libavformat/avidec.c

   1 /*
   2  * AVI decoder.
   3  * Copyright (c) 2001 Fabrice Bellard.
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it under the terms of the GNU Lesser General Public
   7  * License as published by the Free Software Foundation; either
   8  * version 2 of the License, or (at your option) any later version.
   9  *
  10  * This library is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  13  * Lesser General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU Lesser General Public
  16  * License along with this library; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  18  */
  19 #include "avformat.h"
  20 #include "avi.h"
  21 #include "dv.h"
  22
  23 #undef NDEBUG
  24 #include <assert.h>
  25
  26 //#define DEBUG
  27 //#define DEBUG_SEEK
  28
  29 typedef struct AVIStream {
  30     int64_t frame_offset; /* current frame (video) or byte (audio) counter
  31                          (used to compute the pts) */
  32     int remaining;
  33     int packet_size;
  34
  35     int scale;
  36     int rate;
  37     int sample_size; /* audio only data */
  38     int start;
  39
  40     int cum_len; /* temporary storage (used during seek) */
  41
  42     int prefix;                       ///< normally 'd'<<8 + 'c' or 'w'<<8 + 'b'
  43     int prefix_count;
  44 } AVIStream;
  45
  46 typedef struct {
  47     int64_t  riff_end;
  48     int64_t  movi_end;
  49     offset_t movi_list;
  50     int index_loaded;
  51     int is_odml;
  52     int non_interleaved;
  53     int stream_index;
  54     DVDemuxContext* dv_demux;
  55 } AVIContext;
  56
  57 static int avi_load_index(AVFormatContext *s);
  58
  59 #ifdef DEBUG
  60 static void print_tag(const char *str, unsigned int tag, int size)
  61 {
  62     printf("%s: tag=%c%c%c%c size=0x%x\n",
  63            str, tag & 0xff,
  64            (tag >> 8) & 0xff,
  65            (tag >> 16) & 0xff,
  66            (tag >> 24) & 0xff,
  67            size);
  68 }
  69 #endif
  70
  71 static int get_riff(AVIContext *avi, ByteIOContext *pb)
  72 {
  73     uint32_t tag;
  74     /* check RIFF header */
  75     tag = get_le32(pb);
  76
  77     if (tag != MKTAG('R', 'I', 'F', 'F'))
  78         return -1;
  79     avi->riff_end = get_le32(pb);   /* RIFF chunk size */
  80     avi->riff_end += url_ftell(pb); /* RIFF chunk end */
  81     tag = get_le32(pb);
  82     if (tag != MKTAG('A', 'V', 'I', ' ') && tag != MKTAG('A', 'V', 'I', 'X'))
  83         return -1;
  84
  85     return 0;
  86 }
  87
  88 static int avi_read_header(AVFormatContext *s, AVFormatParameters *ap)
  89 {
  90     AVIContext *avi = s->priv_data;
  91     ByteIOContext *pb = &s->pb;
  92     uint32_t tag, tag1, handler;
  93     int codec_type, stream_index, frame_period, bit_rate;
  94     unsigned int size, nb_frames;
  95     int i, n;
  96     AVStream *st;
  97     AVIStream *ast;
  98     int xan_video = 0;  /* hack to support Xan A/V */
  99
 100     avi->stream_index= -1;
 101
 102     if (get_riff(avi, pb) < 0)
 103         return -1;
 104
 105     /* first list tag */
 106     stream_index = -1;
 107     codec_type = -1;
 108     frame_period = 0;
 109     for(;;) {
 110         if (url_feof(pb))
 111             goto fail;
 112         tag = get_le32(pb);
 113         size = get_le32(pb);
 114 #ifdef DEBUG
 115         print_tag("tag", tag, size);
 116 #endif
 117
 118         switch(tag) {
 119         case MKTAG('L', 'I', 'S', 'T'):
 120             /* ignored, except when start of video packets */
 121             tag1 = get_le32(pb);
 122 #ifdef DEBUG
 123             print_tag("list", tag1, 0);
 124 #endif
 125             if (tag1 == MKTAG('m', 'o', 'v', 'i')) {
 126                 avi->movi_list = url_ftell(pb) - 4;
 127                 if(size) avi->movi_end = avi->movi_list + size;
 128                 else     avi->movi_end = url_filesize(url_fileno(pb));
 129 #ifdef DEBUG
 130                 printf("movi end=%Lx\n", avi->movi_end);
 131 #endif
 132                 goto end_of_header;
 133             }
 134             break;
 135         case MKTAG('d', 'm', 'l', 'h'):
 136             avi->is_odml = 1;
 137             url_fskip(pb, size + (size & 1));
 138             break;
 139         case MKTAG('a', 'v', 'i', 'h'):
 140             /* avi header */
 141             /* using frame_period is bad idea */
 142             frame_period = get_le32(pb);
 143             bit_rate = get_le32(pb) * 8;
 144             url_fskip(pb, 4 * 4);
 145             n = get_le32(pb);
 146             for(i=0;i<n;i++) {
 147                 AVIStream *ast;
 148                 st = av_new_stream(s, i);
 149                 if (!st)
 150                     goto fail;
 151
 152                 ast = av_mallocz(sizeof(AVIStream));
 153                 if (!ast)
 154                     goto fail;
 155                 st->priv_data = ast;
 156             }
 157             url_fskip(pb, size - 7 * 4);
 158             break;
 159         case MKTAG('s', 't', 'r', 'h'):
 160             /* stream header */
 161             stream_index++;
 162             tag1 = get_le32(pb);
 163             handler = get_le32(pb); /* codec tag */
 164 #ifdef DEBUG
 165         print_tag("strh", tag1, -1);
 166 #endif
 167             if(tag1 == MKTAG('i', 'a', 'v', 's') || tag1 == MKTAG('i', 'v', 'a', 's')){
 168                 /*
 169                  * After some consideration -- I don't think we
 170                  * have to support anything but DV in a type1 AVIs.
 171                  */
 172                 if (s->nb_streams != 1)
 173                     goto fail;
 174
 175                 if (handler != MKTAG('d', 'v', 's', 'd') &&
 176                     handler != MKTAG('d', 'v', 'h', 'd') &&
 177                     handler != MKTAG('d', 'v', 's', 'l'))
 178                    goto fail;
 179
 180                 ast = s->streams[0]->priv_data;
 181                 av_freep(&s->streams[0]->codec.extradata);
 182                 av_freep(&s->streams[0]);
 183                 s->nb_streams = 0;
 184                 avi->dv_demux = dv_init_demux(s);
 185                 if (!avi->dv_demux)
 186                     goto fail;
 187                 s->streams[0]->priv_data = ast;
 188                 url_fskip(pb, 3 * 4);
 189                 ast->scale = get_le32(pb);
 190                 ast->rate = get_le32(pb);
 191                 stream_index = s->nb_streams - 1;
 192                 url_fskip(pb, size - 7*4);
 193                 break;
 194             }
 195
 196             if (stream_index >= s->nb_streams) {
 197                 url_fskip(pb, size - 8);
 198                 break;
 199             }
 200             st = s->streams[stream_index];
 201             ast = st->priv_data;
 202             st->codec.stream_codec_tag= handler;
 203
 204             get_le32(pb); /* flags */
 205             get_le16(pb); /* priority */
 206             get_le16(pb); /* language */
 207             get_le32(pb); /* initial frame */
 208             ast->scale = get_le32(pb);
 209             ast->rate = get_le32(pb);
 210             if(ast->scale && ast->rate){
 211             }else if(frame_period){
 212                 ast->rate = 1000000;
 213                 ast->scale = frame_period;
 214             }else{
 215                 ast->rate = 25;
 216                 ast->scale = 1;
 217             }
 218             av_set_pts_info(st, 64, ast->scale, ast->rate);
 219
 220             ast->start= get_le32(pb); /* start */
 221             nb_frames = get_le32(pb);
 222
 223             st->start_time = 0;
 224             st->duration = av_rescale(nb_frames, ast->scale*(int64_t)AV_TIME_BASE, ast->rate);
 225             get_le32(pb); /* buffer size */
 226             get_le32(pb); /* quality */
 227             ast->sample_size = get_le32(pb); /* sample ssize */
 228 //            av_log(NULL, AV_LOG_DEBUG, "%d %d %d %d\n", ast->rate, ast->scale, ast->start, ast->sample_size);
 229
 230             switch(tag1) {
 231             case MKTAG('v', 'i', 'd', 's'):
 232                 codec_type = CODEC_TYPE_VIDEO;
 233
 234                 ast->sample_size = 0;
 235                 st->codec.frame_rate = ast->rate;
 236                 st->codec.frame_rate_base = ast->scale;
 237                 break;
 238             case MKTAG('a', 'u', 'd', 's'):
 239                 codec_type = CODEC_TYPE_AUDIO;
 240                 break;
 241             case MKTAG('t', 'x', 't', 's'):
 242                 //FIXME
 243                 codec_type = CODEC_TYPE_DATA; //CODEC_TYPE_SUB ?  FIXME
 244                 break;
 245             case MKTAG('p', 'a', 'd', 's'):
 246                 codec_type = CODEC_TYPE_UNKNOWN;
 247                 stream_index--;
 248                 break;
 249             default:
 250                 av_log(s, AV_LOG_ERROR, "unknown stream type %X\n", tag1);
 251                 goto fail;
 252             }
 253             url_fskip(pb, size - 12 * 4);
 254             break;
 255         case MKTAG('s', 't', 'r', 'f'):
 256             /* stream header */
 257             if (stream_index >= s->nb_streams || avi->dv_demux) {
 258                 url_fskip(pb, size);
 259             } else {
 260                 st = s->streams[stream_index];
 261                 switch(codec_type) {
 262                 case CODEC_TYPE_VIDEO:
 263                     get_le32(pb); /* size */
 264                     st->codec.width = get_le32(pb);
 265                     st->codec.height = get_le32(pb);
 266                     get_le16(pb); /* panes */
 267                     st->codec.bits_per_sample= get_le16(pb); /* depth */
 268                     tag1 = get_le32(pb);
 269                     get_le32(pb); /* ImageSize */
 270                     get_le32(pb); /* XPelsPerMeter */
 271                     get_le32(pb); /* YPelsPerMeter */
 272                     get_le32(pb); /* ClrUsed */
 273                     get_le32(pb); /* ClrImportant */
 274
 275                  if(size > 10*4 && size<(1<<30)){
 276                     st->codec.extradata_size= size - 10*4;
 277                     st->codec.extradata= av_malloc(st->codec.extradata_size + FF_INPUT_BUFFER_PADDING_SIZE);
 278                     get_buffer(pb, st->codec.extradata, st->codec.extradata_size);
 279                  }
 280
 281                     if(st->codec.extradata_size & 1) //FIXME check if the encoder really did this correctly
 282                         get_byte(pb);
 283
 284                     /* Extract palette from extradata if bpp <= 8 */
 285                     /* This code assumes that extradata contains only palette */
 286                     /* This is true for all paletted codecs implemented in ffmpeg */
 287                     if (st->codec.extradata_size && (st->codec.bits_per_sample <= 8)) {
 288                         st->codec.palctrl = av_mallocz(sizeof(AVPaletteControl));
 289 #ifdef WORDS_BIGENDIAN
 290                         for (i = 0; i < FFMIN(st->codec.extradata_size, AVPALETTE_SIZE)/4; i++)
 291                             st->codec.palctrl->palette[i] = bswap_32(((uint32_t*)st->codec.extradata)[i]);
 292 #else
 293                         memcpy(st->codec.palctrl->palette, st->codec.extradata,
 294                                FFMIN(st->codec.extradata_size, AVPALETTE_SIZE));
 295 #endif
 296                         st->codec.palctrl->palette_changed = 1;
 297                     }
 298
 299 #ifdef DEBUG
 300                     print_tag("video", tag1, 0);
 301 #endif
 302                     st->codec.codec_type = CODEC_TYPE_VIDEO;
 303                     st->codec.codec_tag = tag1;
 304                     st->codec.codec_id = codec_get_id(codec_bmp_tags, tag1);
 305                     if (st->codec.codec_id == CODEC_ID_XAN_WC4)
 306                         xan_video = 1;
 307 //                    url_fskip(pb, size - 5 * 4);
 308                     break;
 309                 case CODEC_TYPE_AUDIO:
 310                     get_wav_header(pb, &st->codec, size);
 311                     if (size%2) /* 2-aligned (fix for Stargate SG-1 - 3x18 - Shades of Grey.avi) */
 312                         url_fskip(pb, 1);
 313                     /* special case time: To support Xan DPCM, hardcode
 314                      * the format if Xxan is the video codec */
 315                     st->need_parsing = 1;
 316                     /* force parsing as several audio frames can be in
 317                        one packet */
 318                     if (xan_video)
 319                         st->codec.codec_id = CODEC_ID_XAN_DPCM;
 320                     break;
 321                 default:
 322                     st->codec.codec_type = CODEC_TYPE_DATA;
 323                     st->codec.codec_id= CODEC_ID_NONE;
 324                     st->codec.codec_tag= 0;
 325                     url_fskip(pb, size);
 326                     break;
 327                 }
 328             }
 329             break;
 330         default:
 331             /* skip tag */
 332             size += (size & 1);
 333             url_fskip(pb, size);
 334             break;
 335         }
 336     }
 337  end_of_header:
 338     /* check stream number */
 339     if (stream_index != s->nb_streams - 1) {
 340     fail:
 341         for(i=0;i<s->nb_streams;i++) {
 342             av_freep(&s->streams[i]->codec.extradata);
 343             av_freep(&s->streams[i]);
 344         }
 345         return -1;
 346     }
 347
 348     assert(!avi->index_loaded);
 349     avi_load_index(s);
 350     avi->index_loaded = 1;
 351
 352     return 0;
 353 }
 354
 355 static int avi_read_packet(AVFormatContext *s, AVPacket *pkt)
 356 {
 357     AVIContext *avi = s->priv_data;
 358     ByteIOContext *pb = &s->pb;
 359     int n, d[8], size;
 360     offset_t i, sync;
 361     void* dstr;
 362
 363     if (avi->dv_demux) {
 364         size = dv_get_packet(avi->dv_demux, pkt);
 365         if (size >= 0)
 366             return size;
 367     }
 368
 369     if(avi->non_interleaved){
 370         int best_stream_index;
 371         AVStream *best_st= NULL;
 372         AVIStream *best_ast;
 373         int64_t best_ts= INT64_MAX;
 374         int i;
 375
 376         for(i=0; i<s->nb_streams; i++){
 377             AVStream *st = s->streams[i];
 378             AVIStream *ast = st->priv_data;
 379             int64_t ts= ast->frame_offset;
 380
 381             if(ast->sample_size)
 382                 ts /= ast->sample_size;
 383             ts= av_rescale(ts, AV_TIME_BASE * (int64_t)st->time_base.num, st->time_base.den);
 384
 385 //            av_log(NULL, AV_LOG_DEBUG, "%Ld %d/%d %Ld\n", ts, st->time_base.num, st->time_base.den, ast->frame_offset);
 386             if(ts < best_ts){
 387                 best_ts= ts;
 388                 best_st= st;
 389                 best_stream_index= i;
 390             }
 391         }
 392         best_ast = best_st->priv_data;
 393         best_ts= av_rescale(best_ts, best_st->time_base.den, AV_TIME_BASE * (int64_t)best_st->time_base.num); //FIXME a little ugly
 394         if(best_ast->remaining)
 395             i= av_index_search_timestamp(best_st, best_ts, AVSEEK_FLAG_ANY | AVSEEK_FLAG_BACKWARD);
 396         else
 397             i= av_index_search_timestamp(best_st, best_ts, AVSEEK_FLAG_ANY);
 398
 399 //        av_log(NULL, AV_LOG_DEBUG, "%d\n", i);
 400         if(i>=0){
 401             int64_t pos= best_st->index_entries[i].pos;
 402             pos += avi->movi_list + best_ast->packet_size - best_ast->remaining;
 403             url_fseek(&s->pb, pos, SEEK_SET);
 404 //        av_log(NULL, AV_LOG_DEBUG, "pos=%Ld\n", pos);
 405
 406             if(best_ast->remaining)
 407                 avi->stream_index= best_stream_index;
 408             else
 409                 avi->stream_index= -1;
 410         }
 411     }
 412
 413 resync:
 414     if(avi->stream_index >= 0){
 415         AVStream *st= s->streams[ avi->stream_index ];
 416         AVIStream *ast= st->priv_data;
 417         int size;
 418
 419         if(ast->sample_size == 0)
 420             size= INT_MAX;
 421         else if(ast->sample_size < 32)
 422             size= 64*ast->sample_size;
 423         else
 424             size= ast->sample_size;
 425
 426         if(size > ast->remaining)
 427             size= ast->remaining;
 428         av_new_packet(pkt, size);
 429         get_buffer(pb, pkt->data, size);
 430
 431         if (avi->dv_demux) {
 432             dstr = pkt->destruct;
 433             size = dv_produce_packet(avi->dv_demux, pkt,
 434                                     pkt->data, pkt->size);
 435             pkt->destruct = dstr;
 436             pkt->flags |= PKT_FLAG_KEY;
 437         } else {
 438             /* XXX: how to handle B frames in avi ? */
 439             pkt->dts = ast->frame_offset;
 440 //                pkt->dts += ast->start;
 441             if(ast->sample_size)
 442                 pkt->dts /= ast->sample_size;
 443 //av_log(NULL, AV_LOG_DEBUG, "dts:%Ld offset:%d %d/%d smpl_siz:%d base:%d st:%d size:%d\n", pkt->dts, ast->frame_offset, ast->scale, ast->rate, ast->sample_size, AV_TIME_BASE, n, size);
 444             pkt->stream_index = avi->stream_index;
 445
 446             if (st->codec.codec_type == CODEC_TYPE_VIDEO) {
 447                 if(st->index_entries){
 448                     AVIndexEntry *e;
 449                     int index;
 450
 451                     index= av_index_search_timestamp(st, pkt->dts, 0);
 452                     e= &st->index_entries[index];
 453
 454                     if(e->timestamp == ast->frame_offset){
 455                         if (e->flags & AVINDEX_KEYFRAME)
 456                             pkt->flags |= PKT_FLAG_KEY;
 457                     }
 458                 } else {
 459                     /* if no index, better to say that all frames
 460                         are key frames */
 461                     pkt->flags |= PKT_FLAG_KEY;
 462                 }
 463             } else {
 464                 pkt->flags |= PKT_FLAG_KEY;
 465             }
 466             if(ast->sample_size)
 467                 ast->frame_offset += pkt->size;
 468             else
 469                 ast->frame_offset++;
 470         }
 471         ast->remaining -= size;
 472         if(!ast->remaining){
 473             avi->stream_index= -1;
 474             ast->packet_size= 0;
 475             if (size & 1) {
 476                 get_byte(pb);
 477                 size++;
 478             }
 479         }
 480
 481         return size;
 482     }
 483
 484     memset(d, -1, sizeof(int)*8);
 485     for(i=sync=url_ftell(pb); !url_feof(pb); i++) {
 486         int j;
 487
 488         if (i >= avi->movi_end) {
 489             if (avi->is_odml) {
 490                 url_fskip(pb, avi->riff_end - i);
 491                 avi->riff_end = avi->movi_end = url_filesize(url_fileno(pb));
 492             } else
 493                 break;
 494         }
 495
 496         for(j=0; j<7; j++)
 497             d[j]= d[j+1];
 498         d[7]= get_byte(pb);
 499
 500         size= d[4] + (d[5]<<8) + (d[6]<<16) + (d[7]<<24);
 501
 502         if(    d[2] >= '0' && d[2] <= '9'
 503             && d[3] >= '0' && d[3] <= '9'){
 504             n= (d[2] - '0') * 10 + (d[3] - '0');
 505         }else{
 506             n= 100; //invalid stream id
 507         }
 508 //av_log(NULL, AV_LOG_DEBUG, "%X %X %X %X %X %X %X %X %lld %d %d\n", d[0], d[1], d[2], d[3], d[4], d[5], d[6], d[7], i, size, n);
 509         if(i + size > avi->movi_end || d[0]<0)
 510             continue;
 511
 512         //parse ix##
 513         if(  (d[0] == 'i' && d[1] == 'x' && n < s->nb_streams)
 514         //parse JUNK
 515            ||(d[0] == 'J' && d[1] == 'U' && d[2] == 'N' && d[3] == 'K')){
 516             url_fskip(pb, size);
 517 //av_log(NULL, AV_LOG_DEBUG, "SKIP\n");
 518             goto resync;
 519         }
 520
 521         if(    d[0] >= '0' && d[0] <= '9'
 522             && d[1] >= '0' && d[1] <= '9'){
 523             n= (d[0] - '0') * 10 + (d[1] - '0');
 524         }else{
 525             n= 100; //invalid stream id
 526         }
 527
 528         //parse ##dc/##wb
 529         if(n < s->nb_streams){
 530           AVStream *st;
 531           AVIStream *ast;
 532           st = s->streams[n];
 533           ast = st->priv_data;
 534
 535           if(st->discard){
 536                 url_fskip(pb, size);
 537                 goto resync;
 538           }
 539
 540           if(   ((ast->prefix_count<5 || sync+9 > i) && d[2]<128 && d[3]<128) ||
 541                 d[2]*256+d[3] == ast->prefix /*||
 542                 (d[2] == 'd' && d[3] == 'c') ||
 543                 (d[2] == 'w' && d[3] == 'b')*/) {
 544
 545 //av_log(NULL, AV_LOG_DEBUG, "OK\n");
 546             if(d[2]*256+d[3] == ast->prefix)
 547                 ast->prefix_count++;
 548             else{
 549                 ast->prefix= d[2]*256+d[3];
 550                 ast->prefix_count= 0;
 551             }
 552
 553             avi->stream_index= n;
 554             ast->packet_size= size + 8;
 555             ast->remaining= size;
 556             goto resync;
 557
 558           }
 559         }
 560         /* palette changed chunk */
 561         if (   d[0] >= '0' && d[0] <= '9'
 562             && d[1] >= '0' && d[1] <= '9'
 563             && ((d[2] == 'p' && d[3] == 'c'))
 564             && n < s->nb_streams && i + size <= avi->movi_end) {
 565
 566             AVStream *st;
 567             int first, clr, flags, k, p;
 568
 569             st = s->streams[n];
 570
 571             first = get_byte(pb);
 572             clr = get_byte(pb);
 573             if(!clr) /* all 256 colors used */
 574                 clr = 256;
 575             flags = get_le16(pb);
 576             p = 4;
 577             for (k = first; k < clr + first; k++) {
 578                 int r, g, b;
 579                 r = get_byte(pb);
 580                 g = get_byte(pb);
 581                 b = get_byte(pb);
 582                     get_byte(pb);
 583                 st->codec.palctrl->palette[k] = b + (g << 8) + (r << 16);
 584             }
 585             st->codec.palctrl->palette_changed = 1;
 586             goto resync;
 587         }
 588
 589     }
 590
 591     return -1;
 592 }
 593
 594 /* XXX: we make the implicit supposition that the position are sorted
 595    for each stream */
 596 static int avi_read_idx1(AVFormatContext *s, int size)
 597 {
 598     AVIContext *avi = s->priv_data;
 599     ByteIOContext *pb = &s->pb;
 600     int nb_index_entries, i;
 601     AVStream *st;
 602     AVIStream *ast;
 603     unsigned int index, tag, flags, pos, len;
 604     unsigned last_pos= -1;
 605
 606     nb_index_entries = size / 16;
 607     if (nb_index_entries <= 0)
 608         return -1;
 609
 610     /* read the entries and sort them in each stream component */
 611     for(i = 0; i < nb_index_entries; i++) {
 612         tag = get_le32(pb);
 613         flags = get_le32(pb);
 614         pos = get_le32(pb);
 615         len = get_le32(pb);
 616 #if defined(DEBUG_SEEK)
 617         av_log(NULL, AV_LOG_DEBUG, "%d: tag=0x%x flags=0x%x pos=0x%x len=%d/",
 618                i, tag, flags, pos, len);
 619 #endif
 620         if(i==0 && pos > avi->movi_list)
 621             avi->movi_list= 0; //FIXME better check
 622
 623         index = ((tag & 0xff) - '0') * 10;
 624         index += ((tag >> 8) & 0xff) - '0';
 625         if (index >= s->nb_streams)
 626             continue;
 627         st = s->streams[index];
 628         ast = st->priv_data;
 629
 630 #if defined(DEBUG_SEEK)
 631         av_log(NULL, AV_LOG_DEBUG, "%d cum_len=%d\n", len, ast->cum_len);
 632 #endif
 633         if(last_pos == pos)
 634             avi->non_interleaved= 1;
 635         else
 636             av_add_index_entry(st, pos, ast->cum_len, 0, (flags&AVIIF_INDEX) ? AVINDEX_KEYFRAME : 0);
 637         if(ast->sample_size)
 638             ast->cum_len += len / ast->sample_size;
 639         else
 640             ast->cum_len ++;
 641         last_pos= pos;
 642     }
 643     return 0;
 644 }
 645
 646 static int guess_ni_flag(AVFormatContext *s){
 647     AVIContext *avi = s->priv_data;
 648     int i;
 649     int64_t last_start=0;
 650     int64_t first_end= INT64_MAX;
 651
 652     for(i=0; i<s->nb_streams; i++){
 653         AVStream *st = s->streams[i];
 654         AVIStream *ast = st->priv_data;
 655         int n= st->nb_index_entries;
 656
 657         if(n <= 0)
 658             continue;
 659
 660         if(st->index_entries[0].pos > last_start)
 661             last_start= st->index_entries[0].pos;
 662         if(st->index_entries[n-1].pos < first_end)
 663             first_end= st->index_entries[n-1].pos;
 664     }
 665     return last_start > first_end;
 666 }
 667
 668 static int avi_load_index(AVFormatContext *s)
 669 {
 670     AVIContext *avi = s->priv_data;
 671     ByteIOContext *pb = &s->pb;
 672     uint32_t tag, size;
 673     offset_t pos= url_ftell(pb);
 674
 675     url_fseek(pb, avi->movi_end, SEEK_SET);
 676 #ifdef DEBUG_SEEK
 677     printf("movi_end=0x%llx\n", avi->movi_end);
 678 #endif
 679     for(;;) {
 680         if (url_feof(pb))
 681             break;
 682         tag = get_le32(pb);
 683         size = get_le32(pb);
 684 #ifdef DEBUG_SEEK
 685         printf("tag=%c%c%c%c size=0x%x\n",
 686                tag & 0xff,
 687                (tag >> 8) & 0xff,
 688                (tag >> 16) & 0xff,
 689                (tag >> 24) & 0xff,
 690                size);
 691 #endif
 692         switch(tag) {
 693         case MKTAG('i', 'd', 'x', '1'):
 694             if (avi_read_idx1(s, size) < 0)
 695                 goto skip;
 696             else
 697                 goto the_end;
 698             break;
 699         default:
 700         skip:
 701             size += (size & 1);
 702             url_fskip(pb, size);
 703             break;
 704         }
 705     }
 706  the_end:
 707     avi->non_interleaved |= guess_ni_flag(s);
 708     url_fseek(pb, pos, SEEK_SET);
 709     return 0;
 710 }
 711
 712 static int avi_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
 713 {
 714     AVIContext *avi = s->priv_data;
 715     AVStream *st;
 716     int i, index;
 717     int64_t pos;
 718
 719     if (!avi->index_loaded) {
 720         /* we only load the index on demand */
 721         avi_load_index(s);
 722         avi->index_loaded = 1;
 723     }
 724     assert(stream_index>= 0);
 725
 726     st = s->streams[stream_index];
 727     index= av_index_search_timestamp(st, timestamp, flags);
 728     if(index<0)
 729         return -1;
 730
 731     /* find the position */
 732     pos = st->index_entries[index].pos;
 733     timestamp = st->index_entries[index].timestamp;
 734
 735 //    av_log(NULL, AV_LOG_DEBUG, "XX %Ld %d %Ld\n", timestamp, index, st->index_entries[index].timestamp);
 736
 737     for(i = 0; i < s->nb_streams; i++) {
 738         AVStream *st2 = s->streams[i];
 739         AVIStream *ast2 = st2->priv_data;
 740
 741         ast2->packet_size=
 742         ast2->remaining= 0;
 743
 744         if (st2->nb_index_entries <= 0)
 745             continue;
 746
 747 //        assert(st2->codec.block_align);
 748         assert(st2->time_base.den == ast2->rate);
 749         assert(st2->time_base.num == ast2->scale);
 750         index = av_index_search_timestamp(
 751                 st2,
 752                 av_rescale(timestamp, st2->time_base.den*(int64_t)st->time_base.num, st->time_base.den * (int64_t)st2->time_base.num),
 753                 flags | AVSEEK_FLAG_BACKWARD);
 754         if(index<0)
 755             index=0;
 756
 757         if(!avi->non_interleaved){
 758             while(index>0 && st2->index_entries[index].pos > pos)
 759                 index--;
 760             while(index+1 < st2->nb_index_entries && st2->index_entries[index].pos < pos)
 761                 index++;
 762         }
 763
 764 //        av_log(NULL, AV_LOG_DEBUG, "%Ld %d %Ld\n", timestamp, index, st2->index_entries[index].timestamp);
 765         /* extract the current frame number */
 766         ast2->frame_offset = st2->index_entries[index].timestamp;
 767         if(ast2->sample_size)
 768             ast2->frame_offset *=ast2->sample_size;
 769     }
 770
 771     if (avi->dv_demux)
 772         dv_flush_audio_packets(avi->dv_demux);
 773     /* do the seek */
 774     pos += avi->movi_list;
 775     url_fseek(&s->pb, pos, SEEK_SET);
 776     avi->stream_index= -1;
 777     return 0;
 778 }
 779
 780 static int avi_read_close(AVFormatContext *s)
 781 {
 782     int i;
 783     AVIContext *avi = s->priv_data;
 784
 785     for(i=0;i<s->nb_streams;i++) {
 786         AVStream *st = s->streams[i];
 787         AVIStream *ast = st->priv_data;
 788         av_free(ast);
 789         av_free(st->codec.extradata);
 790         av_free(st->codec.palctrl);
 791     }
 792
 793     if (avi->dv_demux)
 794         av_free(avi->dv_demux);
 795
 796     return 0;
 797 }
 798
 799 static int avi_probe(AVProbeData *p)
 800 {
 801     /* check file header */
 802     if (p->buf_size <= 32)
 803         return 0;
 804     if (p->buf[0] == 'R' && p->buf[1] == 'I' &&
 805         p->buf[2] == 'F' && p->buf[3] == 'F' &&
 806         p->buf[8] == 'A' && p->buf[9] == 'V' &&
 807         p->buf[10] == 'I' && p->buf[11] == ' ')
 808         return AVPROBE_SCORE_MAX;
 809     else
 810         return 0;
 811 }
 812
 813 static AVInputFormat avi_iformat = {
 814     "avi",
 815     "avi format",
 816     sizeof(AVIContext),
 817     avi_probe,
 818     avi_read_header,
 819     avi_read_packet,
 820     avi_read_close,
 821     avi_read_seek,
 822 };
 823
 824 int avidec_init(void)
 825 {
 826     av_register_input_format(&avi_iformat);
 827     return 0;
 828 }