extern/ffmpeg/libavcodec/smacker.c

   1 /*
   2  * Smacker decoder
   3  * Copyright (c) 2006 Konstantin Shishkov
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  18  *
  19  */
  20
  21 /**
  22  * @file smacker.c
  23  * Smacker decoder
  24  */
  25
  26 /*
  27  * Based on http://wiki.multimedia.cx/index.php?title=Smacker
  28  */
  29
  30 #include <stdio.h>
  31 #include <stdlib.h>
  32
  33 #include "common.h"
  34 #include "avcodec.h"
  35
  36 #define ALT_BITSTREAM_READER_LE
  37 #include "bitstream.h"
  38
  39 #define SMKTREE_BITS 9
  40 #define SMK_NODE 0x80000000
  41
  42 /*
  43  * Decoder context
  44  */
  45 typedef struct SmackVContext {
  46     AVCodecContext *avctx;
  47     AVFrame pic;
  48
  49     int *mmap_tbl, *mclr_tbl, *full_tbl, *type_tbl;
  50     int mmap_last[3], mclr_last[3], full_last[3], type_last[3];
  51 } SmackVContext;
  52
  53 /**
  54  * Context used for code reconstructing
  55  */
  56 typedef struct HuffContext {
  57     int length;
  58     int maxlength;
  59     int current;
  60     uint32_t *bits;
  61     int *lengths;
  62     int *values;
  63 } HuffContext;
  64
  65 /* common parameters used for decode_bigtree */
  66 typedef struct DBCtx {
  67     VLC *v1, *v2;
  68     int *recode1, *recode2;
  69     int escapes[3];
  70     int *last;
  71     int lcur;
  72 } DBCtx;
  73
  74 /* possible runs of blocks */
  75 static const int block_runs[64] = {
  76       1,    2,    3,    4,    5,    6,    7,    8,
  77       9,   10,   11,   12,   13,   14,   15,   16,
  78      17,   18,   19,   20,   21,   22,   23,   24,
  79      25,   26,   27,   28,   29,   30,   31,   32,
  80      33,   34,   35,   36,   37,   38,   39,   40,
  81      41,   42,   43,   44,   45,   46,   47,   48,
  82      49,   50,   51,   52,   53,   54,   55,   56,
  83      57,   58,   59,  128,  256,  512, 1024, 2048 };
  84
  85 enum SmkBlockTypes {
  86     SMK_BLK_MONO = 0,
  87     SMK_BLK_FULL = 1,
  88     SMK_BLK_SKIP = 2,
  89     SMK_BLK_FILL = 3 };
  90
  91 /**
  92  * Decode local frame tree
  93  */
  94 static int smacker_decode_tree(GetBitContext *gb, HuffContext *hc, uint32_t prefix, int length)
  95 {
  96     if(!get_bits1(gb)){ //Leaf
  97         if(hc->current >= 256){
  98             av_log(NULL, AV_LOG_ERROR, "Tree size exceeded!\n");
  99             return -1;
 100         }
 101         if(length){
 102             hc->bits[hc->current] = prefix;
 103             hc->lengths[hc->current] = length;
 104         } else {
 105             hc->bits[hc->current] = 0;
 106             hc->lengths[hc->current] = 0;
 107         }
 108         hc->values[hc->current] = get_bits(gb, 8);
 109         hc->current++;
 110         if(hc->maxlength < length)
 111             hc->maxlength = length;
 112         return 0;
 113     } else { //Node
 114         int r;
 115         length++;
 116         r = smacker_decode_tree(gb, hc, prefix, length);
 117         if(r)
 118             return r;
 119         return smacker_decode_tree(gb, hc, prefix | (1 << (length - 1)), length);
 120     }
 121 }
 122
 123 /**
 124  * Decode header tree
 125  */
 126 static int smacker_decode_bigtree(GetBitContext *gb, HuffContext *hc, DBCtx *ctx)
 127 {
 128     if(!get_bits1(gb)){ //Leaf
 129         int val, i1, i2, b1, b2;
 130         if(hc->current >= hc->length){
 131             av_log(NULL, AV_LOG_ERROR, "Tree size exceeded!\n");
 132             return -1;
 133         }
 134         b1 = get_bits_count(gb);
 135         i1 = get_vlc2(gb, ctx->v1->table, SMKTREE_BITS, 3);
 136         b1 = get_bits_count(gb) - b1;
 137         b2 = get_bits_count(gb);
 138         i2 = get_vlc2(gb, ctx->v2->table, SMKTREE_BITS, 3);
 139         b2 = get_bits_count(gb) - b2;
 140         val = ctx->recode1[i1] | (ctx->recode2[i2] << 8);
 141         if(val == ctx->escapes[0]) {
 142             ctx->last[0] = hc->current;
 143             val = 0;
 144         } else if(val == ctx->escapes[1]) {
 145             ctx->last[1] = hc->current;
 146             val = 0;
 147         } else if(val == ctx->escapes[2]) {
 148             ctx->last[2] = hc->current;
 149             val = 0;
 150         }
 151
 152         hc->values[hc->current++] = val;
 153         return 1;
 154     } else { //Node
 155         int r = 0, t;
 156
 157         t = hc->current++;
 158         r = smacker_decode_bigtree(gb, hc, ctx);
 159         if(r < 0)
 160             return r;
 161         hc->values[t] = SMK_NODE | r;
 162         r++;
 163         r += smacker_decode_bigtree(gb, hc, ctx);
 164         return r;
 165     }
 166 }
 167
 168 /**
 169  * Store large tree as FFmpeg's vlc codes
 170  */
 171 static int smacker_decode_header_tree(SmackVContext *smk, GetBitContext *gb, int **recodes, int *last, int size)
 172 {
 173     int res;
 174     HuffContext huff;
 175     HuffContext tmp1, tmp2;
 176     VLC vlc[2];
 177     int escapes[3];
 178     DBCtx ctx;
 179
 180     if(size >= UINT_MAX>>4){ // (((size + 3) >> 2) + 3) << 2 must not overflow
 181         av_log(smk->avctx, AV_LOG_ERROR, "size too large\n");
 182         return -1;
 183     }
 184
 185     tmp1.length = 256;
 186     tmp1.maxlength = 0;
 187     tmp1.current = 0;
 188     tmp1.bits = av_mallocz(256 * 4);
 189     tmp1.lengths = av_mallocz(256 * sizeof(int));
 190     tmp1.values = av_mallocz(256 * sizeof(int));
 191
 192     tmp2.length = 256;
 193     tmp2.maxlength = 0;
 194     tmp2.current = 0;
 195     tmp2.bits = av_mallocz(256 * 4);
 196     tmp2.lengths = av_mallocz(256 * sizeof(int));
 197     tmp2.values = av_mallocz(256 * sizeof(int));
 198
 199     memset(&vlc[0], 0, sizeof(VLC));
 200     memset(&vlc[1], 0, sizeof(VLC));
 201
 202     if(get_bits1(gb)) {
 203         smacker_decode_tree(gb, &tmp1, 0, 0);
 204         get_bits1(gb);
 205         res = init_vlc(&vlc[0], SMKTREE_BITS, tmp1.length,
 206                     tmp1.lengths, sizeof(int), sizeof(int),
 207                     tmp1.bits, sizeof(uint32_t), sizeof(uint32_t), INIT_VLC_LE);
 208         if(res < 0) {
 209             av_log(smk->avctx, AV_LOG_ERROR, "Cannot build VLC table\n");
 210             return -1;
 211         }
 212     } else {
 213         av_log(smk->avctx, AV_LOG_ERROR, "Skipping low bytes tree\n");
 214     }
 215     if(get_bits1(gb)){
 216         smacker_decode_tree(gb, &tmp2, 0, 0);
 217         get_bits1(gb);
 218         res = init_vlc(&vlc[1], SMKTREE_BITS, tmp2.length,
 219                     tmp2.lengths, sizeof(int), sizeof(int),
 220                     tmp2.bits, sizeof(uint32_t), sizeof(uint32_t), INIT_VLC_LE);
 221         if(res < 0) {
 222             av_log(smk->avctx, AV_LOG_ERROR, "Cannot build VLC table\n");
 223             return -1;
 224         }
 225     } else {
 226         av_log(smk->avctx, AV_LOG_ERROR, "Skipping high bytes tree\n");
 227     }
 228
 229     escapes[0]  = get_bits(gb, 8);
 230     escapes[0] |= get_bits(gb, 8) << 8;
 231     escapes[1]  = get_bits(gb, 8);
 232     escapes[1] |= get_bits(gb, 8) << 8;
 233     escapes[2]  = get_bits(gb, 8);
 234     escapes[2] |= get_bits(gb, 8) << 8;
 235
 236     last[0] = last[1] = last[2] = -1;
 237
 238     ctx.escapes[0] = escapes[0];
 239     ctx.escapes[1] = escapes[1];
 240     ctx.escapes[2] = escapes[2];
 241     ctx.v1 = &vlc[0];
 242     ctx.v2 = &vlc[1];
 243     ctx.recode1 = tmp1.values;
 244     ctx.recode2 = tmp2.values;
 245     ctx.last = last;
 246
 247     huff.length = ((size + 3) >> 2) + 3;
 248     huff.maxlength = 0;
 249     huff.current = 0;
 250     huff.values = av_mallocz(huff.length * sizeof(int));
 251
 252     smacker_decode_bigtree(gb, &huff, &ctx);
 253     get_bits1(gb);
 254     if(ctx.last[0] == -1) ctx.last[0] = huff.current++;
 255     if(ctx.last[1] == -1) ctx.last[1] = huff.current++;
 256     if(ctx.last[2] == -1) ctx.last[2] = huff.current++;
 257
 258     *recodes = huff.values;
 259
 260     if(vlc[0].table)
 261         free_vlc(&vlc[0]);
 262     if(vlc[1].table)
 263         free_vlc(&vlc[1]);
 264     av_free(tmp1.bits);
 265     av_free(tmp1.lengths);
 266     av_free(tmp1.values);
 267     av_free(tmp2.bits);
 268     av_free(tmp2.lengths);
 269     av_free(tmp2.values);
 270
 271     return 0;
 272 }
 273
 274 static int decode_header_trees(SmackVContext *smk) {
 275     GetBitContext gb;
 276     int mmap_size, mclr_size, full_size, type_size;
 277
 278     mmap_size = LE_32(smk->avctx->extradata);
 279     mclr_size = LE_32(smk->avctx->extradata + 4);
 280     full_size = LE_32(smk->avctx->extradata + 8);
 281     type_size = LE_32(smk->avctx->extradata + 12);
 282
 283     init_get_bits(&gb, smk->avctx->extradata + 16, (smk->avctx->extradata_size - 16) * 8);
 284
 285     if(!get_bits1(&gb)) {
 286         av_log(smk->avctx, AV_LOG_INFO, "Skipping MMAP tree\n");
 287         smk->mmap_tbl = av_malloc(sizeof(int) * 2);
 288         smk->mmap_tbl[0] = 0;
 289         smk->mmap_last[0] = smk->mmap_last[1] = smk->mmap_last[2] = 1;
 290     } else {
 291         smacker_decode_header_tree(smk, &gb, &smk->mmap_tbl, smk->mmap_last, mmap_size);
 292     }
 293     if(!get_bits(&gb, 1)) {
 294         av_log(smk->avctx, AV_LOG_INFO, "Skipping MCLR tree\n");
 295         smk->mclr_tbl = av_malloc(sizeof(int) * 2);
 296         smk->mclr_tbl[0] = 0;
 297         smk->mclr_last[0] = smk->mclr_last[1] = smk->mclr_last[2] = 1;
 298     } else {
 299         smacker_decode_header_tree(smk, &gb, &smk->mclr_tbl, smk->mclr_last, mclr_size);
 300     }
 301     if(!get_bits(&gb, 1)) {
 302         av_log(smk->avctx, AV_LOG_INFO, "Skipping FULL tree\n");
 303         smk->full_tbl = av_malloc(sizeof(int) * 2);
 304         smk->full_tbl[0] = 0;
 305         smk->full_last[0] = smk->full_last[1] = smk->full_last[2] = 1;
 306     } else {
 307         smacker_decode_header_tree(smk, &gb, &smk->full_tbl, smk->full_last, full_size);
 308     }
 309     if(!get_bits(&gb, 1)) {
 310         av_log(smk->avctx, AV_LOG_INFO, "Skipping TYPE tree\n");
 311         smk->type_tbl = av_malloc(sizeof(int) * 2);
 312         smk->type_tbl[0] = 0;
 313         smk->type_last[0] = smk->type_last[1] = smk->type_last[2] = 1;
 314     } else {
 315         smacker_decode_header_tree(smk, &gb, &smk->type_tbl, smk->type_last, type_size);
 316     }
 317
 318     return 0;
 319 }
 320
 321 static always_inline void last_reset(int *recode, int *last) {
 322     recode[last[0]] = recode[last[1]] = recode[last[2]] = 0;
 323 }
 324
 325 /* get code and update history */
 326 static always_inline int smk_get_code(GetBitContext *gb, int *recode, int *last) {
 327     register int *table = recode;
 328     int v, b;
 329
 330     b = get_bits_count(gb);
 331     while(*table & SMK_NODE) {
 332         if(get_bits1(gb))
 333             table += (*table) & (~SMK_NODE);
 334         table++;
 335     }
 336     v = *table;
 337     b = get_bits_count(gb) - b;
 338
 339     if(v != recode[last[0]]) {
 340         recode[last[2]] = recode[last[1]];
 341         recode[last[1]] = recode[last[0]];
 342         recode[last[0]] = v;
 343     }
 344     return v;
 345 }
 346
 347 static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, uint8_t *buf, int buf_size)
 348 {
 349     SmackVContext * const smk = (SmackVContext *)avctx->priv_data;
 350     uint8_t *out;
 351     uint32_t *pal;
 352     GetBitContext gb;
 353     int blocks, blk, bw, bh;
 354     int i;
 355     int stride;
 356
 357     if(buf_size == 769)
 358         return 0;
 359     if(smk->pic.data[0])
 360             avctx->release_buffer(avctx, &smk->pic);
 361
 362     smk->pic.reference = 1;
 363     smk->pic.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
 364     if(avctx->reget_buffer(avctx, &smk->pic) < 0){
 365         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 366         return -1;
 367     }
 368
 369     /* make the palette available on the way out */
 370     out = buf + 1;
 371     pal = (uint32_t*)smk->pic.data[1];
 372     smk->pic.palette_has_changed = buf[0] & 1;
 373     smk->pic.key_frame = !!(buf[0] & 2);
 374     if(smk->pic.key_frame)
 375         smk->pic.pict_type = FF_I_TYPE;
 376     else
 377         smk->pic.pict_type = FF_P_TYPE;
 378
 379     for(i = 0; i < 256; i++) {
 380         int r, g, b;
 381         r = *out++;
 382         g = *out++;
 383         b = *out++;
 384         *pal++ = (r << 16) | (g << 8) | b;
 385     }
 386
 387     last_reset(smk->mmap_tbl, smk->mmap_last);
 388     last_reset(smk->mclr_tbl, smk->mclr_last);
 389     last_reset(smk->full_tbl, smk->full_last);
 390     last_reset(smk->type_tbl, smk->type_last);
 391     init_get_bits(&gb, buf + 769, (buf_size - 769) * 8);
 392
 393     blk = 0;
 394     bw = avctx->width >> 2;
 395     bh = avctx->height >> 2;
 396     blocks = bw * bh;
 397     out = smk->pic.data[0];
 398     stride = smk->pic.linesize[0];
 399     while(blk < blocks) {
 400         int type, run, mode;
 401         uint16_t pix;
 402
 403         type = smk_get_code(&gb, smk->type_tbl, smk->type_last);
 404         run = block_runs[(type >> 2) & 0x3F];
 405         switch(type & 3){
 406         case SMK_BLK_MONO:
 407             while(run-- && blk < blocks){
 408                 int clr, map;
 409                 int hi, lo;
 410                 clr = smk_get_code(&gb, smk->mclr_tbl, smk->mclr_last);
 411                 map = smk_get_code(&gb, smk->mmap_tbl, smk->mmap_last);
 412                 out = smk->pic.data[0] + (blk / bw) * (stride * 4) + (blk % bw) * 4;
 413                 hi = clr >> 8;
 414                 lo = clr & 0xFF;
 415                 for(i = 0; i < 4; i++) {
 416                     if(map & 1) out[0] = hi; else out[0] = lo;
 417                     if(map & 2) out[1] = hi; else out[1] = lo;
 418                     if(map & 4) out[2] = hi; else out[2] = lo;
 419                     if(map & 8) out[3] = hi; else out[3] = lo;
 420                     map >>= 4;
 421                     out += stride;
 422                 }
 423                 blk++;
 424             }
 425             break;
 426         case SMK_BLK_FULL:
 427             mode = 0;
 428             if(avctx->codec_tag == MKTAG('S', 'M', 'K', '4')) { // In case of Smacker v4 we have three modes
 429                 if(get_bits1(&gb)) mode = 1;
 430                 else if(get_bits1(&gb)) mode = 2;
 431             }
 432             while(run-- && blk < blocks){
 433                 out = smk->pic.data[0] + (blk / bw) * (stride * 4) + (blk % bw) * 4;
 434                 switch(mode){
 435                 case 0:
 436                     for(i = 0; i < 4; i++) {
 437                         pix = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 438                         out[2] = pix & 0xFF;
 439                         out[3] = pix >> 8;
 440                         pix = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 441                         out[0] = pix & 0xFF;
 442                         out[1] = pix >> 8;
 443                         out += stride;
 444                     }
 445                     break;
 446                 case 1:
 447                     pix = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 448                     out[0] = out[1] = pix & 0xFF;
 449                     out[2] = out[3] = pix >> 8;
 450                     out += stride;
 451                     out[0] = out[1] = pix & 0xFF;
 452                     out[2] = out[3] = pix >> 8;
 453                     out += stride;
 454                     pix = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 455                     out[0] = out[1] = pix & 0xFF;
 456                     out[2] = out[3] = pix >> 8;
 457                     out += stride;
 458                     out[0] = out[1] = pix & 0xFF;
 459                     out[2] = out[3] = pix >> 8;
 460                     out += stride;
 461                     break;
 462                 case 2:
 463                     for(i = 0; i < 2; i++) {
 464                         uint16_t pix1, pix2;
 465                         pix1 = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 466                         pix2 = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 467                         out[0] = pix1 & 0xFF; out[1] = pix1 >> 8;
 468                         out[2] = pix2 & 0xFF; out[3] = pix2 >> 8;
 469                         out += stride;
 470                         out[0] = pix1 & 0xFF; out[1] = pix1 >> 8;
 471                         out[2] = pix2 & 0xFF; out[3] = pix2 >> 8;
 472                         out += stride;
 473                     }
 474                     break;
 475                 }
 476                 blk++;
 477             }
 478             break;
 479         case SMK_BLK_SKIP:
 480             while(run-- && blk < blocks)
 481                 blk++;
 482             break;
 483         case SMK_BLK_FILL:
 484             mode = type >> 8;
 485             while(run-- && blk < blocks){
 486                 uint32_t col;
 487                 out = smk->pic.data[0] + (blk / bw) * (stride * 4) + (blk % bw) * 4;
 488                 col = mode * 0x01010101;
 489                 for(i = 0; i < 4; i++) {
 490                     *((uint32_t*)out) = col;
 491                     out += stride;
 492                 }
 493                 blk++;
 494             }
 495             break;
 496         }
 497
 498     }
 499
 500     *data_size = sizeof(AVFrame);
 501     *(AVFrame*)data = smk->pic;
 502
 503     /* always report that the buffer was completely consumed */
 504     return buf_size;
 505 }
 506
 507
 508
 509 /*
 510  *
 511  * Init smacker decoder
 512  *
 513  */
 514 static int decode_init(AVCodecContext *avctx)
 515 {
 516     SmackVContext * const c = (SmackVContext *)avctx->priv_data;
 517
 518     c->avctx = avctx;
 519     avctx->has_b_frames = 0;
 520
 521     c->pic.data[0] = NULL;
 522
 523     if (avcodec_check_dimensions(avctx, avctx->height, avctx->width) < 0) {
 524         return 1;
 525     }
 526
 527     avctx->pix_fmt = PIX_FMT_PAL8;
 528
 529
 530     /* decode huffman trees from extradata */
 531     if(avctx->extradata_size < 16){
 532         av_log(avctx, AV_LOG_ERROR, "Extradata missing!\n");
 533         return -1;
 534     }
 535
 536     decode_header_trees(c);
 537
 538
 539     return 0;
 540 }
 541
 542
 543
 544 /*
 545  *
 546  * Uninit smacker decoder
 547  *
 548  */
 549 static int decode_end(AVCodecContext *avctx)
 550 {
 551     SmackVContext * const smk = (SmackVContext *)avctx->priv_data;
 552
 553     if(smk->mmap_tbl)
 554         av_free(smk->mmap_tbl);
 555     if(smk->mclr_tbl)
 556         av_free(smk->mclr_tbl);
 557     if(smk->full_tbl)
 558         av_free(smk->full_tbl);
 559     if(smk->type_tbl)
 560         av_free(smk->type_tbl);
 561
 562     if (smk->pic.data[0])
 563         avctx->release_buffer(avctx, &smk->pic);
 564
 565     return 0;
 566 }
 567
 568
 569 static int smka_decode_init(AVCodecContext *avctx)
 570 {
 571     return 0;
 572 }
 573
 574 /**
 575  * Decode Smacker audio data
 576  */
 577 static int smka_decode_frame(AVCodecContext *avctx, void *data, int *data_size, uint8_t *buf, int buf_size)
 578 {
 579     GetBitContext gb;
 580     HuffContext h[4];
 581     VLC vlc[4];
 582     int16_t *samples = data;
 583     int val;
 584     int i, res;
 585     int unp_size;
 586     int bits, stereo;
 587     int pred[2] = {0, 0};
 588
 589     unp_size = LE_32(buf);
 590
 591     init_get_bits(&gb, buf + 4, (buf_size - 4) * 8);
 592
 593     if(!get_bits1(&gb)){
 594         av_log(avctx, AV_LOG_INFO, "Sound: no data\n");
 595         *data_size = 0;
 596         return 1;
 597     }
 598     stereo = get_bits1(&gb);
 599     bits = get_bits1(&gb);
 600
 601     memset(vlc, 0, sizeof(VLC) * 4);
 602     memset(h, 0, sizeof(HuffContext) * 4);
 603     // Initialize
 604     for(i = 0; i < (1 << (bits + stereo)); i++) {
 605         h[i].length = 256;
 606         h[i].maxlength = 0;
 607         h[i].current = 0;
 608         h[i].bits = av_mallocz(256 * 4);
 609         h[i].lengths = av_mallocz(256 * sizeof(int));
 610         h[i].values = av_mallocz(256 * sizeof(int));
 611         get_bits1(&gb);
 612         smacker_decode_tree(&gb, &h[i], 0, 0);
 613         get_bits1(&gb);
 614         if(h[i].current > 1) {
 615             res = init_vlc(&vlc[i], SMKTREE_BITS, h[i].length,
 616                     h[i].lengths, sizeof(int), sizeof(int),
 617                     h[i].bits, sizeof(uint32_t), sizeof(uint32_t), INIT_VLC_LE);
 618             if(res < 0) {
 619                 av_log(avctx, AV_LOG_ERROR, "Cannot build VLC table\n");
 620                 return -1;
 621             }
 622         }
 623     }
 624     if(bits) { //decode 16-bit data
 625         pred[0]  = get_bits(&gb, 8);
 626         pred[0] |= get_bits(&gb, 8);
 627         *samples++ = pred[0];
 628         if(stereo) {
 629             pred[1]  = get_bits(&gb, 8);
 630             pred[1] |= get_bits(&gb, 8);
 631             *samples++ = pred[1];
 632         }
 633         for(i = 0; i < unp_size / 2; i++) {
 634             if(i & stereo) {
 635                 if(vlc[2].table)
 636                     res = get_vlc2(&gb, vlc[2].table, SMKTREE_BITS, 3);
 637                 else
 638                     res = 0;
 639                 val  = h[2].values[res];
 640                 if(vlc[3].table)
 641                     res = get_vlc2(&gb, vlc[3].table, SMKTREE_BITS, 3);
 642                 else
 643                     res = 0;
 644                 val |= h[3].values[res] << 8;
 645                 pred[1] += (int16_t)val;
 646                 *samples++ = pred[1];
 647             } else {
 648                 if(vlc[0].table)
 649                     res = get_vlc2(&gb, vlc[0].table, SMKTREE_BITS, 3);
 650                 else
 651                     res = 0;
 652                 val  = h[0].values[res];
 653                 if(vlc[1].table)
 654                     res = get_vlc2(&gb, vlc[1].table, SMKTREE_BITS, 3);
 655                 else
 656                     res = 0;
 657                 val |= h[1].values[res] << 8;
 658                 pred[0] += val;
 659                 *samples++ = pred[0];
 660             }
 661         }
 662     } else { //8-bit data
 663         pred[0] = get_bits(&gb, 8);
 664         *samples++ = (pred[0] - 0x80) << 8;
 665         if(stereo) {
 666             pred[1] = get_bits(&gb, 8);
 667             *samples++ = (pred[1] - 0x80) << 8;
 668         }
 669         for(i = 0; i < unp_size; i++) {
 670             if(i & stereo){
 671                 if(vlc[1].table)
 672                     res = get_vlc2(&gb, vlc[1].table, SMKTREE_BITS, 3);
 673                 else
 674                     res = 0;
 675                 pred[1] += (int8_t)h[1].values[res];
 676                 *samples++ = (pred[1] - 0x80) << 8;
 677             } else {
 678                 if(vlc[0].table)
 679                     res = get_vlc2(&gb, vlc[0].table, SMKTREE_BITS, 3);
 680                 else
 681                     res = 0;
 682                 pred[0] += (int8_t)h[0].values[res];
 683                 *samples++ = (pred[0] - 0x80) << 8;
 684             }
 685         }
 686         unp_size *= 2;
 687     }
 688
 689     for(i = 0; i < 4; i++) {
 690         if(vlc[i].table)
 691             free_vlc(&vlc[i]);
 692         if(h[i].bits)
 693             av_free(h[i].bits);
 694         if(h[i].lengths)
 695             av_free(h[i].lengths);
 696         if(h[i].values)
 697             av_free(h[i].values);
 698     }
 699
 700     *data_size = unp_size;
 701     return buf_size;
 702 }
 703
 704 AVCodec smacker_decoder = {
 705     "smackvid",
 706     CODEC_TYPE_VIDEO,
 707     CODEC_ID_SMACKVIDEO,
 708     sizeof(SmackVContext),
 709     decode_init,
 710     NULL,
 711     decode_end,
 712     decode_frame
 713 };
 714
 715 AVCodec smackaud_decoder = {
 716     "smackaud",
 717     CODEC_TYPE_AUDIO,
 718     CODEC_ID_SMACKAUDIO,
 719     0,
 720     smka_decode_init,
 721     NULL,
 722     NULL,
 723     smka_decode_frame
 724 };
 725