >>= 32 - 8;
 129             LAST_SKIP_BITS(re, gb, FFMIN(ff_interleaved_golomb_vlc_len[buf], 8));
 130
 131             if (ff_interleaved_golomb_vlc_len[buf] != 9){
 132                 ret <<= (ff_interleaved_golomb_vlc_len[buf] - 1) >> 1;
 133                 ret |= ff_interleaved_dirac_golomb_vlc_code[buf];
 134                 break;
 135             }
 136             ret = (ret << 4) | ff_interleaved_dirac_golomb_vlc_code[buf];
 137             UPDATE_CACHE(re, gb);
 138             buf = GET_CACHE(re, gb);
 139         } while (HAVE_BITS_REMAINING(re, gb));
 140
 141         CLOSE_READER(re, gb);
 142         return ret - 1;
 143     }
 144 }
 145
 146 /**
 147  * read unsigned truncated exp golomb code.
 148  */
 149 static inline int get_te0_golomb(GetBitContext *gb, int range){
 150     assert(range >= 1);
 151
 152     if(range==1)      return 0;
 153     else if(range==2) return get_bits1(gb)^1;
 154     else              return get_ue_golomb(gb);
 155 }
 156
 157 /**
 158  * read unsigned truncated exp golomb code.
 159  */
 160 static inline int get_te_golomb(GetBitContext *gb, int range){
 161     assert(range >= 1);
 162
 163     if(range==2) return get_bits1(gb)^1;
 164     else         return get_ue_golomb(gb);
 165 }
 166
 167
 168 /**
 169  * read signed exp golomb code.
 170  */
 171 static inline int get_se_golomb(GetBitContext *gb){
 172     unsigned int buf;
 173     int log;
 174
 175     OPEN_READER(re, gb);
 176     UPDATE_CACHE(re, gb);
 177     buf=GET_CACHE(re, gb);
 178
 179     if(buf >= (1<<27)){
 180         buf >>= 32 - 9;
 181         LAST_SKIP_BITS(re, gb, ff_golomb_vlc_len[buf]);
 182         CLOSE_READER(re, gb);
 183
 184         return ff_se_golomb_vlc_code[buf];
 185     }else{
 186         log= 2*av_log2(buf) - 31;
 187         buf>>= log;
 188
 189         LAST_SKIP_BITS(re, gb, 32 - log);
 190         CLOSE_READER(re, gb);
 191
 192         if(buf&1) buf= -(buf>>1);
 193         else      buf=  (buf>>1);
 194
 195         return buf;
 196     }
 197 }
 198
 199 static inline int svq3_get_se_golomb(GetBitContext *gb){
 200     unsigned int buf;
 201     int log;
 202
 203     OPEN_READER(re, gb);
 204     UPDATE_CACHE(re, gb);
 205     buf=GET_CACHE(re, gb);
 206
 207     if(buf&0xAA800000){
 208         buf >>= 32 - 8;
 209         LAST_SKIP_BITS(re, gb, ff_interleaved_golomb_vlc_len[buf]);
 210         CLOSE_READER(re, gb);
 211
 212         return ff_interleaved_se_golomb_vlc_code[buf];
 213     }else{
 214         LAST_SKIP_BITS(re, gb, 8);
 215         UPDATE_CACHE(re, gb);
 216         buf |= 1 | (GET_CACHE(re, gb) >> 8);
 217
 218         if((buf & 0xAAAAAAAA) == 0)
 219             return INVALID_VLC;
 220
 221         for(log=31; (buf & 0x80000000) == 0; log--){
 222             buf = (buf << 2) - ((buf << log) >> (log - 1)) + (buf >> 30);
 223         }
 224
 225         LAST_SKIP_BITS(re, gb, 63 - 2*log - 8);
 226         CLOSE_READER(re, gb);
 227
 228         return (signed) (((((buf << log) >> log) - 1) ^ -(buf & 0x1)) + 1) >> 1;
 229     }
 230 }
 231
 232 static inline int dirac_get_se_golomb(GetBitContext *gb){
 233     uint32_t buf;
 234     uint32_t ret;
 235
 236     ret = svq3_get_ue_golomb(gb);
 237
 238     if (ret) {
 239         OPEN_READER(re, gb);
 240         UPDATE_CACHE(re, gb);
 241         buf = SHOW_SBITS(re, gb, 1);
 242         LAST_SKIP_BITS(re, gb, 1);
 243         ret = (ret ^ buf) - buf;
 244         CLOSE_READER(re, gb);
 245     }
 246
 247     return ret;
 248 }
 249
 250 /**
 251  * read unsigned golomb rice code (ffv1).
 252  */
 253 static inline int get_ur_golomb(GetBitContext *gb, int k, int limit, int esc_len){
 254     unsigned int buf;
 255     int log;
 256
 257     OPEN_READER(re, gb);
 258     UPDATE_CACHE(re, gb);
 259     buf=GET_CACHE(re, gb);
 260
 261     log= av_log2(buf);
 262
 263     if(log > 31-limit){
 264         buf >>= log - k;
 265         buf += (30-log)<<k;
 266         LAST_SKIP_BITS(re, gb, 32 + k - log);
 267         CLOSE_READER(re, gb);
 268
 269         return buf;
 270     }else{
 271         LAST_SKIP_BITS(re, gb, limit);
 272         UPDATE_CACHE(re, gb);
 273
 274         buf = SHOW_UBITS(re, gb, esc_len);
 275
 276         LAST_SKIP_BITS(re, gb, esc_len);
 277         CLOSE_READER(re, gb);
 278
 279         return buf + limit - 1;
 280     }
 281 }
 282
 283 /**
 284  * read unsigned golomb rice code (jpegls).
 285  */
 286 static inline int get_ur_golomb_jpegls(GetBitContext *gb, int k, int limit, int esc_len){
 287     unsigned int buf;
 288     int log;
 289
 290     OPEN_READER(re, gb);
 291     UPDATE_CACHE(re, gb);
 292     buf=GET_CACHE(re, gb);
 293
 294     log= av_log2(buf);
 295
 296     if(log - k >= 32-MIN_CACHE_BITS+(MIN_CACHE_BITS==32) && 32-log < limit){
 297         buf >>= log - k;
 298         buf += (30-log)<<k;
 299         LAST_SKIP_BITS(re, gb, 32 + k - log);
 300         CLOSE_READER(re, gb);
 301
 302         return buf;
 303     }else{
 304         int i;
 305         for (i = 0; i < limit && SHOW_UBITS(re, gb, 1) == 0 && HAVE_BITS_REMAINING(re, gb); i++) {
 306             LAST_SKIP_BITS(re, gb, 1);
 307             UPDATE_CACHE(re, gb);
 308         }
 309         SKIP_BITS(re, gb, 1);
 310
 311         if(i < limit - 1){
 312             if(k){
 313                 buf = SHOW_UBITS(re, gb, k);
 314                 LAST_SKIP_BITS(re, gb, k);
 315             }else{
 316                 buf=0;
 317             }
 318
 319             CLOSE_READER(re, gb);
 320             return buf + (i<<k);
 321         }else if(i == limit - 1){
 322             buf = SHOW_UBITS(re, gb, esc_len);
 323             LAST_SKIP_BITS(re, gb, esc_len);
 324             CLOSE_READER(re, gb);
 325
 326             return buf + 1;
 327         }else
 328             return -1;
 329     }
 330 }
 331
 332 /**
 333  * read signed golomb rice code (ffv1).
 334  */
 335 static inline int get_sr_golomb(GetBitContext *gb, int k, int limit, int esc_len){
 336     int v= get_ur_golomb(gb, k, limit, esc_len);
 337
 338     v++;
 339     if (v&1) return v>>1;
 340     else return -(v>>1);
 341
 342 //    return (v>>1) ^ -(v&1);
 343 }
 344
 345 /**
 346  * read signed golomb rice code (flac).
 347  */
 348 static inline int get_sr_golomb_flac(GetBitContext *gb, int k, int limit, int esc_len){
 349     int v= get_ur_golomb_jpegls(gb, k, limit, esc_len);
 350     return (v>>1) ^ -(v&1);
 351 }
 352
 353 /**
 354  * read unsigned golomb rice code (shorten).
 355  */
 356 static inline unsigned int get_ur_golomb_shorten(GetBitContext *gb, int k){
 357         return get_ur_golomb_jpegls(gb, k, INT_MAX, 0);
 358 }
 359
 360 /**
 361  * read signed golomb rice code (shorten).
 362  */
 363 static inline int get_sr_golomb_shorten(GetBitContext* gb, int k)
 364 {
 365     int uvar = get_ur_golomb_jpegls(gb, k + 1, INT_MAX, 0);
 366     if (uvar & 1)
 367         return ~(uvar >> 1);
 368     else
 369         return uvar >> 1;
 370 }
 371
 372
 373
 374 #ifdef TRACE
 375
 376 static inline int get_ue(GetBitContext *s, const char *file, const char *func,
 377                          int line)
 378 {
 379     int show= show_bits(s, 24);
 380     int pos= get_bits_count(s);
 381     int i= get_ue_golomb(s);
 382     int len= get_bits_count(s) - pos;
 383     int bits= show>>(24-len);
 384
 385     print_bin(bits, len);
 386
 387     av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d ue  @%5d in %s %s:%d\n", bits, len, i, pos, file, func, line);
 388
 389     return i;
 390 }
 391
 392 static inline int get_se(GetBitContext *s, const char *file, const char *func,
 393                          int line)
 394 {
 395     int show= show_bits(s, 24);
 396     int pos= get_bits_count(s);
 397     int i= get_se_golomb(s);
 398     int len= get_bits_count(s) - pos;
 399     int bits= show>>(24-len);
 400
 401     print_bin(bits, len);
 402
 403     av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d se  @%5d in %s %s:%d\n", bits, len, i, pos, file, func, line);
 404
 405     return i;
 406 }
 407
 408 static inline int get_te(GetBitContext *s, int r, char *file, const char *func, int line){
 409     int show= show_bits(s, 24);
 410     int pos= get_bits_count(s);
 411     int i= get_te0_golomb(s, r);
 412     int len= get_bits_count(s) - pos;
 413     int bits= show>>(24-len);
 414
 415     print_bin(bits, len);
 416
 417     av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d te  @%5d in %s %s:%d\n", bits, len, i, pos, file, func, line);
 418
 419     return i;
 420 }
 421
 422 #define get_ue_golomb(a) get_ue(a, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 423 #define get_se_golomb(a) get_se(a, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 424 #define get_te_golomb(a, r) get_te(a, r, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 425 #define get_te0_golomb(a, r) get_te(a, r, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 426
 427 #endif
 428
 429 /**
 430  * write unsigned exp golomb code.
 431  */
 432 static inline void set_ue_golomb(PutBitContext *pb, int i){
 433     int e;
 434
 435     assert(i>=0);
 436
 437 #if 0
 438     if(i=0){
 439         put_bits(pb, 1, 1);
 440         return;
 441     }
 442 #endif
 443     if(i<256)
 444         put_bits(pb, ff_ue_golomb_len[i], i+1);
 445     else{
 446         e= av_log2(i+1);
 447
 448         put_bits(pb, 2*e+1, i+1);
 449     }
 450 }
 451
 452 /**
 453  * write truncated unsigned exp golomb code.
 454  */
 455 static inline void set_te_golomb(PutBitContext *pb, int i, int range){
 456     assert(range >= 1);
 457     assert(i<=range);
 458
 459     if(range==2) put_bits(pb, 1, i^1);
 460     else         set_ue_golomb(pb, i);
 461 }
 462
 463 /**
 464  * write signed exp golomb code. 16 bits at most.
 465  */
 466 static inline void set_se_golomb(PutBitContext *pb, int i){
 467 #if 0
 468     if(i<=0) i= -2*i;
 469     else     i=  2*i-1;
 470 #elif 1
 471     i= 2*i-1;
 472     if(i<0) i^= -1; //FIXME check if gcc does the right thing
 473 #else
 474     i= 2*i-1;
 475     i^= (i>>31);
 476 #endif
 477     set_ue_golomb(pb, i);
 478 }
 479
 480 /**
 481  * write unsigned golomb rice code (ffv1).
 482  */
 483 static inline void set_ur_golomb(PutBitContext *pb, int i, int k, int limit, int esc_len){
 484     int e;
 485
 486     assert(i>=0);
 487
 488     e= i>>k;
 489     if(e<limit){
 490         put_bits(pb, e + k + 1, (1<<k) + (i&((1<<k)-1)));
 491     }else{
 492         put_bits(pb, limit + esc_len, i - limit + 1);
 493     }
 494 }
 495
 496 /**
 497  * write unsigned golomb rice code (jpegls).
 498  */
 499 static inline void set_ur_golomb_jpegls(PutBitContext *pb, int i, int k, int limit, int esc_len){
 500     int e;
 501
 502     assert(i>=0);
 503
 504     e= (i>>k) + 1;
 505     if(e<limit){
 506         while(e > 31) {
 507             put_bits(pb, 31, 0);
 508             e -= 31;
 509         }
 510         put_bits(pb, e, 1);
 511         if(k)
 512             put_sbits(pb, k, i);
 513     }else{
 514         while(limit > 31) {
 515             put_bits(pb, 31, 0);
 516             limit -= 31;
 517         }
 518         put_bits(pb, limit  , 1);
 519         put_bits(pb, esc_len, i - 1);
 520     }
 521 }
 522
 523 /**
 524  * write signed golomb rice code (ffv1).
 525  */
 526 static inline void set_sr_golomb(PutBitContext *pb, int i, int k, int limit, int esc_len){
 527     int v;
 528
 529     v = -2*i-1;
 530     v ^= (v>>31);
 531
 532     set_ur_golomb(pb, v, k, limit, esc_len);
 533 }
 534
 535 /**
 536  * write signed golomb rice code (flac).
 537  */
 538 static inline void set_sr_golomb_flac(PutBitContext *pb, int i, int k, int limit, int esc_len){
 539     int v;
 540
 541     v = -2*i-1;
 542     v ^= (v>>31);
 543
 544     set_ur_golomb_jpegls(pb, v, k, limit, esc_len);
 545 }
 546
 547 #endif /* AVCODEC_GOLOMB_H */