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2ba45a60 DM |
1 | /* |
2 | * Apple HTTP Live Streaming Protocol Handler | |
3 | * Copyright (c) 2010 Martin Storsjo | |
4 | * | |
5 | * This file is part of FFmpeg. | |
6 | * | |
7 | * FFmpeg 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. | |
11 | * | |
12 | * FFmpeg 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. | |
16 | * | |
17 | * You should have received a copy of the GNU Lesser General Public | |
18 | * License along with FFmpeg; if not, write to the Free Software | |
19 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
20 | */ | |
21 | ||
22 | /** | |
23 | * @file | |
24 | * Apple HTTP Live Streaming Protocol Handler | |
25 | * http://tools.ietf.org/html/draft-pantos-http-live-streaming | |
26 | */ | |
27 | ||
28 | #include "libavutil/avstring.h" | |
29 | #include "libavutil/time.h" | |
30 | #include "avformat.h" | |
31 | #include "internal.h" | |
32 | #include "url.h" | |
33 | #include "version.h" | |
34 | ||
35 | /* | |
36 | * An apple http stream consists of a playlist with media segment files, | |
37 | * played sequentially. There may be several playlists with the same | |
38 | * video content, in different bandwidth variants, that are played in | |
39 | * parallel (preferably only one bandwidth variant at a time). In this case, | |
40 | * the user supplied the url to a main playlist that only lists the variant | |
41 | * playlists. | |
42 | * | |
43 | * If the main playlist doesn't point at any variants, we still create | |
44 | * one anonymous toplevel variant for this, to maintain the structure. | |
45 | */ | |
46 | ||
47 | struct segment { | |
48 | int64_t duration; | |
49 | char url[MAX_URL_SIZE]; | |
50 | }; | |
51 | ||
52 | struct variant { | |
53 | int bandwidth; | |
54 | char url[MAX_URL_SIZE]; | |
55 | }; | |
56 | ||
57 | typedef struct HLSContext { | |
58 | char playlisturl[MAX_URL_SIZE]; | |
59 | int64_t target_duration; | |
60 | int start_seq_no; | |
61 | int finished; | |
62 | int n_segments; | |
63 | struct segment **segments; | |
64 | int n_variants; | |
65 | struct variant **variants; | |
66 | int cur_seq_no; | |
67 | URLContext *seg_hd; | |
68 | int64_t last_load_time; | |
69 | } HLSContext; | |
70 | ||
71 | static int read_chomp_line(AVIOContext *s, char *buf, int maxlen) | |
72 | { | |
73 | int len = ff_get_line(s, buf, maxlen); | |
74 | while (len > 0 && av_isspace(buf[len - 1])) | |
75 | buf[--len] = '\0'; | |
76 | return len; | |
77 | } | |
78 | ||
79 | static void free_segment_list(HLSContext *s) | |
80 | { | |
81 | int i; | |
82 | for (i = 0; i < s->n_segments; i++) | |
83 | av_free(s->segments[i]); | |
84 | av_freep(&s->segments); | |
85 | s->n_segments = 0; | |
86 | } | |
87 | ||
88 | static void free_variant_list(HLSContext *s) | |
89 | { | |
90 | int i; | |
91 | for (i = 0; i < s->n_variants; i++) | |
92 | av_free(s->variants[i]); | |
93 | av_freep(&s->variants); | |
94 | s->n_variants = 0; | |
95 | } | |
96 | ||
97 | struct variant_info { | |
98 | char bandwidth[20]; | |
99 | }; | |
100 | ||
101 | static void handle_variant_args(struct variant_info *info, const char *key, | |
102 | int key_len, char **dest, int *dest_len) | |
103 | { | |
104 | if (!strncmp(key, "BANDWIDTH=", key_len)) { | |
105 | *dest = info->bandwidth; | |
106 | *dest_len = sizeof(info->bandwidth); | |
107 | } | |
108 | } | |
109 | ||
110 | static int parse_playlist(URLContext *h, const char *url) | |
111 | { | |
112 | HLSContext *s = h->priv_data; | |
113 | AVIOContext *in; | |
114 | int ret = 0, is_segment = 0, is_variant = 0, bandwidth = 0; | |
115 | int64_t duration = 0; | |
116 | char line[1024]; | |
117 | const char *ptr; | |
118 | ||
119 | if ((ret = avio_open2(&in, url, AVIO_FLAG_READ, | |
120 | &h->interrupt_callback, NULL)) < 0) | |
121 | return ret; | |
122 | ||
123 | read_chomp_line(in, line, sizeof(line)); | |
124 | if (strcmp(line, "#EXTM3U")) | |
125 | return AVERROR_INVALIDDATA; | |
126 | ||
127 | free_segment_list(s); | |
128 | s->finished = 0; | |
129 | while (!avio_feof(in)) { | |
130 | read_chomp_line(in, line, sizeof(line)); | |
131 | if (av_strstart(line, "#EXT-X-STREAM-INF:", &ptr)) { | |
132 | struct variant_info info = {{0}}; | |
133 | is_variant = 1; | |
134 | ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_variant_args, | |
135 | &info); | |
136 | bandwidth = atoi(info.bandwidth); | |
137 | } else if (av_strstart(line, "#EXT-X-TARGETDURATION:", &ptr)) { | |
138 | s->target_duration = atoi(ptr) * AV_TIME_BASE; | |
139 | } else if (av_strstart(line, "#EXT-X-MEDIA-SEQUENCE:", &ptr)) { | |
140 | s->start_seq_no = atoi(ptr); | |
141 | } else if (av_strstart(line, "#EXT-X-ENDLIST", &ptr)) { | |
142 | s->finished = 1; | |
143 | } else if (av_strstart(line, "#EXTINF:", &ptr)) { | |
144 | is_segment = 1; | |
145 | duration = atof(ptr) * AV_TIME_BASE; | |
146 | } else if (av_strstart(line, "#", NULL)) { | |
147 | continue; | |
148 | } else if (line[0]) { | |
149 | if (is_segment) { | |
150 | struct segment *seg = av_malloc(sizeof(struct segment)); | |
151 | if (!seg) { | |
152 | ret = AVERROR(ENOMEM); | |
153 | goto fail; | |
154 | } | |
155 | seg->duration = duration; | |
156 | ff_make_absolute_url(seg->url, sizeof(seg->url), url, line); | |
157 | dynarray_add(&s->segments, &s->n_segments, seg); | |
158 | is_segment = 0; | |
159 | } else if (is_variant) { | |
160 | struct variant *var = av_malloc(sizeof(struct variant)); | |
161 | if (!var) { | |
162 | ret = AVERROR(ENOMEM); | |
163 | goto fail; | |
164 | } | |
165 | var->bandwidth = bandwidth; | |
166 | ff_make_absolute_url(var->url, sizeof(var->url), url, line); | |
167 | dynarray_add(&s->variants, &s->n_variants, var); | |
168 | is_variant = 0; | |
169 | } | |
170 | } | |
171 | } | |
f6fa7814 | 172 | s->last_load_time = av_gettime_relative(); |
2ba45a60 DM |
173 | |
174 | fail: | |
175 | avio_close(in); | |
176 | return ret; | |
177 | } | |
178 | ||
179 | static int hls_close(URLContext *h) | |
180 | { | |
181 | HLSContext *s = h->priv_data; | |
182 | ||
183 | free_segment_list(s); | |
184 | free_variant_list(s); | |
185 | ffurl_close(s->seg_hd); | |
186 | return 0; | |
187 | } | |
188 | ||
189 | static int hls_open(URLContext *h, const char *uri, int flags) | |
190 | { | |
191 | HLSContext *s = h->priv_data; | |
192 | int ret, i; | |
193 | const char *nested_url; | |
194 | ||
195 | if (flags & AVIO_FLAG_WRITE) | |
196 | return AVERROR(ENOSYS); | |
197 | ||
198 | h->is_streamed = 1; | |
199 | ||
200 | if (av_strstart(uri, "hls+", &nested_url)) { | |
201 | av_strlcpy(s->playlisturl, nested_url, sizeof(s->playlisturl)); | |
202 | } else if (av_strstart(uri, "hls://", &nested_url)) { | |
203 | av_log(h, AV_LOG_ERROR, | |
204 | "No nested protocol specified. Specify e.g. hls+http://%s\n", | |
205 | nested_url); | |
206 | ret = AVERROR(EINVAL); | |
207 | goto fail; | |
208 | } else { | |
209 | av_log(h, AV_LOG_ERROR, "Unsupported url %s\n", uri); | |
210 | ret = AVERROR(EINVAL); | |
211 | goto fail; | |
212 | } | |
213 | av_log(h, AV_LOG_WARNING, | |
214 | "Using the hls protocol is discouraged, please try using the " | |
215 | "hls demuxer instead. The hls demuxer should be more complete " | |
216 | "and work as well as the protocol implementation. (If not, " | |
217 | "please report it.) To use the demuxer, simply use %s as url.\n", | |
218 | s->playlisturl); | |
219 | ||
220 | if ((ret = parse_playlist(h, s->playlisturl)) < 0) | |
221 | goto fail; | |
222 | ||
223 | if (s->n_segments == 0 && s->n_variants > 0) { | |
224 | int max_bandwidth = 0, maxvar = -1; | |
225 | for (i = 0; i < s->n_variants; i++) { | |
226 | if (s->variants[i]->bandwidth > max_bandwidth || i == 0) { | |
227 | max_bandwidth = s->variants[i]->bandwidth; | |
228 | maxvar = i; | |
229 | } | |
230 | } | |
231 | av_strlcpy(s->playlisturl, s->variants[maxvar]->url, | |
232 | sizeof(s->playlisturl)); | |
233 | if ((ret = parse_playlist(h, s->playlisturl)) < 0) | |
234 | goto fail; | |
235 | } | |
236 | ||
237 | if (s->n_segments == 0) { | |
238 | av_log(h, AV_LOG_WARNING, "Empty playlist\n"); | |
239 | ret = AVERROR(EIO); | |
240 | goto fail; | |
241 | } | |
242 | s->cur_seq_no = s->start_seq_no; | |
243 | if (!s->finished && s->n_segments >= 3) | |
244 | s->cur_seq_no = s->start_seq_no + s->n_segments - 3; | |
245 | ||
246 | return 0; | |
247 | ||
248 | fail: | |
249 | hls_close(h); | |
250 | return ret; | |
251 | } | |
252 | ||
253 | static int hls_read(URLContext *h, uint8_t *buf, int size) | |
254 | { | |
255 | HLSContext *s = h->priv_data; | |
256 | const char *url; | |
257 | int ret; | |
258 | int64_t reload_interval; | |
259 | ||
260 | start: | |
261 | if (s->seg_hd) { | |
262 | ret = ffurl_read(s->seg_hd, buf, size); | |
263 | if (ret > 0) | |
264 | return ret; | |
265 | } | |
266 | if (s->seg_hd) { | |
267 | ffurl_close(s->seg_hd); | |
268 | s->seg_hd = NULL; | |
269 | s->cur_seq_no++; | |
270 | } | |
271 | reload_interval = s->n_segments > 0 ? | |
272 | s->segments[s->n_segments - 1]->duration : | |
273 | s->target_duration; | |
274 | retry: | |
275 | if (!s->finished) { | |
f6fa7814 | 276 | int64_t now = av_gettime_relative(); |
2ba45a60 DM |
277 | if (now - s->last_load_time >= reload_interval) { |
278 | if ((ret = parse_playlist(h, s->playlisturl)) < 0) | |
279 | return ret; | |
280 | /* If we need to reload the playlist again below (if | |
281 | * there's still no more segments), switch to a reload | |
282 | * interval of half the target duration. */ | |
283 | reload_interval = s->target_duration / 2; | |
284 | } | |
285 | } | |
286 | if (s->cur_seq_no < s->start_seq_no) { | |
287 | av_log(h, AV_LOG_WARNING, | |
288 | "skipping %d segments ahead, expired from playlist\n", | |
289 | s->start_seq_no - s->cur_seq_no); | |
290 | s->cur_seq_no = s->start_seq_no; | |
291 | } | |
292 | if (s->cur_seq_no - s->start_seq_no >= s->n_segments) { | |
293 | if (s->finished) | |
294 | return AVERROR_EOF; | |
f6fa7814 | 295 | while (av_gettime_relative() - s->last_load_time < reload_interval) { |
2ba45a60 DM |
296 | if (ff_check_interrupt(&h->interrupt_callback)) |
297 | return AVERROR_EXIT; | |
298 | av_usleep(100*1000); | |
299 | } | |
300 | goto retry; | |
301 | } | |
302 | url = s->segments[s->cur_seq_no - s->start_seq_no]->url, | |
303 | av_log(h, AV_LOG_DEBUG, "opening %s\n", url); | |
304 | ret = ffurl_open(&s->seg_hd, url, AVIO_FLAG_READ, | |
305 | &h->interrupt_callback, NULL); | |
306 | if (ret < 0) { | |
307 | if (ff_check_interrupt(&h->interrupt_callback)) | |
308 | return AVERROR_EXIT; | |
309 | av_log(h, AV_LOG_WARNING, "Unable to open %s\n", url); | |
310 | s->cur_seq_no++; | |
311 | goto retry; | |
312 | } | |
313 | goto start; | |
314 | } | |
315 | ||
316 | URLProtocol ff_hls_protocol = { | |
317 | .name = "hls", | |
318 | .url_open = hls_open, | |
319 | .url_read = hls_read, | |
320 | .url_close = hls_close, | |
321 | .flags = URL_PROTOCOL_FLAG_NESTED_SCHEME, | |
322 | .priv_data_size = sizeof(HLSContext), | |
323 | }; |