2 * Apple HTTP Live Streaming Protocol Handler
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 Protocol Handler
25 * http://tools.ietf.org/html/draft-pantos-http-live-streaming
28 #include "libavutil/avstring.h"
35 * An apple http stream consists of a playlist with media segment files,
36 * played sequentially. There may be several playlists with the same
37 * video content, in different bandwidth variants, that are played in
38 * parallel (preferrably only one bandwidth variant at a time). In this case,
39 * the user supplied the url to a main playlist that only lists the variant
42 * If the main playlist doesn't point at any variants, we still create
43 * one anonymous toplevel variant for this, to maintain the structure.
48 char url[MAX_URL_SIZE];
53 char url[MAX_URL_SIZE];
56 typedef struct AppleHTTPContext {
57 char playlisturl[MAX_URL_SIZE];
62 struct segment **segments;
64 struct variant **variants;
67 int64_t last_load_time;
70 static int read_chomp_line(AVIOContext *s, char *buf, int maxlen)
72 int len = ff_get_line(s, buf, maxlen);
73 while (len > 0 && isspace(buf[len - 1]))
78 static void free_segment_list(AppleHTTPContext *s)
81 for (i = 0; i < s->n_segments; i++)
82 av_free(s->segments[i]);
83 av_freep(&s->segments);
87 static void free_variant_list(AppleHTTPContext *s)
90 for (i = 0; i < s->n_variants; i++)
91 av_free(s->variants[i]);
92 av_freep(&s->variants);
100 static void handle_variant_args(struct variant_info *info, const char *key,
101 int key_len, char **dest, int *dest_len)
103 if (!strncmp(key, "BANDWIDTH=", key_len)) {
104 *dest = info->bandwidth;
105 *dest_len = sizeof(info->bandwidth);
109 static int parse_playlist(URLContext *h, const char *url)
111 AppleHTTPContext *s = h->priv_data;
113 int ret = 0, duration = 0, is_segment = 0, is_variant = 0, bandwidth = 0;
117 if ((ret = avio_open2(&in, url, AVIO_FLAG_READ,
118 &h->interrupt_callback, NULL)) < 0)
121 read_chomp_line(in, line, sizeof(line));
122 if (strcmp(line, "#EXTM3U"))
123 return AVERROR_INVALIDDATA;
125 free_segment_list(s);
127 while (!in->eof_reached) {
128 read_chomp_line(in, line, sizeof(line));
129 if (av_strstart(line, "#EXT-X-STREAM-INF:", &ptr)) {
130 struct variant_info info = {{0}};
132 ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_variant_args,
134 bandwidth = atoi(info.bandwidth);
135 } else if (av_strstart(line, "#EXT-X-TARGETDURATION:", &ptr)) {
136 s->target_duration = atoi(ptr);
137 } else if (av_strstart(line, "#EXT-X-MEDIA-SEQUENCE:", &ptr)) {
138 s->start_seq_no = atoi(ptr);
139 } else if (av_strstart(line, "#EXT-X-ENDLIST", &ptr)) {
141 } else if (av_strstart(line, "#EXTINF:", &ptr)) {
143 duration = atoi(ptr);
144 } else if (av_strstart(line, "#", NULL)) {
146 } else if (line[0]) {
148 struct segment *seg = av_malloc(sizeof(struct segment));
150 ret = AVERROR(ENOMEM);
153 seg->duration = duration;
154 ff_make_absolute_url(seg->url, sizeof(seg->url), url, line);
155 dynarray_add(&s->segments, &s->n_segments, seg);
157 } else if (is_variant) {
158 struct variant *var = av_malloc(sizeof(struct variant));
160 ret = AVERROR(ENOMEM);
163 var->bandwidth = bandwidth;
164 ff_make_absolute_url(var->url, sizeof(var->url), url, line);
165 dynarray_add(&s->variants, &s->n_variants, var);
170 s->last_load_time = av_gettime();
177 static int applehttp_close(URLContext *h)
179 AppleHTTPContext *s = h->priv_data;
181 free_segment_list(s);
182 free_variant_list(s);
183 ffurl_close(s->seg_hd);
187 static int applehttp_open(URLContext *h, const char *uri, int flags)
189 AppleHTTPContext *s = h->priv_data;
191 const char *nested_url;
193 if (flags & AVIO_FLAG_WRITE)
194 return AVERROR(ENOSYS);
198 if (av_strstart(uri, "applehttp+", &nested_url)) {
199 av_strlcpy(s->playlisturl, nested_url, sizeof(s->playlisturl));
200 } else if (av_strstart(uri, "applehttp://", &nested_url)) {
201 av_strlcpy(s->playlisturl, "http://", sizeof(s->playlisturl));
202 av_strlcat(s->playlisturl, nested_url, sizeof(s->playlisturl));
204 av_log(h, AV_LOG_ERROR, "Unsupported url %s\n", uri);
205 ret = AVERROR(EINVAL);
209 if ((ret = parse_playlist(h, s->playlisturl)) < 0)
212 if (s->n_segments == 0 && s->n_variants > 0) {
213 int max_bandwidth = 0, maxvar = -1;
214 for (i = 0; i < s->n_variants; i++) {
215 if (s->variants[i]->bandwidth > max_bandwidth || i == 0) {
216 max_bandwidth = s->variants[i]->bandwidth;
220 av_strlcpy(s->playlisturl, s->variants[maxvar]->url,
221 sizeof(s->playlisturl));
222 if ((ret = parse_playlist(h, s->playlisturl)) < 0)
226 if (s->n_segments == 0) {
227 av_log(h, AV_LOG_WARNING, "Empty playlist\n");
231 s->cur_seq_no = s->start_seq_no;
232 if (!s->finished && s->n_segments >= 3)
233 s->cur_seq_no = s->start_seq_no + s->n_segments - 3;
242 static int applehttp_read(URLContext *h, uint8_t *buf, int size)
244 AppleHTTPContext *s = h->priv_data;
247 int64_t reload_interval;
251 ret = ffurl_read(s->seg_hd, buf, size);
256 ffurl_close(s->seg_hd);
260 reload_interval = s->n_segments > 0 ?
261 s->segments[s->n_segments - 1]->duration :
263 reload_interval *= 1000000;
266 int64_t now = av_gettime();
267 if (now - s->last_load_time >= reload_interval) {
268 if ((ret = parse_playlist(h, s->playlisturl)) < 0)
270 /* If we need to reload the playlist again below (if
271 * there's still no more segments), switch to a reload
272 * interval of half the target duration. */
273 reload_interval = s->target_duration * 500000;
276 if (s->cur_seq_no < s->start_seq_no) {
277 av_log(h, AV_LOG_WARNING,
278 "skipping %d segments ahead, expired from playlist\n",
279 s->start_seq_no - s->cur_seq_no);
280 s->cur_seq_no = s->start_seq_no;
282 if (s->cur_seq_no - s->start_seq_no >= s->n_segments) {
285 while (av_gettime() - s->last_load_time < reload_interval) {
286 if (ff_check_interrupt(&h->interrupt_callback))
292 url = s->segments[s->cur_seq_no - s->start_seq_no]->url,
293 av_log(h, AV_LOG_DEBUG, "opening %s\n", url);
294 ret = ffurl_open(&s->seg_hd, url, AVIO_FLAG_READ,
295 &h->interrupt_callback, NULL);
297 if (ff_check_interrupt(&h->interrupt_callback))
299 av_log(h, AV_LOG_WARNING, "Unable to open %s\n", url);
306 URLProtocol ff_applehttp_protocol = {
308 .url_open = applehttp_open,
309 .url_read = applehttp_read,
310 .url_close = applehttp_close,
311 .flags = URL_PROTOCOL_FLAG_NESTED_SCHEME,
312 .priv_data_size = sizeof(AppleHTTPContext),