libavcodec/smacker.c

   1 /*
   2  * Smacker decoder
   3  * Copyright (c) 2006 Konstantin Shishkov
   4  *
   5  * This file is part of FFmpeg.
   6  *
   7  * FFmpeg is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU Lesser General Public
   9  * License as published by the Free Software Foundation; either
  10  * version 2.1 of the License, or (at your option) any later version.
  11  *
  12  * FFmpeg is distributed in the hope that it will be useful,
  13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15  * Lesser General Public License for more details.
  16  *
  17  * You should have received a copy of the GNU Lesser General Public
  18  * License along with FFmpeg; if not, write to the Free Software
  19  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  20  */
  21
  22 /**
  23  * @file libavcodec/smacker.c
  24  * Smacker decoder
  25  */
  26
  27 /*
  28  * Based on http://wiki.multimedia.cx/index.php?title=Smacker
  29  */
  30
  31 #include <stdio.h>
  32 #include <stdlib.h>
  33
  34 #include "avcodec.h"
  35
  36 #define ALT_BITSTREAM_READER_LE
  37 #include "bitstream.h"
  38 #include "bytestream.h"
  39
  40 #define SMKTREE_BITS 9
  41 #define SMK_NODE 0x80000000
  42
  43 /*
  44  * Decoder context
  45  */
  46 typedef struct SmackVContext {
  47     AVCodecContext *avctx;
  48     AVFrame pic;
  49
  50     int *mmap_tbl, *mclr_tbl, *full_tbl, *type_tbl;
  51     int mmap_last[3], mclr_last[3], full_last[3], type_last[3];
  52 } SmackVContext;
  53
  54 /**
  55  * Context used for code reconstructing
  56  */
  57 typedef struct HuffContext {
  58     int length;
  59     int maxlength;
  60     int current;
  61     uint32_t *bits;
  62     int *lengths;
  63     int *values;
  64 } HuffContext;
  65
  66 /* common parameters used for decode_bigtree */
  67 typedef struct DBCtx {
  68     VLC *v1, *v2;
  69     int *recode1, *recode2;
  70     int escapes[3];
  71     int *last;
  72     int lcur;
  73 } DBCtx;
  74
  75 /* possible runs of blocks */
  76 static const int block_runs[64] = {
  77       1,    2,    3,    4,    5,    6,    7,    8,
  78       9,   10,   11,   12,   13,   14,   15,   16,
  79      17,   18,   19,   20,   21,   22,   23,   24,
  80      25,   26,   27,   28,   29,   30,   31,   32,
  81      33,   34,   35,   36,   37,   38,   39,   40,
  82      41,   42,   43,   44,   45,   46,   47,   48,
  83      49,   50,   51,   52,   53,   54,   55,   56,
  84      57,   58,   59,  128,  256,  512, 1024, 2048 };
  85
  86 enum SmkBlockTypes {
  87     SMK_BLK_MONO = 0,
  88     SMK_BLK_FULL = 1,
  89     SMK_BLK_SKIP = 2,
  90     SMK_BLK_FILL = 3 };
  91
  92 /**
  93  * Decode local frame tree
  94  */
  95 static int smacker_decode_tree(GetBitContext *gb, HuffContext *hc, uint32_t prefix, int length)
  96 {
  97     if(!get_bits1(gb)){ //Leaf
  98         if(hc->current >= 256){
  99             av_log(NULL, AV_LOG_ERROR, "Tree size exceeded!\n");
 100             return -1;
 101         }
 102         if(length){
 103             hc->bits[hc->current] = prefix;
 104             hc->lengths[hc->current] = length;
 105         } else {
 106             hc->bits[hc->current] = 0;
 107             hc->lengths[hc->current] = 0;
 108         }
 109         hc->values[hc->current] = get_bits(gb, 8);
 110         hc->current++;
 111         if(hc->maxlength < length)
 112             hc->maxlength = length;
 113         return 0;
 114     } else { //Node
 115         int r;
 116         length++;
 117         r = smacker_decode_tree(gb, hc, prefix, length);
 118         if(r)
 119             return r;
 120         return smacker_decode_tree(gb, hc, prefix | (1 << (length - 1)), length);
 121     }
 122 }
 123
 124 /**
 125  * Decode header tree
 126  */
 127 static int smacker_decode_bigtree(GetBitContext *gb, HuffContext *hc, DBCtx *ctx)
 128 {
 129     if(!get_bits1(gb)){ //Leaf
 130         int val, i1, i2, b1, b2;
 131         if(hc->current >= hc->length){
 132             av_log(NULL, AV_LOG_ERROR, "Tree size exceeded!\n");
 133             return -1;
 134         }
 135         b1 = get_bits_count(gb);
 136         i1 = get_vlc2(gb, ctx->v1->table, SMKTREE_BITS, 3);
 137         b1 = get_bits_count(gb) - b1;
 138         b2 = get_bits_count(gb);
 139         i2 = get_vlc2(gb, ctx->v2->table, SMKTREE_BITS, 3);
 140         b2 = get_bits_count(gb) - b2;
 141         val = ctx->recode1[i1] | (ctx->recode2[i2] << 8);
 142         if(val == ctx->escapes[0]) {
 143             ctx->last[0] = hc->current;
 144             val = 0;
 145         } else if(val == ctx->escapes[1]) {
 146             ctx->last[1] = hc->current;
 147             val = 0;
 148         } else if(val == ctx->escapes[2]) {
 149             ctx->last[2] = hc->current;
 150             val = 0;
 151         }
 152
 153         hc->values[hc->current++] = val;
 154         return 1;
 155     } else { //Node
 156         int r = 0, t;
 157
 158         t = hc->current++;
 159         r = smacker_decode_bigtree(gb, hc, ctx);
 160         if(r < 0)
 161             return r;
 162         hc->values[t] = SMK_NODE | r;
 163         r++;
 164         r += smacker_decode_bigtree(gb, hc, ctx);
 165         return r;
 166     }
 167 }
 168
 169 /**
 170  * Store large tree as FFmpeg's vlc codes
 171  */
 172 static int smacker_decode_header_tree(SmackVContext *smk, GetBitContext *gb, int **recodes, int *last, int size)
 173 {
 174     int res;
 175     HuffContext huff;
 176     HuffContext tmp1, tmp2;
 177     VLC vlc[2];
 178     int escapes[3];
 179     DBCtx ctx;
 180
 181     if(size >= UINT_MAX>>4){ // (((size + 3) >> 2) + 3) << 2 must not overflow
 182         av_log(smk->avctx, AV_LOG_ERROR, "size too large\n");
 183         return -1;
 184     }
 185
 186     tmp1.length = 256;
 187     tmp1.maxlength = 0;
 188     tmp1.current = 0;
 189     tmp1.bits = av_mallocz(256 * 4);
 190     tmp1.lengths = av_mallocz(256 * sizeof(int));
 191     tmp1.values = av_mallocz(256 * sizeof(int));
 192
 193     tmp2.length = 256;
 194     tmp2.maxlength = 0;
 195     tmp2.current = 0;
 196     tmp2.bits = av_mallocz(256 * 4);
 197     tmp2.lengths = av_mallocz(256 * sizeof(int));
 198     tmp2.values = av_mallocz(256 * sizeof(int));
 199
 200     memset(&vlc[0], 0, sizeof(VLC));
 201     memset(&vlc[1], 0, sizeof(VLC));
 202
 203     if(get_bits1(gb)) {
 204         smacker_decode_tree(gb, &tmp1, 0, 0);
 205         skip_bits1(gb);
 206         res = init_vlc(&vlc[0], SMKTREE_BITS, tmp1.length,
 207                     tmp1.lengths, sizeof(int), sizeof(int),
 208                     tmp1.bits, sizeof(uint32_t), sizeof(uint32_t), INIT_VLC_LE);
 209         if(res < 0) {
 210             av_log(smk->avctx, AV_LOG_ERROR, "Cannot build VLC table\n");
 211             return -1;
 212         }
 213     } else {
 214         av_log(smk->avctx, AV_LOG_ERROR, "Skipping low bytes tree\n");
 215     }
 216     if(get_bits1(gb)){
 217         smacker_decode_tree(gb, &tmp2, 0, 0);
 218         skip_bits1(gb);
 219         res = init_vlc(&vlc[1], SMKTREE_BITS, tmp2.length,
 220                     tmp2.lengths, sizeof(int), sizeof(int),
 221                     tmp2.bits, sizeof(uint32_t), sizeof(uint32_t), INIT_VLC_LE);
 222         if(res < 0) {
 223             av_log(smk->avctx, AV_LOG_ERROR, "Cannot build VLC table\n");
 224             return -1;
 225         }
 226     } else {
 227         av_log(smk->avctx, AV_LOG_ERROR, "Skipping high bytes tree\n");
 228     }
 229
 230     escapes[0]  = get_bits(gb, 8);
 231     escapes[0] |= get_bits(gb, 8) << 8;
 232     escapes[1]  = get_bits(gb, 8);
 233     escapes[1] |= get_bits(gb, 8) << 8;
 234     escapes[2]  = get_bits(gb, 8);
 235     escapes[2] |= get_bits(gb, 8) << 8;
 236
 237     last[0] = last[1] = last[2] = -1;
 238
 239     ctx.escapes[0] = escapes[0];
 240     ctx.escapes[1] = escapes[1];
 241     ctx.escapes[2] = escapes[2];
 242     ctx.v1 = &vlc[0];
 243     ctx.v2 = &vlc[1];
 244     ctx.recode1 = tmp1.values;
 245     ctx.recode2 = tmp2.values;
 246     ctx.last = last;
 247
 248     huff.length = ((size + 3) >> 2) + 3;
 249     huff.maxlength = 0;
 250     huff.current = 0;
 251     huff.values = av_mallocz(huff.length * sizeof(int));
 252
 253     smacker_decode_bigtree(gb, &huff, &ctx);
 254     skip_bits1(gb);
 255     if(ctx.last[0] == -1) ctx.last[0] = huff.current++;
 256     if(ctx.last[1] == -1) ctx.last[1] = huff.current++;
 257     if(ctx.last[2] == -1) ctx.last[2] = huff.current++;
 258
 259     *recodes = huff.values;
 260
 261     if(vlc[0].table)
 262         free_vlc(&vlc[0]);
 263     if(vlc[1].table)
 264         free_vlc(&vlc[1]);
 265     av_free(tmp1.bits);
 266     av_free(tmp1.lengths);
 267     av_free(tmp1.values);
 268     av_free(tmp2.bits);
 269     av_free(tmp2.lengths);
 270     av_free(tmp2.values);
 271
 272     return 0;
 273 }
 274
 275 static int decode_header_trees(SmackVContext *smk) {
 276     GetBitContext gb;
 277     int mmap_size, mclr_size, full_size, type_size;
 278
 279     mmap_size = AV_RL32(smk->avctx->extradata);
 280     mclr_size = AV_RL32(smk->avctx->extradata + 4);
 281     full_size = AV_RL32(smk->avctx->extradata + 8);
 282     type_size = AV_RL32(smk->avctx->extradata + 12);
 283
 284     init_get_bits(&gb, smk->avctx->extradata + 16, (smk->avctx->extradata_size - 16) * 8);
 285
 286     if(!get_bits1(&gb)) {
 287         av_log(smk->avctx, AV_LOG_INFO, "Skipping MMAP tree\n");
 288         smk->mmap_tbl = av_malloc(sizeof(int) * 2);
 289         smk->mmap_tbl[0] = 0;
 290         smk->mmap_last[0] = smk->mmap_last[1] = smk->mmap_last[2] = 1;
 291     } else {
 292         smacker_decode_header_tree(smk, &gb, &smk->mmap_tbl, smk->mmap_last, mmap_size);
 293     }
 294     if(!get_bits1(&gb)) {
 295         av_log(smk->avctx, AV_LOG_INFO, "Skipping MCLR tree\n");
 296         smk->mclr_tbl = av_malloc(sizeof(int) * 2);
 297         smk->mclr_tbl[0] = 0;
 298         smk->mclr_last[0] = smk->mclr_last[1] = smk->mclr_last[2] = 1;
 299     } else {
 300         smacker_decode_header_tree(smk, &gb, &smk->mclr_tbl, smk->mclr_last, mclr_size);
 301     }
 302     if(!get_bits1(&gb)) {
 303         av_log(smk->avctx, AV_LOG_INFO, "Skipping FULL tree\n");
 304         smk->full_tbl = av_malloc(sizeof(int) * 2);
 305         smk->full_tbl[0] = 0;
 306         smk->full_last[0] = smk->full_last[1] = smk->full_last[2] = 1;
 307     } else {
 308         smacker_decode_header_tree(smk, &gb, &smk->full_tbl, smk->full_last, full_size);
 309     }
 310     if(!get_bits1(&gb)) {
 311         av_log(smk->avctx, AV_LOG_INFO, "Skipping TYPE tree\n");
 312         smk->type_tbl = av_malloc(sizeof(int) * 2);
 313         smk->type_tbl[0] = 0;
 314         smk->type_last[0] = smk->type_last[1] = smk->type_last[2] = 1;
 315     } else {
 316         smacker_decode_header_tree(smk, &gb, &smk->type_tbl, smk->type_last, type_size);
 317     }
 318
 319     return 0;
 320 }
 321
 322 static av_always_inline void last_reset(int *recode, int *last) {
 323     recode[last[0]] = recode[last[1]] = recode[last[2]] = 0;
 324 }
 325
 326 /* get code and update history */
 327 static av_always_inline int smk_get_code(GetBitContext *gb, int *recode, int *last) {
 328     register int *table = recode;
 329     int v, b;
 330
 331     b = get_bits_count(gb);
 332     while(*table & SMK_NODE) {
 333         if(get_bits1(gb))
 334             table += (*table) & (~SMK_NODE);
 335         table++;
 336     }
 337     v = *table;
 338     b = get_bits_count(gb) - b;
 339
 340     if(v != recode[last[0]]) {
 341         recode[last[2]] = recode[last[1]];
 342         recode[last[1]] = recode[last[0]];
 343         recode[last[0]] = v;
 344     }
 345     return v;
 346 }
 347
 348 static int decode_frame(AVCodecContext *avctx, void *data, int *data_size, const uint8_t *buf, int buf_size)
 349 {
 350     SmackVContext * const smk = avctx->priv_data;
 351     uint8_t *out;
 352     uint32_t *pal;
 353     GetBitContext gb;
 354     int blocks, blk, bw, bh;
 355     int i;
 356     int stride;
 357
 358     if(buf_size <= 769)
 359         return 0;
 360     if(smk->pic.data[0])
 361             avctx->release_buffer(avctx, &smk->pic);
 362
 363     smk->pic.reference = 1;
 364     smk->pic.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
 365     if(avctx->reget_buffer(avctx, &smk->pic) < 0){
 366         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 367         return -1;
 368     }
 369
 370     /* make the palette available on the way out */
 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     buf++;
 380     for(i = 0; i < 256; i++)
 381         *pal++ = bytestream_get_be24(&buf);
 382     buf_size -= 769;
 383
 384     last_reset(smk->mmap_tbl, smk->mmap_last);
 385     last_reset(smk->mclr_tbl, smk->mclr_last);
 386     last_reset(smk->full_tbl, smk->full_last);
 387     last_reset(smk->type_tbl, smk->type_last);
 388     init_get_bits(&gb, buf, buf_size * 8);
 389
 390     blk = 0;
 391     bw = avctx->width >> 2;
 392     bh = avctx->height >> 2;
 393     blocks = bw * bh;
 394     out = smk->pic.data[0];
 395     stride = smk->pic.linesize[0];
 396     while(blk < blocks) {
 397         int type, run, mode;
 398         uint16_t pix;
 399
 400         type = smk_get_code(&gb, smk->type_tbl, smk->type_last);
 401         run = block_runs[(type >> 2) & 0x3F];
 402         switch(type & 3){
 403         case SMK_BLK_MONO:
 404             while(run-- && blk < blocks){
 405                 int clr, map;
 406                 int hi, lo;
 407                 clr = smk_get_code(&gb, smk->mclr_tbl, smk->mclr_last);
 408                 map = smk_get_code(&gb, smk->mmap_tbl, smk->mmap_last);
 409                 out = smk->pic.data[0] + (blk / bw) * (stride * 4) + (blk % bw) * 4;
 410                 hi = clr >> 8;
 411                 lo = clr & 0xFF;
 412                 for(i = 0; i < 4; i++) {
 413                     if(map & 1) out[0] = hi; else out[0] = lo;
 414                     if(map & 2) out[1] = hi; else out[1] = lo;
 415                     if(map & 4) out[2] = hi; else out[2] = lo;
 416                     if(map & 8) out[3] = hi; else out[3] = lo;
 417                     map >>= 4;
 418                     out += stride;
 419                 }
 420                 blk++;
 421             }
 422             break;
 423         case SMK_BLK_FULL:
 424             mode = 0;
 425             if(avctx->codec_tag == MKTAG('S', 'M', 'K', '4')) { // In case of Smacker v4 we have three modes
 426                 if(get_bits1(&gb)) mode = 1;
 427                 else if(get_bits1(&gb)) mode = 2;
 428             }
 429             while(run-- && blk < blocks){
 430                 out = smk->pic.data[0] + (blk / bw) * (stride * 4) + (blk % bw) * 4;
 431                 switch(mode){
 432                 case 0:
 433                     for(i = 0; i < 4; i++) {
 434                         pix = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 435                         AV_WL16(out+2,pix);
 436                         pix = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 437                         AV_WL16(out,pix);
 438                         out += stride;
 439                     }
 440                     break;
 441                 case 1:
 442                     pix = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 443                     out[0] = out[1] = pix & 0xFF;
 444                     out[2] = out[3] = pix >> 8;
 445                     out += stride;
 446                     out[0] = out[1] = pix & 0xFF;
 447                     out[2] = out[3] = pix >> 8;
 448                     out += stride;
 449                     pix = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 450                     out[0] = out[1] = pix & 0xFF;
 451                     out[2] = out[3] = pix >> 8;
 452                     out += stride;
 453                     out[0] = out[1] = pix & 0xFF;
 454                     out[2] = out[3] = pix >> 8;
 455                     out += stride;
 456                     break;
 457                 case 2:
 458                     for(i = 0; i < 2; i++) {
 459                         uint16_t pix1, pix2;
 460                         pix2 = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 461                         pix1 = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 462                         AV_WL16(out,pix1);
 463                         AV_WL16(out+2,pix2);
 464                         out += stride;
 465                         AV_WL16(out,pix1);
 466                         AV_WL16(out+2,pix2);
 467                         out += stride;
 468                     }
 469                     break;
 470                 }
 471                 blk++;
 472             }
 473             break;
 474         case SMK_BLK_SKIP:
 475             while(run-- && blk < blocks)
 476                 blk++;
 477             break;
 478         case SMK_BLK_FILL:
 479             mode = type >> 8;
 480             while(run-- && blk < blocks){
 481                 uint32_t col;
 482                 out = smk->pic.data[0] + (blk / bw) * (stride * 4) + (blk % bw) * 4;
 483                 col = mode * 0x01010101;
 484                 for(i = 0; i < 4; i++) {
 485                     *((uint32_t*)out) = col;
 486                     out += stride;
 487                 }
 488                 blk++;
 489             }
 490             break;
 491         }
 492
 493     }
 494
 495     *data_size = sizeof(AVFrame);
 496     *(AVFrame*)data = smk->pic;
 497
 498     /* always report that the buffer was completely consumed */
 499     return buf_size;
 500 }
 501
 502
 503
 504 /*
 505  *
 506  * Init smacker decoder
 507  *
 508  */
 509 static av_cold int decode_init(AVCodecContext *avctx)
 510 {
 511     SmackVContext * const c = avctx->priv_data;
 512
 513     c->avctx = avctx;
 514
 515     c->pic.data[0] = NULL;
 516
 517     if (avcodec_check_dimensions(avctx, avctx->width, avctx->height) < 0) {
 518         return 1;
 519     }
 520
 521     avctx->pix_fmt = PIX_FMT_PAL8;
 522
 523
 524     /* decode huffman trees from extradata */
 525     if(avctx->extradata_size < 16){
 526         av_log(avctx, AV_LOG_ERROR, "Extradata missing!\n");
 527         return -1;
 528     }
 529
 530     decode_header_trees(c);
 531
 532
 533     return 0;
 534 }
 535
 536
 537
 538 /*
 539  *
 540  * Uninit smacker decoder
 541  *
 542  */
 543 static av_cold int decode_end(AVCodecContext *avctx)
 544 {
 545     SmackVContext * const smk = avctx->priv_data;
 546
 547     av_freep(&smk->mmap_tbl);
 548     av_freep(&smk->mclr_tbl);
 549     av_freep(&smk->full_tbl);
 550     av_freep(&smk->type_tbl);
 551
 552     if (smk->pic.data[0])
 553         avctx->release_buffer(avctx, &smk->pic);
 554
 555     return 0;
 556 }
 557
 558
 559 static av_cold int smka_decode_init(AVCodecContext *avctx)
 560 {
 561     avctx->channel_layout = (avctx->channels==2) ? CH_LAYOUT_STEREO : CH_LAYOUT_MONO;
 562     return 0;
 563 }
 564
 565 /**
 566  * Decode Smacker audio data
 567  */
 568 static int smka_decode_frame(AVCodecContext *avctx, void *data, int *data_size, const uint8_t *buf, int buf_size)
 569 {
 570     GetBitContext gb;
 571     HuffContext h[4];
 572     VLC vlc[4];
 573     int16_t *samples = data;
 574     int8_t *samples8 = data;
 575     int val;
 576     int i, res;
 577     int unp_size;
 578     int bits, stereo;
 579     int pred[2] = {0, 0};
 580
 581     unp_size = AV_RL32(buf);
 582
 583     init_get_bits(&gb, buf + 4, (buf_size - 4) * 8);
 584
 585     if(!get_bits1(&gb)){
 586         av_log(avctx, AV_LOG_INFO, "Sound: no data\n");
 587         *data_size = 0;
 588         return 1;
 589     }
 590     stereo = get_bits1(&gb);
 591     bits = get_bits1(&gb);
 592     if (unp_size & 0xC0000000 || unp_size > *data_size) {
 593         av_log(avctx, AV_LOG_ERROR, "Frame is too large to fit in buffer\n");
 594         return -1;
 595     }
 596
 597     memset(vlc, 0, sizeof(VLC) * 4);
 598     memset(h, 0, sizeof(HuffContext) * 4);
 599     // Initialize
 600     for(i = 0; i < (1 << (bits + stereo)); i++) {
 601         h[i].length = 256;
 602         h[i].maxlength = 0;
 603         h[i].current = 0;
 604         h[i].bits = av_mallocz(256 * 4);
 605         h[i].lengths = av_mallocz(256 * sizeof(int));
 606         h[i].values = av_mallocz(256 * sizeof(int));
 607         skip_bits1(&gb);
 608         smacker_decode_tree(&gb, &h[i], 0, 0);
 609         skip_bits1(&gb);
 610         if(h[i].current > 1) {
 611             res = init_vlc(&vlc[i], SMKTREE_BITS, h[i].length,
 612                     h[i].lengths, sizeof(int), sizeof(int),
 613                     h[i].bits, sizeof(uint32_t), sizeof(uint32_t), INIT_VLC_LE);
 614             if(res < 0) {
 615                 av_log(avctx, AV_LOG_ERROR, "Cannot build VLC table\n");
 616                 return -1;
 617             }
 618         }
 619     }
 620     if(bits) { //decode 16-bit data
 621         for(i = stereo; i >= 0; i--)
 622             pred[i] = bswap_16(get_bits(&gb, 16));
 623         for(i = 0; i < stereo; i++)
 624             *samples++ = pred[i];
 625         for(i = 0; i < unp_size / 2; i++) {
 626             if(i & stereo) {
 627                 if(vlc[2].table)
 628                     res = get_vlc2(&gb, vlc[2].table, SMKTREE_BITS, 3);
 629                 else
 630                     res = 0;
 631                 val  = h[2].values[res];
 632                 if(vlc[3].table)
 633                     res = get_vlc2(&gb, vlc[3].table, SMKTREE_BITS, 3);
 634                 else
 635                     res = 0;
 636                 val |= h[3].values[res] << 8;
 637                 pred[1] += (int16_t)val;
 638                 *samples++ = pred[1];
 639             } else {
 640                 if(vlc[0].table)
 641                     res = get_vlc2(&gb, vlc[0].table, SMKTREE_BITS, 3);
 642                 else
 643                     res = 0;
 644                 val  = h[0].values[res];
 645                 if(vlc[1].table)
 646                     res = get_vlc2(&gb, vlc[1].table, SMKTREE_BITS, 3);
 647                 else
 648                     res = 0;
 649                 val |= h[1].values[res] << 8;
 650                 pred[0] += val;
 651                 *samples++ = pred[0];
 652             }
 653         }
 654     } else { //8-bit data
 655         for(i = stereo; i >= 0; i--)
 656             pred[i] = get_bits(&gb, 8);
 657         for(i = 0; i < stereo; i++)
 658             *samples8++ = pred[i];
 659         for(i = 0; i < unp_size; i++) {
 660             if(i & stereo){
 661                 if(vlc[1].table)
 662                     res = get_vlc2(&gb, vlc[1].table, SMKTREE_BITS, 3);
 663                 else
 664                     res = 0;
 665                 pred[1] += (int8_t)h[1].values[res];
 666                 *samples8++ = pred[1];
 667             } else {
 668                 if(vlc[0].table)
 669                     res = get_vlc2(&gb, vlc[0].table, SMKTREE_BITS, 3);
 670                 else
 671                     res = 0;
 672                 pred[0] += (int8_t)h[0].values[res];
 673                 *samples8++ = pred[0];
 674             }
 675         }
 676     }
 677
 678     for(i = 0; i < 4; i++) {
 679         if(vlc[i].table)
 680             free_vlc(&vlc[i]);
 681         if(h[i].bits)
 682             av_free(h[i].bits);
 683         if(h[i].lengths)
 684             av_free(h[i].lengths);
 685         if(h[i].values)
 686             av_free(h[i].values);
 687     }
 688
 689     *data_size = unp_size;
 690     return buf_size;
 691 }
 692
 693 AVCodec smacker_decoder = {
 694     "smackvid",
 695     CODEC_TYPE_VIDEO,
 696     CODEC_ID_SMACKVIDEO,
 697     sizeof(SmackVContext),
 698     decode_init,
 699     NULL,
 700     decode_end,
 701     decode_frame,
 702     .long_name = NULL_IF_CONFIG_SMALL("Smacker video"),
 703 };
 704
 705 AVCodec smackaud_decoder = {
 706     "smackaud",
 707     CODEC_TYPE_AUDIO,
 708     CODEC_ID_SMACKAUDIO,
 709     0,
 710     smka_decode_init,
 711     NULL,
 712     NULL,
 713     smka_decode_frame,
 714     .long_name = NULL_IF_CONFIG_SMALL("Smacker audio"),
 715 };
 716