libavformat/vividas.c

   1 /*
   2  * Vividas VIV format Demuxer
   3  * Copyright (c) 2012 Krzysztof Klinikowski
   4  * Copyright (c) 2010 Andrzej Szombierski
   5  * based on vivparse Copyright (c) 2007 Måns Rullgård
   6  *
   7  * This file is part of FFmpeg.
   8  *
   9  * FFmpeg is free software; you can redistribute it and/or
  10  * modify it under the terms of the GNU Lesser General Public
  11  * License as published by the Free Software Foundation; either
  12  * version 2.1 of the License, or (at your option) any later version.
  13  *
  14  * FFmpeg is distributed in the hope that it will be useful,
  15  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  16  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  17  * Lesser General Public License for more details.
  18  *
  19  * You should have received a copy of the GNU Lesser General Public
  20  * License along with FFmpeg; if not, write to the Free Software
  21  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
  22  */
  23
  24 /**
  25  * @file
  26  * @brief Vividas VIV (.viv) file demuxer
  27  * @author Andrzej Szombierski [qq at kuku eu org] (2010-07)
  28  * @sa http://wiki.multimedia.cx/index.php?title=Vividas_VIV
  29  */
  30
  31 #include "libavutil/avassert.h"
  32 #include "libavutil/intreadwrite.h"
  33 #include "avio_internal.h"
  34 #include "avformat.h"
  35 #include "internal.h"
  36
  37 #define MAX_AUDIO_SUBPACKETS 100
  38
  39 typedef struct VIV_SB_block {
  40     int size, n_packets;
  41     int64_t byte_offset;
  42     int64_t packet_offset;
  43 } VIV_SB_block;
  44
  45 typedef struct VIV_SB_entry {
  46     int size, flag;
  47 } VIV_SB_entry;
  48
  49 typedef struct VIV_AudioSubpacket {
  50     int start, pcm_bytes;
  51 } VIV_AudioSubpacket;
  52
  53 typedef struct VividasDemuxContext {
  54     int n_sb_blocks;
  55     VIV_SB_block *sb_blocks;
  56     int num_audio;
  57
  58     uint32_t sb_key;
  59     int64_t sb_offset;
  60
  61     int current_sb, current_sb_entry;
  62     uint8_t *sb_buf;
  63     AVIOContext *sb_pb;
  64     int n_sb_entries;
  65     VIV_SB_entry *sb_entries;
  66
  67     int n_audio_subpackets;
  68     int current_audio_subpacket;
  69
  70     int64_t audio_sample;
  71
  72     VIV_AudioSubpacket audio_subpackets[MAX_AUDIO_SUBPACKETS];
  73 } VividasDemuxContext;
  74
  75 static int viv_probe(const AVProbeData *p)
  76 {
  77     if (memcmp(p->buf, "vividas03", 9))
  78         return 0;
  79
  80     return AVPROBE_SCORE_MAX;
  81 }
  82
  83 static const uint8_t keybits[32] = {
  84  20,  52, 111,  10,  27,  71, 142,  53,
  85  82, 138,   1,  78,  86, 121, 183,  85,
  86 105, 152,  39, 140, 172,  11,  64, 144,
  87 155,   6,  71, 163, 186,  49, 126,  43,
  88 };
  89
  90 static uint32_t decode_key(uint8_t *buf)
  91 {
  92     uint32_t key = 0;
  93
  94     for (int i = 0; i < 32; i++) {
  95         unsigned p = keybits[i];
  96         key |= ((buf[p] >> ((i*5+3)&7)) & 1u) << i;
  97     }
  98
  99     return key;
 100 }
 101
 102 static void put_v(uint8_t *p, unsigned v)
 103 {
 104     if (v>>28)
 105         *p++ = ((v>>28)&0x7f)|0x80;
 106     if (v>>21)
 107         *p++ = ((v>>21)&0x7f)|0x80;
 108     if (v>>14)
 109         *p++ = ((v>>14)&0x7f)|0x80;
 110     if (v>>7)
 111         *p++ =  ((v>>7)&0x7f)|0x80;
 112 }
 113
 114 static unsigned recover_key(unsigned char sample[4], unsigned expected_size)
 115 {
 116     unsigned char plaintext[8] = { 'S', 'B' };
 117
 118     put_v(plaintext+2, expected_size);
 119
 120     return AV_RL32(sample) ^ AV_RL32(plaintext);
 121 }
 122
 123 static void xor_block(void *p1, void *p2, unsigned size, int key, unsigned *key_ptr)
 124 {
 125     unsigned *d1 = p1;
 126     unsigned *d2 = p2;
 127     unsigned k = *key_ptr;
 128
 129     size >>= 2;
 130
 131     while (size > 0) {
 132         *d2 = *d1 ^ (HAVE_BIGENDIAN ? av_bswap32(k) : k);
 133         k += key;
 134         d1++;
 135         d2++;
 136         size--;
 137     }
 138
 139     *key_ptr = k;
 140 }
 141
 142 static void decode_block(uint8_t *src, uint8_t *dest, unsigned size,
 143                          uint32_t key, uint32_t *key_ptr,
 144                          int align)
 145 {
 146     unsigned s = size;
 147     char tmp[4];
 148     int a2;
 149
 150     if (!size)
 151         return;
 152
 153     align &= 3;
 154     a2 = (4 - align) & 3;
 155
 156     if (align) {
 157         uint32_t tmpkey = *key_ptr - key;
 158         if (a2 > s) {
 159             a2 = s;
 160             avpriv_request_sample(NULL, "tiny aligned block\n");
 161         }
 162         memcpy(tmp + align, src, a2);
 163         xor_block(tmp, tmp, 4, key, &tmpkey);
 164         memcpy(dest, tmp + align, a2);
 165         s -= a2;
 166     }
 167
 168     if (s >= 4) {
 169         xor_block(src + a2, dest + a2, s & ~3,
 170                   key, key_ptr);
 171         s &= 3;
 172     }
 173
 174     if (s) {
 175         size -= s;
 176         memcpy(tmp, src + size, s);
 177         xor_block(&tmp, &tmp, 4, key, key_ptr);
 178         memcpy(dest + size, tmp, s);
 179     }
 180 }
 181
 182 static uint32_t get_v(uint8_t *p, int len)
 183 {
 184     uint32_t v = 0;
 185     const uint8_t *end = p + len;
 186
 187     do {
 188         if (p >= end || v >= UINT_MAX / 128 - *p)
 189             return v;
 190         v <<= 7;
 191         v += *p & 0x7f;
 192     } while (*p++ & 0x80);
 193
 194     return v;
 195 }
 196
 197 static uint8_t *read_vblock(AVIOContext *src, uint32_t *size,
 198                             uint32_t key, uint32_t *k2, int align)
 199 {
 200     uint8_t tmp[4];
 201     uint8_t *buf;
 202     unsigned n;
 203
 204     if (avio_read(src, tmp, 4) != 4)
 205         return NULL;
 206
 207     decode_block(tmp, tmp, 4, key, k2, align);
 208
 209     n = get_v(tmp, 4);
 210     if (n < 4)
 211         return NULL;
 212
 213     buf = av_malloc(n);
 214     if (!buf)
 215         return NULL;
 216
 217     *size = n;
 218     n -= 4;
 219
 220     memcpy(buf, tmp, 4);
 221
 222     if (avio_read(src, buf + 4, n) == n) {
 223         decode_block(buf + 4, buf + 4, n, key, k2, align);
 224     } else {
 225         av_free(buf);
 226         buf = NULL;
 227     }
 228
 229     return buf;
 230 }
 231
 232 static uint8_t *read_sb_block(AVIOContext *src, unsigned *size,
 233                               uint32_t *key, unsigned expected_size)
 234 {
 235     uint8_t *buf;
 236     uint8_t ibuf[8], sbuf[8];
 237     uint32_t k2;
 238     unsigned n;
 239
 240     if (avio_read(src, ibuf, 8) < 8)
 241         return NULL;
 242
 243     k2 = *key;
 244     decode_block(ibuf, sbuf, 8, *key, &k2, 0);
 245
 246     n = get_v(sbuf+2, 6);
 247
 248     if (sbuf[0] != 'S' || sbuf[1] != 'B' || (expected_size>0 && n != expected_size)) {
 249         uint32_t tmpkey = recover_key(ibuf, expected_size);
 250         k2 = tmpkey;
 251         decode_block(ibuf, sbuf, 8, tmpkey, &k2, 0);
 252         n = get_v(sbuf+2, 6);
 253         if (sbuf[0] != 'S' || sbuf[1] != 'B' || expected_size != n)
 254             return NULL;
 255         *key = tmpkey;
 256     }
 257
 258     if (n < 8)
 259         return NULL;
 260
 261     buf = av_malloc(n);
 262     if (!buf)
 263         return NULL;
 264
 265     memcpy(buf, sbuf, 8);
 266
 267     *size = n;
 268     n -= 8;
 269
 270     if (avio_read(src, buf+8, n) != n) {
 271         av_free(buf);
 272         return NULL;
 273     }
 274
 275     decode_block(buf + 8, buf + 8, n, *key, &k2, 0);
 276
 277     return buf;
 278 }
 279
 280 static int track_header(VividasDemuxContext *viv, AVFormatContext *s,  uint8_t *buf, int size)
 281 {
 282     int i, j, ret;
 283     int64_t off;
 284     int val_1;
 285     int num_video;
 286     AVIOContext pb0, *pb = &pb0;
 287
 288     ffio_init_context(pb, buf, size, 0, NULL, NULL, NULL, NULL);
 289
 290     ffio_read_varlen(pb); // track_header_len
 291     avio_r8(pb); // '1'
 292
 293     val_1 = ffio_read_varlen(pb);
 294
 295     for (i=0;i<val_1;i++) {
 296         int c = avio_r8(pb);
 297         if (avio_feof(pb))
 298             return AVERROR_EOF;
 299         for (j=0;j<c;j++) {
 300             if (avio_feof(pb))
 301                 return AVERROR_EOF;
 302             avio_r8(pb); // val_3
 303             avio_r8(pb); // val_4
 304         }
 305     }
 306
 307     avio_r8(pb); // num_streams
 308
 309     off = avio_tell(pb);
 310     off += ffio_read_varlen(pb); // val_5
 311
 312     avio_r8(pb); // '2'
 313     num_video = avio_r8(pb);
 314
 315     avio_seek(pb, off, SEEK_SET);
 316     if (num_video != 1) {
 317         av_log(s, AV_LOG_ERROR, "number of video tracks %d is not 1\n", num_video);
 318         return AVERROR_PATCHWELCOME;
 319     }
 320
 321     for (i = 0; i < num_video; i++) {
 322         AVStream *st = avformat_new_stream(s, NULL);
 323         int num, den;
 324
 325         if (!st)
 326             return AVERROR(ENOMEM);
 327
 328         st->id = i;
 329
 330         st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
 331         st->codecpar->codec_id = AV_CODEC_ID_VP6;
 332
 333         off = avio_tell(pb);
 334         off += ffio_read_varlen(pb);
 335         avio_r8(pb); // '3'
 336         avio_r8(pb); // val_7
 337         num = avio_rl32(pb); // frame_time
 338         den = avio_rl32(pb); // time_base
 339         avpriv_set_pts_info(st, 64, num, den);
 340         st->nb_frames = avio_rl32(pb); // n frames
 341         st->codecpar->width = avio_rl16(pb); // width
 342         st->codecpar->height = avio_rl16(pb); // height
 343         avio_r8(pb); // val_8
 344         avio_rl32(pb); // val_9
 345
 346         avio_seek(pb, off, SEEK_SET);
 347     }
 348
 349     off = avio_tell(pb);
 350     off += ffio_read_varlen(pb); // val_10
 351     avio_r8(pb); // '4'
 352     viv->num_audio = avio_r8(pb);
 353     avio_seek(pb, off, SEEK_SET);
 354
 355     if (viv->num_audio != 1)
 356         av_log(s, AV_LOG_WARNING, "number of audio tracks %d is not 1\n", viv->num_audio);
 357
 358     for(i=0;i<viv->num_audio;i++) {
 359         int q;
 360         AVStream *st = avformat_new_stream(s, NULL);
 361         if (!st)
 362             return AVERROR(ENOMEM);
 363
 364         st->id = num_video + i;
 365
 366         st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
 367         st->codecpar->codec_id = AV_CODEC_ID_VORBIS;
 368
 369         off = avio_tell(pb);
 370         off += ffio_read_varlen(pb); // length
 371         avio_r8(pb); // '5'
 372         avio_r8(pb); //codec_id
 373         avio_rl16(pb); //codec_subid
 374         st->codecpar->channels = avio_rl16(pb); // channels
 375         st->codecpar->sample_rate = avio_rl32(pb); // sample_rate
 376         if (st->codecpar->sample_rate <= 0 || st->codecpar->channels <= 0)
 377             return AVERROR_INVALIDDATA;
 378         avio_seek(pb, 10, SEEK_CUR); // data_1
 379         q = avio_r8(pb);
 380         avio_seek(pb, q, SEEK_CUR); // data_2
 381         avio_r8(pb); // zeropad
 382
 383         if (avio_tell(pb) < off) {
 384             int num_data;
 385             int xd_size = 1;
 386             int data_len[256];
 387             int offset = 1;
 388             uint8_t *p;
 389             ffio_read_varlen(pb); // val_13
 390             avio_r8(pb); // '19'
 391             ffio_read_varlen(pb); // len_3
 392             num_data = avio_r8(pb);
 393             for (j = 0; j < num_data; j++) {
 394                 int64_t len = ffio_read_varlen(pb);
 395                 if (len < 0 || len > INT_MAX/2 - xd_size) {
 396                     return AVERROR_INVALIDDATA;
 397                 }
 398                 data_len[j] = len;
 399                 xd_size += len + 1 + len/255;
 400             }
 401
 402             ret = ff_alloc_extradata(st->codecpar, xd_size);
 403             if (ret < 0)
 404                 return ret;
 405
 406             p = st->codecpar->extradata;
 407             p[0] = 2;
 408
 409             for (j = 0; j < num_data - 1; j++) {
 410                 unsigned delta = av_xiphlacing(&p[offset], data_len[j]);
 411                 av_assert0(delta <= xd_size - offset);
 412                 offset += delta;
 413             }
 414
 415             for (j = 0; j < num_data; j++) {
 416                 int ret = avio_read(pb, &p[offset], data_len[j]);
 417                 if (ret < data_len[j]) {
 418                     st->codecpar->extradata_size = 0;
 419                     av_freep(&st->codecpar->extradata);
 420                     break;
 421                 }
 422                 av_assert0(data_len[j] <= xd_size - offset);
 423                 offset += data_len[j];
 424             }
 425
 426             if (offset < st->codecpar->extradata_size)
 427                 st->codecpar->extradata_size = offset;
 428         }
 429     }
 430
 431     return 0;
 432 }
 433
 434 static int track_index(VividasDemuxContext *viv, AVFormatContext *s, uint8_t *buf, unsigned size)
 435 {
 436     int64_t off;
 437     int64_t poff;
 438     int maxnp=0;
 439     AVIOContext pb0, *pb = &pb0;
 440     int i;
 441     int64_t filesize = avio_size(s->pb);
 442     uint64_t n_sb_blocks_tmp;
 443
 444     ffio_init_context(pb, buf, size, 0, NULL, NULL, NULL, NULL);
 445
 446     ffio_read_varlen(pb); // track_index_len
 447     avio_r8(pb); // 'c'
 448     n_sb_blocks_tmp = ffio_read_varlen(pb);
 449     if (n_sb_blocks_tmp > size / 2)
 450         return AVERROR_INVALIDDATA;
 451     viv->sb_blocks = av_calloc(n_sb_blocks_tmp, sizeof(*viv->sb_blocks));
 452     if (!viv->sb_blocks) {
 453         return AVERROR(ENOMEM);
 454     }
 455     viv->n_sb_blocks = n_sb_blocks_tmp;
 456
 457     off = 0;
 458     poff = 0;
 459
 460     for (i = 0; i < viv->n_sb_blocks; i++) {
 461         uint64_t size_tmp      = ffio_read_varlen(pb);
 462         uint64_t n_packets_tmp = ffio_read_varlen(pb);
 463
 464         if (size_tmp > INT_MAX || n_packets_tmp > INT_MAX)
 465             return AVERROR_INVALIDDATA;
 466
 467         viv->sb_blocks[i].byte_offset = off;
 468         viv->sb_blocks[i].packet_offset = poff;
 469
 470         viv->sb_blocks[i].size = size_tmp;
 471         viv->sb_blocks[i].n_packets = n_packets_tmp;
 472
 473         off += viv->sb_blocks[i].size;
 474         poff += viv->sb_blocks[i].n_packets;
 475
 476         if (maxnp < viv->sb_blocks[i].n_packets)
 477             maxnp = viv->sb_blocks[i].n_packets;
 478     }
 479
 480     if (filesize > 0 && poff > filesize)
 481         return AVERROR_INVALIDDATA;
 482
 483     viv->sb_entries = av_calloc(maxnp, sizeof(VIV_SB_entry));
 484     if (!viv->sb_entries)
 485         return AVERROR(ENOMEM);
 486
 487     return 0;
 488 }
 489
 490 static void load_sb_block(AVFormatContext *s, VividasDemuxContext *viv, unsigned expected_size)
 491 {
 492     uint32_t size = 0;
 493     int i;
 494     AVIOContext *pb = 0;
 495
 496     if (viv->sb_pb) {
 497         av_free(viv->sb_pb);
 498         viv->sb_pb = NULL;
 499     }
 500
 501     if (viv->sb_buf)
 502         av_free(viv->sb_buf);
 503
 504     viv->sb_buf = read_sb_block(s->pb, &size, &viv->sb_key, expected_size);
 505     if (!viv->sb_buf) {
 506         return;
 507     }
 508
 509     pb = avio_alloc_context(viv->sb_buf, size, 0, NULL, NULL, NULL, NULL);
 510     if (!pb)
 511         return;
 512
 513     viv->sb_pb = pb;
 514
 515     avio_r8(pb); //  'S'
 516     avio_r8(pb); //  'B'
 517     ffio_read_varlen(pb); //  size
 518     avio_r8(pb); //  junk
 519     ffio_read_varlen(pb); // first packet
 520
 521     viv->n_sb_entries = viv->sb_blocks[viv->current_sb].n_packets;
 522
 523     for (i = 0; i < viv->n_sb_entries; i++) {
 524         viv->sb_entries[i].size = ffio_read_varlen(pb);
 525         viv->sb_entries[i].flag = avio_r8(pb);
 526     }
 527
 528     ffio_read_varlen(pb);
 529     avio_r8(pb);
 530
 531     viv->current_sb_entry = 0;
 532 }
 533
 534 static int viv_read_header(AVFormatContext *s)
 535 {
 536     VividasDemuxContext *viv = s->priv_data;
 537     AVIOContext *pb = s->pb;
 538     int64_t header_end;
 539     int num_tracks;
 540     uint32_t key, k2;
 541     uint32_t v;
 542     uint8_t keybuffer[187];
 543     uint32_t b22_size = 0;
 544     uint32_t b22_key = 0;
 545     uint8_t *buf = 0;
 546     int ret;
 547
 548     avio_skip(pb, 9);
 549
 550     header_end = avio_tell(pb);
 551
 552     header_end += ffio_read_varlen(pb);
 553
 554     num_tracks = avio_r8(pb);
 555
 556     if (num_tracks != 1) {
 557         av_log(s, AV_LOG_ERROR, "number of tracks %d is not 1\n", num_tracks);
 558         return AVERROR(EINVAL);
 559     }
 560
 561     v = avio_r8(pb);
 562     avio_seek(pb, v, SEEK_CUR);
 563
 564     if (avio_read(pb, keybuffer, 187) != 187)
 565         return AVERROR_INVALIDDATA;
 566     key = decode_key(keybuffer);
 567     viv->sb_key = key;
 568
 569     avio_rl32(pb);
 570
 571     for (;;) {
 572         int64_t here = avio_tell(pb);
 573         int block_len, block_type;
 574
 575         if (here >= header_end)
 576             break;
 577
 578         block_len = ffio_read_varlen(pb);
 579         if (avio_feof(pb) || block_len <= 0)
 580             return AVERROR_INVALIDDATA;
 581
 582         block_type = avio_r8(pb);
 583
 584         if (block_type == 22) {
 585             avio_read(pb, keybuffer, 187);
 586             b22_key = decode_key(keybuffer);
 587             b22_size = avio_rl32(pb);
 588         }
 589
 590         avio_seek(pb, here + block_len, SEEK_SET);
 591     }
 592
 593     if (b22_size) {
 594         k2 = b22_key;
 595         buf = read_vblock(pb, &v, b22_key, &k2, 0);
 596         if (!buf)
 597             return AVERROR(EIO);
 598
 599         av_free(buf);
 600     }
 601
 602     k2 = key;
 603     buf = read_vblock(pb, &v, key, &k2, 0);
 604     if (!buf)
 605         return AVERROR(EIO);
 606     ret = track_header(viv, s, buf, v);
 607     av_free(buf);
 608     if (ret < 0)
 609         return ret;
 610
 611     buf = read_vblock(pb, &v, key, &k2, v);
 612     if (!buf)
 613         return AVERROR(EIO);
 614     ret = track_index(viv, s, buf, v);
 615     av_free(buf);
 616     if (ret < 0)
 617         goto fail;
 618
 619     viv->sb_offset = avio_tell(pb);
 620     if (viv->n_sb_blocks > 0) {
 621         viv->current_sb = 0;
 622         load_sb_block(s, viv, viv->sb_blocks[0].size);
 623     } else {
 624         viv->current_sb = -1;
 625     }
 626
 627     return 0;
 628 fail:
 629     av_freep(&viv->sb_blocks);
 630     return ret;
 631 }
 632
 633 static int viv_read_packet(AVFormatContext *s,
 634                            AVPacket *pkt)
 635 {
 636     VividasDemuxContext *viv = s->priv_data;
 637     AVIOContext *pb;
 638     int64_t off;
 639     int ret;
 640
 641     if (!viv->sb_pb)
 642         return AVERROR(EIO);
 643     if (avio_feof(viv->sb_pb))
 644         return AVERROR_EOF;
 645
 646     if (viv->current_audio_subpacket < viv->n_audio_subpackets) {
 647         AVStream *astream;
 648         int size = viv->audio_subpackets[viv->current_audio_subpacket+1].start - viv->audio_subpackets[viv->current_audio_subpacket].start;
 649
 650         pb = viv->sb_pb;
 651         ret = av_get_packet(pb, pkt, size);
 652         if (ret < 0)
 653             return ret;
 654         pkt->pos += viv->sb_offset + viv->sb_blocks[viv->current_sb].byte_offset;
 655
 656         pkt->stream_index = 1;
 657         astream = s->streams[pkt->stream_index];
 658
 659         pkt->pts = av_rescale_q(viv->audio_sample, av_make_q(1, astream->codecpar->sample_rate), astream->time_base);
 660         viv->audio_sample += viv->audio_subpackets[viv->current_audio_subpacket].pcm_bytes / 2 / astream->codecpar->channels;
 661         pkt->flags |= AV_PKT_FLAG_KEY;
 662         viv->current_audio_subpacket++;
 663         return 0;
 664     }
 665
 666     if (viv->current_sb_entry >= viv->n_sb_entries) {
 667         if (viv->current_sb+1 >= viv->n_sb_blocks)
 668             return AVERROR(EIO);
 669         viv->current_sb++;
 670
 671         load_sb_block(s, viv, 0);
 672         viv->current_sb_entry = 0;
 673     }
 674
 675     pb = viv->sb_pb;
 676     if (!pb)
 677         return AVERROR(EIO);
 678     off = avio_tell(pb);
 679
 680     if (viv->current_sb_entry >= viv->n_sb_entries)
 681         return AVERROR_INVALIDDATA;
 682
 683     off += viv->sb_entries[viv->current_sb_entry].size;
 684
 685     if (viv->sb_entries[viv->current_sb_entry].flag == 0) {
 686         uint64_t v_size = ffio_read_varlen(pb);
 687         int last = 0, last_start;
 688
 689         if (!viv->num_audio)
 690             return AVERROR_INVALIDDATA;
 691
 692         ffio_read_varlen(pb);
 693         if (v_size > INT_MAX || !v_size)
 694             return AVERROR_INVALIDDATA;
 695         ret = av_get_packet(pb, pkt, v_size);
 696         if (ret < 0)
 697             return ret;
 698         pkt->pos += viv->sb_offset + viv->sb_blocks[viv->current_sb].byte_offset;
 699
 700         pkt->pts = viv->sb_blocks[viv->current_sb].packet_offset + viv->current_sb_entry;
 701         pkt->flags |= (pkt->data[0]&0x80)?0:AV_PKT_FLAG_KEY;
 702         pkt->stream_index = 0;
 703
 704         for (int i = 0; i < MAX_AUDIO_SUBPACKETS - 1; i++) {
 705             int start, pcm_bytes;
 706             start = ffio_read_varlen(pb);
 707             pcm_bytes = ffio_read_varlen(pb);
 708
 709             if (i > 0 && start == 0)
 710                 break;
 711             if (start < last)
 712                 return AVERROR_INVALIDDATA;
 713
 714             viv->n_audio_subpackets = i + 1;
 715             last =
 716             viv->audio_subpackets[i].start = start;
 717             viv->audio_subpackets[i].pcm_bytes = pcm_bytes;
 718         }
 719         last_start =
 720         viv->audio_subpackets[viv->n_audio_subpackets].start = (int)(off - avio_tell(pb));
 721         if (last_start < last)
 722             return AVERROR_INVALIDDATA;
 723         viv->current_audio_subpacket = 0;
 724
 725     } else {
 726         uint64_t v_size = ffio_read_varlen(pb);
 727
 728         if (v_size > INT_MAX || !v_size)
 729             return AVERROR_INVALIDDATA;
 730         ret = av_get_packet(pb, pkt, v_size);
 731         if (ret < 0)
 732             return ret;
 733         pkt->pos += viv->sb_offset + viv->sb_blocks[viv->current_sb].byte_offset;
 734         pkt->pts = viv->sb_blocks[viv->current_sb].packet_offset + viv->current_sb_entry;
 735         pkt->flags |= (pkt->data[0] & 0x80) ? 0 : AV_PKT_FLAG_KEY;
 736         pkt->stream_index = 0;
 737     }
 738
 739     viv->current_sb_entry++;
 740
 741     return 0;
 742 }
 743
 744 static int viv_read_close(AVFormatContext *s)
 745 {
 746     VividasDemuxContext *viv = s->priv_data;
 747
 748     av_freep(&viv->sb_pb);
 749     av_freep(&viv->sb_buf);
 750     av_freep(&viv->sb_blocks);
 751     av_freep(&viv->sb_entries);
 752
 753     return 0;
 754 }
 755
 756 static int viv_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
 757 {
 758     VividasDemuxContext *viv = s->priv_data;
 759     int64_t frame;
 760
 761     if (stream_index == 0)
 762         frame = timestamp;
 763     else
 764         frame = av_rescale_q(timestamp, s->streams[0]->time_base, s->streams[stream_index]->time_base);
 765
 766     for (int i = 0; i < viv->n_sb_blocks; i++) {
 767         if (frame >= viv->sb_blocks[i].packet_offset && frame < viv->sb_blocks[i].packet_offset + viv->sb_blocks[i].n_packets) {
 768             // flush audio packet queue
 769             viv->current_audio_subpacket = 0;
 770             viv->n_audio_subpackets = 0;
 771             viv->current_sb = i;
 772             // seek to ith sb block
 773             avio_seek(s->pb, viv->sb_offset + viv->sb_blocks[i].byte_offset, SEEK_SET);
 774             // load the block
 775             load_sb_block(s, viv, 0);
 776             // most problematic part: guess audio offset
 777             viv->audio_sample = av_rescale_q(viv->sb_blocks[i].packet_offset, av_make_q(s->streams[1]->codecpar->sample_rate, 1), av_inv_q(s->streams[0]->time_base));
 778             // hand-tuned 1.s a/v offset
 779             viv->audio_sample += s->streams[1]->codecpar->sample_rate;
 780             viv->current_sb_entry = 0;
 781             return 1;
 782         }
 783     }
 784     return 0;
 785 }
 786
 787 AVInputFormat ff_vividas_demuxer = {
 788     .name           = "vividas",
 789     .long_name      = NULL_IF_CONFIG_SMALL("Vividas VIV"),
 790     .priv_data_size = sizeof(VividasDemuxContext),
 791     .read_probe     = viv_probe,
 792     .read_header    = viv_read_header,
 793     .read_packet    = viv_read_packet,
 794     .read_close     = viv_read_close,
 795     .read_seek      = viv_read_seek,
 796 };