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"
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 (preferrably 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;
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 AppleHTTPContext {
98 struct variant **variants;
102 int64_t first_timestamp;
103 AVIOInterruptCB *interrupt_callback;
106 static int read_chomp_line(AVIOContext *s, char *buf, int maxlen)
108 int len = ff_get_line(s, buf, maxlen);
109 while (len > 0 && isspace(buf[len - 1]))
114 static void free_segment_list(struct variant *var)
117 for (i = 0; i < var->n_segments; i++)
118 av_free(var->segments[i]);
119 av_freep(&var->segments);
123 static void free_variant_list(AppleHTTPContext *c)
126 for (i = 0; i < c->n_variants; i++) {
127 struct variant *var = c->variants[i];
128 free_segment_list(var);
129 av_free_packet(&var->pkt);
130 av_free(var->pb.buffer);
132 ffurl_close(var->input);
135 avformat_close_input(&var->ctx);
139 av_freep(&c->variants);
144 * Used to reset a statically allocated AVPacket to a clean slate,
145 * containing no data.
147 static void reset_packet(AVPacket *pkt)
153 static struct variant *new_variant(AppleHTTPContext *c, int bandwidth,
154 const char *url, const char *base)
156 struct variant *var = av_mallocz(sizeof(struct variant));
159 reset_packet(&var->pkt);
160 var->bandwidth = bandwidth;
161 ff_make_absolute_url(var->url, sizeof(var->url), base, url);
162 dynarray_add(&c->variants, &c->n_variants, var);
166 struct variant_info {
170 static void handle_variant_args(struct variant_info *info, const char *key,
171 int key_len, char **dest, int *dest_len)
173 if (!strncmp(key, "BANDWIDTH=", key_len)) {
174 *dest = info->bandwidth;
175 *dest_len = sizeof(info->bandwidth);
180 char uri[MAX_URL_SIZE];
185 static void handle_key_args(struct key_info *info, const char *key,
186 int key_len, char **dest, int *dest_len)
188 if (!strncmp(key, "METHOD=", key_len)) {
189 *dest = info->method;
190 *dest_len = sizeof(info->method);
191 } else if (!strncmp(key, "URI=", key_len)) {
193 *dest_len = sizeof(info->uri);
194 } else if (!strncmp(key, "IV=", key_len)) {
196 *dest_len = sizeof(info->iv);
200 static int parse_playlist(AppleHTTPContext *c, const char *url,
201 struct variant *var, AVIOContext *in)
203 int ret = 0, duration = 0, is_segment = 0, is_variant = 0, bandwidth = 0;
204 enum KeyType key_type = KEY_NONE;
207 char key[MAX_URL_SIZE] = "";
214 if ((ret = avio_open2(&in, url, AVIO_FLAG_READ,
215 c->interrupt_callback, NULL)) < 0)
219 read_chomp_line(in, line, sizeof(line));
220 if (strcmp(line, "#EXTM3U")) {
221 ret = AVERROR_INVALIDDATA;
226 free_segment_list(var);
229 while (!in->eof_reached) {
230 read_chomp_line(in, line, sizeof(line));
231 if (av_strstart(line, "#EXT-X-STREAM-INF:", &ptr)) {
232 struct variant_info info = {{0}};
234 ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_variant_args,
236 bandwidth = atoi(info.bandwidth);
237 } else if (av_strstart(line, "#EXT-X-KEY:", &ptr)) {
238 struct key_info info = {{0}};
239 ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_key_args,
243 if (!strcmp(info.method, "AES-128"))
244 key_type = KEY_AES_128;
245 if (!strncmp(info.iv, "0x", 2) || !strncmp(info.iv, "0X", 2)) {
246 ff_hex_to_data(iv, info.iv + 2);
249 av_strlcpy(key, info.uri, sizeof(key));
250 } else if (av_strstart(line, "#EXT-X-TARGETDURATION:", &ptr)) {
252 var = new_variant(c, 0, url, NULL);
254 ret = AVERROR(ENOMEM);
258 var->target_duration = atoi(ptr);
259 } else if (av_strstart(line, "#EXT-X-MEDIA-SEQUENCE:", &ptr)) {
261 var = new_variant(c, 0, url, NULL);
263 ret = AVERROR(ENOMEM);
267 var->start_seq_no = atoi(ptr);
268 } else if (av_strstart(line, "#EXT-X-ENDLIST", &ptr)) {
271 } else if (av_strstart(line, "#EXTINF:", &ptr)) {
273 duration = atoi(ptr);
274 } else if (av_strstart(line, "#", NULL)) {
276 } else if (line[0]) {
278 if (!new_variant(c, bandwidth, line, url)) {
279 ret = AVERROR(ENOMEM);
288 var = new_variant(c, 0, url, NULL);
290 ret = AVERROR(ENOMEM);
294 seg = av_malloc(sizeof(struct segment));
296 ret = AVERROR(ENOMEM);
299 seg->duration = duration;
300 seg->key_type = key_type;
302 memcpy(seg->iv, iv, sizeof(iv));
304 int seq = var->start_seq_no + var->n_segments;
305 memset(seg->iv, 0, sizeof(seg->iv));
306 AV_WB32(seg->iv + 12, seq);
308 ff_make_absolute_url(seg->key, sizeof(seg->key), url, key);
309 ff_make_absolute_url(seg->url, sizeof(seg->url), url, line);
310 dynarray_add(&var->segments, &var->n_segments, seg);
316 var->last_load_time = av_gettime();
324 static int open_input(struct variant *var)
326 struct segment *seg = var->segments[var->cur_seq_no - var->start_seq_no];
327 if (seg->key_type == KEY_NONE) {
328 return ffurl_open(&var->input, seg->url, AVIO_FLAG_READ,
329 &var->parent->interrupt_callback, NULL);
330 } else if (seg->key_type == KEY_AES_128) {
331 char iv[33], key[33], url[MAX_URL_SIZE];
333 if (strcmp(seg->key, var->key_url)) {
335 if (ffurl_open(&uc, seg->key, AVIO_FLAG_READ,
336 &var->parent->interrupt_callback, NULL) == 0) {
337 if (ffurl_read_complete(uc, var->key, sizeof(var->key))
338 != sizeof(var->key)) {
339 av_log(NULL, AV_LOG_ERROR, "Unable to read key file %s\n",
344 av_log(NULL, AV_LOG_ERROR, "Unable to open key file %s\n",
347 av_strlcpy(var->key_url, seg->key, sizeof(var->key_url));
349 ff_data_to_hex(iv, seg->iv, sizeof(seg->iv), 0);
350 ff_data_to_hex(key, var->key, sizeof(var->key), 0);
351 iv[32] = key[32] = '\0';
352 if (strstr(seg->url, "://"))
353 snprintf(url, sizeof(url), "crypto+%s", seg->url);
355 snprintf(url, sizeof(url), "crypto:%s", seg->url);
356 if ((ret = ffurl_alloc(&var->input, url, AVIO_FLAG_READ,
357 &var->parent->interrupt_callback)) < 0)
359 av_opt_set(var->input->priv_data, "key", key, 0);
360 av_opt_set(var->input->priv_data, "iv", iv, 0);
361 if ((ret = ffurl_connect(var->input, NULL)) < 0) {
362 ffurl_close(var->input);
368 return AVERROR(ENOSYS);
371 static int read_data(void *opaque, uint8_t *buf, int buf_size)
373 struct variant *v = opaque;
374 AppleHTTPContext *c = v->parent->priv_data;
379 /* If this is a live stream and the reload interval has elapsed since
380 * the last playlist reload, reload the variant playlists now. */
381 int64_t reload_interval = v->n_segments > 0 ?
382 v->segments[v->n_segments - 1]->duration :
384 reload_interval *= 1000000;
388 av_gettime() - v->last_load_time >= reload_interval) {
389 if ((ret = parse_playlist(c, v->url, v, NULL)) < 0)
391 /* If we need to reload the playlist again below (if
392 * there's still no more segments), switch to a reload
393 * interval of half the target duration. */
394 reload_interval = v->target_duration * 500000;
396 if (v->cur_seq_no < v->start_seq_no) {
397 av_log(NULL, AV_LOG_WARNING,
398 "skipping %d segments ahead, expired from playlists\n",
399 v->start_seq_no - v->cur_seq_no);
400 v->cur_seq_no = v->start_seq_no;
402 if (v->cur_seq_no >= v->start_seq_no + v->n_segments) {
405 while (av_gettime() - v->last_load_time < reload_interval) {
406 if (ff_check_interrupt(c->interrupt_callback))
410 /* Enough time has elapsed since the last reload */
418 ret = ffurl_read(v->input, buf, buf_size);
421 if (ret < 0 && ret != AVERROR_EOF)
423 ffurl_close(v->input);
427 c->end_of_segment = 1;
428 c->cur_seq_no = v->cur_seq_no;
430 if (v->ctx && v->ctx->nb_streams) {
432 for (i = v->stream_offset; i < v->stream_offset + v->ctx->nb_streams;
434 if (v->parent->streams[i]->discard < AVDISCARD_ALL)
439 av_log(v->parent, AV_LOG_INFO, "No longer receiving variant %d\n",
446 static int applehttp_read_header(AVFormatContext *s, AVFormatParameters *ap)
448 AppleHTTPContext *c = s->priv_data;
449 int ret = 0, i, j, stream_offset = 0;
451 c->interrupt_callback = &s->interrupt_callback;
453 if ((ret = parse_playlist(c, s->filename, NULL, s->pb)) < 0)
456 if (c->n_variants == 0) {
457 av_log(NULL, AV_LOG_WARNING, "Empty playlist\n");
461 /* If the playlist only contained variants, parse each individual
462 * variant playlist. */
463 if (c->n_variants > 1 || c->variants[0]->n_segments == 0) {
464 for (i = 0; i < c->n_variants; i++) {
465 struct variant *v = c->variants[i];
466 if ((ret = parse_playlist(c, v->url, v, NULL)) < 0)
471 if (c->variants[0]->n_segments == 0) {
472 av_log(NULL, AV_LOG_WARNING, "Empty playlist\n");
477 /* If this isn't a live stream, calculate the total duration of the
479 if (c->variants[0]->finished) {
480 int64_t duration = 0;
481 for (i = 0; i < c->variants[0]->n_segments; i++)
482 duration += c->variants[0]->segments[i]->duration;
483 s->duration = duration * AV_TIME_BASE;
486 /* Open the demuxer for each variant */
487 for (i = 0; i < c->n_variants; i++) {
488 struct variant *v = c->variants[i];
489 AVInputFormat *in_fmt = NULL;
490 char bitrate_str[20];
491 if (v->n_segments == 0)
494 if (!(v->ctx = avformat_alloc_context())) {
495 ret = AVERROR(ENOMEM);
503 /* If this is a live stream with more than 3 segments, start at the
504 * third last segment. */
505 v->cur_seq_no = v->start_seq_no;
506 if (!v->finished && v->n_segments > 3)
507 v->cur_seq_no = v->start_seq_no + v->n_segments - 3;
509 v->read_buffer = av_malloc(INITIAL_BUFFER_SIZE);
510 ffio_init_context(&v->pb, v->read_buffer, INITIAL_BUFFER_SIZE, 0, v,
511 read_data, NULL, NULL);
513 ret = av_probe_input_buffer(&v->pb, &in_fmt, v->segments[0]->url,
516 /* Free the ctx - it isn't initialized properly at this point,
517 * so avformat_close_input shouldn't be called. If
518 * avformat_open_input fails below, it frees and zeros the
519 * context, so it doesn't need any special treatment like this. */
520 avformat_free_context(v->ctx);
525 ret = avformat_open_input(&v->ctx, v->segments[0]->url, in_fmt, NULL);
528 v->stream_offset = stream_offset;
529 snprintf(bitrate_str, sizeof(bitrate_str), "%d", v->bandwidth);
530 /* Create new AVStreams for each stream in this variant */
531 for (j = 0; j < v->ctx->nb_streams; j++) {
532 AVStream *st = avformat_new_stream(s, NULL);
534 ret = AVERROR(ENOMEM);
538 avcodec_copy_context(st->codec, v->ctx->streams[j]->codec);
540 av_dict_set(&st->metadata, "variant_bitrate", bitrate_str,
543 stream_offset += v->ctx->nb_streams;
547 c->first_timestamp = AV_NOPTS_VALUE;
551 free_variant_list(c);
555 static int recheck_discard_flags(AVFormatContext *s, int first)
557 AppleHTTPContext *c = s->priv_data;
560 /* Check if any new streams are needed */
561 for (i = 0; i < c->n_variants; i++)
562 c->variants[i]->cur_needed = 0;;
564 for (i = 0; i < s->nb_streams; i++) {
565 AVStream *st = s->streams[i];
566 struct variant *var = c->variants[s->streams[i]->id];
567 if (st->discard < AVDISCARD_ALL)
570 for (i = 0; i < c->n_variants; i++) {
571 struct variant *v = c->variants[i];
572 if (v->cur_needed && !v->needed) {
575 v->cur_seq_no = c->cur_seq_no;
576 v->pb.eof_reached = 0;
577 av_log(s, AV_LOG_INFO, "Now receiving variant %d\n", i);
578 } else if (first && !v->cur_needed && v->needed) {
580 ffurl_close(v->input);
584 av_log(s, AV_LOG_INFO, "No longer receiving variant %d\n", i);
590 static int applehttp_read_packet(AVFormatContext *s, AVPacket *pkt)
592 AppleHTTPContext *c = s->priv_data;
593 int ret, i, minvariant = -1;
595 if (c->first_packet) {
596 recheck_discard_flags(s, 1);
601 c->end_of_segment = 0;
602 for (i = 0; i < c->n_variants; i++) {
603 struct variant *var = c->variants[i];
604 /* Make sure we've got one buffered packet from each open variant
606 if (var->needed && !var->pkt.data) {
607 ret = av_read_frame(var->ctx, &var->pkt);
609 if (!var->pb.eof_reached)
611 reset_packet(&var->pkt);
613 if (c->first_timestamp == AV_NOPTS_VALUE)
614 c->first_timestamp = var->pkt.dts;
617 /* Check if this stream has the packet with the lowest dts */
619 if (minvariant < 0 ||
620 var->pkt.dts < c->variants[minvariant]->pkt.dts)
624 if (c->end_of_segment) {
625 if (recheck_discard_flags(s, 0))
628 /* If we got a packet, return it */
629 if (minvariant >= 0) {
630 *pkt = c->variants[minvariant]->pkt;
631 pkt->stream_index += c->variants[minvariant]->stream_offset;
632 reset_packet(&c->variants[minvariant]->pkt);
638 static int applehttp_close(AVFormatContext *s)
640 AppleHTTPContext *c = s->priv_data;
642 free_variant_list(c);
646 static int applehttp_read_seek(AVFormatContext *s, int stream_index,
647 int64_t timestamp, int flags)
649 AppleHTTPContext *c = s->priv_data;
652 if ((flags & AVSEEK_FLAG_BYTE) || !c->variants[0]->finished)
653 return AVERROR(ENOSYS);
655 timestamp = av_rescale_rnd(timestamp, 1, stream_index >= 0 ?
656 s->streams[stream_index]->time_base.den :
657 AV_TIME_BASE, flags & AVSEEK_FLAG_BACKWARD ?
658 AV_ROUND_DOWN : AV_ROUND_UP);
660 for (i = 0; i < c->n_variants; i++) {
662 struct variant *var = c->variants[i];
663 int64_t pos = c->first_timestamp == AV_NOPTS_VALUE ? 0 :
664 av_rescale_rnd(c->first_timestamp, 1,
665 stream_index >= 0 ? s->streams[stream_index]->time_base.den : AV_TIME_BASE,
666 flags & AVSEEK_FLAG_BACKWARD ? AV_ROUND_DOWN : AV_ROUND_UP);
668 ffurl_close(var->input);
671 av_free_packet(&var->pkt);
672 reset_packet(&var->pkt);
673 var->pb.eof_reached = 0;
675 /* Locate the segment that contains the target timestamp */
676 for (j = 0; j < var->n_segments; j++) {
677 if (timestamp >= pos &&
678 timestamp < pos + var->segments[j]->duration) {
679 var->cur_seq_no = var->start_seq_no + j;
683 pos += var->segments[j]->duration;
689 static int applehttp_probe(AVProbeData *p)
691 /* Require #EXTM3U at the start, and either one of the ones below
692 * somewhere for a proper match. */
693 if (strncmp(p->buf, "#EXTM3U", 7))
695 if (strstr(p->buf, "#EXT-X-STREAM-INF:") ||
696 strstr(p->buf, "#EXT-X-TARGETDURATION:") ||
697 strstr(p->buf, "#EXT-X-MEDIA-SEQUENCE:"))
698 return AVPROBE_SCORE_MAX;
702 AVInputFormat ff_applehttp_demuxer = {
704 .long_name = NULL_IF_CONFIG_SMALL("Apple HTTP Live Streaming format"),
705 .priv_data_size = sizeof(AppleHTTPContext),
706 .read_probe = applehttp_probe,
707 .read_header = applehttp_read_header,
708 .read_packet = applehttp_read_packet,
709 .read_close = applehttp_close,
710 .read_seek = applehttp_read_seek,