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 * https://www.rfc-editor.org/rfc/rfc8216.txt
26 */
27
28 #include "libavutil/avstring.h"
29 #include "libavutil/time.h"
30 #include "avformat.h"
31 #include "avio_internal.h"
32 #include "internal.h"
33 #include "url.h"
34 #include "version.h"
35
36 /*
37 * An apple http stream consists of a playlist with media segment files,
38 * played sequentially. There may be several playlists with the same
39 * video content, in different bandwidth variants, that are played in
40 * parallel (preferably only one bandwidth variant at a time). In this case,
41 * the user supplied the url to a main playlist that only lists the variant
42 * playlists.
43 *
44 * If the main playlist doesn't point at any variants, we still create
45 * one anonymous toplevel variant for this, to maintain the structure.
46 */
47
48 struct segment {
49 int64_t duration;
50 char url[MAX_URL_SIZE];
51 };
52
53 struct variant {
54 int bandwidth;
55 char url[MAX_URL_SIZE];
56 };
57
58 typedef struct HLSContext {
59 char playlisturl[MAX_URL_SIZE];
60 int64_t target_duration;
61 int start_seq_no;
62 int finished;
63 int n_segments;
64 struct segment **segments;
65 int n_variants;
66 struct variant **variants;
67 int cur_seq_no;
68 URLContext *seg_hd;
69 int64_t last_load_time;
70 } HLSContext;
71
free_segment_list(HLSContext * s)72 static void free_segment_list(HLSContext *s)
73 {
74 int i;
75 for (i = 0; i < s->n_segments; i++)
76 av_freep(&s->segments[i]);
77 av_freep(&s->segments);
78 s->n_segments = 0;
79 }
80
free_variant_list(HLSContext * s)81 static void free_variant_list(HLSContext *s)
82 {
83 int i;
84 for (i = 0; i < s->n_variants; i++)
85 av_freep(&s->variants[i]);
86 av_freep(&s->variants);
87 s->n_variants = 0;
88 }
89
90 struct variant_info {
91 char bandwidth[20];
92 };
93
handle_variant_args(struct variant_info * info,const char * key,int key_len,char ** dest,int * dest_len)94 static void handle_variant_args(struct variant_info *info, const char *key,
95 int key_len, char **dest, int *dest_len)
96 {
97 if (!strncmp(key, "BANDWIDTH=", key_len)) {
98 *dest = info->bandwidth;
99 *dest_len = sizeof(info->bandwidth);
100 }
101 }
102
parse_playlist(URLContext * h,const char * url)103 static int parse_playlist(URLContext *h, const char *url)
104 {
105 HLSContext *s = h->priv_data;
106 AVIOContext *in;
107 int ret = 0, is_segment = 0, is_variant = 0, bandwidth = 0;
108 int64_t duration = 0;
109 char line[1024];
110 const char *ptr;
111
112 if ((ret = ffio_open_whitelist(&in, url, AVIO_FLAG_READ,
113 &h->interrupt_callback, NULL,
114 h->protocol_whitelist, h->protocol_blacklist)) < 0)
115 return ret;
116
117 ff_get_chomp_line(in, line, sizeof(line));
118 if (strcmp(line, "#EXTM3U")) {
119 ret = AVERROR_INVALIDDATA;
120 goto fail;
121 }
122
123 free_segment_list(s);
124 s->finished = 0;
125 while (!avio_feof(in)) {
126 ff_get_chomp_line(in, line, sizeof(line));
127 if (av_strstart(line, "#EXT-X-STREAM-INF:", &ptr)) {
128 struct variant_info info = {{0}};
129 is_variant = 1;
130 ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_variant_args,
131 &info);
132 bandwidth = atoi(info.bandwidth);
133 } else if (av_strstart(line, "#EXT-X-TARGETDURATION:", &ptr)) {
134 s->target_duration = atoi(ptr) * AV_TIME_BASE;
135 } else if (av_strstart(line, "#EXT-X-MEDIA-SEQUENCE:", &ptr)) {
136 s->start_seq_no = atoi(ptr);
137 } else if (av_strstart(line, "#EXT-X-ENDLIST", &ptr)) {
138 s->finished = 1;
139 } else if (av_strstart(line, "#EXTINF:", &ptr)) {
140 is_segment = 1;
141 duration = atof(ptr) * AV_TIME_BASE;
142 } else if (av_strstart(line, "#", NULL)) {
143 continue;
144 } else if (line[0]) {
145 if (is_segment) {
146 struct segment *seg = av_malloc(sizeof(struct segment));
147 if (!seg) {
148 ret = AVERROR(ENOMEM);
149 goto fail;
150 }
151 seg->duration = duration;
152 ff_make_absolute_url(seg->url, sizeof(seg->url), url, line);
153 dynarray_add(&s->segments, &s->n_segments, seg);
154 is_segment = 0;
155 } else if (is_variant) {
156 struct variant *var = av_malloc(sizeof(struct variant));
157 if (!var) {
158 ret = AVERROR(ENOMEM);
159 goto fail;
160 }
161 var->bandwidth = bandwidth;
162 ff_make_absolute_url(var->url, sizeof(var->url), url, line);
163 dynarray_add(&s->variants, &s->n_variants, var);
164 is_variant = 0;
165 }
166 }
167 }
168 s->last_load_time = av_gettime_relative();
169
170 fail:
171 avio_close(in);
172 return ret;
173 }
174
hls_close(URLContext * h)175 static int hls_close(URLContext *h)
176 {
177 HLSContext *s = h->priv_data;
178
179 free_segment_list(s);
180 free_variant_list(s);
181 ffurl_closep(&s->seg_hd);
182 return 0;
183 }
184
hls_open(URLContext * h,const char * uri,int flags)185 static int hls_open(URLContext *h, const char *uri, int flags)
186 {
187 HLSContext *s = h->priv_data;
188 int ret, i;
189 const char *nested_url;
190
191 if (flags & AVIO_FLAG_WRITE)
192 return AVERROR(ENOSYS);
193
194 h->is_streamed = 1;
195
196 if (av_strstart(uri, "hls+", &nested_url)) {
197 av_strlcpy(s->playlisturl, nested_url, sizeof(s->playlisturl));
198 } else if (av_strstart(uri, "hls://", &nested_url)) {
199 av_log(h, AV_LOG_ERROR,
200 "No nested protocol specified. Specify e.g. hls+http://%s\n",
201 nested_url);
202 ret = AVERROR(EINVAL);
203 goto fail;
204 } else {
205 av_log(h, AV_LOG_ERROR, "Unsupported url %s\n", uri);
206 ret = AVERROR(EINVAL);
207 goto fail;
208 }
209 av_log(h, AV_LOG_WARNING,
210 "Using the hls protocol is discouraged, please try using the "
211 "hls demuxer instead. The hls demuxer should be more complete "
212 "and work as well as the protocol implementation. (If not, "
213 "please report it.) To use the demuxer, simply use %s as url.\n",
214 s->playlisturl);
215
216 if ((ret = parse_playlist(h, s->playlisturl)) < 0)
217 goto fail;
218
219 if (s->n_segments == 0 && s->n_variants > 0) {
220 int max_bandwidth = 0, maxvar = -1;
221 for (i = 0; i < s->n_variants; i++) {
222 if (s->variants[i]->bandwidth > max_bandwidth || i == 0) {
223 max_bandwidth = s->variants[i]->bandwidth;
224 maxvar = i;
225 }
226 }
227 av_strlcpy(s->playlisturl, s->variants[maxvar]->url,
228 sizeof(s->playlisturl));
229 if ((ret = parse_playlist(h, s->playlisturl)) < 0)
230 goto fail;
231 }
232
233 if (s->n_segments == 0) {
234 av_log(h, AV_LOG_WARNING, "Empty playlist\n");
235 ret = AVERROR(EIO);
236 goto fail;
237 }
238 s->cur_seq_no = s->start_seq_no;
239 if (!s->finished && s->n_segments >= 3)
240 s->cur_seq_no = s->start_seq_no + s->n_segments - 3;
241
242 return 0;
243
244 fail:
245 hls_close(h);
246 return ret;
247 }
248
hls_read(URLContext * h,uint8_t * buf,int size)249 static int hls_read(URLContext *h, uint8_t *buf, int size)
250 {
251 HLSContext *s = h->priv_data;
252 const char *url;
253 int ret;
254 int64_t reload_interval;
255
256 start:
257 if (s->seg_hd) {
258 ret = ffurl_read(s->seg_hd, buf, size);
259 if (ret > 0)
260 return ret;
261 }
262 if (s->seg_hd) {
263 ffurl_closep(&s->seg_hd);
264 s->cur_seq_no++;
265 }
266 reload_interval = s->n_segments > 0 ?
267 s->segments[s->n_segments - 1]->duration :
268 s->target_duration;
269 retry:
270 if (!s->finished) {
271 int64_t now = av_gettime_relative();
272 if (now - s->last_load_time >= reload_interval) {
273 if ((ret = parse_playlist(h, s->playlisturl)) < 0)
274 return ret;
275 /* If we need to reload the playlist again below (if
276 * there's still no more segments), switch to a reload
277 * interval of half the target duration. */
278 reload_interval = s->target_duration / 2;
279 }
280 }
281 if (s->cur_seq_no < s->start_seq_no) {
282 av_log(h, AV_LOG_WARNING,
283 "skipping %d segments ahead, expired from playlist\n",
284 s->start_seq_no - s->cur_seq_no);
285 s->cur_seq_no = s->start_seq_no;
286 }
287 if (s->cur_seq_no - s->start_seq_no >= s->n_segments) {
288 if (s->finished)
289 return AVERROR_EOF;
290 while (av_gettime_relative() - s->last_load_time < reload_interval) {
291 if (ff_check_interrupt(&h->interrupt_callback))
292 return AVERROR_EXIT;
293 av_usleep(100*1000);
294 }
295 goto retry;
296 }
297 url = s->segments[s->cur_seq_no - s->start_seq_no]->url;
298 av_log(h, AV_LOG_DEBUG, "opening %s\n", url);
299 ret = ffurl_open_whitelist(&s->seg_hd, url, AVIO_FLAG_READ,
300 &h->interrupt_callback, NULL,
301 h->protocol_whitelist, h->protocol_blacklist, h);
302 if (ret < 0) {
303 if (ff_check_interrupt(&h->interrupt_callback))
304 return AVERROR_EXIT;
305 av_log(h, AV_LOG_WARNING, "Unable to open %s\n", url);
306 s->cur_seq_no++;
307 goto retry;
308 }
309 goto start;
310 }
311
312 const URLProtocol ff_hls_protocol = {
313 .name = "hls",
314 .url_open = hls_open,
315 .url_read = hls_read,
316 .url_close = hls_close,
317 .flags = URL_PROTOCOL_FLAG_NESTED_SCHEME,
318 .priv_data_size = sizeof(HLSContext),
319 };
320