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 14:

120 case 15:

121 case 16:

122 case 25:

123 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

124 st->codec->codec_id = AV_CODEC_ID_DVVIDEO;

125 break;

126 case 11:

127 case 12:

128 case 20:

129 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

130 st->codec->codec_id = AV_CODEC_ID_MPEG2VIDEO;

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

132 break;

133 case 22:

134 case 23:

135 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

136 st->codec->codec_id = AV_CODEC_ID_MPEG1VIDEO;

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

138 break;

139 case 9:

140 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

141 st->codec->codec_id = AV_CODEC_ID_PCM_S24LE;

142 st->codec->channels = 1;

143 st->codec->channel_layout = AV_CH_LAYOUT_MONO;

144 st->codec->sample_rate = 48000;

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

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

147 st->codec->bits_per_coded_sample = 24;

148 break;

149 case 10:

150 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

151 st->codec->codec_id = AV_CODEC_ID_PCM_S16LE;

152 st->codec->channels = 1;

153 st->codec->channel_layout = AV_CH_LAYOUT_MONO;

154 st->codec->sample_rate = 48000;

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

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

157 st->codec->bits_per_coded_sample = 16;

158 break;

159 case 17:

160 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;

161 st->codec->codec_id = AV_CODEC_ID_AC3;

162 st->codec->channels = 2;

163 st->codec->channel_layout = AV_CH_LAYOUT_STEREO;

164 st->codec->sample_rate = 48000;

165 break;

166 case 26: /* AVCi50 / AVCi100 (AVC Intra) */

167 case 29: /* AVCHD */

168 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

169 st->codec->codec_id = CODEC_ID_H264;

170 st->need_parsing = AVSTREAM_PARSE_HEADERS;

171 break;

172 // timecode tracks:

173 case 7:

174 case 8:

175 case 24:

176 st->codec->codec_type = AVMEDIA_TYPE_DATA;

177 st->codec->codec_id = AV_CODEC_ID_NONE;

178 break;

179 case 30:

180 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;

181 st->codec->codec_id = AV_CODEC_ID_DNXHD;

182 break;

183 default:

184 st->codec->codec_type = AVMEDIA_TYPE_UNKNOWN;

185 st->codec->codec_id = AV_CODEC_ID_NONE;

186 break;

187 }

188 return s->nb_streams - 1;

189 }

190

191 /**

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

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

194 * @param si struct to store collected information into

195 */

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

197 si->first_field = AV_NOPTS_VALUE;

198 si->last_field = AV_NOPTS_VALUE;

199 while (*len >= 2) {

200 GXFMatTag tag = avio_r8(pb);

201 int tlen = avio_r8(pb);

202 *len -= 2;

203 if (tlen > *len)

204 return;

205 *len -= tlen;

206 if (tlen == 4) {

207 uint32_t value = avio_rb32(pb);

208 if (tag == MAT_FIRST_FIELD)

209 si->first_field = value;

210 else if (tag == MAT_LAST_FIELD)

211 si->last_field = value;

212 } else

213 avio_skip(pb, tlen);

214 }

215 }

216

217 static const AVRational frame_rate_tab[] = {

218 { 60, 1},

219 {60000, 1001},

220 { 50, 1},

221 { 30, 1},

222 {30000, 1001},

223 { 25, 1},

224 { 24, 1},

225 {24000, 1001},

226 { 0, 0},

227 };

228

229 /**

230 * @brief convert fps tag value to AVRational fps

231 * @param fps fps value from tag

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

233 */

234 static AVRational fps_tag2avr(int32_t fps) {

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

236 return frame_rate_tab[fps - 1];

237 }

238

239 /**

240 * @brief convert UMF attributes flags to AVRational fps

241 * @param flags UMF flags to convert

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

243 */

244 static AVRational fps_umf2avr(uint32_t flags) {

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

246 {25, 1}, {30000, 1001}};

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

248 return map[idx];

249 }

250

251 /**

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

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

254 * @param si struct to store collected information into

255 */

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

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

258 si->fields_per_frame = 0;

259 si->track_aux_data = 0x80000000;

260 while (*len >= 2) {

261 GXFTrackTag tag = avio_r8(pb);

262 int tlen = avio_r8(pb);

263 *len -= 2;

264 if (tlen > *len)

265 return;

266 *len -= tlen;

267 if (tlen == 4) {

268 uint32_t value = avio_rb32(pb);

269 if (tag == TRACK_FPS)

270 si->frames_per_second = fps_tag2avr(value);

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

272 si->fields_per_frame = value;

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

274 si->track_aux_data = avio_rl64(pb);

275 else

276 avio_skip(pb, tlen);

277 }

278 }

279

280 /**

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

282 */

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

284 AVIOContext *pb = s->pb;

285 AVStream *st;

286 uint32_t fields_per_map = avio_rl32(pb);

287 uint32_t map_cnt = avio_rl32(pb);

288 int i;

289 pkt_len -= 8;

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

291 avio_skip(pb, pkt_len);

292 return;

293 }

294 st = s->streams[0];

295 if (map_cnt > 1000) {

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

297 map_cnt = 1000;

298 }

299 if (pkt_len < 4 * map_cnt) {

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

301 avio_skip(pb, pkt_len);

302 return;

303 }

304 pkt_len -= 4 * map_cnt;

305 av_add_index_entry(st, 0, 0, 0, 0, 0);

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

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

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

309 avio_skip(pb, pkt_len);

310 }

311

312 static int gxf_header(AVFormatContext *s) {

313 AVIOContext *pb = s->pb;

314 GXFPktType pkt_type;

315 int map_len;

316 int len;

317 AVRational main_timebase = {0, 0};

318 struct gxf_stream_info *si = s->priv_data;

319 int i;

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

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

322 return 0;

323 }

324 map_len -= 2;

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

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

327 return 0;

328 }

329 map_len -= 2;

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

331 if (len > map_len) {

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

333 return 0;

334 }

335 map_len -= len;

336 gxf_material_tags(pb, &len, si);

337 avio_skip(pb, len);

338 map_len -= 2;

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

340 if (len > map_len) {

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

342 return 0;

343 }

344 map_len -= len;

345 while (len > 0) {

346 int track_type, track_id, track_len;

347 AVStream *st;

348 int idx;

349 len -= 4;

350 track_type = avio_r8(pb);

351 track_id = avio_r8(pb);

352 track_len = avio_rb16(pb);

353 len -= track_len;

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

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

356 continue;

357 }

358 track_type &= 0x7f;

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

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

361 continue;

362 }

363 track_id &= 0x3f;

364 gxf_track_tags(pb, &track_len, si);

365 // check for timecode tracks

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

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

368 si->track_aux_data & 0xffffffff,

369 si->fields_per_frame);

370

371 }

372 avio_skip(pb, track_len);

373

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

375 if (idx < 0) continue;

376 st = s->streams[idx];

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

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

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

380 }

381 st->start_time = si->first_field;

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

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

384 }

385 if (len < 0)

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

387 if (map_len)

388 avio_skip(pb, map_len);

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

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

391 return -1;

392 }

393 if (pkt_type == PKT_FLT) {

394 gxf_read_index(s, len);

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

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

397 return -1;

398 }

399 }

400 if (pkt_type == PKT_UMF) {

401 if (len >= 0x39) {

402 AVRational fps;

403 len -= 0x39;

404 avio_skip(pb, 5); // preamble

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

406 fps = fps_umf2avr(avio_rl32(pb));

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

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

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

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

411 main_timebase.num = fps.den;

412 main_timebase.den = fps.num * 2;

413 }

414

415 if (len >= 0x18) {

416 len -= 0x18;

417 avio_skip(pb, 0x10);

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

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

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

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

422 }

423 } else

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

425 } else

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

427 avio_skip(pb, len);

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

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

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

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

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

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

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

435 }

436 return 0;

437 }

438

439 #define READ_ONE() \

440 { \

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

442 goto out; \

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

444 }

445

446 /**

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

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

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

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

451 * @return timestamp of packet found

452 */

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

454 uint32_t tmp;

455 uint64_t last_pos;

456 uint64_t last_found_pos = 0;

457 int cur_track;

458 int64_t cur_timestamp = AV_NOPTS_VALUE;

459 int len;

460 AVIOContext *pb = s->pb;

461 GXFPktType type;

462 tmp = avio_rb32(pb);

463 start:

464 while (tmp)

465 READ_ONE();

466 READ_ONE();

467 if (tmp != 1)

468 goto start;

469 last_pos = avio_tell(pb);

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

471 goto out;

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

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

474 goto out;

475 goto start;

476 }

477 avio_r8(pb);

478 cur_track = avio_r8(pb);

479 cur_timestamp = avio_rb32(pb);

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

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

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

483 goto start;

484 }

485 out:

486 if (last_found_pos)

487 avio_seek(pb, last_found_pos, SEEK_SET);

488 return cur_timestamp;

489 }

490

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

492 AVIOContext *pb = s->pb;

493 GXFPktType pkt_type;

494 int pkt_len;

495 struct gxf_stream_info *si = s->priv_data;

496

497 while (!pb->eof_reached) {

498 AVStream *st;

499 int track_type, track_id, ret;

500 int field_nr, field_info, skip = 0;

501 int stream_index;

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

503 if (!url_feof(pb))

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

505 return -1;

506 }

507 if (pkt_type == PKT_FLT) {

508 gxf_read_index(s, pkt_len);

509 continue;

510 }

511 if (pkt_type != PKT_MEDIA) {

512 avio_skip(pb, pkt_len);

513 continue;

514 }

515 if (pkt_len < 16) {

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

517 continue;

518 }

519 pkt_len -= 16;

520 track_type = avio_r8(pb);

521 track_id = avio_r8(pb);

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

523 if (stream_index < 0)

524 return stream_index;

525 st = s->streams[stream_index];

526 field_nr = avio_rb32(pb);

527 field_info = avio_rb32(pb);

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

529 avio_r8(pb); // flags

530 avio_r8(pb); // reserved

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

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

533 int first = field_info >> 16;

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

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

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

537 avio_skip(pb, first*bps);

538 skip = pkt_len - last*bps;

539 pkt_len = (last-first)*bps;

540 } else

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

542 }

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

544 if (skip)

545 avio_skip(pb, skip);

546 pkt->stream_index = stream_index;

547 pkt->dts = field_nr;

548

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

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

551 pkt->duration = si->fields_per_frame;

552

553 return ret;

554 }

555 return AVERROR_EOF;

556 }

557

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

559 int res = 0;

560 uint64_t pos;

561 uint64_t maxlen = 100 * 1024 * 1024;

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

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

564 int64_t found;

565 int idx;

566 if (timestamp < start_time) timestamp = start_time;

567 idx = av_index_search_timestamp(st, timestamp - start_time,

568 AVSEEK_FLAG_ANY | AVSEEK_FLAG_BACKWARD);

569 if (idx < 0)

570 return -1;

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

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

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

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

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

576 if (res < 0)

577 return res;

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

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

580 return -1;

581 return 0;

582 }

583

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

585 int64_t *pos, int64_t pos_limit) {

586 AVIOContext *pb = s->pb;

587 int64_t res;

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

589 return AV_NOPTS_VALUE;

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

591 *pos = avio_tell(pb);

592 return res;

593 }

594

595 AVInputFormat ff_gxf_demuxer = {

596 .name = "gxf",

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

598 .priv_data_size = sizeof(struct gxf_stream_info),

599 .read_probe = gxf_probe,

600 .read_header = gxf_header,

601 .read_packet = gxf_packet,

602 .read_seek = gxf_seek,

603 .read_timestamp = gxf_read_timestamp,

604 };

Generated on Wed Jul 10 2013 23:48:12 for FFmpeg by doxygen 1.8.2