libavcodec/svq1dec.c

   1 /*
   2  * SVQ1 decoder
   3  * ported to MPlayer by Arpi <arpi@thot.banki.hu>
   4  * ported to libavcodec by Nick Kurshev <nickols_k@mail.ru>
   5  *
   6  * Copyright (C) 2002 the xine project
   7  * Copyright (C) 2002 the ffmpeg project
   8  *
   9  * SVQ1 Encoder (c) 2004 Mike Melanson <melanson@pcisys.net>
  10  *
  11  * This file is part of Libav.
  12  *
  13  * Libav is free software; you can redistribute it and/or
  14  * modify it under the terms of the GNU Lesser General Public
  15  * License as published by the Free Software Foundation; either
  16  * version 2.1 of the License, or (at your option) any later version.
  17  *
  18  * Libav is distributed in the hope that it will be useful,
  19  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  20  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  21  * Lesser General Public License for more details.
  22  *
  23  * You should have received a copy of the GNU Lesser General Public
  24  * License along with Libav; if not, write to the Free Software
  25  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  26  */
  27
  28 /**
  29  * @file
  30  * Sorenson Vector Quantizer #1 (SVQ1) video codec.
  31  * For more information of the SVQ1 algorithm, visit:
  32  *   http://www.pcisys.net/~melanson/codecs/
  33  */
  34
  35 #include "avcodec.h"
  36 #include "dsputil.h"
  37 #include "get_bits.h"
  38 #include "internal.h"
  39 #include "mathops.h"
  40 #include "svq1.h"
  41
  42 #undef NDEBUG
  43 #include <assert.h>
  44
  45 extern const uint8_t ff_mvtab[33][2];
  46
  47 static VLC svq1_block_type;
  48 static VLC svq1_motion_component;
  49 static VLC svq1_intra_multistage[6];
  50 static VLC svq1_inter_multistage[6];
  51 static VLC svq1_intra_mean;
  52 static VLC svq1_inter_mean;
  53
  54 /* motion vector (prediction) */
  55 typedef struct svq1_pmv_s {
  56     int x;
  57     int y;
  58 } svq1_pmv;
  59
  60 typedef struct SVQ1Context {
  61     DSPContext dsp;
  62     GetBitContext gb;
  63     AVFrame *cur, *prev;
  64     int width;
  65     int height;
  66     int frame_code;
  67     int nonref;         // 1 if the current frame won't be referenced
  68 } SVQ1Context;
  69
  70 static const uint8_t string_table[256] = {
  71     0x00, 0xD5, 0x7F, 0xAA, 0xFE, 0x2B, 0x81, 0x54,
  72     0x29, 0xFC, 0x56, 0x83, 0xD7, 0x02, 0xA8, 0x7D,
  73     0x52, 0x87, 0x2D, 0xF8, 0xAC, 0x79, 0xD3, 0x06,
  74     0x7B, 0xAE, 0x04, 0xD1, 0x85, 0x50, 0xFA, 0x2F,
  75     0xA4, 0x71, 0xDB, 0x0E, 0x5A, 0x8F, 0x25, 0xF0,
  76     0x8D, 0x58, 0xF2, 0x27, 0x73, 0xA6, 0x0C, 0xD9,
  77     0xF6, 0x23, 0x89, 0x5C, 0x08, 0xDD, 0x77, 0xA2,
  78     0xDF, 0x0A, 0xA0, 0x75, 0x21, 0xF4, 0x5E, 0x8B,
  79     0x9D, 0x48, 0xE2, 0x37, 0x63, 0xB6, 0x1C, 0xC9,
  80     0xB4, 0x61, 0xCB, 0x1E, 0x4A, 0x9F, 0x35, 0xE0,
  81     0xCF, 0x1A, 0xB0, 0x65, 0x31, 0xE4, 0x4E, 0x9B,
  82     0xE6, 0x33, 0x99, 0x4C, 0x18, 0xCD, 0x67, 0xB2,
  83     0x39, 0xEC, 0x46, 0x93, 0xC7, 0x12, 0xB8, 0x6D,
  84     0x10, 0xC5, 0x6F, 0xBA, 0xEE, 0x3B, 0x91, 0x44,
  85     0x6B, 0xBE, 0x14, 0xC1, 0x95, 0x40, 0xEA, 0x3F,
  86     0x42, 0x97, 0x3D, 0xE8, 0xBC, 0x69, 0xC3, 0x16,
  87     0xEF, 0x3A, 0x90, 0x45, 0x11, 0xC4, 0x6E, 0xBB,
  88     0xC6, 0x13, 0xB9, 0x6C, 0x38, 0xED, 0x47, 0x92,
  89     0xBD, 0x68, 0xC2, 0x17, 0x43, 0x96, 0x3C, 0xE9,
  90     0x94, 0x41, 0xEB, 0x3E, 0x6A, 0xBF, 0x15, 0xC0,
  91     0x4B, 0x9E, 0x34, 0xE1, 0xB5, 0x60, 0xCA, 0x1F,
  92     0x62, 0xB7, 0x1D, 0xC8, 0x9C, 0x49, 0xE3, 0x36,
  93     0x19, 0xCC, 0x66, 0xB3, 0xE7, 0x32, 0x98, 0x4D,
  94     0x30, 0xE5, 0x4F, 0x9A, 0xCE, 0x1B, 0xB1, 0x64,
  95     0x72, 0xA7, 0x0D, 0xD8, 0x8C, 0x59, 0xF3, 0x26,
  96     0x5B, 0x8E, 0x24, 0xF1, 0xA5, 0x70, 0xDA, 0x0F,
  97     0x20, 0xF5, 0x5F, 0x8A, 0xDE, 0x0B, 0xA1, 0x74,
  98     0x09, 0xDC, 0x76, 0xA3, 0xF7, 0x22, 0x88, 0x5D,
  99     0xD6, 0x03, 0xA9, 0x7C, 0x28, 0xFD, 0x57, 0x82,
 100     0xFF, 0x2A, 0x80, 0x55, 0x01, 0xD4, 0x7E, 0xAB,
 101     0x84, 0x51, 0xFB, 0x2E, 0x7A, 0xAF, 0x05, 0xD0,
 102     0xAD, 0x78, 0xD2, 0x07, 0x53, 0x86, 0x2C, 0xF9
 103 };
 104
 105 #define SVQ1_PROCESS_VECTOR()                                           \
 106     for (; level > 0; i++) {                                            \
 107         /* process next depth */                                        \
 108         if (i == m) {                                                   \
 109             m = n;                                                      \
 110             if (--level == 0)                                           \
 111                 break;                                                  \
 112         }                                                               \
 113         /* divide block if next bit set */                              \
 114         if (get_bits1(bitbuf) == 0)                                     \
 115             break;                                                      \
 116         /* add child nodes */                                           \
 117         list[n++] = list[i];                                            \
 118         list[n++] = list[i] +                                           \
 119                     (((level & 1) ? pitch : 1) << (level / 2 + 1));     \
 120     }
 121
 122 #define SVQ1_ADD_CODEBOOK()                                             \
 123     /* add codebook entries to vector */                                \
 124     for (j = 0; j < stages; j++) {                                      \
 125         n3  = codebook[entries[j]] ^ 0x80808080;                        \
 126         n1 += (n3 & 0xFF00FF00) >> 8;                                   \
 127         n2 +=  n3 & 0x00FF00FF;                                         \
 128     }                                                                   \
 129                                                                         \
 130     /* clip to [0..255] */                                              \
 131     if (n1 & 0xFF00FF00) {                                              \
 132         n3  = (n1 >> 15  & 0x00010001 | 0x01000100) - 0x00010001;       \
 133         n1 += 0x7F007F00;                                               \
 134         n1 |= (~n1 >> 15 & 0x00010001 | 0x01000100) - 0x00010001;       \
 135         n1 &= n3 & 0x00FF00FF;                                          \
 136     }                                                                   \
 137                                                                         \
 138     if (n2 & 0xFF00FF00) {                                              \
 139         n3  = (n2 >> 15  & 0x00010001 | 0x01000100) - 0x00010001;       \
 140         n2 += 0x7F007F00;                                               \
 141         n2 |= (~n2 >> 15 & 0x00010001 | 0x01000100) - 0x00010001;       \
 142         n2 &= n3 & 0x00FF00FF;                                          \
 143     }
 144
 145 #define SVQ1_CALC_CODEBOOK_ENTRIES(cbook)                               \
 146     codebook = (const uint32_t *)cbook[level];                          \
 147     if (stages > 0)                                                     \
 148         bit_cache = get_bits(bitbuf, 4 * stages);                       \
 149     /* calculate codebook entries for this vector */                    \
 150     for (j = 0; j < stages; j++) {                                      \
 151         entries[j] = (((bit_cache >> (4 * (stages - j - 1))) & 0xF) +   \
 152                       16 * j) << (level + 1);                           \
 153     }                                                                   \
 154     mean -= stages * 128;                                               \
 155     n4    = mean + (mean >> 31) << 16 | (mean & 0xFFFF);
 156
 157 static int svq1_decode_block_intra(GetBitContext *bitbuf, uint8_t *pixels,
 158                                    int pitch)
 159 {
 160     uint32_t bit_cache;
 161     uint8_t *list[63];
 162     uint32_t *dst;
 163     const uint32_t *codebook;
 164     int entries[6];
 165     int i, j, m, n;
 166     int mean, stages;
 167     unsigned x, y, width, height, level;
 168     uint32_t n1, n2, n3, n4;
 169
 170     /* initialize list for breadth first processing of vectors */
 171     list[0] = pixels;
 172
 173     /* recursively process vector */
 174     for (i = 0, m = 1, n = 1, level = 5; i < n; i++) {
 175         SVQ1_PROCESS_VECTOR();
 176
 177         /* destination address and vector size */
 178         dst    = (uint32_t *)list[i];
 179         width  = 1 << ((4 + level) / 2);
 180         height = 1 << ((3 + level) / 2);
 181
 182         /* get number of stages (-1 skips vector, 0 for mean only) */
 183         stages = get_vlc2(bitbuf, svq1_intra_multistage[level].table, 3, 3) - 1;
 184
 185         if (stages == -1) {
 186             for (y = 0; y < height; y++)
 187                 memset(&dst[y * (pitch / 4)], 0, width);
 188             continue;   /* skip vector */
 189         }
 190
 191         if (stages > 0 && level >= 4) {
 192             av_dlog(NULL,
 193                     "Error (svq1_decode_block_intra): invalid vector: stages=%i level=%i\n",
 194                     stages, level);
 195             return AVERROR_INVALIDDATA;  /* invalid vector */
 196         }
 197
 198         mean = get_vlc2(bitbuf, svq1_intra_mean.table, 8, 3);
 199
 200         if (stages == 0) {
 201             for (y = 0; y < height; y++)
 202                 memset(&dst[y * (pitch / 4)], mean, width);
 203         } else {
 204             SVQ1_CALC_CODEBOOK_ENTRIES(ff_svq1_intra_codebooks);
 205
 206             for (y = 0; y < height; y++) {
 207                 for (x = 0; x < width / 4; x++, codebook++) {
 208                     n1 = n4;
 209                     n2 = n4;
 210                     SVQ1_ADD_CODEBOOK()
 211                     /* store result */
 212                     dst[x] = n1 << 8 | n2;
 213                 }
 214                 dst += pitch / 4;
 215             }
 216         }
 217     }
 218
 219     return 0;
 220 }
 221
 222 static int svq1_decode_block_non_intra(GetBitContext *bitbuf, uint8_t *pixels,
 223                                        int pitch)
 224 {
 225     uint32_t bit_cache;
 226     uint8_t *list[63];
 227     uint32_t *dst;
 228     const uint32_t *codebook;
 229     int entries[6];
 230     int i, j, m, n;
 231     int mean, stages;
 232     int x, y, width, height, level;
 233     uint32_t n1, n2, n3, n4;
 234
 235     /* initialize list for breadth first processing of vectors */
 236     list[0] = pixels;
 237
 238     /* recursively process vector */
 239     for (i = 0, m = 1, n = 1, level = 5; i < n; i++) {
 240         SVQ1_PROCESS_VECTOR();
 241
 242         /* destination address and vector size */
 243         dst    = (uint32_t *)list[i];
 244         width  = 1 << ((4 + level) / 2);
 245         height = 1 << ((3 + level) / 2);
 246
 247         /* get number of stages (-1 skips vector, 0 for mean only) */
 248         stages = get_vlc2(bitbuf, svq1_inter_multistage[level].table, 3, 2) - 1;
 249
 250         if (stages == -1)
 251             continue;           /* skip vector */
 252
 253         if ((stages > 0) && (level >= 4)) {
 254             av_dlog(NULL,
 255                     "Error (svq1_decode_block_non_intra): invalid vector: stages=%i level=%i\n",
 256                     stages, level);
 257             return AVERROR_INVALIDDATA;  /* invalid vector */
 258         }
 259
 260         mean = get_vlc2(bitbuf, svq1_inter_mean.table, 9, 3) - 256;
 261
 262         SVQ1_CALC_CODEBOOK_ENTRIES(ff_svq1_inter_codebooks);
 263
 264         for (y = 0; y < height; y++) {
 265             for (x = 0; x < width / 4; x++, codebook++) {
 266                 n3 = dst[x];
 267                 /* add mean value to vector */
 268                 n1 = n4 + ((n3 & 0xFF00FF00) >> 8);
 269                 n2 = n4 +  (n3 & 0x00FF00FF);
 270                 SVQ1_ADD_CODEBOOK()
 271                 /* store result */
 272                 dst[x] = n1 << 8 | n2;
 273             }
 274             dst += pitch / 4;
 275         }
 276     }
 277     return 0;
 278 }
 279
 280 static int svq1_decode_motion_vector(GetBitContext *bitbuf, svq1_pmv *mv,
 281                                      svq1_pmv **pmv)
 282 {
 283     int diff;
 284     int i;
 285
 286     for (i = 0; i < 2; i++) {
 287         /* get motion code */
 288         diff = get_vlc2(bitbuf, svq1_motion_component.table, 7, 2);
 289         if (diff < 0)
 290             return AVERROR_INVALIDDATA;
 291         else if (diff) {
 292             if (get_bits1(bitbuf))
 293                 diff = -diff;
 294         }
 295
 296         /* add median of motion vector predictors and clip result */
 297         if (i == 1)
 298             mv->y = sign_extend(diff + mid_pred(pmv[0]->y, pmv[1]->y, pmv[2]->y), 6);
 299         else
 300             mv->x = sign_extend(diff + mid_pred(pmv[0]->x, pmv[1]->x, pmv[2]->x), 6);
 301     }
 302
 303     return 0;
 304 }
 305
 306 static void svq1_skip_block(uint8_t *current, uint8_t *previous,
 307                             int pitch, int x, int y)
 308 {
 309     uint8_t *src;
 310     uint8_t *dst;
 311     int i;
 312
 313     src = &previous[x + y * pitch];
 314     dst = current;
 315
 316     for (i = 0; i < 16; i++) {
 317         memcpy(dst, src, 16);
 318         src += pitch;
 319         dst += pitch;
 320     }
 321 }
 322
 323 static int svq1_motion_inter_block(DSPContext *dsp, GetBitContext *bitbuf,
 324                                    uint8_t *current, uint8_t *previous,
 325                                    int pitch, svq1_pmv *motion, int x, int y)
 326 {
 327     uint8_t *src;
 328     uint8_t *dst;
 329     svq1_pmv mv;
 330     svq1_pmv *pmv[3];
 331     int result;
 332
 333     /* predict and decode motion vector */
 334     pmv[0] = &motion[0];
 335     if (y == 0) {
 336         pmv[1] =
 337         pmv[2] = pmv[0];
 338     } else {
 339         pmv[1] = &motion[x / 8 + 2];
 340         pmv[2] = &motion[x / 8 + 4];
 341     }
 342
 343     result = svq1_decode_motion_vector(bitbuf, &mv, pmv);
 344
 345     if (result != 0)
 346         return result;
 347
 348     motion[0].x         =
 349     motion[x / 8 + 2].x =
 350     motion[x / 8 + 3].x = mv.x;
 351     motion[0].y         =
 352     motion[x / 8 + 2].y =
 353     motion[x / 8 + 3].y = mv.y;
 354
 355     if (y + (mv.y >> 1) < 0)
 356         mv.y = 0;
 357     if (x + (mv.x >> 1) < 0)
 358         mv.x = 0;
 359
 360     src = &previous[(x + (mv.x >> 1)) + (y + (mv.y >> 1)) * pitch];
 361     dst = current;
 362
 363     dsp->put_pixels_tab[0][(mv.y & 1) << 1 | (mv.x & 1)](dst, src, pitch, 16);
 364
 365     return 0;
 366 }
 367
 368 static int svq1_motion_inter_4v_block(DSPContext *dsp, GetBitContext *bitbuf,
 369                                       uint8_t *current, uint8_t *previous,
 370                                       int pitch, svq1_pmv *motion, int x, int y)
 371 {
 372     uint8_t *src;
 373     uint8_t *dst;
 374     svq1_pmv mv;
 375     svq1_pmv *pmv[4];
 376     int i, result;
 377
 378     /* predict and decode motion vector (0) */
 379     pmv[0] = &motion[0];
 380     if (y == 0) {
 381         pmv[1] =
 382         pmv[2] = pmv[0];
 383     } else {
 384         pmv[1] = &motion[(x / 8) + 2];
 385         pmv[2] = &motion[(x / 8) + 4];
 386     }
 387
 388     result = svq1_decode_motion_vector(bitbuf, &mv, pmv);
 389
 390     if (result != 0)
 391         return result;
 392
 393     /* predict and decode motion vector (1) */
 394     pmv[0] = &mv;
 395     if (y == 0) {
 396         pmv[1] =
 397         pmv[2] = pmv[0];
 398     } else {
 399         pmv[1] = &motion[(x / 8) + 3];
 400     }
 401     result = svq1_decode_motion_vector(bitbuf, &motion[0], pmv);
 402
 403     if (result != 0)
 404         return result;
 405
 406     /* predict and decode motion vector (2) */
 407     pmv[1] = &motion[0];
 408     pmv[2] = &motion[(x / 8) + 1];
 409
 410     result = svq1_decode_motion_vector(bitbuf, &motion[(x / 8) + 2], pmv);
 411
 412     if (result != 0)
 413         return result;
 414
 415     /* predict and decode motion vector (3) */
 416     pmv[2] = &motion[(x / 8) + 2];
 417     pmv[3] = &motion[(x / 8) + 3];
 418
 419     result = svq1_decode_motion_vector(bitbuf, pmv[3], pmv);
 420
 421     if (result != 0)
 422         return result;
 423
 424     /* form predictions */
 425     for (i = 0; i < 4; i++) {
 426         int mvx = pmv[i]->x + (i  & 1) * 16;
 427         int mvy = pmv[i]->y + (i >> 1) * 16;
 428
 429         // FIXME: clipping or padding?
 430         if (y + (mvy >> 1) < 0)
 431             mvy = 0;
 432         if (x + (mvx >> 1) < 0)
 433             mvx = 0;
 434
 435         src = &previous[(x + (mvx >> 1)) + (y + (mvy >> 1)) * pitch];
 436         dst = current;
 437
 438         dsp->put_pixels_tab[1][((mvy & 1) << 1) | (mvx & 1)](dst, src, pitch, 8);
 439
 440         /* select next block */
 441         if (i & 1)
 442             current += 8 * (pitch - 1);
 443         else
 444             current += 8;
 445     }
 446
 447     return 0;
 448 }
 449
 450 static int svq1_decode_delta_block(AVCodecContext *avctx, DSPContext *dsp,
 451                                    GetBitContext *bitbuf,
 452                                    uint8_t *current, uint8_t *previous,
 453                                    int pitch, svq1_pmv *motion, int x, int y)
 454 {
 455     uint32_t block_type;
 456     int result = 0;
 457
 458     /* get block type */
 459     block_type = get_vlc2(bitbuf, svq1_block_type.table, 2, 2);
 460
 461     /* reset motion vectors */
 462     if (block_type == SVQ1_BLOCK_SKIP || block_type == SVQ1_BLOCK_INTRA) {
 463         motion[0].x         =
 464         motion[0].y         =
 465         motion[x / 8 + 2].x =
 466         motion[x / 8 + 2].y =
 467         motion[x / 8 + 3].x =
 468         motion[x / 8 + 3].y = 0;
 469     }
 470
 471     switch (block_type) {
 472     case SVQ1_BLOCK_SKIP:
 473         svq1_skip_block(current, previous, pitch, x, y);
 474         break;
 475
 476     case SVQ1_BLOCK_INTER:
 477         result = svq1_motion_inter_block(dsp, bitbuf, current, previous,
 478                                          pitch, motion, x, y);
 479
 480         if (result != 0) {
 481             av_dlog(avctx, "Error in svq1_motion_inter_block %i\n", result);
 482             break;
 483         }
 484         result = svq1_decode_block_non_intra(bitbuf, current, pitch);
 485         break;
 486
 487     case SVQ1_BLOCK_INTER_4V:
 488         result = svq1_motion_inter_4v_block(dsp, bitbuf, current, previous,
 489                                             pitch, motion, x, y);
 490
 491         if (result != 0) {
 492             av_dlog(avctx, "Error in svq1_motion_inter_4v_block %i\n", result);
 493             break;
 494         }
 495         result = svq1_decode_block_non_intra(bitbuf, current, pitch);
 496         break;
 497
 498     case SVQ1_BLOCK_INTRA:
 499         result = svq1_decode_block_intra(bitbuf, current, pitch);
 500         break;
 501     }
 502
 503     return result;
 504 }
 505
 506 static void svq1_parse_string(GetBitContext *bitbuf, uint8_t *out)
 507 {
 508     uint8_t seed;
 509     int i;
 510
 511     out[0] = get_bits(bitbuf, 8);
 512     seed   = string_table[out[0]];
 513
 514     for (i = 1; i <= out[0]; i++) {
 515         out[i] = get_bits(bitbuf, 8) ^ seed;
 516         seed   = string_table[out[i] ^ seed];
 517     }
 518 }
 519
 520 static int svq1_decode_frame_header(AVCodecContext *avctx, AVFrame *frame)
 521 {
 522     SVQ1Context *s = avctx->priv_data;
 523     GetBitContext *bitbuf = &s->gb;
 524     int frame_size_code;
 525
 526     skip_bits(bitbuf, 8); /* temporal_reference */
 527
 528     /* frame type */
 529     s->nonref = 0;
 530     switch (get_bits(bitbuf, 2)) {
 531     case 0:
 532         frame->pict_type = AV_PICTURE_TYPE_I;
 533         break;
 534     case 2:
 535         s->nonref = 1;
 536     case 1:
 537         frame->pict_type = AV_PICTURE_TYPE_P;
 538         break;
 539     default:
 540         av_log(avctx, AV_LOG_ERROR, "Invalid frame type.\n");
 541         return AVERROR_INVALIDDATA;
 542     }
 543
 544     if (frame->pict_type == AV_PICTURE_TYPE_I) {
 545         /* unknown fields */
 546         if (s->frame_code == 0x50 || s->frame_code == 0x60) {
 547             int csum = get_bits(bitbuf, 16);
 548
 549             csum = ff_svq1_packet_checksum(bitbuf->buffer,
 550                                            bitbuf->size_in_bits >> 3,
 551                                            csum);
 552
 553             av_dlog(avctx, "%s checksum (%02x) for packet data\n",
 554                     (csum == 0) ? "correct" : "incorrect", csum);
 555         }
 556
 557         if ((s->frame_code ^ 0x10) >= 0x50) {
 558             uint8_t msg[256];
 559
 560             svq1_parse_string(bitbuf, msg);
 561
 562             av_log(avctx, AV_LOG_INFO,
 563                    "embedded message: \"%s\"\n", (char *)msg);
 564         }
 565
 566         skip_bits(bitbuf, 2);
 567         skip_bits(bitbuf, 2);
 568         skip_bits1(bitbuf);
 569
 570         /* load frame size */
 571         frame_size_code = get_bits(bitbuf, 3);
 572
 573         if (frame_size_code == 7) {
 574             /* load width, height (12 bits each) */
 575             s->width  = get_bits(bitbuf, 12);
 576             s->height = get_bits(bitbuf, 12);
 577
 578             if (!s->width || !s->height)
 579                 return AVERROR_INVALIDDATA;
 580         } else {
 581             /* get width, height from table */
 582             s->width  = ff_svq1_frame_size_table[frame_size_code][0];
 583             s->height = ff_svq1_frame_size_table[frame_size_code][1];
 584         }
 585     }
 586
 587     /* unknown fields */
 588     if (get_bits1(bitbuf) == 1) {
 589         skip_bits1(bitbuf);    /* use packet checksum if (1) */
 590         skip_bits1(bitbuf);    /* component checksums after image data if (1) */
 591
 592         if (get_bits(bitbuf, 2) != 0)
 593             return AVERROR_INVALIDDATA;
 594     }
 595
 596     if (get_bits1(bitbuf) == 1) {
 597         skip_bits1(bitbuf);
 598         skip_bits(bitbuf, 4);
 599         skip_bits1(bitbuf);
 600         skip_bits(bitbuf, 2);
 601
 602         while (get_bits1(bitbuf) == 1)
 603             skip_bits(bitbuf, 8);
 604     }
 605
 606     return 0;
 607 }
 608
 609 static int svq1_decode_frame(AVCodecContext *avctx, void *data,
 610                              int *got_frame, AVPacket *avpkt)
 611 {
 612     const uint8_t *buf = avpkt->data;
 613     int buf_size       = avpkt->size;
 614     SVQ1Context     *s = avctx->priv_data;
 615     AVFrame       *cur = s->cur;
 616     uint8_t *current;
 617     int result, i, x, y, width, height;
 618     svq1_pmv *pmv;
 619
 620     if (cur->data[0])
 621         avctx->release_buffer(avctx, cur);
 622
 623     /* initialize bit buffer */
 624     init_get_bits(&s->gb, buf, buf_size * 8);
 625
 626     /* decode frame header */
 627     s->frame_code = get_bits(&s->gb, 22);
 628
 629     if ((s->frame_code & ~0x70) || !(s->frame_code & 0x60))
 630         return AVERROR_INVALIDDATA;
 631
 632     /* swap some header bytes (why?) */
 633     if (s->frame_code != 0x20) {
 634         uint32_t *src = (uint32_t *)(buf + 4);
 635
 636         for (i = 0; i < 4; i++)
 637             src[i] = ((src[i] << 16) | (src[i] >> 16)) ^ src[7 - i];
 638     }
 639
 640     result = svq1_decode_frame_header(avctx, cur);
 641
 642     if (result != 0) {
 643         av_dlog(avctx, "Error in svq1_decode_frame_header %i\n", result);
 644         return result;
 645     }
 646     avcodec_set_dimensions(avctx, s->width, s->height);
 647
 648     if ((avctx->skip_frame >= AVDISCARD_NONREF && s->nonref) ||
 649         (avctx->skip_frame >= AVDISCARD_NONKEY &&
 650          cur->pict_type != AV_PICTURE_TYPE_I) ||
 651         avctx->skip_frame >= AVDISCARD_ALL)
 652         return buf_size;
 653
 654     result = ff_get_buffer(avctx, cur);
 655     if (result < 0)
 656         return result;
 657
 658     pmv = av_malloc((FFALIGN(s->width, 16) / 8 + 3) * sizeof(*pmv));
 659     if (!pmv)
 660         return AVERROR(ENOMEM);
 661
 662     /* decode y, u and v components */
 663     for (i = 0; i < 3; i++) {
 664         int linesize = cur->linesize[i];
 665         if (i == 0) {
 666             width    = FFALIGN(s->width,  16);
 667             height   = FFALIGN(s->height, 16);
 668         } else {
 669             if (avctx->flags & CODEC_FLAG_GRAY)
 670                 break;
 671             width    = FFALIGN(s->width  / 4, 16);
 672             height   = FFALIGN(s->height / 4, 16);
 673         }
 674
 675         current = cur->data[i];
 676
 677         if (cur->pict_type == AV_PICTURE_TYPE_I) {
 678             /* keyframe */
 679             for (y = 0; y < height; y += 16) {
 680                 for (x = 0; x < width; x += 16) {
 681                     result = svq1_decode_block_intra(&s->gb, &current[x],
 682                                                      linesize);
 683                     if (result != 0) {
 684                         av_log(avctx, AV_LOG_INFO,
 685                                "Error in svq1_decode_block %i (keyframe)\n",
 686                                result);
 687                         goto err;
 688                     }
 689                 }
 690                 current += 16 * linesize;
 691             }
 692         } else {
 693             /* delta frame */
 694             uint8_t *previous = s->prev->data[i];
 695             if (!previous) {
 696                 av_log(avctx, AV_LOG_ERROR, "Missing reference frame.\n");
 697                 result = AVERROR_INVALIDDATA;
 698                 goto err;
 699             }
 700
 701             memset(pmv, 0, ((width / 8) + 3) * sizeof(svq1_pmv));
 702
 703             for (y = 0; y < height; y += 16) {
 704                 for (x = 0; x < width; x += 16) {
 705                     result = svq1_decode_delta_block(avctx, &s->dsp,
 706                                                      &s->gb, &current[x],
 707                                                      previous, linesize,
 708                                                      pmv, x, y);
 709                     if (result != 0) {
 710                         av_dlog(avctx,
 711                                 "Error in svq1_decode_delta_block %i\n",
 712                                 result);
 713                         goto err;
 714                     }
 715                 }
 716
 717                 pmv[0].x     =
 718                     pmv[0].y = 0;
 719
 720                 current += 16 * linesize;
 721             }
 722         }
 723     }
 724
 725     *(AVFrame*)data = *cur;
 726     if (!s->nonref)
 727         FFSWAP(AVFrame*, s->cur, s->prev);
 728
 729     *got_frame = 1;
 730     result     = buf_size;
 731
 732 err:
 733     av_free(pmv);
 734     return result;
 735 }
 736
 737 static av_cold int svq1_decode_init(AVCodecContext *avctx)
 738 {
 739     SVQ1Context *s = avctx->priv_data;
 740     int i;
 741     int offset = 0;
 742
 743     s->cur  = avcodec_alloc_frame();
 744     s->prev = avcodec_alloc_frame();
 745     if (!s->cur || !s->prev) {
 746         avcodec_free_frame(&s->cur);
 747         avcodec_free_frame(&s->prev);
 748         return AVERROR(ENOMEM);
 749     }
 750
 751     s->width            = avctx->width  + 3 & ~3;
 752     s->height           = avctx->height + 3 & ~3;
 753     avctx->pix_fmt      = AV_PIX_FMT_YUV410P;
 754
 755     ff_dsputil_init(&s->dsp, avctx);
 756
 757     INIT_VLC_STATIC(&svq1_block_type, 2, 4,
 758                     &ff_svq1_block_type_vlc[0][1], 2, 1,
 759                     &ff_svq1_block_type_vlc[0][0], 2, 1, 6);
 760
 761     INIT_VLC_STATIC(&svq1_motion_component, 7, 33,
 762                     &ff_mvtab[0][1], 2, 1,
 763                     &ff_mvtab[0][0], 2, 1, 176);
 764
 765     for (i = 0; i < 6; i++) {
 766         static const uint8_t sizes[2][6] = { { 14, 10, 14, 18, 16, 18 },
 767                                              { 10, 10, 14, 14, 14, 16 } };
 768         static VLC_TYPE table[168][2];
 769         svq1_intra_multistage[i].table           = &table[offset];
 770         svq1_intra_multistage[i].table_allocated = sizes[0][i];
 771         offset                                  += sizes[0][i];
 772         init_vlc(&svq1_intra_multistage[i], 3, 8,
 773                  &ff_svq1_intra_multistage_vlc[i][0][1], 2, 1,
 774                  &ff_svq1_intra_multistage_vlc[i][0][0], 2, 1,
 775                  INIT_VLC_USE_NEW_STATIC);
 776         svq1_inter_multistage[i].table           = &table[offset];
 777         svq1_inter_multistage[i].table_allocated = sizes[1][i];
 778         offset                                  += sizes[1][i];
 779         init_vlc(&svq1_inter_multistage[i], 3, 8,
 780                  &ff_svq1_inter_multistage_vlc[i][0][1], 2, 1,
 781                  &ff_svq1_inter_multistage_vlc[i][0][0], 2, 1,
 782                  INIT_VLC_USE_NEW_STATIC);
 783     }
 784
 785     INIT_VLC_STATIC(&svq1_intra_mean, 8, 256,
 786                     &ff_svq1_intra_mean_vlc[0][1], 4, 2,
 787                     &ff_svq1_intra_mean_vlc[0][0], 4, 2, 632);
 788
 789     INIT_VLC_STATIC(&svq1_inter_mean, 9, 512,
 790                     &ff_svq1_inter_mean_vlc[0][1], 4, 2,
 791                     &ff_svq1_inter_mean_vlc[0][0], 4, 2, 1434);
 792
 793     return 0;
 794 }
 795
 796 static av_cold int svq1_decode_end(AVCodecContext *avctx)
 797 {
 798     SVQ1Context *s = avctx->priv_data;
 799
 800     if (s->cur->data[0])
 801         avctx->release_buffer(avctx, s->cur);
 802     if (s->prev->data[0])
 803         avctx->release_buffer(avctx, s->prev);
 804     avcodec_free_frame(&s->cur);
 805     avcodec_free_frame(&s->prev);
 806
 807     return 0;
 808 }
 809
 810 static void svq1_flush(AVCodecContext *avctx)
 811 {
 812     SVQ1Context *s = avctx->priv_data;
 813
 814     if (s->cur->data[0])
 815         avctx->release_buffer(avctx, s->cur);
 816     if (s->prev->data[0])
 817         avctx->release_buffer(avctx, s->prev);
 818 }
 819
 820 AVCodec ff_svq1_decoder = {
 821     .name           = "svq1",
 822     .type           = AVMEDIA_TYPE_VIDEO,
 823     .id             = AV_CODEC_ID_SVQ1,
 824     .priv_data_size = sizeof(SVQ1Context),
 825     .init           = svq1_decode_init,
 826     .close          = svq1_decode_end,
 827     .decode         = svq1_decode_frame,
 828     .capabilities   = CODEC_CAP_DR1,
 829     .flush          = svq1_flush,
 830     .pix_fmts       = (const enum AVPixelFormat[]) { AV_PIX_FMT_YUV410P,
 831                                                      AV_PIX_FMT_NONE },
 832     .long_name      = NULL_IF_CONFIG_SMALL("Sorenson Vector Quantizer 1 / Sorenson Video 1 / SVQ1"),
 833 };