ffmpeg/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 <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(length > 32 || length > 3*SMKTREE_BITS) {
 101         av_log(NULL, AV_LOG_ERROR, "length too long\n");
 102         return AVERROR_INVALIDDATA;
 103     }
 104     if(!get_bits1(gb)){ //Leaf
 105         if(hc->current >= hc->length){
 106             av_log(NULL, AV_LOG_ERROR, "Tree size exceeded!\n");
 107             return AVERROR_INVALIDDATA;
 108         }
 109         if(length){
 110             hc->bits[hc->current] = prefix;
 111             hc->lengths[hc->current] = length;
 112         } else {
 113             hc->bits[hc->current] = 0;
 114             hc->lengths[hc->current] = 0;
 115         }
 116         hc->values[hc->current] = get_bits(gb, 8);
 117         hc->current++;
 118         if(hc->maxlength < length)
 119             hc->maxlength = length;
 120         return 0;
 121     } else { //Node
 122         int r;
 123         length++;
 124         r = smacker_decode_tree(gb, hc, prefix, length);
 125         if(r)
 126             return r;
 127         return smacker_decode_tree(gb, hc, prefix | (1 << (length - 1)), length);
 128     }
 129 }
 130
 131 /**
 132  * Decode header tree
 133  */
 134 static int smacker_decode_bigtree(GetBitContext *gb, HuffContext *hc, DBCtx *ctx)
 135 {
 136     if (hc->current + 1 >= hc->length) {
 137         av_log(NULL, AV_LOG_ERROR, "Tree size exceeded!\n");
 138         return AVERROR_INVALIDDATA;
 139     }
 140     if(!get_bits1(gb)){ //Leaf
 141         int val, i1, i2;
 142         i1 = ctx->v1->table ? get_vlc2(gb, ctx->v1->table, SMKTREE_BITS, 3) : 0;
 143         i2 = ctx->v2->table ? get_vlc2(gb, ctx->v2->table, SMKTREE_BITS, 3) : 0;
 144         if (i1 < 0 || i2 < 0)
 145             return AVERROR_INVALIDDATA;
 146         val = ctx->recode1[i1] | (ctx->recode2[i2] << 8);
 147         if(val == ctx->escapes[0]) {
 148             ctx->last[0] = hc->current;
 149             val = 0;
 150         } else if(val == ctx->escapes[1]) {
 151             ctx->last[1] = hc->current;
 152             val = 0;
 153         } else if(val == ctx->escapes[2]) {
 154             ctx->last[2] = hc->current;
 155             val = 0;
 156         }
 157
 158         hc->values[hc->current++] = val;
 159         return 1;
 160     } else { //Node
 161         int r = 0, r_new, t;
 162
 163         t = hc->current++;
 164         r = smacker_decode_bigtree(gb, hc, ctx);
 165         if(r < 0)
 166             return r;
 167         hc->values[t] = SMK_NODE | r;
 168         r++;
 169         r_new = smacker_decode_bigtree(gb, hc, ctx);
 170         if (r_new < 0)
 171             return r_new;
 172         return r + r_new;
 173     }
 174 }
 175
 176 /**
 177  * Store large tree as FFmpeg's vlc codes
 178  */
 179 static int smacker_decode_header_tree(SmackVContext *smk, GetBitContext *gb, int **recodes, int *last, int size)
 180 {
 181     int res;
 182     HuffContext huff;
 183     HuffContext tmp1, tmp2;
 184     VLC vlc[2] = { { 0 } };
 185     int escapes[3];
 186     DBCtx ctx;
 187     int err = 0;
 188
 189     if(size >= UINT_MAX>>4){ // (((size + 3) >> 2) + 3) << 2 must not overflow
 190         av_log(smk->avctx, AV_LOG_ERROR, "size too large\n");
 191         return AVERROR_INVALIDDATA;
 192     }
 193
 194     tmp1.length = 256;
 195     tmp1.maxlength = 0;
 196     tmp1.current = 0;
 197     tmp1.bits = av_mallocz(256 * 4);
 198     tmp1.lengths = av_mallocz(256 * sizeof(int));
 199     tmp1.values = av_mallocz(256 * sizeof(int));
 200
 201     tmp2.length = 256;
 202     tmp2.maxlength = 0;
 203     tmp2.current = 0;
 204     tmp2.bits = av_mallocz(256 * 4);
 205     tmp2.lengths = av_mallocz(256 * sizeof(int));
 206     tmp2.values = av_mallocz(256 * sizeof(int));
 207     if (!tmp1.bits || !tmp1.lengths || !tmp1.values ||
 208         !tmp2.bits || !tmp2.lengths || !tmp2.values) {
 209         err = AVERROR(ENOMEM);
 210         goto error;
 211     }
 212
 213     if(get_bits1(gb)) {
 214         res = smacker_decode_tree(gb, &tmp1, 0, 0);
 215         if (res < 0) {
 216             err = res;
 217             goto error;
 218         }
 219         skip_bits1(gb);
 220         if(tmp1.current > 1) {
 221             res = init_vlc(&vlc[0], SMKTREE_BITS, tmp1.length,
 222                         tmp1.lengths, sizeof(int), sizeof(int),
 223                         tmp1.bits, sizeof(uint32_t), sizeof(uint32_t), INIT_VLC_LE);
 224             if(res < 0) {
 225                 av_log(smk->avctx, AV_LOG_ERROR, "Cannot build VLC table\n");
 226                 err = res;
 227                 goto error;
 228             }
 229         }
 230     }
 231     if (!vlc[0].table) {
 232         av_log(smk->avctx, AV_LOG_ERROR, "Skipping low bytes tree\n");
 233     }
 234     if(get_bits1(gb)){
 235         res = smacker_decode_tree(gb, &tmp2, 0, 0);
 236         if (res < 0) {
 237             err = res;
 238             goto error;
 239         }
 240         skip_bits1(gb);
 241         if(tmp2.current > 1) {
 242             res = init_vlc(&vlc[1], SMKTREE_BITS, tmp2.length,
 243                         tmp2.lengths, sizeof(int), sizeof(int),
 244                         tmp2.bits, sizeof(uint32_t), sizeof(uint32_t), INIT_VLC_LE);
 245             if(res < 0) {
 246                 av_log(smk->avctx, AV_LOG_ERROR, "Cannot build VLC table\n");
 247                 err = res;
 248                 goto error;
 249             }
 250         }
 251     }
 252     if (!vlc[1].table) {
 253         av_log(smk->avctx, AV_LOG_ERROR, "Skipping high bytes tree\n");
 254     }
 255
 256     escapes[0]  = get_bits(gb, 16);
 257     escapes[1]  = get_bits(gb, 16);
 258     escapes[2]  = get_bits(gb, 16);
 259
 260     last[0] = last[1] = last[2] = -1;
 261
 262     ctx.escapes[0] = escapes[0];
 263     ctx.escapes[1] = escapes[1];
 264     ctx.escapes[2] = escapes[2];
 265     ctx.v1 = &vlc[0];
 266     ctx.v2 = &vlc[1];
 267     ctx.recode1 = tmp1.values;
 268     ctx.recode2 = tmp2.values;
 269     ctx.last = last;
 270
 271     huff.length = ((size + 3) >> 2) + 4;
 272     huff.maxlength = 0;
 273     huff.current = 0;
 274     huff.values = av_mallocz_array(huff.length, sizeof(int));
 275     if (!huff.values) {
 276         err = AVERROR(ENOMEM);
 277         goto error;
 278     }
 279
 280     if (smacker_decode_bigtree(gb, &huff, &ctx) < 0)
 281         err = -1;
 282     skip_bits1(gb);
 283     if(ctx.last[0] == -1) ctx.last[0] = huff.current++;
 284     if(ctx.last[1] == -1) ctx.last[1] = huff.current++;
 285     if(ctx.last[2] == -1) ctx.last[2] = huff.current++;
 286     if (ctx.last[0] >= huff.length ||
 287         ctx.last[1] >= huff.length ||
 288         ctx.last[2] >= huff.length) {
 289         av_log(smk->avctx, AV_LOG_ERROR, "Huffman codes out of range\n");
 290         err = AVERROR_INVALIDDATA;
 291     }
 292
 293     *recodes = huff.values;
 294
 295 error:
 296     if(vlc[0].table)
 297         ff_free_vlc(&vlc[0]);
 298     if(vlc[1].table)
 299         ff_free_vlc(&vlc[1]);
 300     av_free(tmp1.bits);
 301     av_free(tmp1.lengths);
 302     av_free(tmp1.values);
 303     av_free(tmp2.bits);
 304     av_free(tmp2.lengths);
 305     av_free(tmp2.values);
 306
 307     return err;
 308 }
 309
 310 static int decode_header_trees(SmackVContext *smk) {
 311     GetBitContext gb;
 312     int mmap_size, mclr_size, full_size, type_size, ret;
 313
 314     mmap_size = AV_RL32(smk->avctx->extradata);
 315     mclr_size = AV_RL32(smk->avctx->extradata + 4);
 316     full_size = AV_RL32(smk->avctx->extradata + 8);
 317     type_size = AV_RL32(smk->avctx->extradata + 12);
 318
 319     init_get_bits8(&gb, smk->avctx->extradata + 16, smk->avctx->extradata_size - 16);
 320
 321     if(!get_bits1(&gb)) {
 322         av_log(smk->avctx, AV_LOG_INFO, "Skipping MMAP tree\n");
 323         smk->mmap_tbl = av_malloc(sizeof(int) * 2);
 324         if (!smk->mmap_tbl)
 325             return AVERROR(ENOMEM);
 326         smk->mmap_tbl[0] = 0;
 327         smk->mmap_last[0] = smk->mmap_last[1] = smk->mmap_last[2] = 1;
 328     } else {
 329         ret = smacker_decode_header_tree(smk, &gb, &smk->mmap_tbl, smk->mmap_last, mmap_size);
 330         if (ret < 0)
 331             return ret;
 332     }
 333     if(!get_bits1(&gb)) {
 334         av_log(smk->avctx, AV_LOG_INFO, "Skipping MCLR tree\n");
 335         smk->mclr_tbl = av_malloc(sizeof(int) * 2);
 336         if (!smk->mclr_tbl)
 337             return AVERROR(ENOMEM);
 338         smk->mclr_tbl[0] = 0;
 339         smk->mclr_last[0] = smk->mclr_last[1] = smk->mclr_last[2] = 1;
 340     } else {
 341         ret = smacker_decode_header_tree(smk, &gb, &smk->mclr_tbl, smk->mclr_last, mclr_size);
 342         if (ret < 0)
 343             return ret;
 344     }
 345     if(!get_bits1(&gb)) {
 346         av_log(smk->avctx, AV_LOG_INFO, "Skipping FULL tree\n");
 347         smk->full_tbl = av_malloc(sizeof(int) * 2);
 348         if (!smk->full_tbl)
 349             return AVERROR(ENOMEM);
 350         smk->full_tbl[0] = 0;
 351         smk->full_last[0] = smk->full_last[1] = smk->full_last[2] = 1;
 352     } else {
 353         ret = smacker_decode_header_tree(smk, &gb, &smk->full_tbl, smk->full_last, full_size);
 354         if (ret < 0)
 355             return ret;
 356     }
 357     if(!get_bits1(&gb)) {
 358         av_log(smk->avctx, AV_LOG_INFO, "Skipping TYPE tree\n");
 359         smk->type_tbl = av_malloc(sizeof(int) * 2);
 360         if (!smk->type_tbl)
 361             return AVERROR(ENOMEM);
 362         smk->type_tbl[0] = 0;
 363         smk->type_last[0] = smk->type_last[1] = smk->type_last[2] = 1;
 364     } else {
 365         ret = smacker_decode_header_tree(smk, &gb, &smk->type_tbl, smk->type_last, type_size);
 366         if (ret < 0)
 367             return ret;
 368     }
 369
 370     return 0;
 371 }
 372
 373 static av_always_inline void last_reset(int *recode, int *last) {
 374     recode[last[0]] = recode[last[1]] = recode[last[2]] = 0;
 375 }
 376
 377 /* get code and update history */
 378 static av_always_inline int smk_get_code(GetBitContext *gb, int *recode, int *last) {
 379     register int *table = recode;
 380     int v;
 381
 382     while(*table & SMK_NODE) {
 383         if(get_bits1(gb))
 384             table += (*table) & (~SMK_NODE);
 385         table++;
 386     }
 387     v = *table;
 388
 389     if(v != recode[last[0]]) {
 390         recode[last[2]] = recode[last[1]];
 391         recode[last[1]] = recode[last[0]];
 392         recode[last[0]] = v;
 393     }
 394     return v;
 395 }
 396
 397 static int decode_frame(AVCodecContext *avctx, void *data, int *got_frame,
 398                         AVPacket *avpkt)
 399 {
 400     SmackVContext * const smk = avctx->priv_data;
 401     uint8_t *out;
 402     uint32_t *pal;
 403     GetByteContext gb2;
 404     GetBitContext gb;
 405     int blocks, blk, bw, bh;
 406     int i, ret;
 407     int stride;
 408     int flags;
 409
 410     if (avpkt->size <= 769)
 411         return AVERROR_INVALIDDATA;
 412
 413     if ((ret = ff_reget_buffer(avctx, smk->pic)) < 0)
 414         return ret;
 415
 416     /* make the palette available on the way out */
 417     pal = (uint32_t*)smk->pic->data[1];
 418     bytestream2_init(&gb2, avpkt->data, avpkt->size);
 419     flags = bytestream2_get_byteu(&gb2);
 420     smk->pic->palette_has_changed = flags & 1;
 421     smk->pic->key_frame = !!(flags & 2);
 422     if (smk->pic->key_frame)
 423         smk->pic->pict_type = AV_PICTURE_TYPE_I;
 424     else
 425         smk->pic->pict_type = AV_PICTURE_TYPE_P;
 426
 427     for(i = 0; i < 256; i++)
 428         *pal++ = 0xFFU << 24 | bytestream2_get_be24u(&gb2);
 429
 430     last_reset(smk->mmap_tbl, smk->mmap_last);
 431     last_reset(smk->mclr_tbl, smk->mclr_last);
 432     last_reset(smk->full_tbl, smk->full_last);
 433     last_reset(smk->type_tbl, smk->type_last);
 434     if ((ret = init_get_bits8(&gb, avpkt->data + 769, avpkt->size - 769)) < 0)
 435         return ret;
 436
 437     blk = 0;
 438     bw = avctx->width >> 2;
 439     bh = avctx->height >> 2;
 440     blocks = bw * bh;
 441     stride = smk->pic->linesize[0];
 442     while(blk < blocks) {
 443         int type, run, mode;
 444         uint16_t pix;
 445
 446         type = smk_get_code(&gb, smk->type_tbl, smk->type_last);
 447         run = block_runs[(type >> 2) & 0x3F];
 448         switch(type & 3){
 449         case SMK_BLK_MONO:
 450             while(run-- && blk < blocks){
 451                 int clr, map;
 452                 int hi, lo;
 453                 clr = smk_get_code(&gb, smk->mclr_tbl, smk->mclr_last);
 454                 map = smk_get_code(&gb, smk->mmap_tbl, smk->mmap_last);
 455                 out = smk->pic->data[0] + (blk / bw) * (stride * 4) + (blk % bw) * 4;
 456                 hi = clr >> 8;
 457                 lo = clr & 0xFF;
 458                 for(i = 0; i < 4; i++) {
 459                     if(map & 1) out[0] = hi; else out[0] = lo;
 460                     if(map & 2) out[1] = hi; else out[1] = lo;
 461                     if(map & 4) out[2] = hi; else out[2] = lo;
 462                     if(map & 8) out[3] = hi; else out[3] = lo;
 463                     map >>= 4;
 464                     out += stride;
 465                 }
 466                 blk++;
 467             }
 468             break;
 469         case SMK_BLK_FULL:
 470             mode = 0;
 471             if(avctx->codec_tag == MKTAG('S', 'M', 'K', '4')) { // In case of Smacker v4 we have three modes
 472                 if(get_bits1(&gb)) mode = 1;
 473                 else if(get_bits1(&gb)) mode = 2;
 474             }
 475             while(run-- && blk < blocks){
 476                 out = smk->pic->data[0] + (blk / bw) * (stride * 4) + (blk % bw) * 4;
 477                 switch(mode){
 478                 case 0:
 479                     for(i = 0; i < 4; i++) {
 480                         pix = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 481                         AV_WL16(out+2,pix);
 482                         pix = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 483                         AV_WL16(out,pix);
 484                         out += stride;
 485                     }
 486                     break;
 487                 case 1:
 488                     pix = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 489                     out[0] = out[1] = pix & 0xFF;
 490                     out[2] = out[3] = pix >> 8;
 491                     out += stride;
 492                     out[0] = out[1] = pix & 0xFF;
 493                     out[2] = out[3] = pix >> 8;
 494                     out += stride;
 495                     pix = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 496                     out[0] = out[1] = pix & 0xFF;
 497                     out[2] = out[3] = pix >> 8;
 498                     out += stride;
 499                     out[0] = out[1] = pix & 0xFF;
 500                     out[2] = out[3] = pix >> 8;
 501                     break;
 502                 case 2:
 503                     for(i = 0; i < 2; i++) {
 504                         uint16_t pix1, pix2;
 505                         pix2 = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 506                         pix1 = smk_get_code(&gb, smk->full_tbl, smk->full_last);
 507                         AV_WL16(out,pix1);
 508                         AV_WL16(out+2,pix2);
 509                         out += stride;
 510                         AV_WL16(out,pix1);
 511                         AV_WL16(out+2,pix2);
 512                         out += stride;
 513                     }
 514                     break;
 515                 }
 516                 blk++;
 517             }
 518             break;
 519         case SMK_BLK_SKIP:
 520             while(run-- && blk < blocks)
 521                 blk++;
 522             break;
 523         case SMK_BLK_FILL:
 524             mode = type >> 8;
 525             while(run-- && blk < blocks){
 526                 uint32_t col;
 527                 out = smk->pic->data[0] + (blk / bw) * (stride * 4) + (blk % bw) * 4;
 528                 col = mode * 0x01010101;
 529                 for(i = 0; i < 4; i++) {
 530                     *((uint32_t*)out) = col;
 531                     out += stride;
 532                 }
 533                 blk++;
 534             }
 535             break;
 536         }
 537
 538     }
 539
 540     if ((ret = av_frame_ref(data, smk->pic)) < 0)
 541         return ret;
 542
 543     *got_frame = 1;
 544
 545     /* always report that the buffer was completely consumed */
 546     return avpkt->size;
 547 }
 548
 549
 550
 551 /*
 552  *
 553  * Uninit smacker decoder
 554  *
 555  */
 556 static av_cold int decode_end(AVCodecContext *avctx)
 557 {
 558     SmackVContext * const smk = avctx->priv_data;
 559
 560     av_freep(&smk->mmap_tbl);
 561     av_freep(&smk->mclr_tbl);
 562     av_freep(&smk->full_tbl);
 563     av_freep(&smk->type_tbl);
 564
 565     av_frame_free(&smk->pic);
 566
 567     return 0;
 568 }
 569
 570
 571 /*
 572  *
 573  * Init smacker decoder
 574  *
 575  */
 576 static av_cold int decode_init(AVCodecContext *avctx)
 577 {
 578     SmackVContext * const c = avctx->priv_data;
 579     int ret;
 580
 581     c->avctx = avctx;
 582
 583     avctx->pix_fmt = AV_PIX_FMT_PAL8;
 584
 585     c->pic = av_frame_alloc();
 586     if (!c->pic)
 587         return AVERROR(ENOMEM);
 588
 589     /* decode huffman trees from extradata */
 590     if(avctx->extradata_size < 16){
 591         av_log(avctx, AV_LOG_ERROR, "Extradata missing!\n");
 592         decode_end(avctx);
 593         return AVERROR(EINVAL);
 594     }
 595
 596     ret = decode_header_trees(c);
 597     if (ret < 0) {
 598         decode_end(avctx);
 599         return ret;
 600     }
 601
 602     return 0;
 603 }
 604
 605
 606 static av_cold int smka_decode_init(AVCodecContext *avctx)
 607 {
 608     if (avctx->channels < 1 || avctx->channels > 2) {
 609         av_log(avctx, AV_LOG_ERROR, "invalid number of channels\n");
 610         return AVERROR(EINVAL);
 611     }
 612     avctx->channel_layout = (avctx->channels==2) ? AV_CH_LAYOUT_STEREO : AV_CH_LAYOUT_MONO;
 613     avctx->sample_fmt = avctx->bits_per_coded_sample == 8 ? AV_SAMPLE_FMT_U8 : AV_SAMPLE_FMT_S16;
 614
 615     return 0;
 616 }
 617
 618 /**
 619  * Decode Smacker audio data
 620  */
 621 static int smka_decode_frame(AVCodecContext *avctx, void *data,
 622                              int *got_frame_ptr, AVPacket *avpkt)
 623 {
 624     AVFrame *frame     = data;
 625     const uint8_t *buf = avpkt->data;
 626     int buf_size = avpkt->size;
 627     GetBitContext gb;
 628     HuffContext h[4] = { { 0 } };
 629     VLC vlc[4]       = { { 0 } };
 630     int16_t *samples;
 631     uint8_t *samples8;
 632     int val;
 633     int i, res, ret;
 634     int unp_size;
 635     int bits, stereo;
 636     int pred[2] = {0, 0};
 637
 638     if (buf_size <= 4) {
 639         av_log(avctx, AV_LOG_ERROR, "packet is too small\n");
 640         return AVERROR(EINVAL);
 641     }
 642
 643     unp_size = AV_RL32(buf);
 644
 645     if (unp_size > (1U<<24)) {
 646         av_log(avctx, AV_LOG_ERROR, "packet is too big\n");
 647         return AVERROR_INVALIDDATA;
 648     }
 649
 650     if ((ret = init_get_bits8(&gb, buf + 4, buf_size - 4)) < 0)
 651         return ret;
 652
 653     if(!get_bits1(&gb)){
 654         av_log(avctx, AV_LOG_INFO, "Sound: no data\n");
 655         *got_frame_ptr = 0;
 656         return 1;
 657     }
 658     stereo = get_bits1(&gb);
 659     bits = get_bits1(&gb);
 660     if (stereo ^ (avctx->channels != 1)) {
 661         av_log(avctx, AV_LOG_ERROR, "channels mismatch\n");
 662         return AVERROR(EINVAL);
 663     }
 664     if (bits == (avctx->sample_fmt == AV_SAMPLE_FMT_U8)) {
 665         av_log(avctx, AV_LOG_ERROR, "sample format mismatch\n");
 666         return AVERROR(EINVAL);
 667     }
 668
 669     /* get output buffer */
 670     frame->nb_samples = unp_size / (avctx->channels * (bits + 1));
 671     if ((ret = ff_get_buffer(avctx, frame, 0)) < 0)
 672         return ret;
 673     samples  = (int16_t *)frame->data[0];
 674     samples8 =            frame->data[0];
 675
 676     // Initialize
 677     for(i = 0; i < (1 << (bits + stereo)); i++) {
 678         h[i].length = 256;
 679         h[i].maxlength = 0;
 680         h[i].current = 0;
 681         h[i].bits = av_mallocz(256 * 4);
 682         h[i].lengths = av_mallocz(256 * sizeof(int));
 683         h[i].values = av_mallocz(256 * sizeof(int));
 684         if (!h[i].bits || !h[i].lengths || !h[i].values) {
 685             ret = AVERROR(ENOMEM);
 686             goto error;
 687         }
 688         skip_bits1(&gb);
 689         if (smacker_decode_tree(&gb, &h[i], 0, 0) < 0) {
 690             ret = AVERROR_INVALIDDATA;
 691             goto error;
 692         }
 693         skip_bits1(&gb);
 694         if(h[i].current > 1) {
 695             res = init_vlc(&vlc[i], SMKTREE_BITS, h[i].length,
 696                     h[i].lengths, sizeof(int), sizeof(int),
 697                     h[i].bits, sizeof(uint32_t), sizeof(uint32_t), INIT_VLC_LE);
 698             if(res < 0) {
 699                 av_log(avctx, AV_LOG_ERROR, "Cannot build VLC table\n");
 700                 ret = AVERROR_INVALIDDATA;
 701                 goto error;
 702             }
 703         }
 704     }
 705     /* this codec relies on wraparound instead of clipping audio */
 706     if(bits) { //decode 16-bit data
 707         for(i = stereo; i >= 0; i--)
 708             pred[i] = sign_extend(av_bswap16(get_bits(&gb, 16)), 16);
 709         for(i = 0; i <= stereo; i++)
 710             *samples++ = pred[i];
 711         for(; i < unp_size / 2; i++) {
 712             if(get_bits_left(&gb)<0)
 713                 return AVERROR_INVALIDDATA;
 714             if(i & stereo) {
 715                 if(vlc[2].table)
 716                     res = get_vlc2(&gb, vlc[2].table, SMKTREE_BITS, 3);
 717                 else
 718                     res = 0;
 719                 if (res < 0) {
 720                     av_log(avctx, AV_LOG_ERROR, "invalid vlc\n");
 721                     return AVERROR_INVALIDDATA;
 722                 }
 723                 val  = h[2].values[res];
 724                 if(vlc[3].table)
 725                     res = get_vlc2(&gb, vlc[3].table, SMKTREE_BITS, 3);
 726                 else
 727                     res = 0;
 728                 if (res < 0) {
 729                     av_log(avctx, AV_LOG_ERROR, "invalid vlc\n");
 730                     return AVERROR_INVALIDDATA;
 731                 }
 732                 val |= h[3].values[res] << 8;
 733                 pred[1] += sign_extend(val, 16);
 734                 *samples++ = pred[1];
 735             } else {
 736                 if(vlc[0].table)
 737                     res = get_vlc2(&gb, vlc[0].table, SMKTREE_BITS, 3);
 738                 else
 739                     res = 0;
 740                 if (res < 0) {
 741                     av_log(avctx, AV_LOG_ERROR, "invalid vlc\n");
 742                     return AVERROR_INVALIDDATA;
 743                 }
 744                 val  = h[0].values[res];
 745                 if(vlc[1].table)
 746                     res = get_vlc2(&gb, vlc[1].table, SMKTREE_BITS, 3);
 747                 else
 748                     res = 0;
 749                 if (res < 0) {
 750                     av_log(avctx, AV_LOG_ERROR, "invalid vlc\n");
 751                     return AVERROR_INVALIDDATA;
 752                 }
 753                 val |= h[1].values[res] << 8;
 754                 pred[0] += sign_extend(val, 16);
 755                 *samples++ = pred[0];
 756             }
 757         }
 758     } else { //8-bit data
 759         for(i = stereo; i >= 0; i--)
 760             pred[i] = get_bits(&gb, 8);
 761         for(i = 0; i <= stereo; i++)
 762             *samples8++ = pred[i];
 763         for(; i < unp_size; i++) {
 764             if(get_bits_left(&gb)<0)
 765                 return AVERROR_INVALIDDATA;
 766             if(i & stereo){
 767                 if(vlc[1].table)
 768                     res = get_vlc2(&gb, vlc[1].table, SMKTREE_BITS, 3);
 769                 else
 770                     res = 0;
 771                 if (res < 0) {
 772                     av_log(avctx, AV_LOG_ERROR, "invalid vlc\n");
 773                     return AVERROR_INVALIDDATA;
 774                 }
 775                 pred[1] += sign_extend(h[1].values[res], 8);
 776                 *samples8++ = pred[1];
 777             } else {
 778                 if(vlc[0].table)
 779                     res = get_vlc2(&gb, vlc[0].table, SMKTREE_BITS, 3);
 780                 else
 781                     res = 0;
 782                 if (res < 0) {
 783                     av_log(avctx, AV_LOG_ERROR, "invalid vlc\n");
 784                     return AVERROR_INVALIDDATA;
 785                 }
 786                 pred[0] += sign_extend(h[0].values[res], 8);
 787                 *samples8++ = pred[0];
 788             }
 789         }
 790     }
 791
 792     *got_frame_ptr = 1;
 793     ret = buf_size;
 794
 795 error:
 796     for(i = 0; i < 4; i++) {
 797         if(vlc[i].table)
 798             ff_free_vlc(&vlc[i]);
 799         av_free(h[i].bits);
 800         av_free(h[i].lengths);
 801         av_free(h[i].values);
 802     }
 803
 804     return ret;
 805 }
 806
 807 AVCodec ff_smacker_decoder = {
 808     .name           = "smackvid",
 809     .long_name      = NULL_IF_CONFIG_SMALL("Smacker video"),
 810     .type           = AVMEDIA_TYPE_VIDEO,
 811     .id             = AV_CODEC_ID_SMACKVIDEO,
 812     .priv_data_size = sizeof(SmackVContext),
 813     .init           = decode_init,
 814     .close          = decode_end,
 815     .decode         = decode_frame,
 816     .capabilities   = CODEC_CAP_DR1,
 817 };
 818
 819 AVCodec ff_smackaud_decoder = {
 820     .name           = "smackaud",
 821     .long_name      = NULL_IF_CONFIG_SMALL("Smacker audio"),
 822     .type           = AVMEDIA_TYPE_AUDIO,
 823     .id             = AV_CODEC_ID_SMACKAUDIO,
 824     .init           = smka_decode_init,
 825     .decode         = smka_decode_frame,
 826     .capabilities   = CODEC_CAP_DR1,
 827 };