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 
viv_probe(const AVProbeData *p)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 
decode_key(uint8_t *buf)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 
put_v(uint8_t *p, unsigned v)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 
recover_key(unsigned char sample[4], unsigned expected_size)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 
xor_block(void *p1, void *p2, unsigned size, int key, unsigned *key_ptr)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 
decode_block(uint8_t *src, uint8_t *dest, unsigned size, uint32_t key, uint32_t *key_ptr, int align)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");
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 
get_v(uint8_t *p, int len)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 
read_vblock(AVIOContext *src, uint32_t *size, uint32_t key, uint32_t *k2, int align)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 
read_sb_block(AVIOContext *src, unsigned *size, uint32_t *key, unsigned expected_size)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 
track_header(VividasDemuxContext *viv, AVFormatContext *s, uint8_t *buf, int size)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     FFIOContext pb0;
287     AVIOContext *const pb = &pb0.pub;
288 
289     ffio_init_context(&pb0, buf, size, 0, NULL, NULL, NULL, NULL);
290 
291     ffio_read_varlen(pb); // track_header_len
292     avio_r8(pb); // '1'
293 
294     val_1 = ffio_read_varlen(pb);
295 
296     for (i=0;i<val_1;i++) {
297         int c = avio_r8(pb);
298         if (avio_feof(pb))
299             return AVERROR_EOF;
300         for (j=0;j<c;j++) {
301             if (avio_feof(pb))
302                 return AVERROR_EOF;
303             avio_r8(pb); // val_3
304             avio_r8(pb); // val_4
305         }
306     }
307 
308     avio_r8(pb); // num_streams
309 
310     off = avio_tell(pb);
311     off += ffio_read_varlen(pb); // val_5
312 
313     avio_r8(pb); // '2'
314     num_video = avio_r8(pb);
315 
316     avio_seek(pb, off, SEEK_SET);
317     if (num_video != 1) {
318         av_log(s, AV_LOG_ERROR, "number of video tracks %d is not 1\n", num_video);
319         return AVERROR_PATCHWELCOME;
320     }
321 
322     for (i = 0; i < num_video; i++) {
323         AVStream *st = avformat_new_stream(s, NULL);
324         int num, den;
325 
326         if (!st)
327             return AVERROR(ENOMEM);
328 
329         st->id = i;
330 
331         st->codecpar->codec_type = AVMEDIA_TYPE_VIDEO;
332         st->codecpar->codec_id = AV_CODEC_ID_VP6;
333 
334         off = avio_tell(pb);
335         off += ffio_read_varlen(pb);
336         avio_r8(pb); // '3'
337         avio_r8(pb); // val_7
338         num = avio_rl32(pb); // frame_time
339         den = avio_rl32(pb); // time_base
340         avpriv_set_pts_info(st, 64, num, den);
341         st->nb_frames = avio_rl32(pb); // n frames
342         st->codecpar->width = avio_rl16(pb); // width
343         st->codecpar->height = avio_rl16(pb); // height
344         avio_r8(pb); // val_8
345         avio_rl32(pb); // val_9
346 
347         avio_seek(pb, off, SEEK_SET);
348     }
349 
350     off = avio_tell(pb);
351     off += ffio_read_varlen(pb); // val_10
352     avio_r8(pb); // '4'
353     viv->num_audio = avio_r8(pb);
354     avio_seek(pb, off, SEEK_SET);
355 
356     if (viv->num_audio != 1)
357         av_log(s, AV_LOG_WARNING, "number of audio tracks %d is not 1\n", viv->num_audio);
358 
359     for(i=0;i<viv->num_audio;i++) {
360         int q;
361         AVStream *st = avformat_new_stream(s, NULL);
362         if (!st)
363             return AVERROR(ENOMEM);
364 
365         st->id = num_video + i;
366 
367         st->codecpar->codec_type = AVMEDIA_TYPE_AUDIO;
368         st->codecpar->codec_id = AV_CODEC_ID_VORBIS;
369 
370         off = avio_tell(pb);
371         off += ffio_read_varlen(pb); // length
372         avio_r8(pb); // '5'
373         avio_r8(pb); //codec_id
374         avio_rl16(pb); //codec_subid
375         st->codecpar->ch_layout.nb_channels = avio_rl16(pb); // channels
376         st->codecpar->sample_rate = avio_rl32(pb); // sample_rate
377         if (st->codecpar->sample_rate <= 0 || st->codecpar->ch_layout.nb_channels <= 0)
378             return AVERROR_INVALIDDATA;
379         avio_seek(pb, 10, SEEK_CUR); // data_1
380         q = avio_r8(pb);
381         avio_seek(pb, q, SEEK_CUR); // data_2
382         avio_r8(pb); // zeropad
383 
384         if (avio_tell(pb) < off) {
385             int num_data;
386             int xd_size = 1;
387             int data_len[256];
388             int offset = 1;
389             uint8_t *p;
390             ffio_read_varlen(pb); // val_13
391             avio_r8(pb); // '19'
392             ffio_read_varlen(pb); // len_3
393             num_data = avio_r8(pb);
394             for (j = 0; j < num_data; j++) {
395                 int64_t len = ffio_read_varlen(pb);
396                 if (len < 0 || len > INT_MAX/2 - xd_size) {
397                     return AVERROR_INVALIDDATA;
398                 }
399                 data_len[j] = len;
400                 xd_size += len + 1 + len/255;
401             }
402 
403             ret = ff_alloc_extradata(st->codecpar, xd_size);
404             if (ret < 0)
405                 return ret;
406 
407             p = st->codecpar->extradata;
408             p[0] = 2;
409 
410             for (j = 0; j < num_data - 1; j++) {
411                 unsigned delta = av_xiphlacing(&p[offset], data_len[j]);
412                 av_assert0(delta <= xd_size - offset);
413                 offset += delta;
414             }
415 
416             for (j = 0; j < num_data; j++) {
417                 int ret = avio_read(pb, &p[offset], data_len[j]);
418                 if (ret < data_len[j]) {
419                     st->codecpar->extradata_size = 0;
420                     av_freep(&st->codecpar->extradata);
421                     break;
422                 }
423                 av_assert0(data_len[j] <= xd_size - offset);
424                 offset += data_len[j];
425             }
426 
427             if (offset < st->codecpar->extradata_size)
428                 st->codecpar->extradata_size = offset;
429         }
430     }
431 
432     return 0;
433 }
434 
track_index(VividasDemuxContext *viv, AVFormatContext *s, uint8_t *buf, unsigned size)435 static int track_index(VividasDemuxContext *viv, AVFormatContext *s, uint8_t *buf, unsigned size)
436 {
437     int64_t off;
438     int64_t poff;
439     int maxnp=0;
440     FFIOContext pb0;
441     AVIOContext *const pb = &pb0.pub;
442     int i;
443     int64_t filesize = avio_size(s->pb);
444     uint64_t n_sb_blocks_tmp;
445 
446     ffio_init_context(&pb0, buf, size, 0, NULL, NULL, NULL, NULL);
447 
448     ffio_read_varlen(pb); // track_index_len
449     avio_r8(pb); // 'c'
450     n_sb_blocks_tmp = ffio_read_varlen(pb);
451     if (n_sb_blocks_tmp > size / 2)
452         return AVERROR_INVALIDDATA;
453     viv->sb_blocks = av_calloc(n_sb_blocks_tmp, sizeof(*viv->sb_blocks));
454     if (!viv->sb_blocks) {
455         return AVERROR(ENOMEM);
456     }
457     viv->n_sb_blocks = n_sb_blocks_tmp;
458 
459     off = 0;
460     poff = 0;
461 
462     for (i = 0; i < viv->n_sb_blocks; i++) {
463         uint64_t size_tmp      = ffio_read_varlen(pb);
464         uint64_t n_packets_tmp = ffio_read_varlen(pb);
465 
466         if (size_tmp > INT_MAX || n_packets_tmp > INT_MAX)
467             return AVERROR_INVALIDDATA;
468 
469         viv->sb_blocks[i].byte_offset = off;
470         viv->sb_blocks[i].packet_offset = poff;
471 
472         viv->sb_blocks[i].size = size_tmp;
473         viv->sb_blocks[i].n_packets = n_packets_tmp;
474 
475         off += viv->sb_blocks[i].size;
476         poff += viv->sb_blocks[i].n_packets;
477 
478         if (maxnp < viv->sb_blocks[i].n_packets)
479             maxnp = viv->sb_blocks[i].n_packets;
480     }
481 
482     if (filesize > 0 && poff > filesize)
483         return AVERROR_INVALIDDATA;
484 
485     viv->sb_entries = av_calloc(maxnp, sizeof(VIV_SB_entry));
486     if (!viv->sb_entries)
487         return AVERROR(ENOMEM);
488 
489     return 0;
490 }
491 
load_sb_block(AVFormatContext *s, VividasDemuxContext *viv, unsigned expected_size)492 static void load_sb_block(AVFormatContext *s, VividasDemuxContext *viv, unsigned expected_size)
493 {
494     uint32_t size = 0;
495     int i;
496     AVIOContext *pb = 0;
497 
498     if (viv->sb_pb) {
499         av_free(viv->sb_pb);
500         viv->sb_pb = NULL;
501     }
502 
503     if (viv->sb_buf)
504         av_free(viv->sb_buf);
505 
506     viv->sb_buf = read_sb_block(s->pb, &size, &viv->sb_key, expected_size);
507     if (!viv->sb_buf) {
508         return;
509     }
510 
511     pb = avio_alloc_context(viv->sb_buf, size, 0, NULL, NULL, NULL, NULL);
512     if (!pb)
513         return;
514 
515     viv->sb_pb = pb;
516 
517     avio_r8(pb); //  'S'
518     avio_r8(pb); //  'B'
519     ffio_read_varlen(pb); //  size
520     avio_r8(pb); //  junk
521     ffio_read_varlen(pb); // first packet
522 
523     viv->n_sb_entries = viv->sb_blocks[viv->current_sb].n_packets;
524 
525     for (i = 0; i < viv->n_sb_entries; i++) {
526         viv->sb_entries[i].size = ffio_read_varlen(pb);
527         viv->sb_entries[i].flag = avio_r8(pb);
528     }
529 
530     ffio_read_varlen(pb);
531     avio_r8(pb);
532 
533     viv->current_sb_entry = 0;
534 }
535 
viv_read_header(AVFormatContext *s)536 static int viv_read_header(AVFormatContext *s)
537 {
538     VividasDemuxContext *viv = s->priv_data;
539     AVIOContext *pb = s->pb;
540     int64_t header_end;
541     int num_tracks;
542     uint32_t key, k2;
543     uint32_t v;
544     uint8_t keybuffer[187];
545     uint32_t b22_size = 0;
546     uint32_t b22_key = 0;
547     uint8_t *buf = 0;
548     int ret;
549 
550     avio_skip(pb, 9);
551 
552     header_end = avio_tell(pb);
553 
554     header_end += ffio_read_varlen(pb);
555 
556     num_tracks = avio_r8(pb);
557 
558     if (num_tracks != 1) {
559         av_log(s, AV_LOG_ERROR, "number of tracks %d is not 1\n", num_tracks);
560         return AVERROR(EINVAL);
561     }
562 
563     v = avio_r8(pb);
564     avio_seek(pb, v, SEEK_CUR);
565 
566     avio_read(pb, keybuffer, 187);
567     key = decode_key(keybuffer);
568     viv->sb_key = key;
569 
570     avio_rl32(pb);
571 
572     for (;;) {
573         int64_t here = avio_tell(pb);
574         int block_len, block_type;
575 
576         if (here >= header_end)
577             break;
578 
579         block_len = ffio_read_varlen(pb);
580         if (avio_feof(pb) || block_len <= 0)
581             return AVERROR_INVALIDDATA;
582 
583         block_type = avio_r8(pb);
584 
585         if (block_type == 22) {
586             avio_read(pb, keybuffer, 187);
587             b22_key = decode_key(keybuffer);
588             b22_size = avio_rl32(pb);
589         }
590 
591         avio_seek(pb, here + block_len, SEEK_SET);
592     }
593 
594     if (b22_size) {
595         k2 = b22_key;
596         buf = read_vblock(pb, &v, b22_key, &k2, 0);
597         if (!buf)
598             return AVERROR(EIO);
599 
600         av_free(buf);
601     }
602 
603     k2 = key;
604     buf = read_vblock(pb, &v, key, &k2, 0);
605     if (!buf)
606         return AVERROR(EIO);
607     ret = track_header(viv, s, buf, v);
608     av_free(buf);
609     if (ret < 0)
610         return ret;
611 
612     buf = read_vblock(pb, &v, key, &k2, v);
613     if (!buf)
614         return AVERROR(EIO);
615     ret = track_index(viv, s, buf, v);
616     av_free(buf);
617     if (ret < 0)
618         return ret;
619 
620     viv->sb_offset = avio_tell(pb);
621     if (viv->n_sb_blocks > 0) {
622         viv->current_sb = 0;
623         load_sb_block(s, viv, viv->sb_blocks[0].size);
624     } else {
625         viv->current_sb = -1;
626     }
627 
628     return 0;
629 }
630 
viv_read_packet(AVFormatContext *s, AVPacket *pkt)631 static int viv_read_packet(AVFormatContext *s,
632                            AVPacket *pkt)
633 {
634     VividasDemuxContext *viv = s->priv_data;
635     AVIOContext *pb;
636     int64_t off;
637     int ret;
638 
639     if (!viv->sb_pb)
640         return AVERROR(EIO);
641     if (avio_feof(viv->sb_pb))
642         return AVERROR_EOF;
643 
644     if (viv->current_audio_subpacket < viv->n_audio_subpackets) {
645         AVStream *astream;
646         int size = viv->audio_subpackets[viv->current_audio_subpacket+1].start - viv->audio_subpackets[viv->current_audio_subpacket].start;
647 
648         pb = viv->sb_pb;
649         ret = av_get_packet(pb, pkt, size);
650         if (ret < 0)
651             return ret;
652         pkt->pos += viv->sb_offset + viv->sb_blocks[viv->current_sb].byte_offset;
653 
654         pkt->stream_index = 1;
655         astream = s->streams[pkt->stream_index];
656 
657         pkt->pts = av_rescale_q(viv->audio_sample, av_make_q(1, astream->codecpar->sample_rate), astream->time_base);
658         viv->audio_sample += viv->audio_subpackets[viv->current_audio_subpacket].pcm_bytes / 2 /
659                              astream->codecpar->ch_layout.nb_channels;
660         pkt->flags |= AV_PKT_FLAG_KEY;
661         viv->current_audio_subpacket++;
662         return 0;
663     }
664 
665     if (viv->current_sb_entry >= viv->n_sb_entries) {
666         if (viv->current_sb+1 >= viv->n_sb_blocks)
667             return AVERROR(EIO);
668         viv->current_sb++;
669 
670         load_sb_block(s, viv, 0);
671         viv->current_sb_entry = 0;
672     }
673 
674     pb = viv->sb_pb;
675     if (!pb)
676         return AVERROR(EIO);
677     off = avio_tell(pb);
678 
679     if (viv->current_sb_entry >= viv->n_sb_entries)
680         return AVERROR_INVALIDDATA;
681 
682     off += viv->sb_entries[viv->current_sb_entry].size;
683 
684     if (viv->sb_entries[viv->current_sb_entry].flag == 0) {
685         uint64_t v_size = ffio_read_varlen(pb);
686         int last = 0, last_start;
687 
688         if (!viv->num_audio)
689             return AVERROR_INVALIDDATA;
690 
691         ffio_read_varlen(pb);
692         if (v_size > INT_MAX || !v_size)
693             return AVERROR_INVALIDDATA;
694         ret = av_get_packet(pb, pkt, v_size);
695         if (ret < 0)
696             return ret;
697         pkt->pos += viv->sb_offset + viv->sb_blocks[viv->current_sb].byte_offset;
698 
699         pkt->pts = viv->sb_blocks[viv->current_sb].packet_offset + viv->current_sb_entry;
700         pkt->flags |= (pkt->data[0]&0x80)?0:AV_PKT_FLAG_KEY;
701         pkt->stream_index = 0;
702 
703         for (int i = 0; i < MAX_AUDIO_SUBPACKETS - 1; i++) {
704             int start, pcm_bytes;
705             start = ffio_read_varlen(pb);
706             pcm_bytes = ffio_read_varlen(pb);
707 
708             if (i > 0 && start == 0)
709                 break;
710             if (start < last)
711                 return AVERROR_INVALIDDATA;
712 
713             viv->n_audio_subpackets = i + 1;
714             last =
715             viv->audio_subpackets[i].start = start;
716             viv->audio_subpackets[i].pcm_bytes = pcm_bytes;
717         }
718         last_start =
719         viv->audio_subpackets[viv->n_audio_subpackets].start = (int)(off - avio_tell(pb));
720         if (last_start < last)
721             return AVERROR_INVALIDDATA;
722         viv->current_audio_subpacket = 0;
723 
724     } else {
725         uint64_t v_size = ffio_read_varlen(pb);
726 
727         if (v_size > INT_MAX || !v_size)
728             return AVERROR_INVALIDDATA;
729         ret = av_get_packet(pb, pkt, v_size);
730         if (ret < 0)
731             return ret;
732         pkt->pos += viv->sb_offset + viv->sb_blocks[viv->current_sb].byte_offset;
733         pkt->pts = viv->sb_blocks[viv->current_sb].packet_offset + viv->current_sb_entry;
734         pkt->flags |= (pkt->data[0] & 0x80) ? 0 : AV_PKT_FLAG_KEY;
735         pkt->stream_index = 0;
736     }
737 
738     viv->current_sb_entry++;
739 
740     return 0;
741 }
742 
viv_read_close(AVFormatContext *s)743 static int viv_read_close(AVFormatContext *s)
744 {
745     VividasDemuxContext *viv = s->priv_data;
746 
747     av_freep(&viv->sb_pb);
748     av_freep(&viv->sb_buf);
749     av_freep(&viv->sb_blocks);
750     av_freep(&viv->sb_entries);
751 
752     return 0;
753 }
754 
viv_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)755 static int viv_read_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags)
756 {
757     VividasDemuxContext *viv = s->priv_data;
758     int64_t frame;
759 
760     if (stream_index == 0)
761         frame = timestamp;
762     else
763         frame = av_rescale_q(timestamp, s->streams[0]->time_base, s->streams[stream_index]->time_base);
764 
765     for (int i = 0; i < viv->n_sb_blocks; i++) {
766         if (frame >= viv->sb_blocks[i].packet_offset && frame < viv->sb_blocks[i].packet_offset + viv->sb_blocks[i].n_packets) {
767             viv->current_sb = i;
768             // seek to ith sb block
769             avio_seek(s->pb, viv->sb_offset + viv->sb_blocks[i].byte_offset, SEEK_SET);
770             // load the block
771             load_sb_block(s, viv, 0);
772             if (viv->num_audio) {
773                 const AVCodecParameters *par = s->streams[1]->codecpar;
774                 // flush audio packet queue
775                 viv->current_audio_subpacket = 0;
776                 viv->n_audio_subpackets      = 0;
777                 // most problematic part: guess audio offset
778                 viv->audio_sample = av_rescale_q(viv->sb_blocks[i].packet_offset,
779                                                  av_make_q(par->sample_rate, 1),
780                                                  av_inv_q(s->streams[0]->time_base));
781                 // hand-tuned 1.s a/v offset
782                 viv->audio_sample += par->sample_rate;
783             }
784             viv->current_sb_entry = 0;
785             return 1;
786         }
787     }
788     return 0;
789 }
790 
791 const AVInputFormat ff_vividas_demuxer = {
792     .name           = "vividas",
793     .long_name      = NULL_IF_CONFIG_SMALL("Vividas VIV"),
794     .priv_data_size = sizeof(VividasDemuxContext),
795     .flags_internal = FF_FMT_INIT_CLEANUP,
796     .read_probe     = viv_probe,
797     .read_header    = viv_read_header,
798     .read_packet    = viv_read_packet,
799     .read_close     = viv_read_close,
800     .read_seek      = viv_read_seek,
801 };
802