3 * Copyright (c) 2006 Reimar Doeffinger
5 * This file is part of Libav.
7 * Libav 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.
12 * Libav 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.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
22 #include "libavutil/common.h"
26 #include "libavcodec/mpeg12data.h"
28 struct gxf_stream_info {
31 AVRational frames_per_second;
32 int32_t fields_per_frame;
36 * @brief parses a packet header, extracting type and length
37 * @param pb AVIOContext to read header from
38 * @param type detected packet type is stored here
39 * @param length detected packet length, excluding header is stored here
40 * @return 0 if header not found or contains invalid data, 1 otherwise
42 static int parse_packet_header(AVIOContext *pb, GXFPktType *type, int *length) {
48 *length = avio_rb32(pb);
49 if ((*length >> 24) || *length < 16)
54 if (avio_r8(pb) != 0xe1)
56 if (avio_r8(pb) != 0xe2)
62 * @brief check if file starts with a PKT_MAP header
64 static int gxf_probe(AVProbeData *p) {
65 static const uint8_t startcode[] = {0, 0, 0, 0, 1, 0xbc}; // start with map packet
66 static const uint8_t endcode[] = {0, 0, 0, 0, 0xe1, 0xe2};
67 if (!memcmp(p->buf, startcode, sizeof(startcode)) &&
68 !memcmp(&p->buf[16 - sizeof(endcode)], endcode, sizeof(endcode)))
69 return AVPROBE_SCORE_MAX;
74 * @brief gets the stream index for the track with the specified id, creates new
76 * @param id id of stream to find / add
77 * @param format stream format identifier
79 static int get_sindex(AVFormatContext *s, int id, int format) {
82 i = ff_find_stream_index(s, id);
85 st = avformat_new_stream(s, NULL);
87 return AVERROR(ENOMEM);
92 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
93 st->codec->codec_id = AV_CODEC_ID_MJPEG;
97 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
98 st->codec->codec_id = AV_CODEC_ID_DVVIDEO;
102 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
103 st->codec->codec_id = AV_CODEC_ID_DVVIDEO;
108 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
109 st->codec->codec_id = AV_CODEC_ID_MPEG2VIDEO;
110 st->need_parsing = AVSTREAM_PARSE_HEADERS; //get keyframe flag etc.
114 st->codec->codec_type = AVMEDIA_TYPE_VIDEO;
115 st->codec->codec_id = AV_CODEC_ID_MPEG1VIDEO;
116 st->need_parsing = AVSTREAM_PARSE_HEADERS; //get keyframe flag etc.
119 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
120 st->codec->codec_id = AV_CODEC_ID_PCM_S24LE;
121 st->codec->channels = 1;
122 st->codec->sample_rate = 48000;
123 st->codec->bit_rate = 3 * 1 * 48000 * 8;
124 st->codec->block_align = 3 * 1;
125 st->codec->bits_per_coded_sample = 24;
128 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
129 st->codec->codec_id = AV_CODEC_ID_PCM_S16LE;
130 st->codec->channels = 1;
131 st->codec->sample_rate = 48000;
132 st->codec->bit_rate = 2 * 1 * 48000 * 8;
133 st->codec->block_align = 2 * 1;
134 st->codec->bits_per_coded_sample = 16;
137 st->codec->codec_type = AVMEDIA_TYPE_AUDIO;
138 st->codec->codec_id = AV_CODEC_ID_AC3;
139 st->codec->channels = 2;
140 st->codec->sample_rate = 48000;
146 st->codec->codec_type = AVMEDIA_TYPE_DATA;
147 st->codec->codec_id = AV_CODEC_ID_NONE;
150 st->codec->codec_type = AVMEDIA_TYPE_UNKNOWN;
151 st->codec->codec_id = AV_CODEC_ID_NONE;
154 return s->nb_streams - 1;
158 * @brief filters out interesting tags from material information.
159 * @param len length of tag section, will be adjusted to contain remaining bytes
160 * @param si struct to store collected information into
162 static void gxf_material_tags(AVIOContext *pb, int *len, struct gxf_stream_info *si) {
163 si->first_field = AV_NOPTS_VALUE;
164 si->last_field = AV_NOPTS_VALUE;
166 GXFMatTag tag = avio_r8(pb);
167 int tlen = avio_r8(pb);
173 uint32_t value = avio_rb32(pb);
174 if (tag == MAT_FIRST_FIELD)
175 si->first_field = value;
176 else if (tag == MAT_LAST_FIELD)
177 si->last_field = value;
183 static const AVRational frame_rate_tab[] = {
196 * @brief convert fps tag value to AVRational fps
197 * @param fps fps value from tag
198 * @return fps as AVRational, or 0 / 0 if unknown
200 static AVRational fps_tag2avr(int32_t fps) {
201 if (fps < 1 || fps > 9) fps = 9;
202 return frame_rate_tab[fps - 1];
206 * @brief convert UMF attributes flags to AVRational fps
207 * @param flags UMF flags to convert
208 * @return fps as AVRational, or 0 / 0 if unknown
210 static AVRational fps_umf2avr(uint32_t flags) {
211 static const AVRational map[] = {{50, 1}, {60000, 1001}, {24, 1},
212 {25, 1}, {30000, 1001}};
213 int idx = av_log2((flags & 0x7c0) >> 6);
218 * @brief filters out interesting tags from track information.
219 * @param len length of tag section, will be adjusted to contain remaining bytes
220 * @param si struct to store collected information into
222 static void gxf_track_tags(AVIOContext *pb, int *len, struct gxf_stream_info *si) {
223 si->frames_per_second = (AVRational){0, 0};
224 si->fields_per_frame = 0;
226 GXFTrackTag tag = avio_r8(pb);
227 int tlen = avio_r8(pb);
233 uint32_t value = avio_rb32(pb);
234 if (tag == TRACK_FPS)
235 si->frames_per_second = fps_tag2avr(value);
236 else if (tag == TRACK_FPF && (value == 1 || value == 2))
237 si->fields_per_frame = value;
244 * @brief read index from FLT packet into stream 0 av_index
246 static void gxf_read_index(AVFormatContext *s, int pkt_len) {
247 AVIOContext *pb = s->pb;
248 AVStream *st = s->streams[0];
249 uint32_t fields_per_map = avio_rl32(pb);
250 uint32_t map_cnt = avio_rl32(pb);
253 if (s->flags & AVFMT_FLAG_IGNIDX) {
254 avio_skip(pb, pkt_len);
257 if (map_cnt > 1000) {
258 av_log(s, AV_LOG_ERROR, "too many index entries %u (%x)\n", map_cnt, map_cnt);
261 if (pkt_len < 4 * map_cnt) {
262 av_log(s, AV_LOG_ERROR, "invalid index length\n");
263 avio_skip(pb, pkt_len);
266 pkt_len -= 4 * map_cnt;
267 av_add_index_entry(st, 0, 0, 0, 0, 0);
268 for (i = 0; i < map_cnt; i++)
269 av_add_index_entry(st, (uint64_t)avio_rl32(pb) * 1024,
270 i * (uint64_t)fields_per_map + 1, 0, 0, 0);
271 avio_skip(pb, pkt_len);
274 static int gxf_header(AVFormatContext *s) {
275 AVIOContext *pb = s->pb;
279 AVRational main_timebase = {0, 0};
280 struct gxf_stream_info *si = s->priv_data;
282 if (!parse_packet_header(pb, &pkt_type, &map_len) || pkt_type != PKT_MAP) {
283 av_log(s, AV_LOG_ERROR, "map packet not found\n");
287 if (avio_r8(pb) != 0x0e0 || avio_r8(pb) != 0xff) {
288 av_log(s, AV_LOG_ERROR, "unknown version or invalid map preamble\n");
292 len = avio_rb16(pb); // length of material data section
294 av_log(s, AV_LOG_ERROR, "material data longer than map data\n");
298 gxf_material_tags(pb, &len, si);
301 len = avio_rb16(pb); // length of track description
303 av_log(s, AV_LOG_ERROR, "track description longer than map data\n");
308 int track_type, track_id, track_len;
312 track_type = avio_r8(pb);
313 track_id = avio_r8(pb);
314 track_len = avio_rb16(pb);
316 gxf_track_tags(pb, &track_len, si);
317 avio_skip(pb, track_len);
318 if (!(track_type & 0x80)) {
319 av_log(s, AV_LOG_ERROR, "invalid track type %x\n", track_type);
323 if ((track_id & 0xc0) != 0xc0) {
324 av_log(s, AV_LOG_ERROR, "invalid track id %x\n", track_id);
328 idx = get_sindex(s, track_id, track_type);
329 if (idx < 0) continue;
330 st = s->streams[idx];
331 if (!main_timebase.num || !main_timebase.den) {
332 main_timebase.num = si->frames_per_second.den;
333 main_timebase.den = si->frames_per_second.num * 2;
335 st->start_time = si->first_field;
336 if (si->first_field != AV_NOPTS_VALUE && si->last_field != AV_NOPTS_VALUE)
337 st->duration = si->last_field - si->first_field;
340 av_log(s, AV_LOG_ERROR, "invalid track description length specified\n");
342 avio_skip(pb, map_len);
343 if (!parse_packet_header(pb, &pkt_type, &len)) {
344 av_log(s, AV_LOG_ERROR, "sync lost in header\n");
347 if (pkt_type == PKT_FLT) {
348 gxf_read_index(s, len);
349 if (!parse_packet_header(pb, &pkt_type, &len)) {
350 av_log(s, AV_LOG_ERROR, "sync lost in header\n");
354 if (pkt_type == PKT_UMF) {
358 avio_skip(pb, 5); // preamble
359 avio_skip(pb, 0x30); // payload description
360 fps = fps_umf2avr(avio_rl32(pb));
361 if (!main_timebase.num || !main_timebase.den) {
362 // this may not always be correct, but simply the best we can get
363 main_timebase.num = fps.den;
364 main_timebase.den = fps.num * 2;
367 av_log(s, AV_LOG_INFO, "UMF packet too short\n");
369 av_log(s, AV_LOG_INFO, "UMF packet missing\n");
371 // set a fallback value, 60000/1001 is specified for audio-only files
372 // so use that regardless of why we do not know the video frame rate.
373 if (!main_timebase.num || !main_timebase.den)
374 main_timebase = (AVRational){1001, 60000};
375 for (i = 0; i < s->nb_streams; i++) {
376 AVStream *st = s->streams[i];
377 avpriv_set_pts_info(st, 32, main_timebase.num, main_timebase.den);
384 if (!max_interval-- || pb->eof_reached) \
386 tmp = tmp << 8 | avio_r8(pb); \
390 * @brief resync the stream on the next media packet with specified properties
391 * @param max_interval how many bytes to search for matching packet at most
392 * @param track track id the media packet must belong to, -1 for any
393 * @param timestamp minimum timestamp (== field number) the packet must have, -1 for any
394 * @return timestamp of packet found
396 static int64_t gxf_resync_media(AVFormatContext *s, uint64_t max_interval, int track, int timestamp) {
399 uint64_t last_found_pos = 0;
401 int64_t cur_timestamp = AV_NOPTS_VALUE;
403 AVIOContext *pb = s->pb;
412 last_pos = avio_tell(pb);
413 if (avio_seek(pb, -5, SEEK_CUR) < 0)
415 if (!parse_packet_header(pb, &type, &len) || type != PKT_MEDIA) {
416 if (avio_seek(pb, last_pos, SEEK_SET) < 0)
421 cur_track = avio_r8(pb);
422 cur_timestamp = avio_rb32(pb);
423 last_found_pos = avio_tell(pb) - 16 - 6;
424 if ((track >= 0 && track != cur_track) || (timestamp >= 0 && timestamp > cur_timestamp)) {
425 if (avio_seek(pb, last_pos, SEEK_SET) >= 0)
430 avio_seek(pb, last_found_pos, SEEK_SET);
431 return cur_timestamp;
434 static int gxf_packet(AVFormatContext *s, AVPacket *pkt) {
435 AVIOContext *pb = s->pb;
438 struct gxf_stream_info *si = s->priv_data;
440 while (!pb->eof_reached) {
442 int track_type, track_id, ret;
443 int field_nr, field_info, skip = 0;
445 if (!parse_packet_header(pb, &pkt_type, &pkt_len)) {
446 if (!pb->eof_reached)
447 av_log(s, AV_LOG_ERROR, "sync lost\n");
450 if (pkt_type == PKT_FLT) {
451 gxf_read_index(s, pkt_len);
454 if (pkt_type != PKT_MEDIA) {
455 avio_skip(pb, pkt_len);
459 av_log(s, AV_LOG_ERROR, "invalid media packet length\n");
463 track_type = avio_r8(pb);
464 track_id = avio_r8(pb);
465 stream_index = get_sindex(s, track_id, track_type);
466 if (stream_index < 0)
468 st = s->streams[stream_index];
469 field_nr = avio_rb32(pb);
470 field_info = avio_rb32(pb);
471 avio_rb32(pb); // "timeline" field number
472 avio_r8(pb); // flags
473 avio_r8(pb); // reserved
474 if (st->codec->codec_id == AV_CODEC_ID_PCM_S24LE ||
475 st->codec->codec_id == AV_CODEC_ID_PCM_S16LE) {
476 int first = field_info >> 16;
477 int last = field_info & 0xffff; // last is exclusive
478 int bps = av_get_bits_per_sample(st->codec->codec_id)>>3;
479 if (first <= last && last*bps <= pkt_len) {
480 avio_skip(pb, first*bps);
481 skip = pkt_len - last*bps;
482 pkt_len = (last-first)*bps;
484 av_log(s, AV_LOG_ERROR, "invalid first and last sample values\n");
486 ret = av_get_packet(pb, pkt, pkt_len);
489 pkt->stream_index = stream_index;
492 //set duration manually for DV or else lavf misdetects the frame rate
493 if (st->codec->codec_id == AV_CODEC_ID_DVVIDEO)
494 pkt->duration = si->fields_per_frame;
501 static int gxf_seek(AVFormatContext *s, int stream_index, int64_t timestamp, int flags) {
504 uint64_t maxlen = 100 * 1024 * 1024;
505 AVStream *st = s->streams[0];
506 int64_t start_time = s->streams[stream_index]->start_time;
509 if (timestamp < start_time) timestamp = start_time;
510 idx = av_index_search_timestamp(st, timestamp - start_time,
511 AVSEEK_FLAG_ANY | AVSEEK_FLAG_BACKWARD);
514 pos = st->index_entries[idx].pos;
515 if (idx < st->nb_index_entries - 2)
516 maxlen = st->index_entries[idx + 2].pos - pos;
517 maxlen = FFMAX(maxlen, 200 * 1024);
518 res = avio_seek(s->pb, pos, SEEK_SET);
521 found = gxf_resync_media(s, maxlen, -1, timestamp);
522 if (FFABS(found - timestamp) > 4)
527 static int64_t gxf_read_timestamp(AVFormatContext *s, int stream_index,
528 int64_t *pos, int64_t pos_limit) {
529 AVIOContext *pb = s->pb;
531 if (avio_seek(pb, *pos, SEEK_SET) < 0)
532 return AV_NOPTS_VALUE;
533 res = gxf_resync_media(s, pos_limit - *pos, -1, -1);
534 *pos = avio_tell(pb);
538 AVInputFormat ff_gxf_demuxer = {
540 .long_name = NULL_IF_CONFIG_SMALL("GXF (General eXchange Format)"),
541 .priv_data_size = sizeof(struct gxf_stream_info),
542 .read_probe = gxf_probe,
543 .read_header = gxf_header,
544 .read_packet = gxf_packet,
545 .read_seek = gxf_seek,
546 .read_timestamp = gxf_read_timestamp,