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
  24  * Smacker decoder
  25  */
  26
  27 /*
  28  * Based on http://wiki.multimedia.cx/index.php?title=Smacker
  29  */
  30
  31 #include <stddef.h>
  32
  33 #include "libavutil/channel_layout.h"
  34 #include "libavutil/mem.h"
  35
  36 #include "avcodec.h"
  37
  38 #define SMKTREE_BITS 9
  39 #define SMK_NODE 0x80000000
  40
  41 #define SMKTREE_DECODE_MAX_RECURSION FFMIN(32, 3 * SMKTREE_BITS)
  42 #define SMKTREE_DECODE_BIG_MAX_RECURSION 500
  43
  44 /* The maximum possible unchecked overread happens in decode_header_trees:
  45  * Decoding the MMAP tree can overread by 6 * SMKTREE_BITS + 1, followed by
  46  * three get_bits1, followed by at most 2 + 3 * 16 read bits when reading
  47  * the TYPE tree before the next check. 64 is because of 64 bit reads. */
  48 #if (6 * SMKTREE_BITS + 1 + 3 + (2 + 3 * 16) + 64) <= 8 * AV_INPUT_BUFFER_PADDING_SIZE
  49 #define UNCHECKED_BITSTREAM_READER 1
  50 #endif
  51 #define BITSTREAM_READER_LE
  52 #include "bytestream.h"
  53 #include "codec_internal.h"
  54 #include "decode.h"
  55 #include "get_bits.h"
  56
  57 typedef struct SmackVContext {
  58     AVCodecContext *avctx;
  59     AVFrame *pic;
  60
  61     int *mmap_tbl, *mclr_tbl, *full_tbl, *type_tbl;
  62     int mmap_last[3], mclr_last[3], full_last[3], type_last[3];
  63 } SmackVContext;
  64
  65 typedef struct HuffEntry {
  66     uint8_t value;
  67     uint8_t length;
  68 } HuffEntry;
  69
  70 /**
  71  * Context used for code reconstructing
  72  */
  73 typedef struct HuffContext {
  74     int current;
  75     HuffEntry entries[256];
  76 } HuffContext;
  77
  78 /* common parameters used for decode_bigtree */
  79 typedef struct DBCtx {
  80     int current, length;
  81     int *values;
  82     VLC *v1, *v2;
  83     uint8_t vals[2];
  84     int escapes[3];
  85     int *last;
  86 } DBCtx;
  87
  88 /* possible runs of blocks */
  89 static const int block_runs[64] = {
  90       1,    2,    3,    4,    5,    6,    7,    8,
  91       9,   10,   11,   12,   13,   14,   15,   16,
  92      17,   18,   19,   20,   21,   22,   23,   24,
  93      25,   26,   27,   28,   29,   30,   31,   32,
  94      33,   34,   35,   36,   37,   38,   39,   40,
  95      41,   42,   43,   44,   45,   46,   47,   48,
  96      49,   50,   51,   52,   53,   54,   55,   56,
  97      57,   58,   59,  128,  256,  512, 1024, 2048 };
  98
  99 enum SmkBlockTypes {
 100     SMK_BLK_MONO = 0,
 101     SMK_BLK_FULL = 1,
 102     SMK_BLK_SKIP = 2,
 103     SMK_BLK_FILL = 3 };
 104
 105 /**
 106  * Decode local frame tree
 107  *
 108  * Can read SMKTREE_DECODE_MAX_RECURSION before the first check;
 109  * does not overread gb on success.
 110  */
 111 static int smacker_decode_tree(AVCodecContext *avctx, GetBitContext *gb, HuffContext *hc, int length)
 112 {
 113     if (length > SMKTREE_DECODE_MAX_RECURSION || length > 3 * SMKTREE_BITS) {
 114         av_log(avctx, AV_LOG_ERROR, "Maximum tree recursion level exceeded.\n");
 115         return AVERROR_INVALIDDATA;
 116     }
 117
 118     if(!get_bits1(gb)){ //Leaf
 119         if (hc->current >= 256) {
 120             av_log(avctx, AV_LOG_ERROR, "Tree size exceeded!\n");
 121             return AVERROR_INVALIDDATA;
 122         }
 123         if (get_bits_left(gb) < 8)
 124             return AVERROR_INVALIDDATA;
 125         hc->entries[hc->current++] = (HuffEntry){ get_bits(gb, 8), length };
 126         return 0;
 127     } else { //Node
 128         int r;
 129         length++;
 130         r = smacker_decode_tree(avctx, gb, hc, length);
 131         if(r)
 132             return r;
 133         return smacker_decode_tree(avctx, gb, hc, length);
 134     }
 135 }
 136
 137 /**
 138  * Decode header tree
 139  *
 140  * Checks before the first read, can overread by 6 * SMKTREE_BITS on success.
 141  */
 142 static int smacker_decode_bigtree(AVCodecContext *avctx, GetBitContext *gb, DBCtx *ctx, int length)
 143 {
 144     // Larger length can cause segmentation faults due to too deep recursion.
 145     if (length > SMKTREE_DECODE_BIG_MAX_RECURSION) {
 146         av_log(NULL, AV_LOG_ERROR, "Maximum bigtree recursion level exceeded.\n");
 147         return AVERROR_INVALIDDATA;
 148     }
 149
 150     if (ctx->current >= ctx->length) {
 151         av_log(NULL, AV_LOG_ERROR, "Tree size exceeded!\n");
 152         return AVERROR_INVALIDDATA;
 153     }
 154     if (get_bits_left(gb) <= 0)
 155         return AVERROR_INVALIDDATA;
 156     if(!get_bits1(gb)){ //Leaf
 157         int val, i1, i2;
 158         i1 = ctx->v1->table ? get_vlc2(gb, ctx->v1->table, SMKTREE_BITS, 3)
 159                             : ctx->vals[0];
 160         i2 = ctx->v2->table ? get_vlc2(gb, ctx->v2->table, SMKTREE_BITS, 3)
 161                             : ctx->vals[1];
 162         val = i1 | (i2 << 8);
 163         if(val == ctx->escapes[0]) {
 164             ctx->last[0] = ctx->current;
 165             val = 0;
 166         } else if(val == ctx->escapes[1]) {
 167             ctx->last[1] = ctx->current;
 168             val = 0;
 169         } else if(val == ctx->escapes[2]) {
 170             ctx->last[2] = ctx->current;
 171             val = 0;
 172         }
 173
 174         ctx->values[ctx->current++] = val;
 175         return 1;
 176     } else { //Node
 177         int r = 0, r_new, t;
 178
 179         t = ctx->current++;
 180         r = smacker_decode_bigtree(avctx, gb, ctx, length + 1);
 181         if(r < 0)
 182             return r;
 183         ctx->values[t] = SMK_NODE | r;
 184         r++;
 185         r_new = smacker_decode_bigtree(avctx, gb, ctx, length + 1);
 186         if (r_new < 0)
 187             return r_new;
 188         return r + r_new;
 189     }
 190 }
 191
 192 /**
 193  * Store large tree as FFmpeg's vlc codes
 194  *
 195  * Can read FFMAX(1 + SMKTREE_DECODE_MAX_RECURSION, 2 + 3 * 16) bits
 196  * before the first check; can overread by 6 * SMKTREE_BITS + 1 on success.
 197  */
 198 static int smacker_decode_header_tree(SmackVContext *smk, GetBitContext *gb, int **recodes, int *last, int size)
 199 {
 200     VLC vlc[2] = { { 0 } };
 201     int escapes[3];
 202     DBCtx ctx;
 203     int err;
 204
 205     if(size >= UINT_MAX>>4){ // (((size + 3) >> 2) + 3) << 2 must not overflow
 206         av_log(smk->avctx, AV_LOG_ERROR, "size too large\n");
 207         return AVERROR_INVALIDDATA;
 208     }
 209
 210     for (int i = 0; i < 2; i++) {
 211         HuffContext h;
 212         h.current = 0;
 213         if (!get_bits1(gb)) {
 214             ctx.vals[i] = 0;
 215             av_log(smk->avctx, AV_LOG_ERROR, "Skipping %s bytes tree\n",
 216                    i ? "high" : "low");
 217             continue;
 218         }
 219         err = smacker_decode_tree(smk->avctx, gb, &h, 0);
 220         if (err < 0)
 221             goto error;
 222         skip_bits1(gb);
 223         if (h.current > 1) {
 224             err = ff_vlc_init_from_lengths(&vlc[i], SMKTREE_BITS, h.current,
 225                                            &h.entries[0].length, sizeof(*h.entries),
 226                                            &h.entries[0].value,  sizeof(*h.entries), 1,
 227                                            0, VLC_INIT_OUTPUT_LE, smk->avctx);
 228             if (err < 0) {
 229                 av_log(smk->avctx, AV_LOG_ERROR, "Cannot build VLC table\n");
 230                 goto error;
 231             }
 232         } else
 233             ctx.vals[i] = h.entries[0].value;
 234     }
 235
 236     escapes[0]  = get_bits(gb, 16);
 237     escapes[1]  = get_bits(gb, 16);
 238     escapes[2]  = get_bits(gb, 16);
 239
 240     last[0] = last[1] = last[2] = -1;
 241
 242     ctx.escapes[0] = escapes[0];
 243     ctx.escapes[1] = escapes[1];
 244     ctx.escapes[2] = escapes[2];
 245     ctx.v1 = &vlc[0];
 246     ctx.v2 = &vlc[1];
 247     ctx.last = last;
 248     ctx.length  = (size + 3) >> 2;
 249     ctx.current = 0;
 250     ctx.values  = av_malloc_array(ctx.length + 3, sizeof(ctx.values[0]));
 251     if (!ctx.values) {
 252         err = AVERROR(ENOMEM);
 253         goto error;
 254     }
 255     *recodes = ctx.values;
 256
 257     err = smacker_decode_bigtree(smk->avctx, gb, &ctx, 0);
 258     if (err < 0)
 259         goto error;
 260     skip_bits1(gb);
 261     if (ctx.last[0] == -1) ctx.last[0] = ctx.current++;
 262     if (ctx.last[1] == -1) ctx.last[1] = ctx.current++;
 263     if (ctx.last[2] == -1) ctx.last[2] = ctx.current++;
 264
 265     err = 0;
 266 error:
 267     for (int i = 0; i < 2; i++) {
 268         ff_vlc_free(&vlc[i]);
 269     }
 270
 271     return err;
 272 }
 273
 274 static int decode_header_trees(SmackVContext *smk) {
 275     GetBitContext gb;
 276     int mmap_size, mclr_size, full_size, type_size, ret;
 277     int skip = 0;
 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     ret = init_get_bits8(&gb, smk->avctx->extradata + 16, smk->avctx->extradata_size - 16);
 285     if (ret < 0)
 286         return ret;
 287
 288     if(!get_bits1(&gb)) {
 289         skip ++;
 290         av_log(smk->avctx, AV_LOG_INFO, "Skipping MMAP tree\n");
 291         smk->mmap_tbl = av_malloc(sizeof(int) * 2);
 292         if (!smk->mmap_tbl)
 293             return AVERROR(ENOMEM);
 294         smk->mmap_tbl[0] = 0;
 295         smk->mmap_last[0] = smk->mmap_last[1] = smk->mmap_last[2] = 1;
 296     } else {
 297         ret = smacker_decode_header_tree(smk, &gb, &smk->mmap_tbl, smk->mmap_last, mmap_size);
 298         if (ret < 0)
 299             return ret;
 300     }
 301     if(!get_bits1(&gb)) {
 302         skip ++;
 303         av_log(smk->avctx, AV_LOG_INFO, "Skipping MCLR tree\n");
 304         smk->mclr_tbl = av_malloc(sizeof(int) * 2);
 305         if (!smk->mclr_tbl)
 306             return AVERROR(ENOMEM);
 307         smk->mclr_tbl[0] = 0;
 308         smk->mclr_last[0] = smk->mclr_last[1] = smk->mclr_last[2] = 1;
 309     } else {
 310         ret = smacker_decode_header_tree(smk, &gb, &smk->mclr_tbl, smk->mclr_last, mclr_size);
 311         if (ret < 0)
 312             return ret;
 313     }
 314     if(!get_bits1(&gb)) {
 315         skip ++;
 316         av_log(smk->avctx, AV_LOG_INFO, "Skipping FULL tree\n");
 317         smk->full_tbl = av_malloc(sizeof(int) * 2);
 318         if (!smk->full_tbl)
 319             return AVERROR(ENOMEM);
 320         smk->full_tbl[0] = 0;
 321         smk->full_last[0] = smk->full_last[1] = smk->full_last[2] = 1;
 322     } else {
 323         ret = smacker_decode_header_tree(smk, &gb, &smk->full_tbl, smk->full_last, full_size);
 324         if (ret < 0)
 325             return ret;
 326     }
 327     if(!get_bits1(&gb)) {
 328         skip ++;
 329         av_log(smk->avctx, AV_LOG_INFO, "Skipping TYPE tree\n");
 330         smk->type_tbl = av_malloc(sizeof(int) * 2);
 331         if (!smk->type_tbl)
 332             return AVERROR(ENOMEM);
 333         smk->type_tbl[0] = 0;
 334         smk->type_last[0] = smk->type_last[1] = smk->type_last[2] = 1;
 335     } else {
 336         ret = smacker_decode_header_tree(smk, &gb, &smk->type_tbl, smk->type_last, type_size);
 337         if (ret < 0)
 338             return ret;
 339     }
 340     if (skip == 4 || get_bits_left(&gb) < 0)
 341         return AVERROR_INVALIDDATA;
 342
 343     return 0;
 344 }
 345
 346 static av_always_inline void last_reset(int *recode, int *last) {
 347     recode[last[0]] = recode[last[1]] = recode[last[2]] = 0;
 348 }
 349
 350 /* Get code and update history.
 351  * Checks before reading, does not overread. */
 352 static av_always_inline int smk_get_code(GetBitContext *gb, int *recode, int *last) {
 353     register int *table = recode;
 354     int v;
 355
 356     while(*table & SMK_NODE) {
 357         if (get_bits_left(gb) < 1)
 358             return AVERROR_INVALIDDATA;
 359         if(get_bits1(gb))
 360             table += (*table) & (~SMK_NODE);
 361         table++;
 362     }
 363     v = *table;
 364
 365     if(v != recode[last[0]]) {
 366         recode[last[2]] = recode[last[1]];
 367         recode[last[1]] = recode[last[0]];
 368         recode[last[0]] = v;
 369     }
 370     return v;
 371 }
 372
 373 static int decode_frame(AVCodecContext *avctx, AVFrame *rframe,
 374                         int *got_frame, AVPacket *avpkt)
 375 {
 376     SmackVContext * const smk = avctx->priv_data;
 377     uint8_t *out;
 378     uint32_t *pal;
 379     GetByteContext gb2;
 380     GetBitContext gb;
 381     int blocks, blk, bw, bh;
 382     int i, ret;
 383     int stride;
 384     int flags;
 385
 386     if (avpkt->size <= 769)
 387         return AVERROR_INVALIDDATA;
 388
 389     if ((ret = ff_reget_buffer(avctx, smk->pic, 0)) < 0)
 390         return ret;
 391
 392     /* make the palette available on the way out */
 393     pal = (uint32_t*)smk->pic->data[1];
 394     bytestream2_init(&gb2, avpkt->data, avpkt->size);
 395     flags = bytestream2_get_byteu(&gb2);
 396 #if FF_API_PALETTE_HAS_CHANGED
 397 FF_DISABLE_DEPRECATION_WARNINGS
 398     smk->pic->palette_has_changed = flags & 1;
 399 FF_ENABLE_DEPRECATION_WARNINGS
 400 #endif
 401     if (flags & 2) {
 402         smk->pic->flags |= AV_FRAME_FLAG_KEY;
 403         smk->pic->pict_type = AV_PICTURE_TYPE_I;
 404     } else {
 405         smk->pic->flags &= ~AV_FRAME_FLAG_KEY;
 406         smk->pic->pict_type = AV_PICTURE_TYPE_P;
 407     }
 408
 409     for(i = 0; i < 256; i++)
 410         *pal++ = 0xFFU << 24 | bytestream2_get_be24u(&gb2);
 411
 412     last_reset(smk->mmap_tbl, smk->mmap_last);
 413     last_reset(smk->mclr_tbl, smk->mclr_last);
 414     last_reset(smk->full_tbl, smk->full_last);
 415     last_reset(smk->type_tbl, smk->type_last);
 416     if ((ret = init_get_bits8(&gb, avpkt->data + 769, avpkt->size - 769)) < 0)
 417         return ret;
 418
 419     blk = 0;
 420     bw = avctx->width >> 2;
 421     bh = avctx->height >> 2;
 422     blocks = bw * bh;
 423     stride = smk->pic->linesize[0];
 424     while(blk < blocks) {
 425         int type, run, mode;
 426         uint16_t pix;
 427
 428         type = smk_get_code(&gb, smk->type_tbl, smk->type_last);
 429         if (type < 0)
 430             return type;
 431         run = block_runs[(type >> 2) & 0x3F];
 432         switch(type & 3){
 433         case SMK_BLK_MONO:
 434             while(run-- && blk < blocks){
 435                 int clr, map;
 436                 int hi, lo;
 437                 clr = smk_get_code(&gb, smk->mclr_tbl, smk->mclr_last);
 438                 map = smk_get_code(&gb, smk->mmap_tbl, smk->mmap_last);
 439                 out = smk->pic->data[0] + (blk / bw) * (stride * 4) + (blk % bw) * 4;
 440                 hi = clr >> 8;
 441                 lo = clr & 0xFF;
 442                 for(i = 0; i < 4; i++) {
 443                     if(map & 1) out[0] = hi; else out[0] = lo;
 444                     if(map & 2) out[1] = hi; else out[1] = lo;
 445                     if(map & 4) out[2] = hi; else out[2] = lo;
 446                     if(map & 8) out[3] = hi; else out[3] = lo;
 447                     map >>= 4;
 448                     out += stride;
 449                 }
 450                 blk++;
 451             }
 452             break;
 453         case SMK_BLK_FULL:
 454             mode = 0;
 455             if(avctx->codec_tag == MKTAG('S', 'M', 'K', '4')) { // In case of Smacker v4 we have three modes
 456                 if (get_bits_left(&gb) < 1)
 457                     return AVERROR_INVALIDDATA;
 458                 if(get_bits1(&gb)) mode = 1;
 459                 else if(get_bits1(&gb)) mode = 2;
 460             }
 461             while(run-- && blk < blocks){
 462                 out = smk->pic->data[0] + (blk / bw) * (stride * 4) + (blk % bw) * 4;
 463                 switch(mode){
 464                 case 0:
 465                     for(i = 0; i < 4; i++) {
 466                         pix = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 467                         AV_WL16(out+2,pix);
 468                         pix = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 469                         AV_WL16(out,pix);
 470                         out += stride;
 471                     }
 472                     break;
 473                 case 1:
 474                     pix = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 475                     out[0] = out[1] = pix & 0xFF;
 476                     out[2] = out[3] = pix >> 8;
 477                     out += stride;
 478                     out[0] = out[1] = pix & 0xFF;
 479                     out[2] = out[3] = pix >> 8;
 480                     out += stride;
 481                     pix = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 482                     out[0] = out[1] = pix & 0xFF;
 483                     out[2] = out[3] = pix >> 8;
 484                     out += stride;
 485                     out[0] = out[1] = pix & 0xFF;
 486                     out[2] = out[3] = pix >> 8;
 487                     break;
 488                 case 2:
 489                     for(i = 0; i < 2; i++) {
 490                         uint16_t pix1, pix2;
 491                         pix2 = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 492                         pix1 = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 493                         AV_WL16(out,pix1);
 494                         AV_WL16(out+2,pix2);
 495                         out += stride;
 496                         AV_WL16(out,pix1);
 497                         AV_WL16(out+2,pix2);
 498                         out += stride;
 499                     }
 500                     break;
 501                 }
 502                 blk++;
 503             }
 504             break;
 505         case SMK_BLK_SKIP:
 506             while(run-- && blk < blocks)
 507                 blk++;
 508             break;
 509         case SMK_BLK_FILL:
 510             mode = type >> 8;
 511             while(run-- && blk < blocks){
 512                 uint32_t col;
 513                 out = smk->pic->data[0] + (blk / bw) * (stride * 4) + (blk % bw) * 4;
 514                 col = mode * 0x01010101U;
 515                 for(i = 0; i < 4; i++) {
 516                     *((uint32_t*)out) = col;
 517                     out += stride;
 518                 }
 519                 blk++;
 520             }
 521             break;
 522         }
 523
 524     }
 525
 526     if ((ret = av_frame_ref(rframe, smk->pic)) < 0)
 527         return ret;
 528
 529     *got_frame = 1;
 530
 531     /* always report that the buffer was completely consumed */
 532     return avpkt->size;
 533 }
 534
 535
 536 static av_cold int decode_end(AVCodecContext *avctx)
 537 {
 538     SmackVContext * const smk = avctx->priv_data;
 539
 540     av_freep(&smk->mmap_tbl);
 541     av_freep(&smk->mclr_tbl);
 542     av_freep(&smk->full_tbl);
 543     av_freep(&smk->type_tbl);
 544
 545     av_frame_free(&smk->pic);
 546
 547     return 0;
 548 }
 549
 550
 551 static av_cold int decode_init(AVCodecContext *avctx)
 552 {
 553     SmackVContext * const c = avctx->priv_data;
 554     int ret;
 555
 556     c->avctx = avctx;
 557
 558     avctx->pix_fmt = AV_PIX_FMT_PAL8;
 559
 560     c->pic = av_frame_alloc();
 561     if (!c->pic)
 562         return AVERROR(ENOMEM);
 563
 564     /* decode huffman trees from extradata */
 565     if (avctx->extradata_size <= 16){
 566         av_log(avctx, AV_LOG_ERROR, "Extradata missing!\n");
 567         return AVERROR(EINVAL);
 568     }
 569
 570     ret = decode_header_trees(c);
 571     if (ret < 0) {
 572         return ret;
 573     }
 574
 575     return 0;
 576 }
 577
 578
 579 static av_cold int smka_decode_init(AVCodecContext *avctx)
 580 {
 581     int channels = avctx->ch_layout.nb_channels;
 582     if (channels < 1 || channels > 2) {
 583         av_log(avctx, AV_LOG_ERROR, "invalid number of channels\n");
 584         return AVERROR_INVALIDDATA;
 585     }
 586     av_channel_layout_uninit(&avctx->ch_layout);
 587     av_channel_layout_default(&avctx->ch_layout, channels);
 588     avctx->sample_fmt = avctx->bits_per_coded_sample == 8 ? AV_SAMPLE_FMT_U8 : AV_SAMPLE_FMT_S16;
 589
 590     return 0;
 591 }
 592
 593 /**
 594  * Decode Smacker audio data
 595  */
 596 static int smka_decode_frame(AVCodecContext *avctx, AVFrame *frame,
 597                              int *got_frame_ptr, AVPacket *avpkt)
 598 {
 599     const uint8_t *buf = avpkt->data;
 600     int buf_size = avpkt->size;
 601     GetBitContext gb;
 602     VLC vlc[4]       = { { 0 } };
 603     int16_t *samples;
 604     uint8_t *samples8;
 605     uint8_t values[4];
 606     int i, res, ret;
 607     int unp_size;
 608     int bits, stereo;
 609     unsigned pred[2], val, val2;
 610
 611     if (buf_size <= 4) {
 612         av_log(avctx, AV_LOG_ERROR, "packet is too small\n");
 613         return AVERROR_INVALIDDATA;
 614     }
 615
 616     unp_size = AV_RL32(buf);
 617
 618     if (unp_size > (1U<<24)) {
 619         av_log(avctx, AV_LOG_ERROR, "packet is too big\n");
 620         return AVERROR_INVALIDDATA;
 621     }
 622
 623     if ((ret = init_get_bits8(&gb, buf + 4, buf_size - 4)) < 0)
 624         return ret;
 625
 626     if(!get_bits1(&gb)){
 627         av_log(avctx, AV_LOG_INFO, "Sound: no data\n");
 628         *got_frame_ptr = 0;
 629         return 1;
 630     }
 631     stereo = get_bits1(&gb);
 632     bits = get_bits1(&gb);
 633     if (stereo ^ (avctx->ch_layout.nb_channels != 1)) {
 634         av_log(avctx, AV_LOG_ERROR, "channels mismatch\n");
 635         return AVERROR_INVALIDDATA;
 636     }
 637     if (bits == (avctx->sample_fmt == AV_SAMPLE_FMT_U8)) {
 638         av_log(avctx, AV_LOG_ERROR, "sample format mismatch\n");
 639         return AVERROR_INVALIDDATA;
 640     }
 641
 642     /* get output buffer */
 643     frame->nb_samples = unp_size / (avctx->ch_layout.nb_channels * (bits + 1));
 644     if (unp_size % (avctx->ch_layout.nb_channels * (bits + 1))) {
 645         av_log(avctx, AV_LOG_ERROR,
 646                "The buffer does not contain an integer number of samples\n");
 647         return AVERROR_INVALIDDATA;
 648     }
 649     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
 650         return ret;
 651     samples  = (int16_t *)frame->data[0];
 652     samples8 =            frame->data[0];
 653
 654     // Initialize
 655     for(i = 0; i < (1 << (bits + stereo)); i++) {
 656         HuffContext h;
 657         h.current = 0;
 658         skip_bits1(&gb);
 659         if ((ret = smacker_decode_tree(avctx, &gb, &h, 0)) < 0)
 660             goto error;
 661         skip_bits1(&gb);
 662         if (h.current > 1) {
 663             ret = ff_vlc_init_from_lengths(&vlc[i], SMKTREE_BITS, h.current,
 664                                            &h.entries[0].length, sizeof(*h.entries),
 665                                            &h.entries[0].value,  sizeof(*h.entries), 1,
 666                                            0, VLC_INIT_OUTPUT_LE, avctx);
 667             if (ret < 0) {
 668                 av_log(avctx, AV_LOG_ERROR, "Cannot build VLC table\n");
 669                 goto error;
 670             }
 671         } else
 672             values[i] = h.entries[0].value;
 673     }
 674     /* this codec relies on wraparound instead of clipping audio */
 675     if(bits) { //decode 16-bit data
 676         for(i = stereo; i >= 0; i--)
 677             pred[i] = av_bswap16(get_bits(&gb, 16));
 678         for(i = 0; i <= stereo; i++)
 679             *samples++ = pred[i];
 680         unp_size /= 2;
 681
 682         if (vlc[0       ].table || vlc[         1].table ||
 683             vlc[2*stereo].table || vlc[2*stereo+1].table) {
 684             for(; i < unp_size ; i++) {
 685                 unsigned idx = 2 * (i & stereo);
 686                 if (get_bits_left(&gb) < 0) {
 687                     ret = AVERROR_INVALIDDATA;
 688                     goto error;
 689                 }
 690                 if (vlc[idx].table)
 691                     res = get_vlc2(&gb, vlc[idx].table, SMKTREE_BITS, 3);
 692                 else
 693                     res = values[idx];
 694                 val  = res;
 695                 if (vlc[++idx].table)
 696                     res = get_vlc2(&gb, vlc[idx].table, SMKTREE_BITS, 3);
 697                 else
 698                     res = values[idx];
 699                 val |= res << 8;
 700                 pred[idx / 2] += val;
 701                 *samples++ = pred[idx / 2];
 702             }
 703         } else if (stereo) {
 704             val  = 256*values[1] + values[0];
 705             val2 = 256*values[3] + values[2];
 706             for(; i < unp_size; i+=2) {
 707                 pred[0] += val;
 708                 pred[1] += val2;
 709                 *samples++ = pred[0];
 710                 *samples++ = pred[1];
 711             }
 712         } else {
 713             val = 256*values[1] + values[0];
 714             for(; i < unp_size; i++) {
 715                 pred[0] += val;
 716                 *samples++ = pred[0];
 717             }
 718         }
 719     } else { //8-bit data
 720         for(i = stereo; i >= 0; i--)
 721             pred[i] = get_bits(&gb, 8);
 722         for(i = 0; i <= stereo; i++)
 723             *samples8++ = pred[i];
 724         for(; i < unp_size; i++) {
 725             unsigned idx = i & stereo;
 726             if (get_bits_left(&gb) < 0) {
 727                 ret = AVERROR_INVALIDDATA;
 728                 goto error;
 729             }
 730             if (vlc[idx].table)
 731                 val = get_vlc2(&gb, vlc[idx].table, SMKTREE_BITS, 3);
 732             else
 733                 val = values[idx];
 734             pred[idx] += val;
 735             *samples8++ = pred[idx];
 736         }
 737     }
 738
 739     *got_frame_ptr = 1;
 740     ret = buf_size;
 741
 742 error:
 743     for(i = 0; i < 4; i++) {
 744         ff_vlc_free(&vlc[i]);
 745     }
 746
 747     return ret;
 748 }
 749
 750 const FFCodec ff_smacker_decoder = {
 751     .p.name         = "smackvid",
 752     CODEC_LONG_NAME("Smacker video"),
 753     .p.type         = AVMEDIA_TYPE_VIDEO,
 754     .p.id           = AV_CODEC_ID_SMACKVIDEO,
 755     .priv_data_size = sizeof(SmackVContext),
 756     .init           = decode_init,
 757     .close          = decode_end,
 758     FF_CODEC_DECODE_CB(decode_frame),
 759     .p.capabilities = AV_CODEC_CAP_DR1,
 760     .caps_internal  = FF_CODEC_CAP_INIT_CLEANUP,
 761 };
 762
 763 const FFCodec ff_smackaud_decoder = {
 764     .p.name         = "smackaud",
 765     CODEC_LONG_NAME("Smacker audio"),
 766     .p.type         = AVMEDIA_TYPE_AUDIO,
 767     .p.id           = AV_CODEC_ID_SMACKAUDIO,
 768     .init           = smka_decode_init,
 769     FF_CODEC_DECODE_CB(smka_decode_frame),
 770     .p.capabilities = AV_CODEC_CAP_DR1,
 771 };