FFmpeg: libavformat/mpeg.c Source File

FFmpeg

[フレーム]

libavformat

mpeg.c

Go to the documentation of this file.

1 /*

2 * MPEG1/2 demuxer

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 */

22 #include "avformat.h"

23 #include "internal.h"

24 #include "mpeg.h"

26 #if CONFIG_VOBSUB_DEMUXER

27 # include "subtitles.h"

28 # include "libavutil/bprint.h"

29 #endif

31 #undef NDEBUG

32 #include <assert.h>

34 /*********************************************/

35 /* demux code */

37 #define MAX_SYNC_SIZE 100000

39 static int check_pes(const uint8_t *p, const uint8_t *end){

40 int pes1;

41 int pes2= (p[3] & 0xC0) == 0x80

42 && (p[4] & 0xC0) != 0x40

43 &&((p[4] & 0xC0) == 0x00 || (p[4]&0xC0)>>2 == (p[6]&0xF0));

45 for(p+=3; p<end && *p == 0xFF; p++);

46 if((*p&0xC0) == 0x40) p+=2;

47 if((*p&0xF0) == 0x20){

48 pes1= p[0]&p[2]&p[4]&1;

49 }else if((*p&0xF0) == 0x30){

50 pes1= p[0]&p[2]&p[4]&p[5]&p[7]&p[9]&1;

51 }else

52 pes1 = *p == 0x0F;

54 return pes1||pes2;

55 }

57 static int check_pack_header(const uint8_t *buf) {

58 return (buf[1] & 0xC0) == 0x40 || (buf[1] & 0xF0) == 0x20;

59 }

61 static int mpegps_probe(AVProbeData *p)

62 {

63 uint32_t code= -1;

64 int sys=0, pspack=0, priv1=0, vid=0, audio=0, invalid=0;

65 int i;

66 int score=0;

68 for(i=0; i<p->buf_size; i++){

69 code = (code<<8) + p->buf[i];

70 if ((code & 0xffffff00) == 0x100) {

71 int len= p->buf[i+1] << 8 | p->buf[i+2];

72 int pes= check_pes(p->buf+i, p->buf+p->buf_size);

73 int pack = check_pack_header(p->buf+i);

75 if(code == SYSTEM_HEADER_START_CODE) sys++;

76 else if(code == PACK_START_CODE && pack) pspack++;

77 else if((code & 0xf0) == VIDEO_ID && pes) vid++;

78 // skip pes payload to avoid start code emulation for private

79 // and audio streams

80 else if((code & 0xe0) == AUDIO_ID && pes) {audio++; i+=len;}

81 else if(code == PRIVATE_STREAM_1 && pes) {priv1++; i+=len;}

82 else if(code == 0x1fd && pes) vid++; //VC1

84 else if((code & 0xf0) == VIDEO_ID && !pes) invalid++;

85 else if((code & 0xe0) == AUDIO_ID && !pes) invalid++;

86 else if(code == PRIVATE_STREAM_1 && !pes) invalid++;

87 }

88 }

90 if(vid+audio > invalid+1) /* invalid VDR files nd short PES streams */

91 score= AVPROBE_SCORE_MAX/4;

93 if(sys>invalid && sys*9 <= pspack*10)

94 return (audio > 12 || vid > 3 || pspack > 2) ? AVPROBE_SCORE_MAX/2+2 : AVPROBE_SCORE_MAX/4; // +1 for .mpg

95 if(pspack > invalid && (priv1+vid+audio)*10 >= pspack*9)

96 return pspack > 2 ? AVPROBE_SCORE_MAX/2+2 : AVPROBE_SCORE_MAX/4; // +1 for .mpg

97 if((!!vid ^ !!audio) && (audio > 4 || vid > 1) && !sys && !pspack && p->buf_size>2048 && vid + audio > invalid) /* PES stream */

98 return (audio > 12 || vid > 3 + 2*invalid) ? AVPROBE_SCORE_MAX/2+2 : AVPROBE_SCORE_MAX/4;

100 //02-Penguin.flac has sys:0 priv1:0 pspack:0 vid:0 audio:1

101 //mp3_misidentified_2.mp3 has sys:0 priv1:0 pspack:0 vid:0 audio:6

102 //Have\ Yourself\ a\ Merry\ Little\ Christmas.mp3 0 0 0 5 0 1 len:21618

103 return score;

104 }

105

106

107 typedef struct MpegDemuxContext {

108 int32_t header_state;

109 unsigned char psm_es_type[256];

110 int sofdec;

111 #if CONFIG_VOBSUB_DEMUXER

112 AVFormatContext *sub_ctx;

113 FFDemuxSubtitlesQueue q;

114 #endif

115 } MpegDemuxContext;

116

117 static int mpegps_read_header(AVFormatContext *s)

118 {

119 MpegDemuxContext *m = s->priv_data;

120 const char *sofdec = "Sofdec";

121 int v, i = 0;

122 int64_t last_pos = avio_tell(s->pb);

123

124 m->header_state = 0xff;

125 s->ctx_flags |= AVFMTCTX_NOHEADER;

126

127 m->sofdec = -1;

128 do {

129 v = avio_r8(s->pb);

130 m->sofdec++;

131 } while (v == sofdec[i] && i++ < 6);

132

133 m->sofdec = (m->sofdec == 6) ? 1 : 0;

134

135 if (!m->sofdec)

136 avio_seek(s->pb, last_pos, SEEK_SET);

137

138 /* no need to do more */

139 return 0;

140 }

141

142 static int64_t get_pts(AVIOContext *pb, int c)

143 {

144 uint8_t buf[5];

145

146 buf[0] = c<0 ? avio_r8(pb) : c;

147 avio_read(pb, buf+1, 4);

148

149 return ff_parse_pes_pts(buf);

150 }

151

152 static int find_next_start_code(AVIOContext *pb, int *size_ptr,

153 int32_t *header_state)

154 {

155 unsigned int state, v;

156 int val, n;

157

158 state = *header_state;

159 n = *size_ptr;

160 while (n > 0) {

161 if (url_feof(pb))

162 break;

163 v = avio_r8(pb);

164 n--;

165 if (state == 0x000001) {

166 state = ((state << 8) | v) & 0xffffff;

167 val = state;

168 goto found;

169 }

170 state = ((state << 8) | v) & 0xffffff;

171 }

172 val = -1;

173 found:

174 *header_state = state;

175 *size_ptr = n;

176 return val;

177 }

178

179 /**

180 * Extract stream types from a program stream map

181 * According to ISO/IEC 13818-1 ('MPEG-2 Systems') table 2-35

182 *

183 * @return number of bytes occupied by PSM in the bitstream

184 */

185 static long mpegps_psm_parse(MpegDemuxContext *m, AVIOContext *pb)

186 {

187 int psm_length, ps_info_length, es_map_length;

188

189 psm_length = avio_rb16(pb);

190 avio_r8(pb);

191 avio_r8(pb);

192 ps_info_length = avio_rb16(pb);

193

194 /* skip program_stream_info */

195 avio_skip(pb, ps_info_length);

196 es_map_length = avio_rb16(pb);

197

198 /* at least one es available? */

199 while (es_map_length >= 4){

200 unsigned char type = avio_r8(pb);

201 unsigned char es_id = avio_r8(pb);

202 uint16_t es_info_length = avio_rb16(pb);

203 /* remember mapping from stream id to stream type */

204 m->psm_es_type[es_id] = type;

205 /* skip program_stream_info */

206 avio_skip(pb, es_info_length);

207 es_map_length -= 4 + es_info_length;

208 }

209 avio_rb32(pb); /* crc32 */

210 return 2 + psm_length;

211 }

212

213 /* read the next PES header. Return its position in ppos

214 (if not NULL), and its start code, pts and dts.

215 */

216 static int mpegps_read_pes_header(AVFormatContext *s,

217 int64_t *ppos, int *pstart_code,

218 int64_t *ppts, int64_t *pdts)

219 {

220 MpegDemuxContext *m = s->priv_data;

221 int len, size, startcode, c, flags, header_len;

222 int pes_ext, ext2_len, id_ext, skip;

223 int64_t pts, dts;

224 int64_t last_sync= avio_tell(s->pb);

225

226 error_redo:

227 avio_seek(s->pb, last_sync, SEEK_SET);

228 redo:

229 /* next start code (should be immediately after) */

230 m->header_state = 0xff;

231 size = MAX_SYNC_SIZE;

232 startcode = find_next_start_code(s->pb, &size, &m->header_state);

233 last_sync = avio_tell(s->pb);

234 if (startcode < 0){

235 if(url_feof(s->pb))

236 return AVERROR_EOF;

237 //FIXME we should remember header_state

238 return AVERROR(EAGAIN);

239 }

240

241 if (startcode == PACK_START_CODE)

242 goto redo;

243 if (startcode == SYSTEM_HEADER_START_CODE)

244 goto redo;

245 if (startcode == PADDING_STREAM) {

246 avio_skip(s->pb, avio_rb16(s->pb));

247 goto redo;

248 }

249 if (startcode == PRIVATE_STREAM_2) {

250 len = avio_rb16(s->pb);

251 if (!m->sofdec) {

252 while (len-- >= 6) {

253 if (avio_r8(s->pb) == 'S') {

254 uint8_t buf[5];

255 avio_read(s->pb, buf, sizeof(buf));

256 m->sofdec = !memcmp(buf, "ofdec", 5);

257 len -= sizeof(buf);

258 break;

259 }

260 }

261 m->sofdec -= !m->sofdec;

262 }

263 avio_skip(s->pb, len);

264 goto redo;

265 }

266 if (startcode == PROGRAM_STREAM_MAP) {

267 mpegps_psm_parse(m, s->pb);

268 goto redo;

269 }

270

271 /* find matching stream */

272 if (!((startcode >= 0x1c0 && startcode <= 0x1df) ||

273 (startcode >= 0x1e0 && startcode <= 0x1ef) ||

274 (startcode == 0x1bd) || (startcode == 0x1fd)))

275 goto redo;

276 if (ppos) {

277 *ppos = avio_tell(s->pb) - 4;

278 }

279 len = avio_rb16(s->pb);

280 pts =

281 dts = AV_NOPTS_VALUE;

282 /* stuffing */

283 for(;;) {

284 if (len < 1)

285 goto error_redo;

286 c = avio_r8(s->pb);

287 len--;

288 /* XXX: for mpeg1, should test only bit 7 */

289 if (c != 0xff)

290 break;

291 }

292 if ((c & 0xc0) == 0x40) {

293 /* buffer scale & size */

294 avio_r8(s->pb);

295 c = avio_r8(s->pb);

296 len -= 2;

297 }

298 if ((c & 0xe0) == 0x20) {

299 dts = pts = get_pts(s->pb, c);

300 len -= 4;

301 if (c & 0x10){

302 dts = get_pts(s->pb, -1);

303 len -= 5;

304 }

305 } else if ((c & 0xc0) == 0x80) {

306 /* mpeg 2 PES */

307 flags = avio_r8(s->pb);

308 header_len = avio_r8(s->pb);

309 len -= 2;

310 if (header_len > len)

311 goto error_redo;

312 len -= header_len;

313 if (flags & 0x80) {

314 dts = pts = get_pts(s->pb, -1);

315 header_len -= 5;

316 if (flags & 0x40) {

317 dts = get_pts(s->pb, -1);

318 header_len -= 5;

319 }

320 }

321 if (flags & 0x3f && header_len == 0){

322 flags &= 0xC0;

323 av_log(s, AV_LOG_WARNING, "Further flags set but no bytes left\n");

324 }

325 if (flags & 0x01) { /* PES extension */

326 pes_ext = avio_r8(s->pb);

327 header_len--;

328 /* Skip PES private data, program packet sequence counter and P-STD buffer */

329 skip = (pes_ext >> 4) & 0xb;

330 skip += skip & 0x9;

331 if (pes_ext & 0x40 || skip > header_len){

332 av_log(s, AV_LOG_WARNING, "pes_ext %X is invalid\n", pes_ext);

333 pes_ext=skip=0;

334 }

335 avio_skip(s->pb, skip);

336 header_len -= skip;

337

338 if (pes_ext & 0x01) { /* PES extension 2 */

339 ext2_len = avio_r8(s->pb);

340 header_len--;

341 if ((ext2_len & 0x7f) > 0) {

342 id_ext = avio_r8(s->pb);

343 if ((id_ext & 0x80) == 0)

344 startcode = ((startcode & 0xff) << 8) | id_ext;

345 header_len--;

346 }

347 }

348 }

349 if(header_len < 0)

350 goto error_redo;

351 avio_skip(s->pb, header_len);

352 }

353 else if( c!= 0xf )

354 goto redo;

355

356 if (startcode == PRIVATE_STREAM_1) {

357 startcode = avio_r8(s->pb);

358 len--;

359 }

360 if(len<0)

361 goto error_redo;

362 if(dts != AV_NOPTS_VALUE && ppos){

363 int i;

364 for(i=0; i<s->nb_streams; i++){

365 if(startcode == s->streams[i]->id &&

366 s->pb->seekable /* index useless on streams anyway */) {

367 ff_reduce_index(s, i);

368 av_add_index_entry(s->streams[i], *ppos, dts, 0, 0, AVINDEX_KEYFRAME /* FIXME keyframe? */);

369 }

370 }

371 }

372

373 *pstart_code = startcode;

374 *ppts = pts;

375 *pdts = dts;

376 return len;

377 }

378

379 static int mpegps_read_packet(AVFormatContext *s,

380 AVPacket *pkt)

381 {

382 MpegDemuxContext *m = s->priv_data;

383 AVStream *st;

384 int len, startcode, i, es_type, ret;

385 int lpcm_header_len = -1; //Init to supress warning

386 int request_probe= 0;

387 enum AVCodecID codec_id = AV_CODEC_ID_NONE;

388 enum AVMediaType type;

389 int64_t pts, dts, dummy_pos; //dummy_pos is needed for the index building to work

390

391 redo:

392 len = mpegps_read_pes_header(s, &dummy_pos, &startcode, &pts, &dts);

393 if (len < 0)

394 return len;

395

396 if (startcode >= 0x80 && startcode <= 0xcf) {

397 if(len < 4)

398 goto skip;

399

400 /* audio: skip header */

401 avio_r8(s->pb);

402 lpcm_header_len = avio_rb16(s->pb);

403 len -= 3;

404 if (startcode >= 0xb0 && startcode <= 0xbf) {

405 /* MLP/TrueHD audio has a 4-byte header */

406 avio_r8(s->pb);

407 len--;

408 }

409 }

410

411 /* now find stream */

412 for(i=0;i<s->nb_streams;i++) {

413 st = s->streams[i];

414 if (st->id == startcode)

415 goto found;

416 }

417

418 es_type = m->psm_es_type[startcode & 0xff];

419 if(es_type == STREAM_TYPE_VIDEO_MPEG1){

420 codec_id = AV_CODEC_ID_MPEG2VIDEO;

421 type = AVMEDIA_TYPE_VIDEO;

422 } else if(es_type == STREAM_TYPE_VIDEO_MPEG2){

423 codec_id = AV_CODEC_ID_MPEG2VIDEO;

424 type = AVMEDIA_TYPE_VIDEO;

425 } else if(es_type == STREAM_TYPE_AUDIO_MPEG1 ||

426 es_type == STREAM_TYPE_AUDIO_MPEG2){

427 codec_id = AV_CODEC_ID_MP3;

428 type = AVMEDIA_TYPE_AUDIO;

429 } else if(es_type == STREAM_TYPE_AUDIO_AAC){

430 codec_id = AV_CODEC_ID_AAC;

431 type = AVMEDIA_TYPE_AUDIO;

432 } else if(es_type == STREAM_TYPE_VIDEO_MPEG4){

433 codec_id = AV_CODEC_ID_MPEG4;

434 type = AVMEDIA_TYPE_VIDEO;

435 } else if(es_type == STREAM_TYPE_VIDEO_H264){

436 codec_id = AV_CODEC_ID_H264;

437 type = AVMEDIA_TYPE_VIDEO;

438 } else if(es_type == STREAM_TYPE_AUDIO_AC3){

439 codec_id = AV_CODEC_ID_AC3;

440 type = AVMEDIA_TYPE_AUDIO;

441 } else if (startcode >= 0x1e0 && startcode <= 0x1ef) {

442 static const unsigned char avs_seqh[4] = { 0, 0, 1, 0xb0 };

443 unsigned char buf[8];

444 avio_read(s->pb, buf, 8);

445 avio_seek(s->pb, -8, SEEK_CUR);

446 if(!memcmp(buf, avs_seqh, 4) && (buf[6] != 0 || buf[7] != 1))

447 codec_id = AV_CODEC_ID_CAVS;

448 else

449 request_probe= 1;

450 type = AVMEDIA_TYPE_VIDEO;

451 } else if (startcode >= 0x1c0 && startcode <= 0x1df) {

452 type = AVMEDIA_TYPE_AUDIO;

453 codec_id = m->sofdec > 0 ? AV_CODEC_ID_ADPCM_ADX : AV_CODEC_ID_MP2;

454 } else if (startcode >= 0x80 && startcode <= 0x87) {

455 type = AVMEDIA_TYPE_AUDIO;

456 codec_id = AV_CODEC_ID_AC3;

457 } else if ( ( startcode >= 0x88 && startcode <= 0x8f)

458 ||( startcode >= 0x98 && startcode <= 0x9f)) {

459 /* 0x90 - 0x97 is reserved for SDDS in DVD specs */

460 type = AVMEDIA_TYPE_AUDIO;

461 codec_id = AV_CODEC_ID_DTS;

462 } else if (startcode >= 0xa0 && startcode <= 0xaf) {

463 type = AVMEDIA_TYPE_AUDIO;

464 if(lpcm_header_len == 6) {

465 codec_id = AV_CODEC_ID_MLP;

466 } else {

467 /* 16 bit form will be handled as AV_CODEC_ID_PCM_S16BE */

468 codec_id = AV_CODEC_ID_PCM_DVD;

469 }

470 } else if (startcode >= 0xb0 && startcode <= 0xbf) {

471 type = AVMEDIA_TYPE_AUDIO;

472 codec_id = AV_CODEC_ID_TRUEHD;

473 } else if (startcode >= 0xc0 && startcode <= 0xcf) {

474 /* Used for both AC-3 and E-AC-3 in EVOB files */

475 type = AVMEDIA_TYPE_AUDIO;

476 codec_id = AV_CODEC_ID_AC3;

477 } else if (startcode >= 0x20 && startcode <= 0x3f) {

478 type = AVMEDIA_TYPE_SUBTITLE;

479 codec_id = AV_CODEC_ID_DVD_SUBTITLE;

480 } else if (startcode >= 0xfd55 && startcode <= 0xfd5f) {

481 type = AVMEDIA_TYPE_VIDEO;

482 codec_id = AV_CODEC_ID_VC1;

483 } else {

484 skip:

485 /* skip packet */

486 avio_skip(s->pb, len);

487 goto redo;

488 }

489 /* no stream found: add a new stream */

490 st = avformat_new_stream(s, NULL);

491 if (!st)

492 goto skip;

493 st->id = startcode;

494 st->codec->codec_type = type;

495 st->codec->codec_id = codec_id;

496 st->request_probe = request_probe;

497 if (codec_id != AV_CODEC_ID_PCM_S16BE)

498 st->need_parsing = AVSTREAM_PARSE_FULL;

499 found:

500 if(st->discard >= AVDISCARD_ALL)

501 goto skip;

502 if (startcode >= 0xa0 && startcode <= 0xaf) {

503 if (lpcm_header_len == 6 && st->codec->codec_id == AV_CODEC_ID_MLP) {

504 if (len < 6)

505 goto skip;

506 avio_skip(s->pb, 6);

507 len -=6;

508 } else {

509 int b1, freq;

510

511 /* for LPCM, we just skip the header and consider it is raw

512 audio data */

513 if (len <= 3)

514 goto skip;

515 avio_r8(s->pb); /* emphasis (1), muse(1), reserved(1), frame number(5) */

516 b1 = avio_r8(s->pb); /* quant (2), freq(2), reserved(1), channels(3) */

517 avio_r8(s->pb); /* dynamic range control (0x80 = off) */

518 len -= 3;

519 freq = (b1 >> 4) & 3;

520 st->codec->sample_rate = lpcm_freq_tab[freq];

521 st->codec->channels = 1 + (b1 & 7);

522 st->codec->bits_per_coded_sample = 16 + ((b1 >> 6) & 3) * 4;

523 st->codec->bit_rate = st->codec->channels *

524 st->codec->sample_rate *

525 st->codec->bits_per_coded_sample;

526 if (st->codec->bits_per_coded_sample == 16)

527 st->codec->codec_id = AV_CODEC_ID_PCM_S16BE;

528 else if (st->codec->bits_per_coded_sample == 28)

529 return AVERROR(EINVAL);

530 }

531 }

532 ret = av_get_packet(s->pb, pkt, len);

533 pkt->pts = pts;

534 pkt->dts = dts;

535 pkt->pos = dummy_pos;

536 pkt->stream_index = st->index;

537 av_dlog(s, "%d: pts=%0.3f dts=%0.3f size=%d\n",

538 pkt->stream_index, pkt->pts / 90000.0, pkt->dts / 90000.0,

539 pkt->size);

540

541 return (ret < 0) ? ret : 0;

542 }

543

544 static int64_t mpegps_read_dts(AVFormatContext *s, int stream_index,

545 int64_t *ppos, int64_t pos_limit)

546 {

547 int len, startcode;

548 int64_t pos, pts, dts;

549

550 pos = *ppos;

551 if (avio_seek(s->pb, pos, SEEK_SET) < 0)

552 return AV_NOPTS_VALUE;

553

554 for(;;) {

555 len = mpegps_read_pes_header(s, &pos, &startcode, &pts, &dts);

556 if (len < 0) {

557 av_dlog(s, "none (ret=%d)\n", len);

558 return AV_NOPTS_VALUE;

559 }

560 if (startcode == s->streams[stream_index]->id &&

561 dts != AV_NOPTS_VALUE) {

562 break;

563 }

564 avio_skip(s->pb, len);

565 }

566 av_dlog(s, "pos=0x%"PRIx64" dts=0x%"PRIx64" %0.3f\n",

567 pos, dts, dts / 90000.0);

568 *ppos = pos;

569 return dts;

570 }

571

572 AVInputFormat ff_mpegps_demuxer = {

573 .name = "mpeg",

574 .long_name = NULL_IF_CONFIG_SMALL("MPEG-PS (MPEG-2 Program Stream)"),

575 .priv_data_size = sizeof(MpegDemuxContext),

576 .read_probe = mpegps_probe,

577 .read_header = mpegps_read_header,

578 .read_packet = mpegps_read_packet,

579 .read_timestamp = mpegps_read_dts,

580 .flags = AVFMT_SHOW_IDS | AVFMT_TS_DISCONT,

581 };

582

583 #if CONFIG_VOBSUB_DEMUXER

584

585 #define REF_STRING "# VobSub index file,"

586

587 static int vobsub_probe(AVProbeData *p)

588 {

589 if (!strncmp(p->buf, REF_STRING, sizeof(REF_STRING) - 1))

590 return AVPROBE_SCORE_MAX;

591 return 0;

592 }

593

594 static int vobsub_read_header(AVFormatContext *s)

595 {

596 int i, ret = 0, header_parsed = 0, langidx = 0;

597 MpegDemuxContext *vobsub = s->priv_data;

598 char *sub_name = NULL;

599 size_t fname_len;

600 char *ext, *header_str;

601 AVBPrint header;

602 int64_t delay = 0;

603 AVStream *st = NULL;

604

605 sub_name = av_strdup(s->filename);

606 fname_len = strlen(sub_name);

607 ext = sub_name - 3 + fname_len;

608 if (fname_len < 4 || *(ext - 1) != '.') {

609 av_log(s, AV_LOG_ERROR, "The input index filename is too short "

610 "to guess the associated .SUB file\n");

611 ret = AVERROR_INVALIDDATA;

612 goto end;

613 }

614 memcpy(ext, !strncmp(ext, "IDX", 3) ? "SUB" : "sub", 3);

615 av_log(s, AV_LOG_VERBOSE, "IDX/SUB: %s -> %s\n", s->filename, sub_name);

616 ret = avformat_open_input(&vobsub->sub_ctx, sub_name, &ff_mpegps_demuxer, NULL);

617 if (ret < 0) {

618 av_log(s, AV_LOG_ERROR, "Unable to open %s as MPEG subtitles\n", sub_name);

619 goto end;

620 }

621

622 av_bprint_init(&header, 0, AV_BPRINT_SIZE_UNLIMITED);

623 while (!url_feof(s->pb)) {

624 char line[2048];

625 int len = ff_get_line(s->pb, line, sizeof(line));

626

627 if (!len)

628 break;

629

630 line[strcspn(line, "\r\n")] = 0;

631

632 if (!strncmp(line, "id:", 3)) {

633 int n, stream_id = 0;

634 char id[64] = {0};

635

636 n = sscanf(line, "id: %63[^,], index: %u", id, &stream_id);

637 if (n != 2) {

638 av_log(s, AV_LOG_WARNING, "Unable to parse index line '%s', "

639 "assuming 'id: und, index: 0'\n", line);

640 strcpy(id, "und");

641 stream_id = 0;

642 }

643

644 st = avformat_new_stream(s, NULL);

645 if (!st) {

646 ret = AVERROR(ENOMEM);

647 goto end;

648 }

649 st->id = stream_id;

650 st->codec->codec_type = AVMEDIA_TYPE_SUBTITLE;

651 st->codec->codec_id = AV_CODEC_ID_DVD_SUBTITLE;

652 av_dict_set(&st->metadata, "language", id, 0);

653 av_log(s, AV_LOG_DEBUG, "IDX stream[%d] id=%s\n", stream_id, id);

654 header_parsed = 1;

655

656 } else if (st && !strncmp(line, "timestamp:", 10)) {

657 AVPacket *sub;

658 int hh, mm, ss, ms;

659 int64_t pos, timestamp;

660 const char *p = line + 10;

661

662 if (sscanf(p, "%02d:%02d:%02d:%03d, filepos: %"PRIx64,

663 &hh, &mm, &ss, &ms, &pos) != 5) {

664 av_log(s, AV_LOG_ERROR, "Unable to parse timestamp line '%s', "

665 "abort parsing\n", line);

666 break;

667 }

668 timestamp = (hh*3600LL + mm*60LL + ss) * 1000LL + ms + delay;

669 timestamp = av_rescale_q(timestamp, (AVRational){1,1000}, st->time_base);

670

671 sub = ff_subtitles_queue_insert(&vobsub->q, "", 0, 0);

672 if (!sub) {

673 ret = AVERROR(ENOMEM);

674 goto end;

675 }

676 sub->pos = pos;

677 sub->pts = timestamp;

678 sub->stream_index = s->nb_streams - 1;

679

680 } else if (st && !strncmp(line, "alt:", 4)) {

681 const char *p = line + 4;

682

683 while (*p == ' ')

684 p++;

685 av_dict_set(&st->metadata, "title", p, 0);

686 av_log(s, AV_LOG_DEBUG, "IDX stream[%d] name=%s\n", st->id, p);

687 header_parsed = 1;

688

689 } else if (!strncmp(line, "delay:", 6)) {

690 int sign = 1, hh = 0, mm = 0, ss = 0, ms = 0;

691 const char *p = line + 6;

692

693 while (*p == ' ')

694 p++;

695 if (*p == '-' || *p == '+') {

696 sign = *p == '-' ? -1 : 1;

697 p++;

698 }

699 sscanf(p, "%d:%d:%d:%d", &hh, &mm, &ss, &ms);

700 delay = ((hh*3600LL + mm*60LL + ss) * 1000LL + ms) * sign;

701

702 } else if (!strncmp(line, "langidx:", 8)) {

703 const char *p = line + 8;

704

705 if (sscanf(p, "%d", &langidx) != 1)

706 av_log(s, AV_LOG_ERROR, "Invalid langidx specified\n");

707

708 } else if (!header_parsed) {

709 if (line[0] && line[0] != '#')

710 av_bprintf(&header, "%s\n", line);

711 }

712 }

713

714 if (langidx < s->nb_streams)

715 s->streams[langidx]->disposition |= AV_DISPOSITION_DEFAULT;

716

717 ff_subtitles_queue_finalize(&vobsub->q);

718

719 if (!av_bprint_is_complete(&header)) {

720 av_bprint_finalize(&header, NULL);

721 ret = AVERROR(ENOMEM);

722 goto end;

723 }

724 av_bprint_finalize(&header, &header_str);

725 for (i = 0; i < s->nb_streams; i++) {

726 AVStream *sub_st = s->streams[i];

727 sub_st->codec->extradata = av_strdup(header_str);

728 sub_st->codec->extradata_size = header.len;

729 }

730 av_free(header_str);

731

732 end:

733 av_free(sub_name);

734 return ret;

735 }

736

737 static int vobsub_read_packet(AVFormatContext *s, AVPacket *pkt)

738 {

739 MpegDemuxContext *vobsub = s->priv_data;

740 FFDemuxSubtitlesQueue *q = &vobsub->q;

741 AVIOContext *pb = vobsub->sub_ctx->pb;

742 int ret, psize, len16 = -1;

743 AVPacket idx_pkt;

744

745 ret = ff_subtitles_queue_read_packet(q, &idx_pkt);

746 if (ret < 0)

747 return ret;

748

749 /* compute maximum packet size using the next packet position. This is

750 * useful when the len in the header is non-sense */

751 if (q->current_sub_idx < q->nb_subs) {

752 psize = q->subs[q->current_sub_idx].pos - idx_pkt.pos;

753 } else {

754 int64_t fsize = avio_size(pb);

755 psize = fsize < 0 ? 0xffff : fsize - idx_pkt.pos;

756 }

757

758 avio_seek(pb, idx_pkt.pos, SEEK_SET);

759

760 av_init_packet(pkt);

761 pkt->size = 0;

762 pkt->data = NULL;

763

764 do {

765 int n, to_read, startcode;

766 int64_t pts, dts;

767

768 ret = mpegps_read_pes_header(vobsub->sub_ctx, NULL, &startcode, &pts, &dts);

769 if (ret < 0)

770 return ret;

771 to_read = ret & 0xffff;

772

773 /* this prevents reads above the current packet */

774 if (pkt->size + to_read > psize)

775 break;

776

777 /* if the len is computed, we check for overread */

778 if (len16 != -1 && pkt->size + to_read > len16)

779 break;

780

781 /* the current chunk doesn't match the stream index (unlikely) */

782 if ((startcode & 0x1f) != idx_pkt.stream_index)

783 break;

784

785 ret = av_grow_packet(pkt, to_read);

786 if (ret < 0)

787 return ret;

788

789 n = avio_read(pb, pkt->data + (pkt->size - to_read), to_read);

790 if (n < to_read)

791 pkt->size -= to_read - n;

792

793 /* first chunk contains the total len of the packet to raise */

794 if (len16 == -1 && n > 2)

795 len16 = AV_RB16(pkt->data);

796 } while (len16 != -1 && pkt->size != len16);

797

798 pkt->pts = pkt->dts = idx_pkt.pts;

799 pkt->pos = idx_pkt.pos;

800 pkt->stream_index = idx_pkt.stream_index;

801

802 return 0;

803 }

804

805 static int vobsub_read_seek(AVFormatContext *s, int stream_index,

806 int64_t min_ts, int64_t ts, int64_t max_ts, int flags)

807 {

808 MpegDemuxContext *vobsub = s->priv_data;

809 return ff_subtitles_queue_seek(&vobsub->q, s, stream_index,

810 min_ts, ts, max_ts, flags);

811 }

812

813 static int vobsub_read_close(AVFormatContext *s)

814 {

815 MpegDemuxContext *vobsub = s->priv_data;

816 ff_subtitles_queue_clean(&vobsub->q);

817 if (vobsub->sub_ctx)

818 avformat_close_input(&vobsub->sub_ctx);

819 return 0;

820 }

821

822 AVInputFormat ff_vobsub_demuxer = {

823 .name = "vobsub",

824 .long_name = NULL_IF_CONFIG_SMALL("VobSub subtitle format"),

825 .priv_data_size = sizeof(MpegDemuxContext),

826 .read_probe = vobsub_probe,

827 .read_header = vobsub_read_header,

828 .read_packet = vobsub_read_packet,

829 .read_seek2 = vobsub_read_seek,

830 .read_close = vobsub_read_close,

831 .flags = AVFMT_SHOW_IDS,

832 .extensions = "idx",

833 };

834 #endif

Generated on Sat May 25 2013 04:01:18 for FFmpeg by doxygen 1.8.2