FFmpeg: libavformat/gxf.c Source File

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libavformat

gxf.c

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1 /*

2 * GXF 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 "libavutil/channel_layout.h"

23 #include "libavutil/common.h"

24 #include "avformat.h"

25 #include "internal.h"

26 #include "gxf.h"

27 #include "libavcodec/mpeg12data.h"

29 struct gxf_stream_info {

30 int64_t first_field;

31 int64_t last_field;

32 AVRational frames_per_second;

33 int32_t fields_per_frame;

34 int64_t track_aux_data;

35 };

37 /**

38 * @brief parse gxf timecode and add it to metadata

39 */

40 static int add_timecode_metadata(AVDictionary **pm, const char *key, uint32_t timecode, int fields_per_frame)

41 {

42 char tmp[128];

43 int field = timecode & 0xff;

44 int frame = fields_per_frame ? field / fields_per_frame : field;

45 int second = (timecode >> 8) & 0xff;

46 int minute = (timecode >> 16) & 0xff;

47 int hour = (timecode >> 24) & 0x1f;

48 int drop = (timecode >> 29) & 1;

49 // bit 30: color_frame, unused

50 // ignore invalid time code

51 if (timecode >> 31)

52 return 0;

53 snprintf(tmp, sizeof(tmp), "%02d:%02d:%02d%c%02d",

54 hour, minute, second, drop ? ';' : ':', frame);

55 return av_dict_set(pm, key, tmp, 0);

56 }

58 /**

59 * @brief parses a packet header, extracting type and length

60 * @param pb AVIOContext to read header from

61 * @param type detected packet type is stored here

62 * @param length detected packet length, excluding header is stored here

63 * @return 0 if header not found or contains invalid data, 1 otherwise

64 */

65 static int parse_packet_header(AVIOContext *pb, GXFPktType *type, int *length) {

66 if (avio_rb32(pb))

67 return 0;

68 if (avio_r8(pb) != 1)

69 return 0;

70 *type = avio_r8(pb);

71 *length = avio_rb32(pb);

72 if ((*length >> 24) || *length < 16)

73 return 0;

74 *length -= 16;

75 if (avio_rb32(pb))

76 return 0;

77 if (avio_r8(pb) != 0xe1)

78 return 0;

79 if (avio_r8(pb) != 0xe2)

80 return 0;

81 return 1;

82 }

84 /**

85 * @brief check if file starts with a PKT_MAP header

86 */

87 static int gxf_probe(AVProbeData *p) {

88 static const uint8_t startcode[] = {0, 0, 0, 0, 1, 0xbc}; // start with map packet

89 static const uint8_t endcode[] = {0, 0, 0, 0, 0xe1, 0xe2};

90 if (!memcmp(p->buf, startcode, sizeof(startcode)) &&

91 !memcmp(&p->buf[16 - sizeof(endcode)], endcode, sizeof(endcode)))

92 return AVPROBE_SCORE_MAX;

93 return 0;

94 }

96 /**

97 * @brief gets the stream index for the track with the specified id, creates new

98 * stream if not found

99 * @param id id of stream to find / add

100 * @param format stream format identifier

101 */

102 static int get_sindex(AVFormatContext *s, int id, int format) {

103 int i;

104 AVStream *st = NULL;

105 i = ff_find_stream_index(s, id);

106 if (i >= 0)

107 return i;

108 st = avformat_new_stream(s, NULL);

109 if (!st)

110 return AVERROR(ENOMEM);

111 st->id = id;

112 switch (format) {

113 case 3:

114 case 4:

115 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

116 st->codec->codec_id = AV_CODEC_ID_MJPEG;

117 break;

118 case 13:

119 case 15:

120 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

121 st->codec->codec_id = AV_CODEC_ID_DVVIDEO;

122 break;

123 case 14:

124 case 16:

125 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

126 st->codec->codec_id = AV_CODEC_ID_DVVIDEO;

127 break;

128 case 11:

129 case 12:

130 case 20:

131 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

132 st->codec->codec_id = AV_CODEC_ID_MPEG2VIDEO;

133 st->need_parsing = AVSTREAM_PARSE_HEADERS; //get keyframe flag etc.

134 break;

135 case 22:

136 case 23:

137 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

138 st->codec->codec_id = AV_CODEC_ID_MPEG1VIDEO;

139 st->need_parsing = AVSTREAM_PARSE_HEADERS; //get keyframe flag etc.

140 break;

141 case 9:

142 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

143 st->codec->codec_id = AV_CODEC_ID_PCM_S24LE;

144 st->codec->channels = 1;

145 st->codec->channel_layout = AV_CH_LAYOUT_MONO;

146 st->codec->sample_rate = 48000;

147 st->codec->bit_rate = 3 * 1 * 48000 * 8;

148 st->codec->block_align = 3 * 1;

149 st->codec->bits_per_coded_sample = 24;

150 break;

151 case 10:

152 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

153 st->codec->codec_id = AV_CODEC_ID_PCM_S16LE;

154 st->codec->channels = 1;

155 st->codec->channel_layout = AV_CH_LAYOUT_MONO;

156 st->codec->sample_rate = 48000;

157 st->codec->bit_rate = 2 * 1 * 48000 * 8;

158 st->codec->block_align = 2 * 1;

159 st->codec->bits_per_coded_sample = 16;

160 break;

161 case 17:

162 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

163 st->codec->codec_id = AV_CODEC_ID_AC3;

164 st->codec->channels = 2;

165 st->codec->channel_layout = AV_CH_LAYOUT_STEREO;

166 st->codec->sample_rate = 48000;

167 break;

168 // timecode tracks:

169 case 7:

170 case 8:

171 case 24:

172 st->codec->codec_type = AVMEDIA_TYPE_DATA;

173 st->codec->codec_id = AV_CODEC_ID_NONE;

174 break;

175 default:

176 st->codec->codec_type = AVMEDIA_TYPE_UNKNOWN;

177 st->codec->codec_id = AV_CODEC_ID_NONE;

178 break;

179 }

180 return s->nb_streams - 1;

181 }

182

183 /**

184 * @brief filters out interesting tags from material information.

185 * @param len length of tag section, will be adjusted to contain remaining bytes

186 * @param si struct to store collected information into

187 */

188 static void gxf_material_tags(AVIOContext *pb, int *len, struct gxf_stream_info *si) {

189 si->first_field = AV_NOPTS_VALUE;

190 si->last_field = AV_NOPTS_VALUE;

191 while (*len >= 2) {

192 GXFMatTag tag = avio_r8(pb);

193 int tlen = avio_r8(pb);

194 *len -= 2;

195 if (tlen > *len)

196 return;

197 *len -= tlen;

198 if (tlen == 4) {

199 uint32_t value = avio_rb32(pb);

200 if (tag == MAT_FIRST_FIELD)

201 si->first_field = value;

202 else if (tag == MAT_LAST_FIELD)

203 si->last_field = value;

204 } else

205 avio_skip(pb, tlen);

206 }

207 }

208

209 static const AVRational frame_rate_tab[] = {

210 { 60, 1},

211 {60000, 1001},

212 { 50, 1},

213 { 30, 1},

214 {30000, 1001},

215 { 25, 1},

216 { 24, 1},

217 {24000, 1001},

218 { 0, 0},

219 };

220

221 /**

222 * @brief convert fps tag value to AVRational fps

223 * @param fps fps value from tag

224 * @return fps as AVRational, or 0 / 0 if unknown

225 */

226 static AVRational fps_tag2avr(int32_t fps) {

227 if (fps < 1 || fps > 9) fps = 9;

228 return frame_rate_tab[fps - 1];

229 }

230

231 /**

232 * @brief convert UMF attributes flags to AVRational fps

233 * @param flags UMF flags to convert

234 * @return fps as AVRational, or 0 / 0 if unknown

235 */

236 static AVRational fps_umf2avr(uint32_t flags) {

237 static const AVRational map[] = {{50, 1}, {60000, 1001}, {24, 1},

238 {25, 1}, {30000, 1001}};

239 int idx = av_log2((flags & 0x7c0) >> 6);

240 return map[idx];

241 }

242

243 /**

244 * @brief filters out interesting tags from track information.

245 * @param len length of tag section, will be adjusted to contain remaining bytes

246 * @param si struct to store collected information into

247 */

248 static void gxf_track_tags(AVIOContext *pb, int *len, struct gxf_stream_info *si) {

249 si->frames_per_second = (AVRational){0, 0};

250 si->fields_per_frame = 0;

251 si->track_aux_data = 0x80000000;

252 while (*len >= 2) {

253 GXFTrackTag tag = avio_r8(pb);

254 int tlen = avio_r8(pb);

255 *len -= 2;

256 if (tlen > *len)

257 return;

258 *len -= tlen;

259 if (tlen == 4) {

260 uint32_t value = avio_rb32(pb);

261 if (tag == TRACK_FPS)

262 si->frames_per_second = fps_tag2avr(value);

263 else if (tag == TRACK_FPF && (value == 1 || value == 2))

264 si->fields_per_frame = value;

265 } else if (tlen == 8 && tag == TRACK_AUX)

266 si->track_aux_data = avio_rl64(pb);

267 else

268 avio_skip(pb, tlen);

269 }

270 }

271

272 /**

273 * @brief read index from FLT packet into stream 0 av_index

274 */

275 static void gxf_read_index(AVFormatContext *s, int pkt_len) {

276 AVIOContext *pb = s->pb;

277 AVStream *st;

278 uint32_t fields_per_map = avio_rl32(pb);

279 uint32_t map_cnt = avio_rl32(pb);

280 int i;

281 pkt_len -= 8;

282 if ((s->flags & AVFMT_FLAG_IGNIDX) || !s->streams) {

283 avio_skip(pb, pkt_len);

284 return;

285 }

286 st = s->streams[0];

287 if (map_cnt > 1000) {

288 av_log(s, AV_LOG_ERROR, "too many index entries %u (%x)\n", map_cnt, map_cnt);

289 map_cnt = 1000;

290 }

291 if (pkt_len < 4 * map_cnt) {

292 av_log(s, AV_LOG_ERROR, "invalid index length\n");

293 avio_skip(pb, pkt_len);

294 return;

295 }

296 pkt_len -= 4 * map_cnt;

297 av_add_index_entry(st, 0, 0, 0, 0, 0);

298 for (i = 0; i < map_cnt; i++)

299 av_add_index_entry(st, (uint64_t)avio_rl32(pb) * 1024,

300 i * (uint64_t)fields_per_map + 1, 0, 0, 0);

301 avio_skip(pb, pkt_len);

302 }

303

304 static int gxf_header(AVFormatContext *s) {

305 AVIOContext *pb = s->pb;

306 GXFPktType pkt_type;

307 int map_len;

308 int len;

309 AVRational main_timebase = {0, 0};

310 struct gxf_stream_info *si = s->priv_data;

311 int i;

312 if (!parse_packet_header(pb, &pkt_type, &map_len) || pkt_type != PKT_MAP) {

313 av_log(s, AV_LOG_ERROR, "map packet not found\n");

314 return 0;

315 }

316 map_len -= 2;

317 if (avio_r8(pb) != 0x0e0 || avio_r8(pb) != 0xff) {

318 av_log(s, AV_LOG_ERROR, "unknown version or invalid map preamble\n");

319 return 0;

320 }

321 map_len -= 2;

322 len = avio_rb16(pb); // length of material data section

323 if (len > map_len) {

324 av_log(s, AV_LOG_ERROR, "material data longer than map data\n");

325 return 0;

326 }

327 map_len -= len;

328 gxf_material_tags(pb, &len, si);

329 avio_skip(pb, len);

330 map_len -= 2;

331 len = avio_rb16(pb); // length of track description

332 if (len > map_len) {

333 av_log(s, AV_LOG_ERROR, "track description longer than map data\n");

334 return 0;

335 }

336 map_len -= len;

337 while (len > 0) {

338 int track_type, track_id, track_len;

339 AVStream *st;

340 int idx;

341 len -= 4;

342 track_type = avio_r8(pb);

343 track_id = avio_r8(pb);

344 track_len = avio_rb16(pb);

345 len -= track_len;

346 if (!(track_type & 0x80)) {

347 av_log(s, AV_LOG_ERROR, "invalid track type %x\n", track_type);

348 continue;

349 }

350 track_type &= 0x7f;

351 if ((track_id & 0xc0) != 0xc0) {

352 av_log(s, AV_LOG_ERROR, "invalid track id %x\n", track_id);

353 continue;

354 }

355 track_id &= 0x3f;

356 gxf_track_tags(pb, &track_len, si);

357 // check for timecode tracks

358 if (track_type == 7 || track_type == 8 || track_type == 24) {

359 add_timecode_metadata(&s->metadata, "timecode",

360 si->track_aux_data & 0xffffffff,

361 si->fields_per_frame);

362

363 }

364 avio_skip(pb, track_len);

365

366 idx = get_sindex(s, track_id, track_type);

367 if (idx < 0) continue;

368 st = s->streams[idx];

369 if (!main_timebase.num || !main_timebase.den) {

370 main_timebase.num = si->frames_per_second.den;

371 main_timebase.den = si->frames_per_second.num * 2;

372 }

373 st->start_time = si->first_field;

374 if (si->first_field != AV_NOPTS_VALUE && si->last_field != AV_NOPTS_VALUE)

375 st->duration = si->last_field - si->first_field;

376 }

377 if (len < 0)

378 av_log(s, AV_LOG_ERROR, "invalid track description length specified\n");

379 if (map_len)

380 avio_skip(pb, map_len);

381 if (!parse_packet_header(pb, &pkt_type, &len)) {

382 av_log(s, AV_LOG_ERROR, "sync lost in header\n");

383 return -1;

384 }

385 if (pkt_type == PKT_FLT) {

386 gxf_read_index(s, len);

387 if (!parse_packet_header(pb, &pkt_type, &len)) {

388 av_log(s, AV_LOG_ERROR, "sync lost in header\n");

389 return -1;

390 }

391 }

392 if (pkt_type == PKT_UMF) {

393 if (len >= 0x39) {

394 AVRational fps;

395 len -= 0x39;

396 avio_skip(pb, 5); // preamble

397 avio_skip(pb, 0x30); // payload description

398 fps = fps_umf2avr(avio_rl32(pb));

399 if (!main_timebase.num || !main_timebase.den) {

400 av_log(s, AV_LOG_WARNING, "No FPS track tag, using UMF fps tag."

401 " This might give wrong results.\n");

402 // this may not always be correct, but simply the best we can get

403 main_timebase.num = fps.den;

404 main_timebase.den = fps.num * 2;

405 }

406

407 if (len >= 0x18) {

408 len -= 0x18;

409 avio_skip(pb, 0x10);

410 add_timecode_metadata(&s->metadata, "timecode_at_mark_in",

411 avio_rl32(pb), si->fields_per_frame);

412 add_timecode_metadata(&s->metadata, "timecode_at_mark_out",

413 avio_rl32(pb), si->fields_per_frame);

414 }

415 } else

416 av_log(s, AV_LOG_INFO, "UMF packet too short\n");

417 } else

418 av_log(s, AV_LOG_INFO, "UMF packet missing\n");

419 avio_skip(pb, len);

420 // set a fallback value, 60000/1001 is specified for audio-only files

421 // so use that regardless of why we do not know the video frame rate.

422 if (!main_timebase.num || !main_timebase.den)

423 main_timebase = (AVRational){1001, 60000};

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

425 AVStream *st = s->streams[i];

426 avpriv_set_pts_info(st, 32, main_timebase.num, main_timebase.den);

427 }

428 return 0;

429 }

430

431 #define READ_ONE() \

432 { \

433 if (!max_interval-- || url_feof(pb)) \

434 goto out; \

435 tmp = tmp << 8 | avio_r8(pb); \

436 }

437

438 /**

439 * @brief resync the stream on the next media packet with specified properties

440 * @param max_interval how many bytes to search for matching packet at most

441 * @param track track id the media packet must belong to, -1 for any

442 * @param timestamp minimum timestamp (== field number) the packet must have, -1 for any

443 * @return timestamp of packet found

444 */

445 static int64_t gxf_resync_media(AVFormatContext *s, uint64_t max_interval, int track, int timestamp) {

446 uint32_t tmp;

447 uint64_t last_pos;

448 uint64_t last_found_pos = 0;

449 int cur_track;

450 int64_t cur_timestamp = AV_NOPTS_VALUE;

451 int len;

452 AVIOContext *pb = s->pb;

453 GXFPktType type;

454 tmp = avio_rb32(pb);

455 start:

456 while (tmp)

457 READ_ONE();

458 READ_ONE();

459 if (tmp != 1)

460 goto start;

461 last_pos = avio_tell(pb);

462 if (avio_seek(pb, -5, SEEK_CUR) < 0)

463 goto out;

464 if (!parse_packet_header(pb, &type, &len) || type != PKT_MEDIA) {

465 if (avio_seek(pb, last_pos, SEEK_SET) < 0)

466 goto out;

467 goto start;

468 }

469 avio_r8(pb);

470 cur_track = avio_r8(pb);

471 cur_timestamp = avio_rb32(pb);

472 last_found_pos = avio_tell(pb) - 16 - 6;

473 if ((track >= 0 && track != cur_track) || (timestamp >= 0 && timestamp > cur_timestamp)) {

474 if (avio_seek(pb, last_pos, SEEK_SET) >= 0)

475 goto start;

476 }

477 out:

478 if (last_found_pos)

479 avio_seek(pb, last_found_pos, SEEK_SET);

480 return cur_timestamp;

481 }

482

483 static int gxf_packet(AVFormatContext *s, AVPacket *pkt) {

484 AVIOContext *pb = s->pb;

485 GXFPktType pkt_type;

486 int pkt_len;

487 struct gxf_stream_info *si = s->priv_data;

488

489 while (!pb->eof_reached) {

490 AVStream *st;

491 int track_type, track_id, ret;

492 int field_nr, field_info, skip = 0;

493 int stream_index;

494 if (!parse_packet_header(pb, &pkt_type, &pkt_len)) {

495 if (!url_feof(pb))

496 av_log(s, AV_LOG_ERROR, "sync lost\n");

497 return -1;

498 }

499 if (pkt_type == PKT_FLT) {

500 gxf_read_index(s, pkt_len);

501 continue;

502 }

503 if (pkt_type != PKT_MEDIA) {

504 avio_skip(pb, pkt_len);

505 continue;

506 }

507 if (pkt_len < 16) {

508 av_log(s, AV_LOG_ERROR, "invalid media packet length\n");

509 continue;

510 }

511 pkt_len -= 16;

512 track_type = avio_r8(pb);

513 track_id = avio_r8(pb);

514 stream_index = get_sindex(s, track_id, track_type);

515 if (stream_index < 0)

516 return stream_index;

517 st = s->streams[stream_index];

518 field_nr = avio_rb32(pb);

519 field_info = avio_rb32(pb);

520 avio_rb32(pb); // "timeline" field number

521 avio_r8(pb); // flags

522 avio_r8(pb); // reserved

523 if (st->codec->codec_id == AV_CODEC_ID_PCM_S24LE ||

524 st->codec->codec_id == AV_CODEC_ID_PCM_S16LE) {

525 int first = field_info >> 16;

526 int last = field_info & 0xffff; // last is exclusive

527 int bps = av_get_bits_per_sample(st->codec->codec_id)>>3;

528 if (first <= last && last*bps <= pkt_len) {

529 avio_skip(pb, first*bps);

530 skip = pkt_len - last*bps;

531 pkt_len = (last-first)*bps;

532 } else

533 av_log(s, AV_LOG_ERROR, "invalid first and last sample values\n");

534 }

535 ret = av_get_packet(pb, pkt, pkt_len);

536 if (skip)

537 avio_skip(pb, skip);

538 pkt->stream_index = stream_index;

539 pkt->dts = field_nr;

540

541 //set duration manually for DV or else lavf misdetects the frame rate

542 if (st->codec->codec_id == AV_CODEC_ID_DVVIDEO)

543 pkt->duration = si->fields_per_frame;

544

545 return ret;

546 }

547 return AVERROR_EOF;

548 }

549

550 static int gxf_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags) {

551 int res = 0;

552 uint64_t pos;

553 uint64_t maxlen = 100 * 1024 * 1024;

554 AVStream *st = s->streams[0];

555 int64_t start_time = s->streams[stream_index]->start_time;

556 int64_t found;

557 int idx;

558 if (timestamp < start_time) timestamp = start_time;

559 idx = av_index_search_timestamp(st, timestamp - start_time,

560 AVSEEK_FLAG_ANY | AVSEEK_FLAG_BACKWARD);

561 if (idx < 0)

562 return -1;

563 pos = st->index_entries[idx].pos;

564 if (idx < st->nb_index_entries - 2)

565 maxlen = st->index_entries[idx + 2].pos - pos;

566 maxlen = FFMAX(maxlen, 200 * 1024);

567 res = avio_seek(s->pb, pos, SEEK_SET);

568 if (res < 0)

569 return res;

570 found = gxf_resync_media(s, maxlen, -1, timestamp);

571 if (FFABS(found - timestamp) > 4)

572 return -1;

573 return 0;

574 }

575

576 static int64_t gxf_read_timestamp(AVFormatContext *s, int stream_index,

577 int64_t *pos, int64_t pos_limit) {

578 AVIOContext *pb = s->pb;

579 int64_t res;

580 if (avio_seek(pb, *pos, SEEK_SET) < 0)

581 return AV_NOPTS_VALUE;

582 res = gxf_resync_media(s, pos_limit - *pos, -1, -1);

583 *pos = avio_tell(pb);

584 return res;

585 }

586

587 AVInputFormat ff_gxf_demuxer = {

588 .name = "gxf",

589 .long_name = NULL_IF_CONFIG_SMALL("GXF (General eXchange Format)"),

590 .priv_data_size = sizeof(struct gxf_stream_info),

591 .read_probe = gxf_probe,

592 .read_header = gxf_header,

593 .read_packet = gxf_packet,

594 .read_seek = gxf_seek,

595 .read_timestamp = gxf_read_timestamp,

596 };

Generated on Sat May 25 2013 03:58:46 for FFmpeg by doxygen 1.8.2