libavcodec/smacker.c

   1 /*
   2  * Smacker decoder
   3  * Copyright (c) 2006 Konstantin Shishkov
   4  *
   5  * This file is part of Libav.
   6  *
   7  * Libav 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  * Libav 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 Libav; 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
  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 "libavutil/channel_layout.h"
  35 #include "avcodec.h"
  36 #include "internal.h"
  37 #include "mathops.h"
  38
  39 #define BITSTREAM_READER_LE
  40 #include "get_bits.h"
  41 #include "bytestream.h"
  42
  43 #define SMKTREE_BITS 9
  44 #define SMK_NODE 0x80000000
  45
  46 /*
  47  * Decoder context
  48  */
  49 typedef struct SmackVContext {
  50     AVCodecContext *avctx;
  51     AVFrame pic;
  52
  53     int *mmap_tbl, *mclr_tbl, *full_tbl, *type_tbl;
  54     int mmap_last[3], mclr_last[3], full_last[3], type_last[3];
  55 } SmackVContext;
  56
  57 /**
  58  * Context used for code reconstructing
  59  */
  60 typedef struct HuffContext {
  61     int length;
  62     int maxlength;
  63     int current;
  64     uint32_t *bits;
  65     int *lengths;
  66     int *values;
  67 } HuffContext;
  68
  69 /* common parameters used for decode_bigtree */
  70 typedef struct DBCtx {
  71     VLC *v1, *v2;
  72     int *recode1, *recode2;
  73     int escapes[3];
  74     int *last;
  75     int lcur;
  76 } DBCtx;
  77
  78 /* possible runs of blocks */
  79 static const int block_runs[64] = {
  80       1,    2,    3,    4,    5,    6,    7,    8,
  81       9,   10,   11,   12,   13,   14,   15,   16,
  82      17,   18,   19,   20,   21,   22,   23,   24,
  83      25,   26,   27,   28,   29,   30,   31,   32,
  84      33,   34,   35,   36,   37,   38,   39,   40,
  85      41,   42,   43,   44,   45,   46,   47,   48,
  86      49,   50,   51,   52,   53,   54,   55,   56,
  87      57,   58,   59,  128,  256,  512, 1024, 2048 };
  88
  89 enum SmkBlockTypes {
  90     SMK_BLK_MONO = 0,
  91     SMK_BLK_FULL = 1,
  92     SMK_BLK_SKIP = 2,
  93     SMK_BLK_FILL = 3 };
  94
  95 /**
  96  * Decode local frame tree
  97  */
  98 static int smacker_decode_tree(GetBitContext *gb, HuffContext *hc, uint32_t prefix, int length)
  99 {
 100     if(!get_bits1(gb)){ //Leaf
 101         if(hc->current >= 256){
 102             av_log(NULL, AV_LOG_ERROR, "Tree size exceeded!\n");
 103             return -1;
 104         }
 105         if(length){
 106             hc->bits[hc->current] = prefix;
 107             hc->lengths[hc->current] = length;
 108         } else {
 109             hc->bits[hc->current] = 0;
 110             hc->lengths[hc->current] = 0;
 111         }
 112         hc->values[hc->current] = get_bits(gb, 8);
 113         hc->current++;
 114         if(hc->maxlength < length)
 115             hc->maxlength = length;
 116         return 0;
 117     } else { //Node
 118         int r;
 119         length++;
 120         r = smacker_decode_tree(gb, hc, prefix, length);
 121         if(r)
 122             return r;
 123         return smacker_decode_tree(gb, hc, prefix | (1 << (length - 1)), length);
 124     }
 125 }
 126
 127 /**
 128  * Decode header tree
 129  */
 130 static int smacker_decode_bigtree(GetBitContext *gb, HuffContext *hc, DBCtx *ctx)
 131 {
 132     if (hc->current + 1 >= hc->length) {
 133         av_log(NULL, AV_LOG_ERROR, "Tree size exceeded!\n");
 134         return -1;
 135     }
 136     if(!get_bits1(gb)){ //Leaf
 137         int val, i1, i2;
 138         i1 = ctx->v1->table ? get_vlc2(gb, ctx->v1->table, SMKTREE_BITS, 3) : 0;
 139         i2 = ctx->v2->table ? get_vlc2(gb, ctx->v2->table, SMKTREE_BITS, 3) : 0;
 140         if (i1 < 0 || i2 < 0)
 141             return -1;
 142         val = ctx->recode1[i1] | (ctx->recode2[i2] << 8);
 143         if(val == ctx->escapes[0]) {
 144             ctx->last[0] = hc->current;
 145             val = 0;
 146         } else if(val == ctx->escapes[1]) {
 147             ctx->last[1] = hc->current;
 148             val = 0;
 149         } else if(val == ctx->escapes[2]) {
 150             ctx->last[2] = hc->current;
 151             val = 0;
 152         }
 153
 154         hc->values[hc->current++] = val;
 155         return 1;
 156     } else { //Node
 157         int r = 0, r_new, t;
 158
 159         t = hc->current++;
 160         r = smacker_decode_bigtree(gb, hc, ctx);
 161         if(r < 0)
 162             return r;
 163         hc->values[t] = SMK_NODE | r;
 164         r++;
 165         r_new = smacker_decode_bigtree(gb, hc, ctx);
 166         if (r_new < 0)
 167             return r_new;
 168         return r + r_new;
 169     }
 170 }
 171
 172 /**
 173  * Store large tree as Libav's vlc codes
 174  */
 175 static int smacker_decode_header_tree(SmackVContext *smk, GetBitContext *gb, int **recodes, int *last, int size)
 176 {
 177     int res;
 178     HuffContext huff;
 179     HuffContext tmp1, tmp2;
 180     VLC vlc[2] = { { 0 } };
 181     int escapes[3];
 182     DBCtx ctx;
 183     int err = 0;
 184
 185     if(size >= UINT_MAX>>4){ // (((size + 3) >> 2) + 3) << 2 must not overflow
 186         av_log(smk->avctx, AV_LOG_ERROR, "size too large\n");
 187         return -1;
 188     }
 189
 190     tmp1.length = 256;
 191     tmp1.maxlength = 0;
 192     tmp1.current = 0;
 193     tmp1.bits = av_mallocz(256 * 4);
 194     tmp1.lengths = av_mallocz(256 * sizeof(int));
 195     tmp1.values = av_mallocz(256 * sizeof(int));
 196
 197     tmp2.length = 256;
 198     tmp2.maxlength = 0;
 199     tmp2.current = 0;
 200     tmp2.bits = av_mallocz(256 * 4);
 201     tmp2.lengths = av_mallocz(256 * sizeof(int));
 202     tmp2.values = av_mallocz(256 * sizeof(int));
 203
 204     if(get_bits1(gb)) {
 205         smacker_decode_tree(gb, &tmp1, 0, 0);
 206         skip_bits1(gb);
 207         res = init_vlc(&vlc[0], SMKTREE_BITS, tmp1.length,
 208                     tmp1.lengths, sizeof(int), sizeof(int),
 209                     tmp1.bits, sizeof(uint32_t), sizeof(uint32_t), INIT_VLC_LE);
 210         if(res < 0) {
 211             av_log(smk->avctx, AV_LOG_ERROR, "Cannot build VLC table\n");
 212             return -1;
 213         }
 214     } else {
 215         av_log(smk->avctx, AV_LOG_ERROR, "Skipping low bytes tree\n");
 216     }
 217     if(get_bits1(gb)){
 218         smacker_decode_tree(gb, &tmp2, 0, 0);
 219         skip_bits1(gb);
 220         res = init_vlc(&vlc[1], SMKTREE_BITS, tmp2.length,
 221                     tmp2.lengths, sizeof(int), sizeof(int),
 222                     tmp2.bits, sizeof(uint32_t), sizeof(uint32_t), INIT_VLC_LE);
 223         if(res < 0) {
 224             av_log(smk->avctx, AV_LOG_ERROR, "Cannot build VLC table\n");
 225             return -1;
 226         }
 227     } else {
 228         av_log(smk->avctx, AV_LOG_ERROR, "Skipping high bytes tree\n");
 229     }
 230
 231     escapes[0]  = get_bits(gb, 8);
 232     escapes[0] |= get_bits(gb, 8) << 8;
 233     escapes[1]  = get_bits(gb, 8);
 234     escapes[1] |= get_bits(gb, 8) << 8;
 235     escapes[2]  = get_bits(gb, 8);
 236     escapes[2] |= get_bits(gb, 8) << 8;
 237
 238     last[0] = last[1] = last[2] = -1;
 239
 240     ctx.escapes[0] = escapes[0];
 241     ctx.escapes[1] = escapes[1];
 242     ctx.escapes[2] = escapes[2];
 243     ctx.v1 = &vlc[0];
 244     ctx.v2 = &vlc[1];
 245     ctx.recode1 = tmp1.values;
 246     ctx.recode2 = tmp2.values;
 247     ctx.last = last;
 248
 249     huff.length = ((size + 3) >> 2) + 3;
 250     huff.maxlength = 0;
 251     huff.current = 0;
 252     huff.values = av_mallocz(huff.length * sizeof(int));
 253
 254     if (smacker_decode_bigtree(gb, &huff, &ctx) < 0)
 255         err = -1;
 256     skip_bits1(gb);
 257     if(ctx.last[0] == -1) ctx.last[0] = huff.current++;
 258     if(ctx.last[1] == -1) ctx.last[1] = huff.current++;
 259     if(ctx.last[2] == -1) ctx.last[2] = huff.current++;
 260
 261     *recodes = huff.values;
 262
 263     if(vlc[0].table)
 264         ff_free_vlc(&vlc[0]);
 265     if(vlc[1].table)
 266         ff_free_vlc(&vlc[1]);
 267     av_free(tmp1.bits);
 268     av_free(tmp1.lengths);
 269     av_free(tmp1.values);
 270     av_free(tmp2.bits);
 271     av_free(tmp2.lengths);
 272     av_free(tmp2.values);
 273
 274     return err;
 275 }
 276
 277 static int decode_header_trees(SmackVContext *smk) {
 278     GetBitContext gb;
 279     int mmap_size, mclr_size, full_size, type_size;
 280
 281     mmap_size = AV_RL32(smk->avctx->extradata);
 282     mclr_size = AV_RL32(smk->avctx->extradata + 4);
 283     full_size = AV_RL32(smk->avctx->extradata + 8);
 284     type_size = AV_RL32(smk->avctx->extradata + 12);
 285
 286     init_get_bits(&gb, smk->avctx->extradata + 16, (smk->avctx->extradata_size - 16) * 8);
 287
 288     if(!get_bits1(&gb)) {
 289         av_log(smk->avctx, AV_LOG_INFO, "Skipping MMAP tree\n");
 290         smk->mmap_tbl = av_malloc(sizeof(int) * 2);
 291         smk->mmap_tbl[0] = 0;
 292         smk->mmap_last[0] = smk->mmap_last[1] = smk->mmap_last[2] = 1;
 293     } else {
 294         if (smacker_decode_header_tree(smk, &gb, &smk->mmap_tbl, smk->mmap_last, mmap_size))
 295             return -1;
 296     }
 297     if(!get_bits1(&gb)) {
 298         av_log(smk->avctx, AV_LOG_INFO, "Skipping MCLR tree\n");
 299         smk->mclr_tbl = av_malloc(sizeof(int) * 2);
 300         smk->mclr_tbl[0] = 0;
 301         smk->mclr_last[0] = smk->mclr_last[1] = smk->mclr_last[2] = 1;
 302     } else {
 303         if (smacker_decode_header_tree(smk, &gb, &smk->mclr_tbl, smk->mclr_last, mclr_size))
 304             return -1;
 305     }
 306     if(!get_bits1(&gb)) {
 307         av_log(smk->avctx, AV_LOG_INFO, "Skipping FULL tree\n");
 308         smk->full_tbl = av_malloc(sizeof(int) * 2);
 309         smk->full_tbl[0] = 0;
 310         smk->full_last[0] = smk->full_last[1] = smk->full_last[2] = 1;
 311     } else {
 312         if (smacker_decode_header_tree(smk, &gb, &smk->full_tbl, smk->full_last, full_size))
 313             return -1;
 314     }
 315     if(!get_bits1(&gb)) {
 316         av_log(smk->avctx, AV_LOG_INFO, "Skipping TYPE tree\n");
 317         smk->type_tbl = av_malloc(sizeof(int) * 2);
 318         smk->type_tbl[0] = 0;
 319         smk->type_last[0] = smk->type_last[1] = smk->type_last[2] = 1;
 320     } else {
 321         if (smacker_decode_header_tree(smk, &gb, &smk->type_tbl, smk->type_last, type_size))
 322             return -1;
 323     }
 324
 325     return 0;
 326 }
 327
 328 static av_always_inline void last_reset(int *recode, int *last) {
 329     recode[last[0]] = recode[last[1]] = recode[last[2]] = 0;
 330 }
 331
 332 /* get code and update history */
 333 static av_always_inline int smk_get_code(GetBitContext *gb, int *recode, int *last) {
 334     register int *table = recode;
 335     int v;
 336
 337     while(*table & SMK_NODE) {
 338         if(get_bits1(gb))
 339             table += (*table) & (~SMK_NODE);
 340         table++;
 341     }
 342     v = *table;
 343
 344     if(v != recode[last[0]]) {
 345         recode[last[2]] = recode[last[1]];
 346         recode[last[1]] = recode[last[0]];
 347         recode[last[0]] = v;
 348     }
 349     return v;
 350 }
 351
 352 static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
 353                         AVPacket *avpkt)
 354 {
 355     SmackVContext * const smk = avctx->priv_data;
 356     uint8_t *out;
 357     uint32_t *pal;
 358     GetByteContext gb2;
 359     GetBitContext gb;
 360     int blocks, blk, bw, bh;
 361     int i;
 362     int stride;
 363     int flags;
 364
 365     if (avpkt->size <= 769)
 366         return 0;
 367
 368     smk->pic.reference = 1;
 369     smk->pic.buffer_hints = FF_BUFFER_HINTS_VALID | FF_BUFFER_HINTS_PRESERVE | FF_BUFFER_HINTS_REUSABLE;
 370     if(avctx->reget_buffer(avctx, &smk->pic) < 0){
 371         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 372         return -1;
 373     }
 374
 375     /* make the palette available on the way out */
 376     pal = (uint32_t*)smk->pic.data[1];
 377     bytestream2_init(&gb2, avpkt->data, avpkt->size);
 378     flags = bytestream2_get_byteu(&gb2);
 379     smk->pic.palette_has_changed = flags & 1;
 380     smk->pic.key_frame = !!(flags & 2);
 381     if(smk->pic.key_frame)
 382         smk->pic.pict_type = AV_PICTURE_TYPE_I;
 383     else
 384         smk->pic.pict_type = AV_PICTURE_TYPE_P;
 385
 386     for(i = 0; i < 256; i++)
 387         *pal++ = bytestream2_get_be24u(&gb2);
 388
 389     last_reset(smk->mmap_tbl, smk->mmap_last);
 390     last_reset(smk->mclr_tbl, smk->mclr_last);
 391     last_reset(smk->full_tbl, smk->full_last);
 392     last_reset(smk->type_tbl, smk->type_last);
 393     init_get_bits(&gb, avpkt->data + 769, (avpkt->size - 769) * 8);
 394
 395     blk = 0;
 396     bw = avctx->width >> 2;
 397     bh = avctx->height >> 2;
 398     blocks = bw * bh;
 399     out = smk->pic.data[0];
 400     stride = smk->pic.linesize[0];
 401     while(blk < blocks) {
 402         int type, run, mode;
 403         uint16_t pix;
 404
 405         type = smk_get_code(&gb, smk->type_tbl, smk->type_last);
 406         run = block_runs[(type >> 2) & 0x3F];
 407         switch(type & 3){
 408         case SMK_BLK_MONO:
 409             while(run-- && blk < blocks){
 410                 int clr, map;
 411                 int hi, lo;
 412                 clr = smk_get_code(&gb, smk->mclr_tbl, smk->mclr_last);
 413                 map = smk_get_code(&gb, smk->mmap_tbl, smk->mmap_last);
 414                 out = smk->pic.data[0] + (blk / bw) * (stride * 4) + (blk % bw) * 4;
 415                 hi = clr >> 8;
 416                 lo = clr & 0xFF;
 417                 for(i = 0; i < 4; i++) {
 418                     if(map & 1) out[0] = hi; else out[0] = lo;
 419                     if(map & 2) out[1] = hi; else out[1] = lo;
 420                     if(map & 4) out[2] = hi; else out[2] = lo;
 421                     if(map & 8) out[3] = hi; else out[3] = lo;
 422                     map >>= 4;
 423                     out += stride;
 424                 }
 425                 blk++;
 426             }
 427             break;
 428         case SMK_BLK_FULL:
 429             mode = 0;
 430             if(avctx->codec_tag == MKTAG('S', 'M', 'K', '4')) { // In case of Smacker v4 we have three modes
 431                 if(get_bits1(&gb)) mode = 1;
 432                 else if(get_bits1(&gb)) mode = 2;
 433             }
 434             while(run-- && blk < blocks){
 435                 out = smk->pic.data[0] + (blk / bw) * (stride * 4) + (blk % bw) * 4;
 436                 switch(mode){
 437                 case 0:
 438                     for(i = 0; i < 4; i++) {
 439                         pix = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 440                         AV_WL16(out+2,pix);
 441                         pix = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 442                         AV_WL16(out,pix);
 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                         pix2 = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 466                         pix1 = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 467                         AV_WL16(out,pix1);
 468                         AV_WL16(out+2,pix2);
 469                         out += stride;
 470                         AV_WL16(out,pix1);
 471                         AV_WL16(out+2,pix2);
 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     *got_frame = 1;
 501     *(AVFrame*)data = smk->pic;
 502
 503     /* always report that the buffer was completely consumed */
 504     return avpkt->size;
 505 }
 506
 507
 508
 509 /*
 510  *
 511  * Init smacker decoder
 512  *
 513  */
 514 static av_cold int decode_init(AVCodecContext *avctx)
 515 {
 516     SmackVContext * const c = avctx->priv_data;
 517
 518     c->avctx = avctx;
 519
 520     avctx->pix_fmt = AV_PIX_FMT_PAL8;
 521
 522
 523     /* decode huffman trees from extradata */
 524     if(avctx->extradata_size < 16){
 525         av_log(avctx, AV_LOG_ERROR, "Extradata missing!\n");
 526         return -1;
 527     }
 528
 529     if (decode_header_trees(c))
 530         return -1;
 531
 532     return 0;
 533 }
 534
 535
 536
 537 /*
 538  *
 539  * Uninit smacker decoder
 540  *
 541  */
 542 static av_cold int decode_end(AVCodecContext *avctx)
 543 {
 544     SmackVContext * const smk = avctx->priv_data;
 545
 546     av_freep(&smk->mmap_tbl);
 547     av_freep(&smk->mclr_tbl);
 548     av_freep(&smk->full_tbl);
 549     av_freep(&smk->type_tbl);
 550
 551     if (smk->pic.data[0])
 552         avctx->release_buffer(avctx, &smk->pic);
 553
 554     return 0;
 555 }
 556
 557
 558 typedef struct SmackerAudioContext {
 559     AVFrame frame;
 560 } SmackerAudioContext;
 561
 562 static av_cold int smka_decode_init(AVCodecContext *avctx)
 563 {
 564     SmackerAudioContext *s = avctx->priv_data;
 565
 566     if (avctx->channels < 1 || avctx->channels > 2) {
 567         av_log(avctx, AV_LOG_ERROR, "invalid number of channels\n");
 568         return AVERROR(EINVAL);
 569     }
 570     avctx->channel_layout = (avctx->channels==2) ? AV_CH_LAYOUT_STEREO : AV_CH_LAYOUT_MONO;
 571     avctx->sample_fmt = avctx->bits_per_coded_sample == 8 ? AV_SAMPLE_FMT_U8 : AV_SAMPLE_FMT_S16;
 572
 573     avcodec_get_frame_defaults(&s->frame);
 574     avctx->coded_frame = &s->frame;
 575
 576     return 0;
 577 }
 578
 579 /**
 580  * Decode Smacker audio data
 581  */
 582 static int smka_decode_frame(AVCodecContext *avctx, void *data,
 583                              int *got_frame_ptr, AVPacket *avpkt)
 584 {
 585     SmackerAudioContext *s = avctx->priv_data;
 586     const uint8_t *buf = avpkt->data;
 587     int buf_size = avpkt->size;
 588     GetBitContext gb;
 589     HuffContext h[4] = { { 0 } };
 590     VLC vlc[4]       = { { 0 } };
 591     int16_t *samples;
 592     uint8_t *samples8;
 593     int val;
 594     int i, res, ret;
 595     int unp_size;
 596     int bits, stereo;
 597     int pred[2] = {0, 0};
 598
 599     if (buf_size <= 4) {
 600         av_log(avctx, AV_LOG_ERROR, "packet is too small\n");
 601         return AVERROR(EINVAL);
 602     }
 603
 604     unp_size = AV_RL32(buf);
 605
 606     init_get_bits(&gb, buf + 4, (buf_size - 4) * 8);
 607
 608     if(!get_bits1(&gb)){
 609         av_log(avctx, AV_LOG_INFO, "Sound: no data\n");
 610         *got_frame_ptr = 0;
 611         return 1;
 612     }
 613     stereo = get_bits1(&gb);
 614     bits = get_bits1(&gb);
 615     if (stereo ^ (avctx->channels != 1)) {
 616         av_log(avctx, AV_LOG_ERROR, "channels mismatch\n");
 617         return AVERROR(EINVAL);
 618     }
 619     if (bits && avctx->sample_fmt == AV_SAMPLE_FMT_U8) {
 620         av_log(avctx, AV_LOG_ERROR, "sample format mismatch\n");
 621         return AVERROR(EINVAL);
 622     }
 623
 624     /* get output buffer */
 625     s->frame.nb_samples = unp_size / (avctx->channels * (bits + 1));
 626     if ((ret = ff_get_buffer(avctx, &s->frame)) < 0) {
 627         av_log(avctx, AV_LOG_ERROR, "get_buffer() failed\n");
 628         return ret;
 629     }
 630     samples  = (int16_t *)s->frame.data[0];
 631     samples8 =            s->frame.data[0];
 632
 633     // Initialize
 634     for(i = 0; i < (1 << (bits + stereo)); i++) {
 635         h[i].length = 256;
 636         h[i].maxlength = 0;
 637         h[i].current = 0;
 638         h[i].bits = av_mallocz(256 * 4);
 639         h[i].lengths = av_mallocz(256 * sizeof(int));
 640         h[i].values = av_mallocz(256 * sizeof(int));
 641         skip_bits1(&gb);
 642         smacker_decode_tree(&gb, &h[i], 0, 0);
 643         skip_bits1(&gb);
 644         if(h[i].current > 1) {
 645             res = init_vlc(&vlc[i], SMKTREE_BITS, h[i].length,
 646                     h[i].lengths, sizeof(int), sizeof(int),
 647                     h[i].bits, sizeof(uint32_t), sizeof(uint32_t), INIT_VLC_LE);
 648             if(res < 0) {
 649                 av_log(avctx, AV_LOG_ERROR, "Cannot build VLC table\n");
 650                 return -1;
 651             }
 652         }
 653     }
 654     if(bits) { //decode 16-bit data
 655         for(i = stereo; i >= 0; i--)
 656             pred[i] = sign_extend(av_bswap16(get_bits(&gb, 16)), 16);
 657         for(i = 0; i <= stereo; i++)
 658             *samples++ = pred[i];
 659         for(; i < unp_size / 2; i++) {
 660             if(i & stereo) {
 661                 if(vlc[2].table)
 662                     res = get_vlc2(&gb, vlc[2].table, SMKTREE_BITS, 3);
 663                 else
 664                     res = 0;
 665                 val  = h[2].values[res];
 666                 if(vlc[3].table)
 667                     res = get_vlc2(&gb, vlc[3].table, SMKTREE_BITS, 3);
 668                 else
 669                     res = 0;
 670                 val |= h[3].values[res] << 8;
 671                 pred[1] += sign_extend(val, 16);
 672                 *samples++ = av_clip_int16(pred[1]);
 673             } else {
 674                 if(vlc[0].table)
 675                     res = get_vlc2(&gb, vlc[0].table, SMKTREE_BITS, 3);
 676                 else
 677                     res = 0;
 678                 val  = h[0].values[res];
 679                 if(vlc[1].table)
 680                     res = get_vlc2(&gb, vlc[1].table, SMKTREE_BITS, 3);
 681                 else
 682                     res = 0;
 683                 val |= h[1].values[res] << 8;
 684                 pred[0] += sign_extend(val, 16);
 685                 *samples++ = av_clip_int16(pred[0]);
 686             }
 687         }
 688     } else { //8-bit data
 689         for(i = stereo; i >= 0; i--)
 690             pred[i] = get_bits(&gb, 8);
 691         for(i = 0; i <= stereo; i++)
 692             *samples8++ = pred[i];
 693         for(; i < unp_size; i++) {
 694             if(i & stereo){
 695                 if(vlc[1].table)
 696                     res = get_vlc2(&gb, vlc[1].table, SMKTREE_BITS, 3);
 697                 else
 698                     res = 0;
 699                 pred[1] += sign_extend(h[1].values[res], 8);
 700                 *samples8++ = av_clip_uint8(pred[1]);
 701             } else {
 702                 if(vlc[0].table)
 703                     res = get_vlc2(&gb, vlc[0].table, SMKTREE_BITS, 3);
 704                 else
 705                     res = 0;
 706                 pred[0] += sign_extend(h[0].values[res], 8);
 707                 *samples8++ = av_clip_uint8(pred[0]);
 708             }
 709         }
 710     }
 711
 712     for(i = 0; i < 4; i++) {
 713         if(vlc[i].table)
 714             ff_free_vlc(&vlc[i]);
 715         av_free(h[i].bits);
 716         av_free(h[i].lengths);
 717         av_free(h[i].values);
 718     }
 719
 720     *got_frame_ptr   = 1;
 721     *(AVFrame *)data = s->frame;
 722
 723     return buf_size;
 724 }
 725
 726 AVCodec ff_smacker_decoder = {
 727     .name           = "smackvid",
 728     .type           = AVMEDIA_TYPE_VIDEO,
 729     .id             = AV_CODEC_ID_SMACKVIDEO,
 730     .priv_data_size = sizeof(SmackVContext),
 731     .init           = decode_init,
 732     .close          = decode_end,
 733     .decode         = decode_frame,
 734     .capabilities   = CODEC_CAP_DR1,
 735     .long_name      = NULL_IF_CONFIG_SMALL("Smacker video"),
 736 };
 737
 738 AVCodec ff_smackaud_decoder = {
 739     .name           = "smackaud",
 740     .type           = AVMEDIA_TYPE_AUDIO,
 741     .id             = AV_CODEC_ID_SMACKAUDIO,
 742     .priv_data_size = sizeof(SmackerAudioContext),
 743     .init           = smka_decode_init,
 744     .decode         = smka_decode_frame,
 745     .capabilities   = CODEC_CAP_DR1,
 746     .long_name      = NULL_IF_CONFIG_SMALL("Smacker audio"),
 747 };