2 * Apple HTTP Live Streaming demuxer
3 * Copyright (c) 2010 Martin Storsjo
4 * Copyright (c) 2013 Anssi Hannula
6 * This file is part of FFmpeg.
8 * FFmpeg is free software; you can redistribute it and/or
9 * modify it under the terms of the GNU Lesser General Public
10 * License as published by the Free Software Foundation; either
11 * version 2.1 of the License, or (at your option) any later version.
13 * FFmpeg is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * Lesser General Public License for more details.
18 * You should have received a copy of the GNU Lesser General Public
19 * License along with FFmpeg; if not, write to the Free Software
20 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
25 * Apple HTTP Live Streaming demuxer
26 * http://tools.ietf.org/html/draft-pantos-http-live-streaming
29 #include "libavformat/http.h"
30 #include "libavutil/avstring.h"
31 #include "libavutil/avassert.h"
32 #include "libavutil/intreadwrite.h"
33 #include "libavutil/mathematics.h"
34 #include "libavutil/opt.h"
35 #include "libavutil/dict.h"
36 #include "libavutil/time.h"
39 #include "avio_internal.h"
42 #define INITIAL_BUFFER_SIZE 32768
44 #define MAX_FIELD_LEN 64
45 #define MAX_CHARACTERISTICS_LEN 512
47 #define MPEG_TIME_BASE 90000
48 #define MPEG_TIME_BASE_Q (AVRational){1, MPEG_TIME_BASE}
51 * An apple http stream consists of a playlist with media segment files,
52 * played sequentially. There may be several playlists with the same
53 * video content, in different bandwidth variants, that are played in
54 * parallel (preferably only one bandwidth variant at a time). In this case,
55 * the user supplied the url to a main playlist that only lists the variant
58 * If the main playlist doesn't point at any variants, we still create
59 * one anonymous toplevel variant for this, to maintain the structure.
74 enum KeyType key_type;
76 /* associated Media Initialization Section, treated as a segment */
77 struct segment *init_section;
89 * Each playlist has its own demuxer. If it currently is active,
90 * it has an open AVIOContext too, and potentially an AVPacket
91 * containing the next packet from this stream.
94 char url[MAX_URL_SIZE];
99 AVIOContext *input_next;
100 int input_next_requested;
101 AVFormatContext *parent;
103 AVFormatContext *ctx;
105 int has_noheader_flag;
107 /* main demuxer streams associated with this playlist
108 * indexed by the subdemuxer stream indexes */
109 AVStream **main_streams;
113 enum PlaylistType type;
114 int64_t target_duration;
117 struct segment **segments;
120 int64_t cur_seg_offset;
121 int64_t last_load_time;
123 /* Currently active Media Initialization Section */
124 struct segment *cur_init_section;
125 uint8_t *init_sec_buf;
126 unsigned int init_sec_buf_size;
127 unsigned int init_sec_data_len;
128 unsigned int init_sec_buf_read_offset;
130 char key_url[MAX_URL_SIZE];
133 /* ID3 timestamp handling (elementary audio streams have ID3 timestamps
134 * (and possibly other ID3 tags) in the beginning of each segment) */
135 int is_id3_timestamped; /* -1: not yet known */
136 int64_t id3_mpegts_timestamp; /* in mpegts tb */
137 int64_t id3_offset; /* in stream original tb */
138 uint8_t* id3_buf; /* temp buffer for id3 parsing */
139 unsigned int id3_buf_size;
140 AVDictionary *id3_initial; /* data from first id3 tag */
141 int id3_found; /* ID3 tag found at some point */
142 int id3_changed; /* ID3 tag data has changed at some point */
143 ID3v2ExtraMeta *id3_deferred_extra; /* stored here until subdemuxer is opened */
145 int64_t seek_timestamp;
147 int seek_stream_index; /* into subdemuxer stream array */
149 /* Renditions associated with this playlist, if any.
150 * Alternative rendition playlists have a single rendition associated
151 * with them, and variant main Media Playlists may have
152 * multiple (playlist-less) renditions associated with them. */
154 struct rendition **renditions;
156 /* Media Initialization Sections (EXT-X-MAP) associated with this
157 * playlist, if any. */
159 struct segment **init_sections;
163 * Renditions are e.g. alternative subtitle or audio streams.
164 * The rendition may either be an external playlist or it may be
165 * contained in the main Media Playlist of the variant (in which case
169 enum AVMediaType type;
170 struct playlist *playlist;
171 char group_id[MAX_FIELD_LEN];
172 char language[MAX_FIELD_LEN];
173 char name[MAX_FIELD_LEN];
180 /* every variant contains at least the main Media Playlist in index 0 */
182 struct playlist **playlists;
184 char audio_group[MAX_FIELD_LEN];
185 char video_group[MAX_FIELD_LEN];
186 char subtitles_group[MAX_FIELD_LEN];
189 typedef struct HLSContext {
191 AVFormatContext *ctx;
193 struct variant **variants;
195 struct playlist **playlists;
197 struct rendition **renditions;
200 int live_start_index;
202 int64_t first_timestamp;
203 int64_t cur_timestamp;
204 AVIOInterruptCB *interrupt_callback;
205 char *user_agent; ///< holds HTTP user agent set as an AVOption to the HTTP protocol context
206 char *cookies; ///< holds HTTP cookie values set in either the initial response or as an AVOption to the HTTP protocol context
207 char *headers; ///< holds HTTP headers set as an AVOption to the HTTP protocol context
208 char *http_proxy; ///< holds the address of the HTTP proxy server
209 AVDictionary *avio_opts;
210 int strict_std_compliance;
211 char *allowed_extensions;
215 AVIOContext *playlist_pb;
218 static int read_chomp_line(AVIOContext *s, char *buf, int maxlen)
220 int len = ff_get_line(s, buf, maxlen);
221 while (len > 0 && av_isspace(buf[len - 1]))
226 static void free_segment_list(struct playlist *pls)
229 for (i = 0; i < pls->n_segments; i++) {
230 av_freep(&pls->segments[i]->key);
231 av_freep(&pls->segments[i]->url);
232 av_freep(&pls->segments[i]);
234 av_freep(&pls->segments);
238 static void free_init_section_list(struct playlist *pls)
241 for (i = 0; i < pls->n_init_sections; i++) {
242 av_freep(&pls->init_sections[i]->url);
243 av_freep(&pls->init_sections[i]);
245 av_freep(&pls->init_sections);
246 pls->n_init_sections = 0;
249 static void free_playlist_list(HLSContext *c)
252 for (i = 0; i < c->n_playlists; i++) {
253 struct playlist *pls = c->playlists[i];
254 free_segment_list(pls);
255 free_init_section_list(pls);
256 av_freep(&pls->main_streams);
257 av_freep(&pls->renditions);
258 av_freep(&pls->id3_buf);
259 av_dict_free(&pls->id3_initial);
260 ff_id3v2_free_extra_meta(&pls->id3_deferred_extra);
261 av_freep(&pls->init_sec_buf);
262 av_packet_unref(&pls->pkt);
263 av_freep(&pls->pb.buffer);
265 ff_format_io_close(c->ctx, &pls->input);
266 pls->input_read_done = 0;
268 ff_format_io_close(c->ctx, &pls->input_next);
269 pls->input_next_requested = 0;
272 avformat_close_input(&pls->ctx);
276 av_freep(&c->playlists);
277 av_freep(&c->cookies);
278 av_freep(&c->user_agent);
279 av_freep(&c->headers);
280 av_freep(&c->http_proxy);
284 static void free_variant_list(HLSContext *c)
287 for (i = 0; i < c->n_variants; i++) {
288 struct variant *var = c->variants[i];
289 av_freep(&var->playlists);
292 av_freep(&c->variants);
296 static void free_rendition_list(HLSContext *c)
299 for (i = 0; i < c->n_renditions; i++)
300 av_freep(&c->renditions[i]);
301 av_freep(&c->renditions);
306 * Used to reset a statically allocated AVPacket to a clean slate,
307 * containing no data.
309 static void reset_packet(AVPacket *pkt)
315 static struct playlist *new_playlist(HLSContext *c, const char *url,
318 struct playlist *pls = av_mallocz(sizeof(struct playlist));
321 reset_packet(&pls->pkt);
322 ff_make_absolute_url(pls->url, sizeof(pls->url), base, url);
323 pls->seek_timestamp = AV_NOPTS_VALUE;
325 pls->is_id3_timestamped = -1;
326 pls->id3_mpegts_timestamp = AV_NOPTS_VALUE;
328 dynarray_add(&c->playlists, &c->n_playlists, pls);
332 struct variant_info {
334 /* variant group ids: */
335 char audio[MAX_FIELD_LEN];
336 char video[MAX_FIELD_LEN];
337 char subtitles[MAX_FIELD_LEN];
340 static struct variant *new_variant(HLSContext *c, struct variant_info *info,
341 const char *url, const char *base)
344 struct playlist *pls;
346 pls = new_playlist(c, url, base);
350 var = av_mallocz(sizeof(struct variant));
355 var->bandwidth = atoi(info->bandwidth);
356 strcpy(var->audio_group, info->audio);
357 strcpy(var->video_group, info->video);
358 strcpy(var->subtitles_group, info->subtitles);
361 dynarray_add(&c->variants, &c->n_variants, var);
362 dynarray_add(&var->playlists, &var->n_playlists, pls);
366 static void handle_variant_args(struct variant_info *info, const char *key,
367 int key_len, char **dest, int *dest_len)
369 if (!strncmp(key, "BANDWIDTH=", key_len)) {
370 *dest = info->bandwidth;
371 *dest_len = sizeof(info->bandwidth);
372 } else if (!strncmp(key, "AUDIO=", key_len)) {
374 *dest_len = sizeof(info->audio);
375 } else if (!strncmp(key, "VIDEO=", key_len)) {
377 *dest_len = sizeof(info->video);
378 } else if (!strncmp(key, "SUBTITLES=", key_len)) {
379 *dest = info->subtitles;
380 *dest_len = sizeof(info->subtitles);
385 char uri[MAX_URL_SIZE];
390 static void handle_key_args(struct key_info *info, const char *key,
391 int key_len, char **dest, int *dest_len)
393 if (!strncmp(key, "METHOD=", key_len)) {
394 *dest = info->method;
395 *dest_len = sizeof(info->method);
396 } else if (!strncmp(key, "URI=", key_len)) {
398 *dest_len = sizeof(info->uri);
399 } else if (!strncmp(key, "IV=", key_len)) {
401 *dest_len = sizeof(info->iv);
405 struct init_section_info {
406 char uri[MAX_URL_SIZE];
410 static struct segment *new_init_section(struct playlist *pls,
411 struct init_section_info *info,
412 const char *url_base)
416 char tmp_str[MAX_URL_SIZE];
421 sec = av_mallocz(sizeof(*sec));
425 ff_make_absolute_url(tmp_str, sizeof(tmp_str), url_base, info->uri);
426 sec->url = av_strdup(tmp_str);
432 if (info->byterange[0]) {
433 sec->size = strtoll(info->byterange, NULL, 10);
434 ptr = strchr(info->byterange, '@');
436 sec->url_offset = strtoll(ptr+1, NULL, 10);
438 /* the entire file is the init section */
442 dynarray_add(&pls->init_sections, &pls->n_init_sections, sec);
447 static void handle_init_section_args(struct init_section_info *info, const char *key,
448 int key_len, char **dest, int *dest_len)
450 if (!strncmp(key, "URI=", key_len)) {
452 *dest_len = sizeof(info->uri);
453 } else if (!strncmp(key, "BYTERANGE=", key_len)) {
454 *dest = info->byterange;
455 *dest_len = sizeof(info->byterange);
459 struct rendition_info {
461 char uri[MAX_URL_SIZE];
462 char group_id[MAX_FIELD_LEN];
463 char language[MAX_FIELD_LEN];
464 char assoc_language[MAX_FIELD_LEN];
465 char name[MAX_FIELD_LEN];
468 char characteristics[MAX_CHARACTERISTICS_LEN];
471 static struct rendition *new_rendition(HLSContext *c, struct rendition_info *info,
472 const char *url_base)
474 struct rendition *rend;
475 enum AVMediaType type = AVMEDIA_TYPE_UNKNOWN;
476 char *characteristic;
480 if (!strcmp(info->type, "AUDIO"))
481 type = AVMEDIA_TYPE_AUDIO;
482 else if (!strcmp(info->type, "VIDEO"))
483 type = AVMEDIA_TYPE_VIDEO;
484 else if (!strcmp(info->type, "SUBTITLES"))
485 type = AVMEDIA_TYPE_SUBTITLE;
486 else if (!strcmp(info->type, "CLOSED-CAPTIONS"))
487 /* CLOSED-CAPTIONS is ignored since we do not support CEA-608 CC in
488 * AVC SEI RBSP anyway */
491 if (type == AVMEDIA_TYPE_UNKNOWN)
494 /* URI is mandatory for subtitles as per spec */
495 if (type == AVMEDIA_TYPE_SUBTITLE && !info->uri[0])
498 /* TODO: handle subtitles (each segment has to parsed separately) */
499 if (c->strict_std_compliance > FF_COMPLIANCE_EXPERIMENTAL)
500 if (type == AVMEDIA_TYPE_SUBTITLE)
503 rend = av_mallocz(sizeof(struct rendition));
507 dynarray_add(&c->renditions, &c->n_renditions, rend);
510 strcpy(rend->group_id, info->group_id);
511 strcpy(rend->language, info->language);
512 strcpy(rend->name, info->name);
514 /* add the playlist if this is an external rendition */
516 rend->playlist = new_playlist(c, info->uri, url_base);
518 dynarray_add(&rend->playlist->renditions,
519 &rend->playlist->n_renditions, rend);
522 if (info->assoc_language[0]) {
523 int langlen = strlen(rend->language);
524 if (langlen < sizeof(rend->language) - 3) {
525 rend->language[langlen] = ',';
526 strncpy(rend->language + langlen + 1, info->assoc_language,
527 sizeof(rend->language) - langlen - 2);
531 if (!strcmp(info->defaultr, "YES"))
532 rend->disposition |= AV_DISPOSITION_DEFAULT;
533 if (!strcmp(info->forced, "YES"))
534 rend->disposition |= AV_DISPOSITION_FORCED;
536 chr_ptr = info->characteristics;
537 while ((characteristic = av_strtok(chr_ptr, ",", &saveptr))) {
538 if (!strcmp(characteristic, "public.accessibility.describes-music-and-sound"))
539 rend->disposition |= AV_DISPOSITION_HEARING_IMPAIRED;
540 else if (!strcmp(characteristic, "public.accessibility.describes-video"))
541 rend->disposition |= AV_DISPOSITION_VISUAL_IMPAIRED;
549 static void handle_rendition_args(struct rendition_info *info, const char *key,
550 int key_len, char **dest, int *dest_len)
552 if (!strncmp(key, "TYPE=", key_len)) {
554 *dest_len = sizeof(info->type);
555 } else if (!strncmp(key, "URI=", key_len)) {
557 *dest_len = sizeof(info->uri);
558 } else if (!strncmp(key, "GROUP-ID=", key_len)) {
559 *dest = info->group_id;
560 *dest_len = sizeof(info->group_id);
561 } else if (!strncmp(key, "LANGUAGE=", key_len)) {
562 *dest = info->language;
563 *dest_len = sizeof(info->language);
564 } else if (!strncmp(key, "ASSOC-LANGUAGE=", key_len)) {
565 *dest = info->assoc_language;
566 *dest_len = sizeof(info->assoc_language);
567 } else if (!strncmp(key, "NAME=", key_len)) {
569 *dest_len = sizeof(info->name);
570 } else if (!strncmp(key, "DEFAULT=", key_len)) {
571 *dest = info->defaultr;
572 *dest_len = sizeof(info->defaultr);
573 } else if (!strncmp(key, "FORCED=", key_len)) {
574 *dest = info->forced;
575 *dest_len = sizeof(info->forced);
576 } else if (!strncmp(key, "CHARACTERISTICS=", key_len)) {
577 *dest = info->characteristics;
578 *dest_len = sizeof(info->characteristics);
582 * - AUTOSELECT: client may autoselect based on e.g. system language
583 * - INSTREAM-ID: EIA-608 closed caption number ("CC1".."CC4")
587 /* used by parse_playlist to allocate a new variant+playlist when the
588 * playlist is detected to be a Media Playlist (not Master Playlist)
589 * and we have no parent Master Playlist (parsing of which would have
590 * allocated the variant and playlist already)
591 * *pls == NULL => Master Playlist or parentless Media Playlist
592 * *pls != NULL => parented Media Playlist, playlist+variant allocated */
593 static int ensure_playlist(HLSContext *c, struct playlist **pls, const char *url)
597 if (!new_variant(c, NULL, url, NULL))
598 return AVERROR(ENOMEM);
599 *pls = c->playlists[c->n_playlists - 1];
603 static void update_options(char **dest, const char *name, void *src)
606 av_opt_get(src, name, AV_OPT_SEARCH_CHILDREN, (uint8_t**)dest);
607 if (*dest && !strlen(*dest))
611 static int open_url_keepalive(AVFormatContext *s, AVIOContext **pb,
614 #if !CONFIG_HTTP_PROTOCOL
615 return AVERROR_PROTOCOL_NOT_FOUND;
618 URLContext *uc = ffio_geturlcontext(*pb);
620 (*pb)->eof_reached = 0;
621 ret = ff_http_do_new_request(uc, url);
623 ff_format_io_close(s, pb);
629 static int open_url(AVFormatContext *s, AVIOContext **pb, const char *url,
630 AVDictionary *opts, AVDictionary *opts2, int *is_http_out)
632 HLSContext *c = s->priv_data;
633 AVDictionary *tmp = NULL;
634 const char *proto_name = NULL;
638 av_dict_copy(&tmp, opts, 0);
639 av_dict_copy(&tmp, opts2, 0);
641 if (av_strstart(url, "crypto", NULL)) {
642 if (url[6] == '+' || url[6] == ':')
643 proto_name = avio_find_protocol_name(url + 7);
647 proto_name = avio_find_protocol_name(url);
650 return AVERROR_INVALIDDATA;
652 // only http(s) & file are allowed
653 if (av_strstart(proto_name, "file", NULL)) {
654 if (strcmp(c->allowed_extensions, "ALL") && !av_match_ext(url, c->allowed_extensions)) {
655 av_log(s, AV_LOG_ERROR,
656 "Filename extension of \'%s\' is not a common multimedia extension, blocked for security reasons.\n"
657 "If you wish to override this adjust allowed_extensions, you can set it to \'ALL\' to allow all\n",
659 return AVERROR_INVALIDDATA;
661 } else if (av_strstart(proto_name, "http", NULL)) {
664 return AVERROR_INVALIDDATA;
666 if (!strncmp(proto_name, url, strlen(proto_name)) && url[strlen(proto_name)] == ':')
668 else if (av_strstart(url, "crypto", NULL) && !strncmp(proto_name, url + 7, strlen(proto_name)) && url[7 + strlen(proto_name)] == ':')
670 else if (strcmp(proto_name, "file") || !strncmp(url, "file,", 5))
671 return AVERROR_INVALIDDATA;
673 if (is_http && c->http_persistent && *pb) {
674 ret = open_url_keepalive(c->ctx, pb, url);
675 if (ret == AVERROR_EXIT) {
677 } else if (ret < 0) {
678 if (ret != AVERROR_EOF)
679 av_log(s, AV_LOG_WARNING,
680 "keepalive request failed for '%s', retrying with new connection: %s\n",
681 url, av_err2str(ret));
682 ret = s->io_open(s, pb, url, AVIO_FLAG_READ, &tmp);
685 ret = s->io_open(s, pb, url, AVIO_FLAG_READ, &tmp);
688 // update cookies on http response with setcookies.
689 char *new_cookies = NULL;
691 if (!(s->flags & AVFMT_FLAG_CUSTOM_IO))
692 av_opt_get(*pb, "cookies", AV_OPT_SEARCH_CHILDREN, (uint8_t**)&new_cookies);
696 c->cookies = new_cookies;
699 av_dict_set(&opts, "cookies", c->cookies, 0);
705 *is_http_out = is_http;
710 static int parse_playlist(HLSContext *c, const char *url,
711 struct playlist *pls, AVIOContext *in)
713 int ret = 0, is_segment = 0, is_variant = 0;
714 int64_t duration = 0;
715 enum KeyType key_type = KEY_NONE;
718 char key[MAX_URL_SIZE] = "";
719 char line[MAX_URL_SIZE];
722 int64_t seg_offset = 0;
723 int64_t seg_size = -1;
724 uint8_t *new_url = NULL;
725 struct variant_info variant_info;
726 char tmp_str[MAX_URL_SIZE];
727 struct segment *cur_init_section = NULL;
728 int is_http = av_strstart(url, "http", NULL);
730 if (is_http && !in && c->http_persistent && c->playlist_pb) {
732 ret = open_url_keepalive(c->ctx, &c->playlist_pb, url);
733 if (ret == AVERROR_EXIT) {
735 } else if (ret < 0) {
736 if (ret != AVERROR_EOF)
737 av_log(c->ctx, AV_LOG_WARNING,
738 "keepalive request failed for '%s', retrying with new connection: %s\n",
739 url, av_err2str(ret));
746 AVDictionary *opts = NULL;
747 /* Some HLS servers don't like being sent the range header */
748 av_dict_set(&opts, "seekable", "0", 0);
750 // broker prior HTTP options that should be consistent across requests
751 av_dict_set(&opts, "user_agent", c->user_agent, 0);
752 av_dict_set(&opts, "cookies", c->cookies, 0);
753 av_dict_set(&opts, "headers", c->headers, 0);
754 av_dict_set(&opts, "http_proxy", c->http_proxy, 0);
756 if (c->http_persistent)
757 av_dict_set(&opts, "multiple_requests", "1", 0);
759 ret = c->ctx->io_open(c->ctx, &in, url, AVIO_FLAG_READ, &opts);
764 if (is_http && c->http_persistent)
769 ret = open_in(c, &in, url);
776 if (av_opt_get(in, "location", AV_OPT_SEARCH_CHILDREN, &new_url) >= 0)
779 read_chomp_line(in, line, sizeof(line));
780 if (strcmp(line, "#EXTM3U")) {
781 ret = AVERROR_INVALIDDATA;
786 free_segment_list(pls);
788 pls->type = PLS_TYPE_UNSPECIFIED;
790 while (!avio_feof(in)) {
791 read_chomp_line(in, line, sizeof(line));
792 if (av_strstart(line, "#EXT-X-STREAM-INF:", &ptr)) {
794 memset(&variant_info, 0, sizeof(variant_info));
795 ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_variant_args,
797 } else if (av_strstart(line, "#EXT-X-KEY:", &ptr)) {
798 struct key_info info = {{0}};
799 ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_key_args,
803 if (!strcmp(info.method, "AES-128"))
804 key_type = KEY_AES_128;
805 if (!strcmp(info.method, "SAMPLE-AES"))
806 key_type = KEY_SAMPLE_AES;
807 if (!strncmp(info.iv, "0x", 2) || !strncmp(info.iv, "0X", 2)) {
808 ff_hex_to_data(iv, info.iv + 2);
811 av_strlcpy(key, info.uri, sizeof(key));
812 } else if (av_strstart(line, "#EXT-X-MEDIA:", &ptr)) {
813 struct rendition_info info = {{0}};
814 ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_rendition_args,
816 new_rendition(c, &info, url);
817 } else if (av_strstart(line, "#EXT-X-TARGETDURATION:", &ptr)) {
818 ret = ensure_playlist(c, &pls, url);
821 pls->target_duration = strtoll(ptr, NULL, 10) * AV_TIME_BASE;
822 } else if (av_strstart(line, "#EXT-X-MEDIA-SEQUENCE:", &ptr)) {
823 ret = ensure_playlist(c, &pls, url);
826 pls->start_seq_no = atoi(ptr);
827 } else if (av_strstart(line, "#EXT-X-PLAYLIST-TYPE:", &ptr)) {
828 ret = ensure_playlist(c, &pls, url);
831 if (!strcmp(ptr, "EVENT"))
832 pls->type = PLS_TYPE_EVENT;
833 else if (!strcmp(ptr, "VOD"))
834 pls->type = PLS_TYPE_VOD;
835 } else if (av_strstart(line, "#EXT-X-MAP:", &ptr)) {
836 struct init_section_info info = {{0}};
837 ret = ensure_playlist(c, &pls, url);
840 ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_init_section_args,
842 cur_init_section = new_init_section(pls, &info, url);
843 } else if (av_strstart(line, "#EXT-X-ENDLIST", &ptr)) {
846 } else if (av_strstart(line, "#EXTINF:", &ptr)) {
848 duration = atof(ptr) * AV_TIME_BASE;
849 } else if (av_strstart(line, "#EXT-X-BYTERANGE:", &ptr)) {
850 seg_size = strtoll(ptr, NULL, 10);
851 ptr = strchr(ptr, '@');
853 seg_offset = strtoll(ptr+1, NULL, 10);
854 } else if (av_strstart(line, "#", NULL)) {
856 } else if (line[0]) {
858 if (!new_variant(c, &variant_info, line, url)) {
859 ret = AVERROR(ENOMEM);
867 if (!new_variant(c, 0, url, NULL)) {
868 ret = AVERROR(ENOMEM);
871 pls = c->playlists[c->n_playlists - 1];
873 seg = av_malloc(sizeof(struct segment));
875 ret = AVERROR(ENOMEM);
878 seg->duration = duration;
879 seg->key_type = key_type;
881 memcpy(seg->iv, iv, sizeof(iv));
883 int seq = pls->start_seq_no + pls->n_segments;
884 memset(seg->iv, 0, sizeof(seg->iv));
885 AV_WB32(seg->iv + 12, seq);
888 if (key_type != KEY_NONE) {
889 ff_make_absolute_url(tmp_str, sizeof(tmp_str), url, key);
890 seg->key = av_strdup(tmp_str);
893 ret = AVERROR(ENOMEM);
900 ff_make_absolute_url(tmp_str, sizeof(tmp_str), url, line);
901 seg->url = av_strdup(tmp_str);
905 ret = AVERROR(ENOMEM);
909 dynarray_add(&pls->segments, &pls->n_segments, seg);
912 seg->size = seg_size;
914 seg->url_offset = seg_offset;
915 seg_offset += seg_size;
922 seg->init_section = cur_init_section;
927 pls->last_load_time = av_gettime_relative();
932 ff_format_io_close(c->ctx, &in);
936 static struct segment *current_segment(struct playlist *pls)
938 return pls->segments[pls->cur_seq_no - pls->start_seq_no];
941 static struct segment *next_segment(struct playlist *pls)
943 int n = pls->cur_seq_no - pls->start_seq_no + 1;
944 if (n >= pls->n_segments)
946 return pls->segments[n];
949 enum ReadFromURLMode {
954 static int read_from_url(struct playlist *pls, struct segment *seg,
955 uint8_t *buf, int buf_size,
956 enum ReadFromURLMode mode)
960 /* limit read if the segment was only a part of a file */
962 buf_size = FFMIN(buf_size, seg->size - pls->cur_seg_offset);
964 if (mode == READ_COMPLETE) {
965 ret = avio_read(pls->input, buf, buf_size);
967 av_log(NULL, AV_LOG_ERROR, "Could not read complete segment.\n");
969 ret = avio_read(pls->input, buf, buf_size);
972 pls->cur_seg_offset += ret;
977 /* Parse the raw ID3 data and pass contents to caller */
978 static void parse_id3(AVFormatContext *s, AVIOContext *pb,
979 AVDictionary **metadata, int64_t *dts,
980 ID3v2ExtraMetaAPIC **apic, ID3v2ExtraMeta **extra_meta)
982 static const char id3_priv_owner_ts[] = "com.apple.streaming.transportStreamTimestamp";
983 ID3v2ExtraMeta *meta;
985 ff_id3v2_read_dict(pb, metadata, ID3v2_DEFAULT_MAGIC, extra_meta);
986 for (meta = *extra_meta; meta; meta = meta->next) {
987 if (!strcmp(meta->tag, "PRIV")) {
988 ID3v2ExtraMetaPRIV *priv = meta->data;
989 if (priv->datasize == 8 && !strcmp(priv->owner, id3_priv_owner_ts)) {
990 /* 33-bit MPEG timestamp */
991 int64_t ts = AV_RB64(priv->data);
992 av_log(s, AV_LOG_DEBUG, "HLS ID3 audio timestamp %"PRId64"\n", ts);
993 if ((ts & ~((1ULL << 33) - 1)) == 0)
996 av_log(s, AV_LOG_ERROR, "Invalid HLS ID3 audio timestamp %"PRId64"\n", ts);
998 } else if (!strcmp(meta->tag, "APIC") && apic)
1003 /* Check if the ID3 metadata contents have changed */
1004 static int id3_has_changed_values(struct playlist *pls, AVDictionary *metadata,
1005 ID3v2ExtraMetaAPIC *apic)
1007 AVDictionaryEntry *entry = NULL;
1008 AVDictionaryEntry *oldentry;
1009 /* check that no keys have changed values */
1010 while ((entry = av_dict_get(metadata, "", entry, AV_DICT_IGNORE_SUFFIX))) {
1011 oldentry = av_dict_get(pls->id3_initial, entry->key, NULL, AV_DICT_MATCH_CASE);
1012 if (!oldentry || strcmp(oldentry->value, entry->value) != 0)
1016 /* check if apic appeared */
1017 if (apic && (pls->ctx->nb_streams != 2 || !pls->ctx->streams[1]->attached_pic.data))
1021 int size = pls->ctx->streams[1]->attached_pic.size;
1022 if (size != apic->buf->size - AV_INPUT_BUFFER_PADDING_SIZE)
1025 if (memcmp(apic->buf->data, pls->ctx->streams[1]->attached_pic.data, size) != 0)
1032 /* Parse ID3 data and handle the found data */
1033 static void handle_id3(AVIOContext *pb, struct playlist *pls)
1035 AVDictionary *metadata = NULL;
1036 ID3v2ExtraMetaAPIC *apic = NULL;
1037 ID3v2ExtraMeta *extra_meta = NULL;
1038 int64_t timestamp = AV_NOPTS_VALUE;
1040 parse_id3(pls->ctx, pb, &metadata, ×tamp, &apic, &extra_meta);
1042 if (timestamp != AV_NOPTS_VALUE) {
1043 pls->id3_mpegts_timestamp = timestamp;
1044 pls->id3_offset = 0;
1047 if (!pls->id3_found) {
1048 /* initial ID3 tags */
1049 av_assert0(!pls->id3_deferred_extra);
1052 /* get picture attachment and set text metadata */
1053 if (pls->ctx->nb_streams)
1054 ff_id3v2_parse_apic(pls->ctx, &extra_meta);
1056 /* demuxer not yet opened, defer picture attachment */
1057 pls->id3_deferred_extra = extra_meta;
1059 av_dict_copy(&pls->ctx->metadata, metadata, 0);
1060 pls->id3_initial = metadata;
1063 if (!pls->id3_changed && id3_has_changed_values(pls, metadata, apic)) {
1064 avpriv_report_missing_feature(pls->ctx, "Changing ID3 metadata in HLS audio elementary stream");
1065 pls->id3_changed = 1;
1067 av_dict_free(&metadata);
1070 if (!pls->id3_deferred_extra)
1071 ff_id3v2_free_extra_meta(&extra_meta);
1074 static void intercept_id3(struct playlist *pls, uint8_t *buf,
1075 int buf_size, int *len)
1077 /* intercept id3 tags, we do not want to pass them to the raw
1078 * demuxer on all segment switches */
1080 int id3_buf_pos = 0;
1082 struct segment *seg = current_segment(pls);
1084 /* gather all the id3 tags */
1086 /* see if we can retrieve enough data for ID3 header */
1087 if (*len < ID3v2_HEADER_SIZE && buf_size >= ID3v2_HEADER_SIZE) {
1088 bytes = read_from_url(pls, seg, buf + *len, ID3v2_HEADER_SIZE - *len, READ_COMPLETE);
1091 if (bytes == ID3v2_HEADER_SIZE - *len)
1092 /* no EOF yet, so fill the caller buffer again after
1093 * we have stripped the ID3 tags */
1098 } else if (*len <= 0) {
1105 if (*len < ID3v2_HEADER_SIZE)
1108 if (ff_id3v2_match(buf, ID3v2_DEFAULT_MAGIC)) {
1109 int64_t maxsize = seg->size >= 0 ? seg->size : 1024*1024;
1110 int taglen = ff_id3v2_tag_len(buf);
1111 int tag_got_bytes = FFMIN(taglen, *len);
1112 int remaining = taglen - tag_got_bytes;
1114 if (taglen > maxsize) {
1115 av_log(pls->ctx, AV_LOG_ERROR, "Too large HLS ID3 tag (%d > %"PRId64" bytes)\n",
1121 * Copy the id3 tag to our temporary id3 buffer.
1122 * We could read a small id3 tag directly without memcpy, but
1123 * we would still need to copy the large tags, and handling
1124 * both of those cases together with the possibility for multiple
1125 * tags would make the handling a bit complex.
1127 pls->id3_buf = av_fast_realloc(pls->id3_buf, &pls->id3_buf_size, id3_buf_pos + taglen);
1130 memcpy(pls->id3_buf + id3_buf_pos, buf, tag_got_bytes);
1131 id3_buf_pos += tag_got_bytes;
1133 /* strip the intercepted bytes */
1134 *len -= tag_got_bytes;
1135 memmove(buf, buf + tag_got_bytes, *len);
1136 av_log(pls->ctx, AV_LOG_DEBUG, "Stripped %d HLS ID3 bytes\n", tag_got_bytes);
1138 if (remaining > 0) {
1139 /* read the rest of the tag in */
1140 if (read_from_url(pls, seg, pls->id3_buf + id3_buf_pos, remaining, READ_COMPLETE) != remaining)
1142 id3_buf_pos += remaining;
1143 av_log(pls->ctx, AV_LOG_DEBUG, "Stripped additional %d HLS ID3 bytes\n", remaining);
1147 /* no more ID3 tags */
1152 /* re-fill buffer for the caller unless EOF */
1153 if (*len >= 0 && (fill_buf || *len == 0)) {
1154 bytes = read_from_url(pls, seg, buf + *len, buf_size - *len, READ_NORMAL);
1156 /* ignore error if we already had some data */
1164 /* Now parse all the ID3 tags */
1165 AVIOContext id3ioctx;
1166 ffio_init_context(&id3ioctx, pls->id3_buf, id3_buf_pos, 0, NULL, NULL, NULL, NULL);
1167 handle_id3(&id3ioctx, pls);
1170 if (pls->is_id3_timestamped == -1)
1171 pls->is_id3_timestamped = (pls->id3_mpegts_timestamp != AV_NOPTS_VALUE);
1174 static int open_input(HLSContext *c, struct playlist *pls, struct segment *seg, AVIOContext **in)
1176 AVDictionary *opts = NULL;
1180 // broker prior HTTP options that should be consistent across requests
1181 av_dict_set(&opts, "user_agent", c->user_agent, 0);
1182 av_dict_set(&opts, "cookies", c->cookies, 0);
1183 av_dict_set(&opts, "headers", c->headers, 0);
1184 av_dict_set(&opts, "http_proxy", c->http_proxy, 0);
1185 av_dict_set(&opts, "seekable", "0", 0);
1187 if (c->http_persistent)
1188 av_dict_set(&opts, "multiple_requests", "1", 0);
1190 if (seg->size >= 0) {
1191 /* try to restrict the HTTP request to the part we want
1192 * (if this is in fact a HTTP request) */
1193 av_dict_set_int(&opts, "offset", seg->url_offset, 0);
1194 av_dict_set_int(&opts, "end_offset", seg->url_offset + seg->size, 0);
1197 av_log(pls->parent, AV_LOG_VERBOSE, "HLS request for url '%s', offset %"PRId64", playlist %d\n",
1198 seg->url, seg->url_offset, pls->index);
1200 if (seg->key_type == KEY_NONE) {
1201 ret = open_url(pls->parent, in, seg->url, c->avio_opts, opts, &is_http);
1202 } else if (seg->key_type == KEY_AES_128) {
1203 AVDictionary *opts2 = NULL;
1204 char iv[33], key[33], url[MAX_URL_SIZE];
1205 if (strcmp(seg->key, pls->key_url)) {
1206 AVIOContext *pb = NULL;
1207 if (open_url(pls->parent, &pb, seg->key, c->avio_opts, opts, NULL) == 0) {
1208 ret = avio_read(pb, pls->key, sizeof(pls->key));
1209 if (ret != sizeof(pls->key)) {
1210 av_log(NULL, AV_LOG_ERROR, "Unable to read key file %s\n",
1213 ff_format_io_close(pls->parent, &pb);
1215 av_log(NULL, AV_LOG_ERROR, "Unable to open key file %s\n",
1218 av_strlcpy(pls->key_url, seg->key, sizeof(pls->key_url));
1220 ff_data_to_hex(iv, seg->iv, sizeof(seg->iv), 0);
1221 ff_data_to_hex(key, pls->key, sizeof(pls->key), 0);
1222 iv[32] = key[32] = '\0';
1223 if (strstr(seg->url, "://"))
1224 snprintf(url, sizeof(url), "crypto+%s", seg->url);
1226 snprintf(url, sizeof(url), "crypto:%s", seg->url);
1228 av_dict_copy(&opts2, c->avio_opts, 0);
1229 av_dict_set(&opts2, "key", key, 0);
1230 av_dict_set(&opts2, "iv", iv, 0);
1232 ret = open_url(pls->parent, in, url, opts2, opts, &is_http);
1234 av_dict_free(&opts2);
1240 } else if (seg->key_type == KEY_SAMPLE_AES) {
1241 av_log(pls->parent, AV_LOG_ERROR,
1242 "SAMPLE-AES encryption is not supported yet\n");
1243 ret = AVERROR_PATCHWELCOME;
1246 ret = AVERROR(ENOSYS);
1248 /* Seek to the requested position. If this was a HTTP request, the offset
1249 * should already be where want it to, but this allows e.g. local testing
1250 * without a HTTP server.
1252 * This is not done for HTTP at all as avio_seek() does internal bookkeeping
1253 * of file offset which is out-of-sync with the actual offset when "offset"
1254 * AVOption is used with http protocol, causing the seek to not be a no-op
1255 * as would be expected. Wrong offset received from the server will not be
1256 * noticed without the call, though.
1258 if (ret == 0 && !is_http && seg->key_type == KEY_NONE && seg->url_offset) {
1259 int64_t seekret = avio_seek(*in, seg->url_offset, SEEK_SET);
1261 av_log(pls->parent, AV_LOG_ERROR, "Unable to seek to offset %"PRId64" of HLS segment '%s'\n", seg->url_offset, seg->url);
1263 ff_format_io_close(pls->parent, in);
1268 av_dict_free(&opts);
1269 pls->cur_seg_offset = 0;
1273 static int update_init_section(struct playlist *pls, struct segment *seg)
1275 static const int max_init_section_size = 1024*1024;
1276 HLSContext *c = pls->parent->priv_data;
1281 if (seg->init_section == pls->cur_init_section)
1284 pls->cur_init_section = NULL;
1286 if (!seg->init_section)
1289 ret = open_input(c, pls, seg->init_section, &pls->input);
1291 av_log(pls->parent, AV_LOG_WARNING,
1292 "Failed to open an initialization section in playlist %d\n",
1297 if (seg->init_section->size >= 0)
1298 sec_size = seg->init_section->size;
1299 else if ((urlsize = avio_size(pls->input)) >= 0)
1302 sec_size = max_init_section_size;
1304 av_log(pls->parent, AV_LOG_DEBUG,
1305 "Downloading an initialization section of size %"PRId64"\n",
1308 sec_size = FFMIN(sec_size, max_init_section_size);
1310 av_fast_malloc(&pls->init_sec_buf, &pls->init_sec_buf_size, sec_size);
1312 ret = read_from_url(pls, seg->init_section, pls->init_sec_buf,
1313 pls->init_sec_buf_size, READ_COMPLETE);
1314 ff_format_io_close(pls->parent, &pls->input);
1319 pls->cur_init_section = seg->init_section;
1320 pls->init_sec_data_len = ret;
1321 pls->init_sec_buf_read_offset = 0;
1323 /* spec says audio elementary streams do not have media initialization
1324 * sections, so there should be no ID3 timestamps */
1325 pls->is_id3_timestamped = 0;
1330 static int64_t default_reload_interval(struct playlist *pls)
1332 return pls->n_segments > 0 ?
1333 pls->segments[pls->n_segments - 1]->duration :
1334 pls->target_duration;
1337 static int playlist_needed(struct playlist *pls)
1339 AVFormatContext *s = pls->parent;
1341 int stream_needed = 0;
1344 /* If there is no context or streams yet, the playlist is needed */
1345 if (!pls->ctx || !pls->n_main_streams)
1348 /* check if any of the streams in the playlist are needed */
1349 for (i = 0; i < pls->n_main_streams; i++) {
1350 if (pls->main_streams[i]->discard < AVDISCARD_ALL) {
1356 /* If all streams in the playlist were discarded, the playlist is not
1357 * needed (regardless of whether whole programs are discarded or not). */
1361 /* Otherwise, check if all the programs (variants) this playlist is in are
1362 * discarded. Since all streams in the playlist are part of the same programs
1363 * we can just check the programs of the first stream. */
1365 first_st = pls->main_streams[0]->index;
1367 for (i = 0; i < s->nb_programs; i++) {
1368 AVProgram *program = s->programs[i];
1369 if (program->discard < AVDISCARD_ALL) {
1370 for (j = 0; j < program->nb_stream_indexes; j++) {
1371 if (program->stream_index[j] == first_st) {
1372 /* playlist is in an undiscarded program */
1379 /* some streams were not discarded but all the programs were */
1383 static int read_data(void *opaque, uint8_t *buf, int buf_size)
1385 struct playlist *v = opaque;
1386 HLSContext *c = v->parent->priv_data;
1388 int just_opened = 0;
1389 int reload_count = 0;
1390 struct segment *seg;
1396 if (!v->input || (c->http_persistent && v->input_read_done)) {
1397 int64_t reload_interval;
1399 /* Check that the playlist is still needed before opening a new
1401 v->needed = playlist_needed(v);
1404 av_log(v->parent, AV_LOG_INFO, "No longer receiving playlist %d\n",
1409 /* If this is a live stream and the reload interval has elapsed since
1410 * the last playlist reload, reload the playlists now. */
1411 reload_interval = default_reload_interval(v);
1415 if (reload_count > c->max_reload)
1418 av_gettime_relative() - v->last_load_time >= reload_interval) {
1419 if ((ret = parse_playlist(c, v->url, v, NULL)) < 0) {
1420 av_log(v->parent, AV_LOG_WARNING, "Failed to reload playlist %d\n",
1424 /* If we need to reload the playlist again below (if
1425 * there's still no more segments), switch to a reload
1426 * interval of half the target duration. */
1427 reload_interval = v->target_duration / 2;
1429 if (v->cur_seq_no < v->start_seq_no) {
1430 av_log(NULL, AV_LOG_WARNING,
1431 "skipping %d segments ahead, expired from playlists\n",
1432 v->start_seq_no - v->cur_seq_no);
1433 v->cur_seq_no = v->start_seq_no;
1435 if (v->cur_seq_no >= v->start_seq_no + v->n_segments) {
1438 while (av_gettime_relative() - v->last_load_time < reload_interval) {
1439 if (ff_check_interrupt(c->interrupt_callback))
1440 return AVERROR_EXIT;
1441 av_usleep(100*1000);
1443 /* Enough time has elapsed since the last reload */
1447 v->input_read_done = 0;
1448 seg = current_segment(v);
1450 /* load/update Media Initialization Section, if any */
1451 ret = update_init_section(v, seg);
1455 if (c->http_multiple == 1 && v->input_next_requested) {
1456 FFSWAP(AVIOContext *, v->input, v->input_next);
1457 v->input_next_requested = 0;
1460 ret = open_input(c, v, seg, &v->input);
1463 if (ff_check_interrupt(c->interrupt_callback))
1464 return AVERROR_EXIT;
1465 av_log(v->parent, AV_LOG_WARNING, "Failed to open segment %d of playlist %d\n",
1474 if (c->http_multiple == -1) {
1475 uint8_t *http_version_opt = NULL;
1476 int r = av_opt_get(v->input, "http_version", AV_OPT_SEARCH_CHILDREN, &http_version_opt);
1478 c->http_multiple = strncmp((const char *)http_version_opt, "1.1", 3) == 0;
1479 av_freep(&http_version_opt);
1483 seg = next_segment(v);
1484 if (c->http_multiple == 1 && !v->input_next_requested &&
1485 seg && seg->key_type == KEY_NONE && av_strstart(seg->url, "http", NULL)) {
1486 ret = open_input(c, v, seg, &v->input_next);
1488 if (ff_check_interrupt(c->interrupt_callback))
1489 return AVERROR_EXIT;
1490 av_log(v->parent, AV_LOG_WARNING, "Failed to open segment %d of playlist %d\n",
1494 v->input_next_requested = 1;
1498 if (v->init_sec_buf_read_offset < v->init_sec_data_len) {
1499 /* Push init section out first before first actual segment */
1500 int copy_size = FFMIN(v->init_sec_data_len - v->init_sec_buf_read_offset, buf_size);
1501 memcpy(buf, v->init_sec_buf, copy_size);
1502 v->init_sec_buf_read_offset += copy_size;
1506 seg = current_segment(v);
1507 ret = read_from_url(v, seg, buf, buf_size, READ_NORMAL);
1509 if (just_opened && v->is_id3_timestamped != 0) {
1510 /* Intercept ID3 tags here, elementary audio streams are required
1511 * to convey timestamps using them in the beginning of each segment. */
1512 intercept_id3(v, buf, buf_size, &ret);
1517 if (c->http_persistent &&
1518 seg->key_type == KEY_NONE && av_strstart(seg->url, "http", NULL)) {
1519 v->input_read_done = 1;
1521 ff_format_io_close(v->parent, &v->input);
1525 c->cur_seq_no = v->cur_seq_no;
1530 static void add_renditions_to_variant(HLSContext *c, struct variant *var,
1531 enum AVMediaType type, const char *group_id)
1535 for (i = 0; i < c->n_renditions; i++) {
1536 struct rendition *rend = c->renditions[i];
1538 if (rend->type == type && !strcmp(rend->group_id, group_id)) {
1541 /* rendition is an external playlist
1542 * => add the playlist to the variant */
1543 dynarray_add(&var->playlists, &var->n_playlists, rend->playlist);
1545 /* rendition is part of the variant main Media Playlist
1546 * => add the rendition to the main Media Playlist */
1547 dynarray_add(&var->playlists[0]->renditions,
1548 &var->playlists[0]->n_renditions,
1554 static void add_metadata_from_renditions(AVFormatContext *s, struct playlist *pls,
1555 enum AVMediaType type)
1560 for (i = 0; i < pls->n_main_streams; i++) {
1561 AVStream *st = pls->main_streams[i];
1563 if (st->codecpar->codec_type != type)
1566 for (; rend_idx < pls->n_renditions; rend_idx++) {
1567 struct rendition *rend = pls->renditions[rend_idx];
1569 if (rend->type != type)
1572 if (rend->language[0])
1573 av_dict_set(&st->metadata, "language", rend->language, 0);
1575 av_dict_set(&st->metadata, "comment", rend->name, 0);
1577 st->disposition |= rend->disposition;
1579 if (rend_idx >=pls->n_renditions)
1584 /* if timestamp was in valid range: returns 1 and sets seq_no
1585 * if not: returns 0 and sets seq_no to closest segment */
1586 static int find_timestamp_in_playlist(HLSContext *c, struct playlist *pls,
1587 int64_t timestamp, int *seq_no)
1590 int64_t pos = c->first_timestamp == AV_NOPTS_VALUE ?
1591 0 : c->first_timestamp;
1593 if (timestamp < pos) {
1594 *seq_no = pls->start_seq_no;
1598 for (i = 0; i < pls->n_segments; i++) {
1599 int64_t diff = pos + pls->segments[i]->duration - timestamp;
1601 *seq_no = pls->start_seq_no + i;
1604 pos += pls->segments[i]->duration;
1607 *seq_no = pls->start_seq_no + pls->n_segments - 1;
1612 static int select_cur_seq_no(HLSContext *c, struct playlist *pls)
1616 if (!pls->finished && !c->first_packet &&
1617 av_gettime_relative() - pls->last_load_time >= default_reload_interval(pls))
1618 /* reload the playlist since it was suspended */
1619 parse_playlist(c, pls->url, pls, NULL);
1621 /* If playback is already in progress (we are just selecting a new
1622 * playlist) and this is a complete file, find the matching segment
1623 * by counting durations. */
1624 if (pls->finished && c->cur_timestamp != AV_NOPTS_VALUE) {
1625 find_timestamp_in_playlist(c, pls, c->cur_timestamp, &seq_no);
1629 if (!pls->finished) {
1630 if (!c->first_packet && /* we are doing a segment selection during playback */
1631 c->cur_seq_no >= pls->start_seq_no &&
1632 c->cur_seq_no < pls->start_seq_no + pls->n_segments)
1633 /* While spec 3.4.3 says that we cannot assume anything about the
1634 * content at the same sequence number on different playlists,
1635 * in practice this seems to work and doing it otherwise would
1636 * require us to download a segment to inspect its timestamps. */
1637 return c->cur_seq_no;
1639 /* If this is a live stream, start live_start_index segments from the
1641 if (c->live_start_index < 0)
1642 return pls->start_seq_no + FFMAX(pls->n_segments + c->live_start_index, 0);
1644 return pls->start_seq_no + FFMIN(c->live_start_index, pls->n_segments - 1);
1647 /* Otherwise just start on the first segment. */
1648 return pls->start_seq_no;
1651 static int save_avio_options(AVFormatContext *s)
1653 HLSContext *c = s->priv_data;
1654 static const char * const opts[] = {
1655 "headers", "http_proxy", "user_agent", "user-agent", "cookies", NULL };
1656 const char * const * opt = opts;
1661 if (av_opt_get(s->pb, *opt, AV_OPT_SEARCH_CHILDREN | AV_OPT_ALLOW_NULL, &buf) >= 0) {
1662 ret = av_dict_set(&c->avio_opts, *opt, buf,
1663 AV_DICT_DONT_STRDUP_VAL);
1673 static int nested_io_open(AVFormatContext *s, AVIOContext **pb, const char *url,
1674 int flags, AVDictionary **opts)
1676 av_log(s, AV_LOG_ERROR,
1677 "A HLS playlist item '%s' referred to an external file '%s'. "
1678 "Opening this file was forbidden for security reasons\n",
1680 return AVERROR(EPERM);
1683 static void add_stream_to_programs(AVFormatContext *s, struct playlist *pls, AVStream *stream)
1685 HLSContext *c = s->priv_data;
1689 for (i = 0; i < c->n_variants; i++) {
1690 struct variant *v = c->variants[i];
1692 for (j = 0; j < v->n_playlists; j++) {
1693 if (v->playlists[j] != pls)
1696 av_program_add_stream_index(s, i, stream->index);
1699 bandwidth = v->bandwidth;
1700 else if (bandwidth != v->bandwidth)
1701 bandwidth = -1; /* stream in multiple variants with different bandwidths */
1706 av_dict_set_int(&stream->metadata, "variant_bitrate", bandwidth, 0);
1709 static int set_stream_info_from_input_stream(AVStream *st, struct playlist *pls, AVStream *ist)
1713 err = avcodec_parameters_copy(st->codecpar, ist->codecpar);
1717 if (pls->is_id3_timestamped) /* custom timestamps via id3 */
1718 avpriv_set_pts_info(st, 33, 1, MPEG_TIME_BASE);
1720 avpriv_set_pts_info(st, ist->pts_wrap_bits, ist->time_base.num, ist->time_base.den);
1722 st->internal->need_context_update = 1;
1727 /* add new subdemuxer streams to our context, if any */
1728 static int update_streams_from_subdemuxer(AVFormatContext *s, struct playlist *pls)
1732 while (pls->n_main_streams < pls->ctx->nb_streams) {
1733 int ist_idx = pls->n_main_streams;
1734 AVStream *st = avformat_new_stream(s, NULL);
1735 AVStream *ist = pls->ctx->streams[ist_idx];
1738 return AVERROR(ENOMEM);
1740 st->id = pls->index;
1741 dynarray_add(&pls->main_streams, &pls->n_main_streams, st);
1743 add_stream_to_programs(s, pls, st);
1745 err = set_stream_info_from_input_stream(st, pls, ist);
1753 static void update_noheader_flag(AVFormatContext *s)
1755 HLSContext *c = s->priv_data;
1756 int flag_needed = 0;
1759 for (i = 0; i < c->n_playlists; i++) {
1760 struct playlist *pls = c->playlists[i];
1762 if (pls->has_noheader_flag) {
1769 s->ctx_flags |= AVFMTCTX_NOHEADER;
1771 s->ctx_flags &= ~AVFMTCTX_NOHEADER;
1774 static int hls_close(AVFormatContext *s)
1776 HLSContext *c = s->priv_data;
1778 free_playlist_list(c);
1779 free_variant_list(c);
1780 free_rendition_list(c);
1782 av_dict_free(&c->avio_opts);
1783 ff_format_io_close(c->ctx, &c->playlist_pb);
1788 static int hls_read_header(AVFormatContext *s)
1790 void *u = (s->flags & AVFMT_FLAG_CUSTOM_IO) ? NULL : s->pb;
1791 HLSContext *c = s->priv_data;
1793 int highest_cur_seq_no = 0;
1796 c->interrupt_callback = &s->interrupt_callback;
1797 c->strict_std_compliance = s->strict_std_compliance;
1799 c->first_packet = 1;
1800 c->first_timestamp = AV_NOPTS_VALUE;
1801 c->cur_timestamp = AV_NOPTS_VALUE;
1804 // get the previous user agent & set back to null if string size is zero
1805 update_options(&c->user_agent, "user_agent", u);
1807 // get the previous cookies & set back to null if string size is zero
1808 update_options(&c->cookies, "cookies", u);
1810 // get the previous headers & set back to null if string size is zero
1811 update_options(&c->headers, "headers", u);
1813 // get the previous http proxt & set back to null if string size is zero
1814 update_options(&c->http_proxy, "http_proxy", u);
1817 if ((ret = parse_playlist(c, s->filename, NULL, s->pb)) < 0)
1820 if ((ret = save_avio_options(s)) < 0)
1823 /* Some HLS servers don't like being sent the range header */
1824 av_dict_set(&c->avio_opts, "seekable", "0", 0);
1826 if (c->n_variants == 0) {
1827 av_log(NULL, AV_LOG_WARNING, "Empty playlist\n");
1831 /* If the playlist only contained playlists (Master Playlist),
1832 * parse each individual playlist. */
1833 if (c->n_playlists > 1 || c->playlists[0]->n_segments == 0) {
1834 for (i = 0; i < c->n_playlists; i++) {
1835 struct playlist *pls = c->playlists[i];
1836 if ((ret = parse_playlist(c, pls->url, pls, NULL)) < 0)
1841 if (c->variants[0]->playlists[0]->n_segments == 0) {
1842 av_log(NULL, AV_LOG_WARNING, "Empty playlist\n");
1847 /* If this isn't a live stream, calculate the total duration of the
1849 if (c->variants[0]->playlists[0]->finished) {
1850 int64_t duration = 0;
1851 for (i = 0; i < c->variants[0]->playlists[0]->n_segments; i++)
1852 duration += c->variants[0]->playlists[0]->segments[i]->duration;
1853 s->duration = duration;
1856 /* Associate renditions with variants */
1857 for (i = 0; i < c->n_variants; i++) {
1858 struct variant *var = c->variants[i];
1860 if (var->audio_group[0])
1861 add_renditions_to_variant(c, var, AVMEDIA_TYPE_AUDIO, var->audio_group);
1862 if (var->video_group[0])
1863 add_renditions_to_variant(c, var, AVMEDIA_TYPE_VIDEO, var->video_group);
1864 if (var->subtitles_group[0])
1865 add_renditions_to_variant(c, var, AVMEDIA_TYPE_SUBTITLE, var->subtitles_group);
1868 /* Create a program for each variant */
1869 for (i = 0; i < c->n_variants; i++) {
1870 struct variant *v = c->variants[i];
1873 program = av_new_program(s, i);
1876 av_dict_set_int(&program->metadata, "variant_bitrate", v->bandwidth, 0);
1879 /* Select the starting segments */
1880 for (i = 0; i < c->n_playlists; i++) {
1881 struct playlist *pls = c->playlists[i];
1883 if (pls->n_segments == 0)
1886 pls->cur_seq_no = select_cur_seq_no(c, pls);
1887 highest_cur_seq_no = FFMAX(highest_cur_seq_no, pls->cur_seq_no);
1890 /* Open the demuxer for each playlist */
1891 for (i = 0; i < c->n_playlists; i++) {
1892 struct playlist *pls = c->playlists[i];
1893 AVInputFormat *in_fmt = NULL;
1895 if (!(pls->ctx = avformat_alloc_context())) {
1896 ret = AVERROR(ENOMEM);
1900 if (pls->n_segments == 0)
1908 * If this is a live stream and this playlist looks like it is one segment
1909 * behind, try to sync it up so that every substream starts at the same
1910 * time position (so e.g. avformat_find_stream_info() will see packets from
1911 * all active streams within the first few seconds). This is not very generic,
1912 * though, as the sequence numbers are technically independent.
1914 if (!pls->finished && pls->cur_seq_no == highest_cur_seq_no - 1 &&
1915 highest_cur_seq_no < pls->start_seq_no + pls->n_segments) {
1916 pls->cur_seq_no = highest_cur_seq_no;
1919 pls->read_buffer = av_malloc(INITIAL_BUFFER_SIZE);
1920 if (!pls->read_buffer){
1921 ret = AVERROR(ENOMEM);
1922 avformat_free_context(pls->ctx);
1926 ffio_init_context(&pls->pb, pls->read_buffer, INITIAL_BUFFER_SIZE, 0, pls,
1927 read_data, NULL, NULL);
1928 pls->pb.seekable = 0;
1929 ret = av_probe_input_buffer(&pls->pb, &in_fmt, pls->segments[0]->url,
1932 /* Free the ctx - it isn't initialized properly at this point,
1933 * so avformat_close_input shouldn't be called. If
1934 * avformat_open_input fails below, it frees and zeros the
1935 * context, so it doesn't need any special treatment like this. */
1936 av_log(s, AV_LOG_ERROR, "Error when loading first segment '%s'\n", pls->segments[0]->url);
1937 avformat_free_context(pls->ctx);
1941 pls->ctx->pb = &pls->pb;
1942 pls->ctx->io_open = nested_io_open;
1943 pls->ctx->flags |= s->flags & ~AVFMT_FLAG_CUSTOM_IO;
1945 if ((ret = ff_copy_whiteblacklists(pls->ctx, s)) < 0)
1948 ret = avformat_open_input(&pls->ctx, pls->segments[0]->url, in_fmt, NULL);
1952 if (pls->id3_deferred_extra && pls->ctx->nb_streams == 1) {
1953 ff_id3v2_parse_apic(pls->ctx, &pls->id3_deferred_extra);
1954 avformat_queue_attached_pictures(pls->ctx);
1955 ff_id3v2_free_extra_meta(&pls->id3_deferred_extra);
1956 pls->id3_deferred_extra = NULL;
1959 if (pls->is_id3_timestamped == -1)
1960 av_log(s, AV_LOG_WARNING, "No expected HTTP requests have been made\n");
1963 * For ID3 timestamped raw audio streams we need to detect the packet
1964 * durations to calculate timestamps in fill_timing_for_id3_timestamped_stream(),
1965 * but for other streams we can rely on our user calling avformat_find_stream_info()
1966 * on us if they want to.
1968 if (pls->is_id3_timestamped) {
1969 ret = avformat_find_stream_info(pls->ctx, NULL);
1974 pls->has_noheader_flag = !!(pls->ctx->ctx_flags & AVFMTCTX_NOHEADER);
1976 /* Create new AVStreams for each stream in this playlist */
1977 ret = update_streams_from_subdemuxer(s, pls);
1981 add_metadata_from_renditions(s, pls, AVMEDIA_TYPE_AUDIO);
1982 add_metadata_from_renditions(s, pls, AVMEDIA_TYPE_VIDEO);
1983 add_metadata_from_renditions(s, pls, AVMEDIA_TYPE_SUBTITLE);
1986 update_noheader_flag(s);
1994 static int recheck_discard_flags(AVFormatContext *s, int first)
1996 HLSContext *c = s->priv_data;
2000 /* Check if any new streams are needed */
2001 for (i = 0; i < c->n_playlists; i++) {
2002 struct playlist *pls = c->playlists[i];
2004 cur_needed = playlist_needed(c->playlists[i]);
2006 if (cur_needed && !pls->needed) {
2009 pls->cur_seq_no = select_cur_seq_no(c, pls);
2010 pls->pb.eof_reached = 0;
2011 if (c->cur_timestamp != AV_NOPTS_VALUE) {
2013 pls->seek_timestamp = c->cur_timestamp;
2014 pls->seek_flags = AVSEEK_FLAG_ANY;
2015 pls->seek_stream_index = -1;
2017 av_log(s, AV_LOG_INFO, "Now receiving playlist %d, segment %d\n", i, pls->cur_seq_no);
2018 } else if (first && !cur_needed && pls->needed) {
2020 ff_format_io_close(pls->parent, &pls->input);
2021 pls->input_read_done = 0;
2022 if (pls->input_next)
2023 ff_format_io_close(pls->parent, &pls->input_next);
2024 pls->input_next_requested = 0;
2027 av_log(s, AV_LOG_INFO, "No longer receiving playlist %d\n", i);
2033 static void fill_timing_for_id3_timestamped_stream(struct playlist *pls)
2035 if (pls->id3_offset >= 0) {
2036 pls->pkt.dts = pls->id3_mpegts_timestamp +
2037 av_rescale_q(pls->id3_offset,
2038 pls->ctx->streams[pls->pkt.stream_index]->time_base,
2040 if (pls->pkt.duration)
2041 pls->id3_offset += pls->pkt.duration;
2043 pls->id3_offset = -1;
2045 /* there have been packets with unknown duration
2046 * since the last id3 tag, should not normally happen */
2047 pls->pkt.dts = AV_NOPTS_VALUE;
2050 if (pls->pkt.duration)
2051 pls->pkt.duration = av_rescale_q(pls->pkt.duration,
2052 pls->ctx->streams[pls->pkt.stream_index]->time_base,
2055 pls->pkt.pts = AV_NOPTS_VALUE;
2058 static AVRational get_timebase(struct playlist *pls)
2060 if (pls->is_id3_timestamped)
2061 return MPEG_TIME_BASE_Q;
2063 return pls->ctx->streams[pls->pkt.stream_index]->time_base;
2066 static int compare_ts_with_wrapdetect(int64_t ts_a, struct playlist *pls_a,
2067 int64_t ts_b, struct playlist *pls_b)
2069 int64_t scaled_ts_a = av_rescale_q(ts_a, get_timebase(pls_a), MPEG_TIME_BASE_Q);
2070 int64_t scaled_ts_b = av_rescale_q(ts_b, get_timebase(pls_b), MPEG_TIME_BASE_Q);
2072 return av_compare_mod(scaled_ts_a, scaled_ts_b, 1LL << 33);
2075 static int hls_read_packet(AVFormatContext *s, AVPacket *pkt)
2077 HLSContext *c = s->priv_data;
2078 int ret, i, minplaylist = -1;
2080 recheck_discard_flags(s, c->first_packet);
2081 c->first_packet = 0;
2083 for (i = 0; i < c->n_playlists; i++) {
2084 struct playlist *pls = c->playlists[i];
2085 /* Make sure we've got one buffered packet from each open playlist
2087 if (pls->needed && !pls->pkt.data) {
2091 ret = av_read_frame(pls->ctx, &pls->pkt);
2093 if (!avio_feof(&pls->pb) && ret != AVERROR_EOF)
2095 reset_packet(&pls->pkt);
2098 /* stream_index check prevents matching picture attachments etc. */
2099 if (pls->is_id3_timestamped && pls->pkt.stream_index == 0) {
2100 /* audio elementary streams are id3 timestamped */
2101 fill_timing_for_id3_timestamped_stream(pls);
2104 if (c->first_timestamp == AV_NOPTS_VALUE &&
2105 pls->pkt.dts != AV_NOPTS_VALUE)
2106 c->first_timestamp = av_rescale_q(pls->pkt.dts,
2107 get_timebase(pls), AV_TIME_BASE_Q);
2110 if (pls->seek_timestamp == AV_NOPTS_VALUE)
2113 if (pls->seek_stream_index < 0 ||
2114 pls->seek_stream_index == pls->pkt.stream_index) {
2116 if (pls->pkt.dts == AV_NOPTS_VALUE) {
2117 pls->seek_timestamp = AV_NOPTS_VALUE;
2121 tb = get_timebase(pls);
2122 ts_diff = av_rescale_rnd(pls->pkt.dts, AV_TIME_BASE,
2123 tb.den, AV_ROUND_DOWN) -
2124 pls->seek_timestamp;
2125 if (ts_diff >= 0 && (pls->seek_flags & AVSEEK_FLAG_ANY ||
2126 pls->pkt.flags & AV_PKT_FLAG_KEY)) {
2127 pls->seek_timestamp = AV_NOPTS_VALUE;
2131 av_packet_unref(&pls->pkt);
2132 reset_packet(&pls->pkt);
2135 /* Check if this stream has the packet with the lowest dts */
2136 if (pls->pkt.data) {
2137 struct playlist *minpls = minplaylist < 0 ?
2138 NULL : c->playlists[minplaylist];
2139 if (minplaylist < 0) {
2142 int64_t dts = pls->pkt.dts;
2143 int64_t mindts = minpls->pkt.dts;
2145 if (dts == AV_NOPTS_VALUE ||
2146 (mindts != AV_NOPTS_VALUE && compare_ts_with_wrapdetect(dts, pls, mindts, minpls) < 0))
2152 /* If we got a packet, return it */
2153 if (minplaylist >= 0) {
2154 struct playlist *pls = c->playlists[minplaylist];
2158 ret = update_streams_from_subdemuxer(s, pls);
2160 av_packet_unref(&pls->pkt);
2161 reset_packet(&pls->pkt);
2165 /* check if noheader flag has been cleared by the subdemuxer */
2166 if (pls->has_noheader_flag && !(pls->ctx->ctx_flags & AVFMTCTX_NOHEADER)) {
2167 pls->has_noheader_flag = 0;
2168 update_noheader_flag(s);
2171 if (pls->pkt.stream_index >= pls->n_main_streams) {
2172 av_log(s, AV_LOG_ERROR, "stream index inconsistency: index %d, %d main streams, %d subdemuxer streams\n",
2173 pls->pkt.stream_index, pls->n_main_streams, pls->ctx->nb_streams);
2174 av_packet_unref(&pls->pkt);
2175 reset_packet(&pls->pkt);
2179 ist = pls->ctx->streams[pls->pkt.stream_index];
2180 st = pls->main_streams[pls->pkt.stream_index];
2183 pkt->stream_index = st->index;
2184 reset_packet(&c->playlists[minplaylist]->pkt);
2186 if (pkt->dts != AV_NOPTS_VALUE)
2187 c->cur_timestamp = av_rescale_q(pkt->dts,
2191 /* There may be more situations where this would be useful, but this at least
2192 * handles newly probed codecs properly (i.e. request_probe by mpegts). */
2193 if (ist->codecpar->codec_id != st->codecpar->codec_id) {
2194 ret = set_stream_info_from_input_stream(st, pls, ist);
2196 av_packet_unref(pkt);
2206 static int hls_read_seek(AVFormatContext *s, int stream_index,
2207 int64_t timestamp, int flags)
2209 HLSContext *c = s->priv_data;
2210 struct playlist *seek_pls = NULL;
2213 int stream_subdemuxer_index;
2214 int64_t first_timestamp, seek_timestamp, duration;
2216 if ((flags & AVSEEK_FLAG_BYTE) ||
2217 !(c->variants[0]->playlists[0]->finished || c->variants[0]->playlists[0]->type == PLS_TYPE_EVENT))
2218 return AVERROR(ENOSYS);
2220 first_timestamp = c->first_timestamp == AV_NOPTS_VALUE ?
2221 0 : c->first_timestamp;
2223 seek_timestamp = av_rescale_rnd(timestamp, AV_TIME_BASE,
2224 s->streams[stream_index]->time_base.den,
2225 flags & AVSEEK_FLAG_BACKWARD ?
2226 AV_ROUND_DOWN : AV_ROUND_UP);
2228 duration = s->duration == AV_NOPTS_VALUE ?
2231 if (0 < duration && duration < seek_timestamp - first_timestamp)
2232 return AVERROR(EIO);
2234 /* find the playlist with the specified stream */
2235 for (i = 0; i < c->n_playlists; i++) {
2236 struct playlist *pls = c->playlists[i];
2237 for (j = 0; j < pls->n_main_streams; j++) {
2238 if (pls->main_streams[j] == s->streams[stream_index]) {
2240 stream_subdemuxer_index = j;
2245 /* check if the timestamp is valid for the playlist with the
2246 * specified stream index */
2247 if (!seek_pls || !find_timestamp_in_playlist(c, seek_pls, seek_timestamp, &seq_no))
2248 return AVERROR(EIO);
2250 /* set segment now so we do not need to search again below */
2251 seek_pls->cur_seq_no = seq_no;
2252 seek_pls->seek_stream_index = stream_subdemuxer_index;
2254 for (i = 0; i < c->n_playlists; i++) {
2256 struct playlist *pls = c->playlists[i];
2258 ff_format_io_close(pls->parent, &pls->input);
2259 pls->input_read_done = 0;
2260 if (pls->input_next)
2261 ff_format_io_close(pls->parent, &pls->input_next);
2262 pls->input_next_requested = 0;
2263 av_packet_unref(&pls->pkt);
2264 reset_packet(&pls->pkt);
2265 pls->pb.eof_reached = 0;
2266 /* Clear any buffered data */
2267 pls->pb.buf_end = pls->pb.buf_ptr = pls->pb.buffer;
2268 /* Reset the pos, to let the mpegts demuxer know we've seeked. */
2270 /* Flush the packet queue of the subdemuxer. */
2271 ff_read_frame_flush(pls->ctx);
2273 pls->seek_timestamp = seek_timestamp;
2274 pls->seek_flags = flags;
2276 if (pls != seek_pls) {
2277 /* set closest segment seq_no for playlists not handled above */
2278 find_timestamp_in_playlist(c, pls, seek_timestamp, &pls->cur_seq_no);
2279 /* seek the playlist to the given position without taking
2280 * keyframes into account since this playlist does not have the
2281 * specified stream where we should look for the keyframes */
2282 pls->seek_stream_index = -1;
2283 pls->seek_flags |= AVSEEK_FLAG_ANY;
2287 c->cur_timestamp = seek_timestamp;
2292 static int hls_probe(AVProbeData *p)
2294 /* Require #EXTM3U at the start, and either one of the ones below
2295 * somewhere for a proper match. */
2296 if (strncmp(p->buf, "#EXTM3U", 7))
2299 if (strstr(p->buf, "#EXT-X-STREAM-INF:") ||
2300 strstr(p->buf, "#EXT-X-TARGETDURATION:") ||
2301 strstr(p->buf, "#EXT-X-MEDIA-SEQUENCE:"))
2302 return AVPROBE_SCORE_MAX;
2306 #define OFFSET(x) offsetof(HLSContext, x)
2307 #define FLAGS AV_OPT_FLAG_DECODING_PARAM
2308 static const AVOption hls_options[] = {
2309 {"live_start_index", "segment index to start live streams at (negative values are from the end)",
2310 OFFSET(live_start_index), AV_OPT_TYPE_INT, {.i64 = -3}, INT_MIN, INT_MAX, FLAGS},
2311 {"allowed_extensions", "List of file extensions that hls is allowed to access",
2312 OFFSET(allowed_extensions), AV_OPT_TYPE_STRING,
2313 {.str = "3gp,aac,avi,flac,mkv,m3u8,m4a,m4s,m4v,mpg,mov,mp2,mp3,mp4,mpeg,mpegts,ogg,ogv,oga,ts,vob,wav"},
2314 INT_MIN, INT_MAX, FLAGS},
2315 {"max_reload", "Maximum number of times a insufficient list is attempted to be reloaded",
2316 OFFSET(max_reload), AV_OPT_TYPE_INT, {.i64 = 1000}, 0, INT_MAX, FLAGS},
2317 {"http_persistent", "Use persistent HTTP connections",
2318 OFFSET(http_persistent), AV_OPT_TYPE_BOOL, {.i64 = 1}, 0, 1, FLAGS },
2319 {"http_multiple", "Use multiple HTTP connections for fetching segments",
2320 OFFSET(http_multiple), AV_OPT_TYPE_BOOL, {.i64 = -1}, -1, 1, FLAGS},
2324 static const AVClass hls_class = {
2325 .class_name = "hls,applehttp",
2326 .item_name = av_default_item_name,
2327 .option = hls_options,
2328 .version = LIBAVUTIL_VERSION_INT,
2331 AVInputFormat ff_hls_demuxer = {
2332 .name = "hls,applehttp",
2333 .long_name = NULL_IF_CONFIG_SMALL("Apple HTTP Live Streaming"),
2334 .priv_class = &hls_class,
2335 .priv_data_size = sizeof(HLSContext),
2336 .read_probe = hls_probe,
2337 .read_header = hls_read_header,
2338 .read_packet = hls_read_packet,
2339 .read_close = hls_close,
2340 .read_seek = hls_read_seek,