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 #define _XOPEN_SOURCE 600
29 #include "libavutil/avstring.h"
33 #include "avio_internal.h"
36 #define INITIAL_BUFFER_SIZE 32768
39 * An apple http stream consists of a playlist with media segment files,
40 * played sequentially. There may be several playlists with the same
41 * video content, in different bandwidth variants, that are played in
42 * parallel (preferrably only one bandwidth variant at a time). In this case,
43 * the user supplied the url to a main playlist that only lists the variant
46 * If the main playlist doesn't point at any variants, we still create
47 * one anonymous toplevel variant for this, to maintain the structure.
52 char url[MAX_URL_SIZE];
56 * Each variant has its own demuxer. If it currently is active,
57 * it has an open AVIOContext too, and potentially an AVPacket
58 * containing the next packet from this stream.
62 char url[MAX_URL_SIZE];
66 AVFormatContext *parent;
76 struct segment **segments;
77 int needed, cur_needed;
79 int64_t last_load_time;
82 typedef struct AppleHTTPContext {
84 struct variant **variants;
90 static int read_chomp_line(AVIOContext *s, char *buf, int maxlen)
92 int len = ff_get_line(s, buf, maxlen);
93 while (len > 0 && isspace(buf[len - 1]))
98 static void free_segment_list(struct variant *var)
101 for (i = 0; i < var->n_segments; i++)
102 av_free(var->segments[i]);
103 av_freep(&var->segments);
107 static void free_variant_list(AppleHTTPContext *c)
110 for (i = 0; i < c->n_variants; i++) {
111 struct variant *var = c->variants[i];
112 free_segment_list(var);
113 av_free_packet(&var->pkt);
114 av_free(var->pb.buffer);
116 ffurl_close(var->input);
119 av_close_input_file(var->ctx);
123 av_freep(&c->variants);
128 * Used to reset a statically allocated AVPacket to a clean slate,
129 * containing no data.
131 static void reset_packet(AVPacket *pkt)
137 static struct variant *new_variant(AppleHTTPContext *c, int bandwidth,
138 const char *url, const char *base)
140 struct variant *var = av_mallocz(sizeof(struct variant));
143 reset_packet(&var->pkt);
144 var->bandwidth = bandwidth;
145 ff_make_absolute_url(var->url, sizeof(var->url), base, url);
146 dynarray_add(&c->variants, &c->n_variants, var);
150 struct variant_info {
154 static void handle_variant_args(struct variant_info *info, const char *key,
155 int key_len, char **dest, int *dest_len)
157 if (!strncmp(key, "BANDWIDTH=", key_len)) {
158 *dest = info->bandwidth;
159 *dest_len = sizeof(info->bandwidth);
163 static int parse_playlist(AppleHTTPContext *c, const char *url,
164 struct variant *var, AVIOContext *in)
166 int ret = 0, duration = 0, is_segment = 0, is_variant = 0, bandwidth = 0;
173 if ((ret = avio_open(&in, url, AVIO_RDONLY)) < 0)
177 read_chomp_line(in, line, sizeof(line));
178 if (strcmp(line, "#EXTM3U")) {
179 ret = AVERROR_INVALIDDATA;
184 free_segment_list(var);
187 while (!in->eof_reached) {
188 read_chomp_line(in, line, sizeof(line));
189 if (av_strstart(line, "#EXT-X-STREAM-INF:", &ptr)) {
190 struct variant_info info = {{0}};
192 ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_variant_args,
194 bandwidth = atoi(info.bandwidth);
195 } else if (av_strstart(line, "#EXT-X-TARGETDURATION:", &ptr)) {
197 var = new_variant(c, 0, url, NULL);
199 ret = AVERROR(ENOMEM);
203 var->target_duration = atoi(ptr);
204 } else if (av_strstart(line, "#EXT-X-MEDIA-SEQUENCE:", &ptr)) {
206 var = new_variant(c, 0, url, NULL);
208 ret = AVERROR(ENOMEM);
212 var->start_seq_no = atoi(ptr);
213 } else if (av_strstart(line, "#EXT-X-ENDLIST", &ptr)) {
216 } else if (av_strstart(line, "#EXTINF:", &ptr)) {
218 duration = atoi(ptr);
219 } else if (av_strstart(line, "#", NULL)) {
221 } else if (line[0]) {
223 if (!new_variant(c, bandwidth, line, url)) {
224 ret = AVERROR(ENOMEM);
233 var = new_variant(c, 0, url, NULL);
235 ret = AVERROR(ENOMEM);
239 seg = av_malloc(sizeof(struct segment));
241 ret = AVERROR(ENOMEM);
244 seg->duration = duration;
245 ff_make_absolute_url(seg->url, sizeof(seg->url), url, line);
246 dynarray_add(&var->segments, &var->n_segments, seg);
252 var->last_load_time = av_gettime();
260 static int read_data(void *opaque, uint8_t *buf, int buf_size)
262 struct variant *v = opaque;
263 AppleHTTPContext *c = v->parent->priv_data;
269 /* If this is a live stream and target_duration has elapsed since
270 * the last playlist reload, reload the variant playlists now. */
272 av_gettime() - v->last_load_time >= v->target_duration*1000000 &&
273 (ret = parse_playlist(c, v->url, v, NULL)) < 0)
275 if (v->cur_seq_no < v->start_seq_no) {
276 av_log(NULL, AV_LOG_WARNING,
277 "skipping %d segments ahead, expired from playlists\n",
278 v->start_seq_no - v->cur_seq_no);
279 v->cur_seq_no = v->start_seq_no;
281 if (v->cur_seq_no >= v->start_seq_no + v->n_segments) {
284 while (av_gettime() - v->last_load_time <
285 v->target_duration*1000000) {
286 if (url_interrupt_cb())
290 /* Enough time has elapsed since the last reload */
294 ret = ffurl_open(&v->input,
295 v->segments[v->cur_seq_no - v->start_seq_no]->url,
300 ret = ffurl_read(v->input, buf, buf_size);
303 if (ret < 0 && ret != AVERROR_EOF)
305 ffurl_close(v->input);
309 c->end_of_segment = 1;
310 c->cur_seq_no = v->cur_seq_no;
313 for (i = v->stream_offset; i < v->stream_offset + v->ctx->nb_streams; i++) {
314 if (v->parent->streams[i]->discard < AVDISCARD_ALL)
318 av_log(v->parent, AV_LOG_INFO, "No longer receiving variant %d\n",
325 static int applehttp_read_header(AVFormatContext *s, AVFormatParameters *ap)
327 AppleHTTPContext *c = s->priv_data;
328 int ret = 0, i, j, stream_offset = 0;
330 if ((ret = parse_playlist(c, s->filename, NULL, s->pb)) < 0)
333 if (c->n_variants == 0) {
334 av_log(NULL, AV_LOG_WARNING, "Empty playlist\n");
338 /* If the playlist only contained variants, parse each individual
339 * variant playlist. */
340 if (c->n_variants > 1 || c->variants[0]->n_segments == 0) {
341 for (i = 0; i < c->n_variants; i++) {
342 struct variant *v = c->variants[i];
343 if ((ret = parse_playlist(c, v->url, v, NULL)) < 0)
348 if (c->variants[0]->n_segments == 0) {
349 av_log(NULL, AV_LOG_WARNING, "Empty playlist\n");
354 /* If this isn't a live stream, calculate the total duration of the
356 if (c->variants[0]->finished) {
357 int64_t duration = 0;
358 for (i = 0; i < c->variants[0]->n_segments; i++)
359 duration += c->variants[0]->segments[i]->duration;
360 s->duration = duration * AV_TIME_BASE;
363 /* Open the demuxer for each variant */
364 for (i = 0; i < c->n_variants; i++) {
365 struct variant *v = c->variants[i];
366 AVInputFormat *in_fmt = NULL;
367 if (v->n_segments == 0)
374 /* If this is a live stream with more than 3 segments, start at the
375 * third last segment. */
376 v->cur_seq_no = v->start_seq_no;
377 if (!v->finished && v->n_segments > 3)
378 v->cur_seq_no = v->start_seq_no + v->n_segments - 3;
380 v->read_buffer = av_malloc(INITIAL_BUFFER_SIZE);
381 ffio_init_context(&v->pb, v->read_buffer, INITIAL_BUFFER_SIZE, 0, v,
382 read_data, NULL, NULL);
384 ret = av_probe_input_buffer(&v->pb, &in_fmt, v->segments[0]->url,
388 ret = av_open_input_stream(&v->ctx, &v->pb, v->segments[0]->url,
392 v->stream_offset = stream_offset;
393 /* Create new AVStreams for each stream in this variant */
394 for (j = 0; j < v->ctx->nb_streams; j++) {
395 AVStream *st = av_new_stream(s, i);
397 ret = AVERROR(ENOMEM);
400 avcodec_copy_context(st->codec, v->ctx->streams[j]->codec);
402 stream_offset += v->ctx->nb_streams;
409 free_variant_list(c);
413 static int recheck_discard_flags(AVFormatContext *s, int first)
415 AppleHTTPContext *c = s->priv_data;
418 /* Check if any new streams are needed */
419 for (i = 0; i < c->n_variants; i++)
420 c->variants[i]->cur_needed = 0;;
422 for (i = 0; i < s->nb_streams; i++) {
423 AVStream *st = s->streams[i];
424 struct variant *var = c->variants[s->streams[i]->id];
425 if (st->discard < AVDISCARD_ALL)
428 for (i = 0; i < c->n_variants; i++) {
429 struct variant *v = c->variants[i];
430 if (v->cur_needed && !v->needed) {
433 v->cur_seq_no = c->cur_seq_no;
434 v->pb.eof_reached = 0;
435 av_log(s, AV_LOG_INFO, "Now receiving variant %d\n", i);
436 } else if (first && !v->cur_needed && v->needed) {
438 ffurl_close(v->input);
442 av_log(s, AV_LOG_INFO, "No longer receiving variant %d\n", i);
448 static int applehttp_read_packet(AVFormatContext *s, AVPacket *pkt)
450 AppleHTTPContext *c = s->priv_data;
451 int ret, i, minvariant = -1;
453 if (c->first_packet) {
454 recheck_discard_flags(s, 1);
459 c->end_of_segment = 0;
460 for (i = 0; i < c->n_variants; i++) {
461 struct variant *var = c->variants[i];
462 /* Make sure we've got one buffered packet from each open variant
464 if (var->needed && !var->pkt.data) {
465 ret = av_read_frame(var->ctx, &var->pkt);
467 if (!var->pb.eof_reached)
469 reset_packet(&var->pkt);
472 /* Check if this stream has the packet with the lowest dts */
474 if (minvariant < 0 ||
475 var->pkt.dts < c->variants[minvariant]->pkt.dts)
479 if (c->end_of_segment) {
480 if (recheck_discard_flags(s, 0))
483 /* If we got a packet, return it */
484 if (minvariant >= 0) {
485 *pkt = c->variants[minvariant]->pkt;
486 pkt->stream_index += c->variants[minvariant]->stream_offset;
487 reset_packet(&c->variants[minvariant]->pkt);
493 static int applehttp_close(AVFormatContext *s)
495 AppleHTTPContext *c = s->priv_data;
497 free_variant_list(c);
501 static int applehttp_read_seek(AVFormatContext *s, int stream_index,
502 int64_t timestamp, int flags)
504 AppleHTTPContext *c = s->priv_data;
507 if ((flags & AVSEEK_FLAG_BYTE) || !c->variants[0]->finished)
508 return AVERROR(ENOSYS);
510 timestamp = av_rescale_rnd(timestamp, 1, stream_index >= 0 ?
511 s->streams[stream_index]->time_base.den :
512 AV_TIME_BASE, flags & AVSEEK_FLAG_BACKWARD ?
513 AV_ROUND_DOWN : AV_ROUND_UP);
515 for (i = 0; i < c->n_variants; i++) {
517 struct variant *var = c->variants[i];
520 ffurl_close(var->input);
523 av_free_packet(&var->pkt);
524 reset_packet(&var->pkt);
525 var->pb.eof_reached = 0;
527 /* Locate the segment that contains the target timestamp */
528 for (j = 0; j < var->n_segments; j++) {
529 if (timestamp >= pos &&
530 timestamp < pos + var->segments[j]->duration) {
531 var->cur_seq_no = var->start_seq_no + j;
535 pos += var->segments[j]->duration;
541 static int applehttp_probe(AVProbeData *p)
543 /* Require #EXTM3U at the start, and either one of the ones below
544 * somewhere for a proper match. */
545 if (strncmp(p->buf, "#EXTM3U", 7))
547 if (strstr(p->buf, "#EXT-X-STREAM-INF:") ||
548 strstr(p->buf, "#EXT-X-TARGETDURATION:") ||
549 strstr(p->buf, "#EXT-X-MEDIA-SEQUENCE:"))
550 return AVPROBE_SCORE_MAX;
554 AVInputFormat ff_applehttp_demuxer = {
556 NULL_IF_CONFIG_SMALL("Apple HTTP Live Streaming format"),
557 sizeof(AppleHTTPContext),
559 applehttp_read_header,
560 applehttp_read_packet,