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 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 libavcodec/golomb.h
  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 "bitstream.h"
  35
  36 #define INVALID_VLC           0x80000000
  37
  38 extern const uint8_t ff_golomb_vlc_len[512];
  39 extern const uint8_t ff_ue_golomb_vlc_code[512];
  40 extern const  int8_t ff_se_golomb_vlc_code[512];
  41 extern const uint8_t ff_ue_golomb_len[256];
  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  /**
  50  * read unsigned exp golomb code.
  51  */
  52 static inline int get_ue_golomb(GetBitContext *gb){
  53     unsigned int buf;
  54     int log;
  55
  56     OPEN_READER(re, gb);
  57     UPDATE_CACHE(re, gb);
  58     buf=GET_CACHE(re, gb);
  59
  60     if(buf >= (1<<27)){
  61         buf >>= 32 - 9;
  62         LAST_SKIP_BITS(re, gb, ff_golomb_vlc_len[buf]);
  63         CLOSE_READER(re, gb);
  64
  65         return ff_ue_golomb_vlc_code[buf];
  66     }else{
  67         log= 2*av_log2(buf) - 31;
  68         buf>>= log;
  69         buf--;
  70         LAST_SKIP_BITS(re, gb, 32 - log);
  71         CLOSE_READER(re, gb);
  72
  73         return buf;
  74     }
  75 }
  76
  77  /**
  78  * read unsigned exp golomb code, constraint to a max of 31.
  79  * the return value is undefined if the stored value exceeds 31.
  80  */
  81 static inline int get_ue_golomb_31(GetBitContext *gb){
  82     unsigned int buf;
  83
  84     OPEN_READER(re, gb);
  85     UPDATE_CACHE(re, gb);
  86     buf=GET_CACHE(re, gb);
  87
  88     buf >>= 32 - 9;
  89     LAST_SKIP_BITS(re, gb, ff_golomb_vlc_len[buf]);
  90     CLOSE_READER(re, gb);
  91
  92     return ff_ue_golomb_vlc_code[buf];
  93 }
  94
  95 static inline int svq3_get_ue_golomb(GetBitContext *gb){
  96     uint32_t buf;
  97
  98     OPEN_READER(re, gb);
  99     UPDATE_CACHE(re, gb);
 100     buf=GET_CACHE(re, gb);
 101
 102     if(buf&0xAA800000){
 103         buf >>= 32 - 8;
 104         LAST_SKIP_BITS(re, gb, ff_interleaved_golomb_vlc_len[buf]);
 105         CLOSE_READER(re, gb);
 106
 107         return ff_interleaved_ue_golomb_vlc_code[buf];
 108     }else{
 109         int ret = 1;
 110
 111         while (1) {
 112             buf >>= 32 - 8;
 113             LAST_SKIP_BITS(re, gb, FFMIN(ff_interleaved_golomb_vlc_len[buf], 8));
 114
 115             if (ff_interleaved_golomb_vlc_len[buf] != 9){
 116                 ret <<= (ff_interleaved_golomb_vlc_len[buf] - 1) >> 1;
 117                 ret |= ff_interleaved_dirac_golomb_vlc_code[buf];
 118                 break;
 119             }
 120             ret = (ret << 4) | ff_interleaved_dirac_golomb_vlc_code[buf];
 121             UPDATE_CACHE(re, gb);
 122             buf = GET_CACHE(re, gb);
 123         }
 124
 125         CLOSE_READER(re, gb);
 126         return ret - 1;
 127     }
 128 }
 129
 130 /**
 131  * read unsigned truncated exp golomb code.
 132  */
 133 static inline int get_te0_golomb(GetBitContext *gb, int range){
 134     assert(range >= 1);
 135
 136     if(range==1)      return 0;
 137     else if(range==2) return get_bits1(gb)^1;
 138     else              return get_ue_golomb(gb);
 139 }
 140
 141 /**
 142  * read unsigned truncated exp golomb code.
 143  */
 144 static inline int get_te_golomb(GetBitContext *gb, int range){
 145     assert(range >= 1);
 146
 147     if(range==2) return get_bits1(gb)^1;
 148     else         return get_ue_golomb(gb);
 149 }
 150
 151
 152 /**
 153  * read signed exp golomb code.
 154  */
 155 static inline int get_se_golomb(GetBitContext *gb){
 156     unsigned int buf;
 157     int log;
 158
 159     OPEN_READER(re, gb);
 160     UPDATE_CACHE(re, gb);
 161     buf=GET_CACHE(re, gb);
 162
 163     if(buf >= (1<<27)){
 164         buf >>= 32 - 9;
 165         LAST_SKIP_BITS(re, gb, ff_golomb_vlc_len[buf]);
 166         CLOSE_READER(re, gb);
 167
 168         return ff_se_golomb_vlc_code[buf];
 169     }else{
 170         log= 2*av_log2(buf) - 31;
 171         buf>>= log;
 172
 173         LAST_SKIP_BITS(re, gb, 32 - log);
 174         CLOSE_READER(re, gb);
 175
 176         if(buf&1) buf= -(buf>>1);
 177         else      buf=  (buf>>1);
 178
 179         return buf;
 180     }
 181 }
 182
 183 static inline int svq3_get_se_golomb(GetBitContext *gb){
 184     unsigned int buf;
 185     int log;
 186
 187     OPEN_READER(re, gb);
 188     UPDATE_CACHE(re, gb);
 189     buf=GET_CACHE(re, gb);
 190
 191     if(buf&0xAA800000){
 192         buf >>= 32 - 8;
 193         LAST_SKIP_BITS(re, gb, ff_interleaved_golomb_vlc_len[buf]);
 194         CLOSE_READER(re, gb);
 195
 196         return ff_interleaved_se_golomb_vlc_code[buf];
 197     }else{
 198         LAST_SKIP_BITS(re, gb, 8);
 199         UPDATE_CACHE(re, gb);
 200         buf |= 1 | (GET_CACHE(re, gb) >> 8);
 201
 202         if((buf & 0xAAAAAAAA) == 0)
 203             return INVALID_VLC;
 204
 205         for(log=31; (buf & 0x80000000) == 0; log--){
 206             buf = (buf << 2) - ((buf << log) >> (log - 1)) + (buf >> 30);
 207         }
 208
 209         LAST_SKIP_BITS(re, gb, 63 - 2*log - 8);
 210         CLOSE_READER(re, gb);
 211
 212         return (signed) (((((buf << log) >> log) - 1) ^ -(buf & 0x1)) + 1) >> 1;
 213     }
 214 }
 215
 216 static inline int dirac_get_se_golomb(GetBitContext *gb){
 217     uint32_t buf;
 218     uint32_t ret;
 219
 220     ret = svq3_get_ue_golomb(gb);
 221
 222     if (ret) {
 223         OPEN_READER(re, gb);
 224         UPDATE_CACHE(re, gb);
 225         buf = SHOW_SBITS(re, gb, 1);
 226         LAST_SKIP_BITS(re, gb, 1);
 227         ret = (ret ^ buf) - buf;
 228         CLOSE_READER(re, gb);
 229     }
 230
 231     return ret;
 232 }
 233
 234 /**
 235  * read unsigned golomb rice code (ffv1).
 236  */
 237 static inline int get_ur_golomb(GetBitContext *gb, int k, int limit, int esc_len){
 238     unsigned int buf;
 239     int log;
 240
 241     OPEN_READER(re, gb);
 242     UPDATE_CACHE(re, gb);
 243     buf=GET_CACHE(re, gb);
 244
 245     log= av_log2(buf);
 246
 247     if(log > 31-limit){
 248         buf >>= log - k;
 249         buf += (30-log)<<k;
 250         LAST_SKIP_BITS(re, gb, 32 + k - log);
 251         CLOSE_READER(re, gb);
 252
 253         return buf;
 254     }else{
 255         buf >>= 32 - limit - esc_len;
 256         LAST_SKIP_BITS(re, gb, esc_len + limit);
 257         CLOSE_READER(re, gb);
 258
 259         return buf + limit - 1;
 260     }
 261 }
 262
 263 /**
 264  * read unsigned golomb rice code (jpegls).
 265  */
 266 static inline int get_ur_golomb_jpegls(GetBitContext *gb, int k, int limit, int esc_len){
 267     unsigned int buf;
 268     int log;
 269
 270     OPEN_READER(re, gb);
 271     UPDATE_CACHE(re, gb);
 272     buf=GET_CACHE(re, gb);
 273
 274     log= av_log2(buf);
 275
 276     if(log - k >= 32-MIN_CACHE_BITS+(MIN_CACHE_BITS==32) && 32-log < limit){
 277         buf >>= log - k;
 278         buf += (30-log)<<k;
 279         LAST_SKIP_BITS(re, gb, 32 + k - log);
 280         CLOSE_READER(re, gb);
 281
 282         return buf;
 283     }else{
 284         int i;
 285         for(i=0; SHOW_UBITS(re, gb, 1) == 0; i++){
 286             LAST_SKIP_BITS(re, gb, 1);
 287             UPDATE_CACHE(re, gb);
 288         }
 289         SKIP_BITS(re, gb, 1);
 290
 291         if(i < limit - 1){
 292             if(k){
 293                 buf = SHOW_UBITS(re, gb, k);
 294                 LAST_SKIP_BITS(re, gb, k);
 295             }else{
 296                 buf=0;
 297             }
 298
 299             CLOSE_READER(re, gb);
 300             return buf + (i<<k);
 301         }else if(i == limit - 1){
 302             buf = SHOW_UBITS(re, gb, esc_len);
 303             LAST_SKIP_BITS(re, gb, esc_len);
 304             CLOSE_READER(re, gb);
 305
 306             return buf + 1;
 307         }else
 308             return -1;
 309     }
 310 }
 311
 312 /**
 313  * read signed golomb rice code (ffv1).
 314  */
 315 static inline int get_sr_golomb(GetBitContext *gb, int k, int limit, int esc_len){
 316     int v= get_ur_golomb(gb, k, limit, esc_len);
 317
 318     v++;
 319     if (v&1) return v>>1;
 320     else return -(v>>1);
 321
 322 //    return (v>>1) ^ -(v&1);
 323 }
 324
 325 /**
 326  * read signed golomb rice code (flac).
 327  */
 328 static inline int get_sr_golomb_flac(GetBitContext *gb, int k, int limit, int esc_len){
 329     int v= get_ur_golomb_jpegls(gb, k, limit, esc_len);
 330     return (v>>1) ^ -(v&1);
 331 }
 332
 333 /**
 334  * read unsigned golomb rice code (shorten).
 335  */
 336 static inline unsigned int get_ur_golomb_shorten(GetBitContext *gb, int k){
 337         return get_ur_golomb_jpegls(gb, k, INT_MAX, 0);
 338 }
 339
 340 /**
 341  * read signed golomb rice code (shorten).
 342  */
 343 static inline int get_sr_golomb_shorten(GetBitContext* gb, int k)
 344 {
 345     int uvar = get_ur_golomb_jpegls(gb, k + 1, INT_MAX, 0);
 346     if (uvar & 1)
 347         return ~(uvar >> 1);
 348     else
 349         return uvar >> 1;
 350 }
 351
 352
 353
 354 #ifdef TRACE
 355
 356 static inline int get_ue(GetBitContext *s, char *file, const char *func, int line){
 357     int show= show_bits(s, 24);
 358     int pos= get_bits_count(s);
 359     int i= get_ue_golomb(s);
 360     int len= get_bits_count(s) - pos;
 361     int bits= show>>(24-len);
 362
 363     print_bin(bits, len);
 364
 365     av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d ue  @%5d in %s %s:%d\n", bits, len, i, pos, file, func, line);
 366
 367     return i;
 368 }
 369
 370 static inline int get_se(GetBitContext *s, char *file, const char *func, int line){
 371     int show= show_bits(s, 24);
 372     int pos= get_bits_count(s);
 373     int i= get_se_golomb(s);
 374     int len= get_bits_count(s) - pos;
 375     int bits= show>>(24-len);
 376
 377     print_bin(bits, len);
 378
 379     av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d se  @%5d in %s %s:%d\n", bits, len, i, pos, file, func, line);
 380
 381     return i;
 382 }
 383
 384 static inline int get_te(GetBitContext *s, int r, char *file, const char *func, int line){
 385     int show= show_bits(s, 24);
 386     int pos= get_bits_count(s);
 387     int i= get_te0_golomb(s, r);
 388     int len= get_bits_count(s) - pos;
 389     int bits= show>>(24-len);
 390
 391     print_bin(bits, len);
 392
 393     av_log(NULL, AV_LOG_DEBUG, "%5d %2d %3d te  @%5d in %s %s:%d\n", bits, len, i, pos, file, func, line);
 394
 395     return i;
 396 }
 397
 398 #define get_ue_golomb(a) get_ue(a, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 399 #define get_se_golomb(a) get_se(a, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 400 #define get_te_golomb(a, r) get_te(a, r, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 401 #define get_te0_golomb(a, r) get_te(a, r, __FILE__, __PRETTY_FUNCTION__, __LINE__)
 402
 403 #endif
 404
 405 /**
 406  * write unsigned exp golomb code.
 407  */
 408 static inline void set_ue_golomb(PutBitContext *pb, int i){
 409     int e;
 410
 411     assert(i>=0);
 412
 413 #if 0
 414     if(i=0){
 415         put_bits(pb, 1, 1);
 416         return;
 417     }
 418 #endif
 419     if(i<256)
 420         put_bits(pb, ff_ue_golomb_len[i], i+1);
 421     else{
 422         e= av_log2(i+1);
 423
 424         put_bits(pb, 2*e+1, i+1);
 425     }
 426 }
 427
 428 /**
 429  * write truncated unsigned exp golomb code.
 430  */
 431 static inline void set_te_golomb(PutBitContext *pb, int i, int range){
 432     assert(range >= 1);
 433     assert(i<=range);
 434
 435     if(range==2) put_bits(pb, 1, i^1);
 436     else         set_ue_golomb(pb, i);
 437 }
 438
 439 /**
 440  * write signed exp golomb code. 16 bits at most.
 441  */
 442 static inline void set_se_golomb(PutBitContext *pb, int i){
 443 //    if (i>32767 || i<-32767)
 444 //        av_log(NULL,AV_LOG_ERROR,"value out of range %d\n", i);
 445 #if 0
 446     if(i<=0) i= -2*i;
 447     else     i=  2*i-1;
 448 #elif 1
 449     i= 2*i-1;
 450     if(i<0) i^= -1; //FIXME check if gcc does the right thing
 451 #else
 452     i= 2*i-1;
 453     i^= (i>>31);
 454 #endif
 455     set_ue_golomb(pb, i);
 456 }
 457
 458 /**
 459  * write unsigned golomb rice code (ffv1).
 460  */
 461 static inline void set_ur_golomb(PutBitContext *pb, int i, int k, int limit, int esc_len){
 462     int e;
 463
 464     assert(i>=0);
 465
 466     e= i>>k;
 467     if(e<limit){
 468         put_bits(pb, e + k + 1, (1<<k) + (i&((1<<k)-1)));
 469     }else{
 470         put_bits(pb, limit + esc_len, i - limit + 1);
 471     }
 472 }
 473
 474 /**
 475  * write unsigned golomb rice code (jpegls).
 476  */
 477 static inline void set_ur_golomb_jpegls(PutBitContext *pb, int i, int k, int limit, int esc_len){
 478     int e;
 479
 480     assert(i>=0);
 481
 482     e= (i>>k) + 1;
 483     if(e<limit){
 484         while(e > 31) {
 485             put_bits(pb, 31, 0);
 486             e -= 31;
 487         }
 488         put_bits(pb, e, 1);
 489         if(k)
 490             put_sbits(pb, k, i);
 491     }else{
 492         while(limit > 31) {
 493             put_bits(pb, 31, 0);
 494             limit -= 31;
 495         }
 496         put_bits(pb, limit  , 1);
 497         put_bits(pb, esc_len, i - 1);
 498     }
 499 }
 500
 501 /**
 502  * write signed golomb rice code (ffv1).
 503  */
 504 static inline void set_sr_golomb(PutBitContext *pb, int i, int k, int limit, int esc_len){
 505     int v;
 506
 507     v = -2*i-1;
 508     v ^= (v>>31);
 509
 510     set_ur_golomb(pb, v, k, limit, esc_len);
 511 }
 512
 513 /**
 514  * write signed golomb rice code (flac).
 515  */
 516 static inline void set_sr_golomb_flac(PutBitContext *pb, int i, int k, int limit, int esc_len){
 517     int v;
 518
 519     v = -2*i-1;
 520     v ^= (v>>31);
 521
 522     set_ur_golomb_jpegls(pb, v, k, limit, esc_len);
 523 }
 524
 525 #endif /* AVCODEC_GOLOMB_H */