2 * Apple HTTP Live Streaming demuxer
3 * Copyright (c) 2010 Martin Storsjo
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
24 * Apple HTTP Live Streaming demuxer
25 * http://tools.ietf.org/html/draft-pantos-http-live-streaming
28 #include "libavutil/avstring.h"
29 #include "libavutil/intreadwrite.h"
30 #include "libavutil/mathematics.h"
31 #include "libavutil/opt.h"
32 #include "libavutil/dict.h"
33 #include "libavutil/time.h"
36 #include "avio_internal.h"
39 #define INITIAL_BUFFER_SIZE 32768
42 * An apple http stream consists of a playlist with media segment files,
43 * played sequentially. There may be several playlists with the same
44 * video content, in different bandwidth variants, that are played in
45 * parallel (preferably only one bandwidth variant at a time). In this case,
46 * the user supplied the url to a main playlist that only lists the variant
49 * If the main playlist doesn't point at any variants, we still create
50 * one anonymous toplevel variant for this, to maintain the structure.
60 char url[MAX_URL_SIZE];
61 char key[MAX_URL_SIZE];
62 enum KeyType key_type;
67 * Each variant has its own demuxer. If it currently is active,
68 * it has an open AVIOContext too, and potentially an AVPacket
69 * containing the next packet from this stream.
73 char url[MAX_URL_SIZE];
77 AVFormatContext *parent;
84 int64_t target_duration;
87 struct segment **segments;
88 int needed, cur_needed;
90 int64_t last_load_time;
92 char key_url[MAX_URL_SIZE];
96 typedef struct HLSContext {
98 struct variant **variants;
102 int64_t first_timestamp;
103 int64_t seek_timestamp;
105 AVIOInterruptCB *interrupt_callback;
106 AVDictionary *avio_opts;
109 static int read_chomp_line(AVIOContext *s, char *buf, int maxlen)
111 int len = ff_get_line(s, buf, maxlen);
112 while (len > 0 && av_isspace(buf[len - 1]))
117 static void free_segment_list(struct variant *var)
120 for (i = 0; i < var->n_segments; i++)
121 av_free(var->segments[i]);
122 av_freep(&var->segments);
126 static void free_variant_list(HLSContext *c)
129 for (i = 0; i < c->n_variants; i++) {
130 struct variant *var = c->variants[i];
131 free_segment_list(var);
132 av_packet_unref(&var->pkt);
133 av_free(var->pb.buffer);
135 ffurl_close(var->input);
138 avformat_close_input(&var->ctx);
142 av_freep(&c->variants);
147 * Used to reset a statically allocated AVPacket to a clean slate,
148 * containing no data.
150 static void reset_packet(AVPacket *pkt)
156 static struct variant *new_variant(HLSContext *c, int bandwidth,
157 const char *url, const char *base)
159 struct variant *var = av_mallocz(sizeof(struct variant));
162 reset_packet(&var->pkt);
163 var->bandwidth = bandwidth;
164 ff_make_absolute_url(var->url, sizeof(var->url), base, url);
165 dynarray_add(&c->variants, &c->n_variants, var);
169 struct variant_info {
173 static void handle_variant_args(struct variant_info *info, const char *key,
174 int key_len, char **dest, int *dest_len)
176 if (!strncmp(key, "BANDWIDTH=", key_len)) {
177 *dest = info->bandwidth;
178 *dest_len = sizeof(info->bandwidth);
183 char uri[MAX_URL_SIZE];
188 static void handle_key_args(struct key_info *info, const char *key,
189 int key_len, char **dest, int *dest_len)
191 if (!strncmp(key, "METHOD=", key_len)) {
192 *dest = info->method;
193 *dest_len = sizeof(info->method);
194 } else if (!strncmp(key, "URI=", key_len)) {
196 *dest_len = sizeof(info->uri);
197 } else if (!strncmp(key, "IV=", key_len)) {
199 *dest_len = sizeof(info->iv);
203 static int open_in(HLSContext *c, AVIOContext **in, const char *url)
205 AVDictionary *tmp = NULL;
208 av_dict_copy(&tmp, c->avio_opts, 0);
210 ret = avio_open2(in, url, AVIO_FLAG_READ, c->interrupt_callback, &tmp);
216 static int url_connect(struct variant *var, AVDictionary *opts)
218 AVDictionary *tmp = NULL;
221 av_dict_copy(&tmp, opts, 0);
223 if ((ret = av_opt_set_dict(var->input, &tmp)) < 0 ||
224 (ret = ffurl_connect(var->input, NULL)) < 0) {
225 ffurl_close(var->input);
233 static int open_url(HLSContext *c, URLContext **uc, const char *url)
235 AVDictionary *tmp = NULL;
238 av_dict_copy(&tmp, c->avio_opts, 0);
240 ret = ffurl_open(uc, url, AVIO_FLAG_READ, c->interrupt_callback, &tmp);
247 static int parse_playlist(HLSContext *c, const char *url,
248 struct variant *var, AVIOContext *in)
250 int ret = 0, is_segment = 0, is_variant = 0, bandwidth = 0;
251 int64_t duration = 0;
252 enum KeyType key_type = KEY_NONE;
255 char key[MAX_URL_SIZE] = "";
259 uint8_t *new_url = NULL;
262 ret = open_in(c, &in, url);
268 if (av_opt_get(in, "location", AV_OPT_SEARCH_CHILDREN, &new_url) >= 0)
271 read_chomp_line(in, line, sizeof(line));
272 if (strcmp(line, "#EXTM3U")) {
273 ret = AVERROR_INVALIDDATA;
278 free_segment_list(var);
281 while (!in->eof_reached) {
282 read_chomp_line(in, line, sizeof(line));
283 if (av_strstart(line, "#EXT-X-STREAM-INF:", &ptr)) {
284 struct variant_info info = {{0}};
286 ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_variant_args,
288 bandwidth = atoi(info.bandwidth);
289 } else if (av_strstart(line, "#EXT-X-KEY:", &ptr)) {
290 struct key_info info = {{0}};
291 ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_key_args,
295 if (!strcmp(info.method, "AES-128"))
296 key_type = KEY_AES_128;
297 if (!strncmp(info.iv, "0x", 2) || !strncmp(info.iv, "0X", 2)) {
298 ff_hex_to_data(iv, info.iv + 2);
301 av_strlcpy(key, info.uri, sizeof(key));
302 } else if (av_strstart(line, "#EXT-X-TARGETDURATION:", &ptr)) {
304 var = new_variant(c, 0, url, NULL);
306 ret = AVERROR(ENOMEM);
310 var->target_duration = atoi(ptr) * AV_TIME_BASE;
311 } else if (av_strstart(line, "#EXT-X-MEDIA-SEQUENCE:", &ptr)) {
313 var = new_variant(c, 0, url, NULL);
315 ret = AVERROR(ENOMEM);
319 var->start_seq_no = atoi(ptr);
320 } else if (av_strstart(line, "#EXT-X-ENDLIST", &ptr)) {
323 } else if (av_strstart(line, "#EXTINF:", &ptr)) {
325 duration = atof(ptr) * AV_TIME_BASE;
326 } else if (av_strstart(line, "#", NULL)) {
328 } else if (line[0]) {
330 if (!new_variant(c, bandwidth, line, url)) {
331 ret = AVERROR(ENOMEM);
340 var = new_variant(c, 0, url, NULL);
342 ret = AVERROR(ENOMEM);
346 seg = av_malloc(sizeof(struct segment));
348 ret = AVERROR(ENOMEM);
351 seg->duration = duration;
352 seg->key_type = key_type;
354 memcpy(seg->iv, iv, sizeof(iv));
356 int seq = var->start_seq_no + var->n_segments;
357 memset(seg->iv, 0, sizeof(seg->iv));
358 AV_WB32(seg->iv + 12, seq);
360 ff_make_absolute_url(seg->key, sizeof(seg->key), url, key);
361 ff_make_absolute_url(seg->url, sizeof(seg->url), url, line);
362 dynarray_add(&var->segments, &var->n_segments, seg);
368 var->last_load_time = av_gettime_relative();
377 static int open_input(struct variant *var)
379 struct segment *seg = var->segments[var->cur_seq_no - var->start_seq_no];
380 if (seg->key_type == KEY_NONE) {
381 return open_url(var->parent->priv_data, &var->input, seg->url);
382 } else if (seg->key_type == KEY_AES_128) {
383 HLSContext *c = var->parent->priv_data;
384 char iv[33], key[33], url[MAX_URL_SIZE];
386 if (strcmp(seg->key, var->key_url)) {
388 if (open_url(var->parent->priv_data, &uc, seg->key) == 0) {
389 if (ffurl_read_complete(uc, var->key, sizeof(var->key))
390 != sizeof(var->key)) {
391 av_log(NULL, AV_LOG_ERROR, "Unable to read key file %s\n",
396 av_log(NULL, AV_LOG_ERROR, "Unable to open key file %s\n",
399 av_strlcpy(var->key_url, seg->key, sizeof(var->key_url));
401 ff_data_to_hex(iv, seg->iv, sizeof(seg->iv), 0);
402 ff_data_to_hex(key, var->key, sizeof(var->key), 0);
403 iv[32] = key[32] = '\0';
404 if (strstr(seg->url, "://"))
405 snprintf(url, sizeof(url), "crypto+%s", seg->url);
407 snprintf(url, sizeof(url), "crypto:%s", seg->url);
408 if ((ret = ffurl_alloc(&var->input, url, AVIO_FLAG_READ,
409 &var->parent->interrupt_callback)) < 0)
411 av_opt_set(var->input->priv_data, "key", key, 0);
412 av_opt_set(var->input->priv_data, "iv", iv, 0);
414 return url_connect(var, c->avio_opts);
416 return AVERROR(ENOSYS);
419 static int read_data(void *opaque, uint8_t *buf, int buf_size)
421 struct variant *v = opaque;
422 HLSContext *c = v->parent->priv_data;
427 /* If this is a live stream and the reload interval has elapsed since
428 * the last playlist reload, reload the variant playlists now. */
429 int64_t reload_interval = v->n_segments > 0 ?
430 v->segments[v->n_segments - 1]->duration :
435 av_gettime_relative() - v->last_load_time >= reload_interval) {
436 if ((ret = parse_playlist(c, v->url, v, NULL)) < 0)
438 /* If we need to reload the playlist again below (if
439 * there's still no more segments), switch to a reload
440 * interval of half the target duration. */
441 reload_interval = v->target_duration / 2;
443 if (v->cur_seq_no < v->start_seq_no) {
444 av_log(NULL, AV_LOG_WARNING,
445 "skipping %d segments ahead, expired from playlists\n",
446 v->start_seq_no - v->cur_seq_no);
447 v->cur_seq_no = v->start_seq_no;
449 if (v->cur_seq_no >= v->start_seq_no + v->n_segments) {
452 while (av_gettime_relative() - v->last_load_time < reload_interval) {
453 if (ff_check_interrupt(c->interrupt_callback))
457 /* Enough time has elapsed since the last reload */
465 ret = ffurl_read(v->input, buf, buf_size);
468 ffurl_close(v->input);
472 c->end_of_segment = 1;
473 c->cur_seq_no = v->cur_seq_no;
475 if (v->ctx && v->ctx->nb_streams &&
476 v->parent->nb_streams >= v->stream_offset + v->ctx->nb_streams) {
478 for (i = v->stream_offset; i < v->stream_offset + v->ctx->nb_streams;
480 if (v->parent->streams[i]->discard < AVDISCARD_ALL)
485 av_log(v->parent, AV_LOG_INFO, "No longer receiving variant %d\n",
492 static int save_avio_options(AVFormatContext *s)
494 HLSContext *c = s->priv_data;
495 const char *opts[] = { "headers", "user_agent", NULL }, **opt = opts;
500 if (av_opt_get(s->pb, *opt, AV_OPT_SEARCH_CHILDREN, &buf) >= 0) {
501 ret = av_dict_set(&c->avio_opts, *opt, buf,
502 AV_DICT_DONT_STRDUP_VAL);
512 static int hls_read_header(AVFormatContext *s)
514 HLSContext *c = s->priv_data;
515 int ret = 0, i, j, stream_offset = 0;
517 c->interrupt_callback = &s->interrupt_callback;
519 if ((ret = parse_playlist(c, s->filename, NULL, s->pb)) < 0)
522 if ((ret = save_avio_options(s)) < 0)
525 if (c->n_variants == 0) {
526 av_log(NULL, AV_LOG_WARNING, "Empty playlist\n");
530 /* If the playlist only contained variants, parse each individual
531 * variant playlist. */
532 if (c->n_variants > 1 || c->variants[0]->n_segments == 0) {
533 for (i = 0; i < c->n_variants; i++) {
534 struct variant *v = c->variants[i];
535 if ((ret = parse_playlist(c, v->url, v, NULL)) < 0)
540 if (c->variants[0]->n_segments == 0) {
541 av_log(NULL, AV_LOG_WARNING, "Empty playlist\n");
546 /* If this isn't a live stream, calculate the total duration of the
548 if (c->variants[0]->finished) {
549 int64_t duration = 0;
550 for (i = 0; i < c->variants[0]->n_segments; i++)
551 duration += c->variants[0]->segments[i]->duration;
552 s->duration = duration;
555 /* Open the demuxer for each variant */
556 for (i = 0; i < c->n_variants; i++) {
557 struct variant *v = c->variants[i];
558 AVInputFormat *in_fmt = NULL;
559 char bitrate_str[20];
562 if (v->n_segments == 0)
565 if (!(v->ctx = avformat_alloc_context())) {
566 ret = AVERROR(ENOMEM);
574 /* If this is a live stream with more than 3 segments, start at the
575 * third last segment. */
576 v->cur_seq_no = v->start_seq_no;
577 if (!v->finished && v->n_segments > 3)
578 v->cur_seq_no = v->start_seq_no + v->n_segments - 3;
580 v->read_buffer = av_malloc(INITIAL_BUFFER_SIZE);
581 ffio_init_context(&v->pb, v->read_buffer, INITIAL_BUFFER_SIZE, 0, v,
582 read_data, NULL, NULL);
584 ret = av_probe_input_buffer(&v->pb, &in_fmt, v->segments[0]->url,
587 /* Free the ctx - it isn't initialized properly at this point,
588 * so avformat_close_input shouldn't be called. If
589 * avformat_open_input fails below, it frees and zeros the
590 * context, so it doesn't need any special treatment like this. */
591 avformat_free_context(v->ctx);
596 v->stream_offset = stream_offset;
597 ret = avformat_open_input(&v->ctx, v->segments[0]->url, in_fmt, NULL);
601 v->ctx->ctx_flags &= ~AVFMTCTX_NOHEADER;
602 ret = avformat_find_stream_info(v->ctx, NULL);
605 snprintf(bitrate_str, sizeof(bitrate_str), "%d", v->bandwidth);
607 program = av_new_program(s, i);
610 av_dict_set(&program->metadata, "variant_bitrate", bitrate_str, 0);
612 /* Create new AVStreams for each stream in this variant */
613 for (j = 0; j < v->ctx->nb_streams; j++) {
614 AVStream *st = avformat_new_stream(s, NULL);
615 AVStream *ist = v->ctx->streams[j];
617 ret = AVERROR(ENOMEM);
620 ff_program_add_stream_index(s, i, stream_offset + j);
622 avpriv_set_pts_info(st, ist->pts_wrap_bits, ist->time_base.num, ist->time_base.den);
623 avcodec_copy_context(st->codec, v->ctx->streams[j]->codec);
625 av_dict_set(&st->metadata, "variant_bitrate", bitrate_str,
628 stream_offset += v->ctx->nb_streams;
632 c->first_timestamp = AV_NOPTS_VALUE;
633 c->seek_timestamp = AV_NOPTS_VALUE;
637 free_variant_list(c);
641 static int recheck_discard_flags(AVFormatContext *s, int first)
643 HLSContext *c = s->priv_data;
646 /* Check if any new streams are needed */
647 for (i = 0; i < c->n_variants; i++)
648 c->variants[i]->cur_needed = 0;;
650 for (i = 0; i < s->nb_streams; i++) {
651 AVStream *st = s->streams[i];
652 struct variant *var = c->variants[s->streams[i]->id];
653 if (st->discard < AVDISCARD_ALL)
656 for (i = 0; i < c->n_variants; i++) {
657 struct variant *v = c->variants[i];
658 if (v->cur_needed && !v->needed) {
661 v->cur_seq_no = c->cur_seq_no;
662 v->pb.eof_reached = 0;
663 av_log(s, AV_LOG_INFO, "Now receiving variant %d\n", i);
664 } else if (first && !v->cur_needed && v->needed) {
666 ffurl_close(v->input);
670 av_log(s, AV_LOG_INFO, "No longer receiving variant %d\n", i);
676 static int hls_read_packet(AVFormatContext *s, AVPacket *pkt)
678 HLSContext *c = s->priv_data;
679 int ret, i, minvariant = -1;
681 if (c->first_packet) {
682 recheck_discard_flags(s, 1);
687 c->end_of_segment = 0;
688 for (i = 0; i < c->n_variants; i++) {
689 struct variant *var = c->variants[i];
690 /* Make sure we've got one buffered packet from each open variant
692 if (var->needed && !var->pkt.data) {
696 ret = av_read_frame(var->ctx, &var->pkt);
698 if (!var->pb.eof_reached)
700 reset_packet(&var->pkt);
703 if (c->first_timestamp == AV_NOPTS_VALUE &&
704 var->pkt.dts != AV_NOPTS_VALUE)
705 c->first_timestamp = av_rescale_q(var->pkt.dts,
706 var->ctx->streams[var->pkt.stream_index]->time_base,
710 if (c->seek_timestamp == AV_NOPTS_VALUE)
713 if (var->pkt.dts == AV_NOPTS_VALUE) {
714 c->seek_timestamp = AV_NOPTS_VALUE;
718 st = var->ctx->streams[var->pkt.stream_index];
719 ts_diff = av_rescale_rnd(var->pkt.dts, AV_TIME_BASE,
720 st->time_base.den, AV_ROUND_DOWN) -
722 if (ts_diff >= 0 && (c->seek_flags & AVSEEK_FLAG_ANY ||
723 var->pkt.flags & AV_PKT_FLAG_KEY)) {
724 c->seek_timestamp = AV_NOPTS_VALUE;
727 av_packet_unref(&var->pkt);
728 reset_packet(&var->pkt);
731 /* Check if this stream still is on an earlier segment number, or
732 * has the packet with the lowest dts */
734 struct variant *minvar = minvariant < 0 ?
735 NULL : c->variants[minvariant];
736 if (minvariant < 0 || var->cur_seq_no < minvar->cur_seq_no) {
738 } else if (var->cur_seq_no == minvar->cur_seq_no) {
739 int64_t dts = var->pkt.dts;
740 int64_t mindts = minvar->pkt.dts;
741 AVStream *st = var->ctx->streams[var->pkt.stream_index];
742 AVStream *minst = minvar->ctx->streams[minvar->pkt.stream_index];
744 if (dts == AV_NOPTS_VALUE) {
746 } else if (mindts != AV_NOPTS_VALUE) {
747 if (st->start_time != AV_NOPTS_VALUE)
748 dts -= st->start_time;
749 if (minst->start_time != AV_NOPTS_VALUE)
750 mindts -= minst->start_time;
752 if (av_compare_ts(dts, st->time_base,
753 mindts, minst->time_base) < 0)
759 if (c->end_of_segment) {
760 if (recheck_discard_flags(s, 0))
763 /* If we got a packet, return it */
764 if (minvariant >= 0) {
765 *pkt = c->variants[minvariant]->pkt;
766 pkt->stream_index += c->variants[minvariant]->stream_offset;
767 reset_packet(&c->variants[minvariant]->pkt);
773 static int hls_close(AVFormatContext *s)
775 HLSContext *c = s->priv_data;
777 free_variant_list(c);
779 av_dict_free(&c->avio_opts);
784 static int hls_read_seek(AVFormatContext *s, int stream_index,
785 int64_t timestamp, int flags)
787 HLSContext *c = s->priv_data;
790 if ((flags & AVSEEK_FLAG_BYTE) || !c->variants[0]->finished)
791 return AVERROR(ENOSYS);
793 c->seek_flags = flags;
794 c->seek_timestamp = stream_index < 0 ? timestamp :
795 av_rescale_rnd(timestamp, AV_TIME_BASE,
796 s->streams[stream_index]->time_base.den,
797 flags & AVSEEK_FLAG_BACKWARD ?
798 AV_ROUND_DOWN : AV_ROUND_UP);
799 timestamp = av_rescale_rnd(timestamp, AV_TIME_BASE, stream_index >= 0 ?
800 s->streams[stream_index]->time_base.den :
801 AV_TIME_BASE, flags & AVSEEK_FLAG_BACKWARD ?
802 AV_ROUND_DOWN : AV_ROUND_UP);
803 if (s->duration < c->seek_timestamp) {
804 c->seek_timestamp = AV_NOPTS_VALUE;
809 for (i = 0; i < c->n_variants; i++) {
811 struct variant *var = c->variants[i];
812 int64_t pos = c->first_timestamp == AV_NOPTS_VALUE ?
813 0 : c->first_timestamp;
815 ffurl_close(var->input);
818 av_packet_unref(&var->pkt);
819 reset_packet(&var->pkt);
820 var->pb.eof_reached = 0;
821 /* Clear any buffered data */
822 var->pb.buf_end = var->pb.buf_ptr = var->pb.buffer;
823 /* Reset the pos, to let the mpegts demuxer know we've seeked. */
826 /* Locate the segment that contains the target timestamp */
827 for (j = 0; j < var->n_segments; j++) {
828 if (timestamp >= pos &&
829 timestamp < pos + var->segments[j]->duration) {
830 var->cur_seq_no = var->start_seq_no + j;
834 pos += var->segments[j]->duration;
837 c->seek_timestamp = AV_NOPTS_VALUE;
842 static int hls_probe(AVProbeData *p)
844 /* Require #EXTM3U at the start, and either one of the ones below
845 * somewhere for a proper match. */
846 if (strncmp(p->buf, "#EXTM3U", 7))
848 if (strstr(p->buf, "#EXT-X-STREAM-INF:") ||
849 strstr(p->buf, "#EXT-X-TARGETDURATION:") ||
850 strstr(p->buf, "#EXT-X-MEDIA-SEQUENCE:"))
851 return AVPROBE_SCORE_MAX;
855 AVInputFormat ff_hls_demuxer = {
856 .name = "hls,applehttp",
857 .long_name = NULL_IF_CONFIG_SMALL("Apple HTTP Live Streaming"),
858 .priv_data_size = sizeof(HLSContext),
859 .read_probe = hls_probe,
860 .read_header = hls_read_header,
861 .read_packet = hls_read_packet,
862 .read_close = hls_close,
863 .read_seek = hls_read_seek,