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hlsproto.c
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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  int 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 {
61  int finished;
63  struct segment **segments;
64  int n_variants;
65  struct variant **variants;
66  int cur_seq_no;
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 
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 
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, duration = 0, is_segment = 0, is_variant = 0, bandwidth = 0;
115  char line[1024];
116  const char *ptr;
117 
118  if ((ret = avio_open2(&in, url, AVIO_FLAG_READ,
119  &h->interrupt_callback, NULL)) < 0)
120  return ret;
121 
122  read_chomp_line(in, line, sizeof(line));
123  if (strcmp(line, "#EXTM3U"))
124  return AVERROR_INVALIDDATA;
125 
127  s->finished = 0;
128  while (!url_feof(in)) {
129  read_chomp_line(in, line, sizeof(line));
130  if (av_strstart(line, "#EXT-X-STREAM-INF:", &ptr)) {
131  struct variant_info info = {{0}};
132  is_variant = 1;
134  &info);
135  bandwidth = atoi(info.bandwidth);
136  } else if (av_strstart(line, "#EXT-X-TARGETDURATION:", &ptr)) {
137  s->target_duration = atoi(ptr);
138  } else if (av_strstart(line, "#EXT-X-MEDIA-SEQUENCE:", &ptr)) {
139  s->start_seq_no = atoi(ptr);
140  } else if (av_strstart(line, "#EXT-X-ENDLIST", &ptr)) {
141  s->finished = 1;
142  } else if (av_strstart(line, "#EXTINF:", &ptr)) {
143  is_segment = 1;
144  duration = atoi(ptr);
145  } else if (av_strstart(line, "#", NULL)) {
146  continue;
147  } else if (line[0]) {
148  if (is_segment) {
149  struct segment *seg = av_malloc(sizeof(struct segment));
150  if (!seg) {
151  ret = AVERROR(ENOMEM);
152  goto fail;
153  }
154  seg->duration = duration;
155  ff_make_absolute_url(seg->url, sizeof(seg->url), url, line);
156  dynarray_add(&s->segments, &s->n_segments, seg);
157  is_segment = 0;
158  } else if (is_variant) {
159  struct variant *var = av_malloc(sizeof(struct variant));
160  if (!var) {
161  ret = AVERROR(ENOMEM);
162  goto fail;
163  }
164  var->bandwidth = bandwidth;
165  ff_make_absolute_url(var->url, sizeof(var->url), url, line);
166  dynarray_add(&s->variants, &s->n_variants, var);
167  is_variant = 0;
168  }
169  }
170  }
171  s->last_load_time = av_gettime();
172 
173 fail:
174  avio_close(in);
175  return ret;
176 }
177 
178 static int hls_close(URLContext *h)
179 {
180  HLSContext *s = h->priv_data;
181 
184  ffurl_close(s->seg_hd);
185  return 0;
186 }
187 
188 static int hls_open(URLContext *h, const char *uri, int flags)
189 {
190  HLSContext *s = h->priv_data;
191  int ret, i;
192  const char *nested_url;
193 
194  if (flags & AVIO_FLAG_WRITE)
195  return AVERROR(ENOSYS);
196 
197  h->is_streamed = 1;
198 
199  if (av_strstart(uri, "hls+", &nested_url)) {
200  av_strlcpy(s->playlisturl, nested_url, sizeof(s->playlisturl));
201  } else if (av_strstart(uri, "hls://", &nested_url)) {
202  av_log(h, AV_LOG_ERROR,
203  "No nested protocol specified. Specify e.g. hls+http://%s\n",
204  nested_url);
205  ret = AVERROR(EINVAL);
206  goto fail;
207 #if FF_API_APPLEHTTP_PROTO
208  } else if (av_strstart(uri, "applehttp+", &nested_url)) {
209  av_strlcpy(s->playlisturl, nested_url, sizeof(s->playlisturl));
211  "The applehttp protocol is deprecated, use hls+%s as url "
212  "instead.\n", nested_url);
213  } else if (av_strstart(uri, "applehttp://", &nested_url)) {
214  av_strlcpy(s->playlisturl, "http://", sizeof(s->playlisturl));
215  av_strlcat(s->playlisturl, nested_url, sizeof(s->playlisturl));
217  "The applehttp protocol is deprecated, use hls+http://%s as url "
218  "instead.\n", nested_url);
219 #endif
220  } else {
221  av_log(h, AV_LOG_ERROR, "Unsupported url %s\n", uri);
222  ret = AVERROR(EINVAL);
223  goto fail;
224  }
226  "Using the hls protocol is discouraged, please try using the "
227  "hls demuxer instead. The hls demuxer should be more complete "
228  "and work as well as the protocol implementation. (If not, "
229  "please report it.) To use the demuxer, simply use %s as url.\n",
230  s->playlisturl);
231 
232  if ((ret = parse_playlist(h, s->playlisturl)) < 0)
233  goto fail;
234 
235  if (s->n_segments == 0 && s->n_variants > 0) {
236  int max_bandwidth = 0, maxvar = -1;
237  for (i = 0; i < s->n_variants; i++) {
238  if (s->variants[i]->bandwidth > max_bandwidth || i == 0) {
239  max_bandwidth = s->variants[i]->bandwidth;
240  maxvar = i;
241  }
242  }
243  av_strlcpy(s->playlisturl, s->variants[maxvar]->url,
244  sizeof(s->playlisturl));
245  if ((ret = parse_playlist(h, s->playlisturl)) < 0)
246  goto fail;
247  }
248 
249  if (s->n_segments == 0) {
250  av_log(h, AV_LOG_WARNING, "Empty playlist\n");
251  ret = AVERROR(EIO);
252  goto fail;
253  }
254  s->cur_seq_no = s->start_seq_no;
255  if (!s->finished && s->n_segments >= 3)
256  s->cur_seq_no = s->start_seq_no + s->n_segments - 3;
257 
258  return 0;
259 
260 fail:
261  hls_close(h);
262  return ret;
263 }
264 
265 static int hls_read(URLContext *h, uint8_t *buf, int size)
266 {
267  HLSContext *s = h->priv_data;
268  const char *url;
269  int ret;
270  int64_t reload_interval;
271 
272 start:
273  if (s->seg_hd) {
274  ret = ffurl_read(s->seg_hd, buf, size);
275  if (ret > 0)
276  return ret;
277  }
278  if (s->seg_hd) {
279  ffurl_close(s->seg_hd);
280  s->seg_hd = NULL;
281  s->cur_seq_no++;
282  }
283  reload_interval = s->n_segments > 0 ?
284  s->segments[s->n_segments - 1]->duration :
285  s->target_duration;
286  reload_interval *= 1000000;
287 retry:
288  if (!s->finished) {
289  int64_t now = av_gettime();
290  if (now - s->last_load_time >= reload_interval) {
291  if ((ret = parse_playlist(h, s->playlisturl)) < 0)
292  return ret;
293  /* If we need to reload the playlist again below (if
294  * there's still no more segments), switch to a reload
295  * interval of half the target duration. */
296  reload_interval = s->target_duration * 500000LL;
297  }
298  }
299  if (s->cur_seq_no < s->start_seq_no) {
301  "skipping %d segments ahead, expired from playlist\n",
302  s->start_seq_no - s->cur_seq_no);
303  s->cur_seq_no = s->start_seq_no;
304  }
305  if (s->cur_seq_no - s->start_seq_no >= s->n_segments) {
306  if (s->finished)
307  return AVERROR_EOF;
308  while (av_gettime() - s->last_load_time < reload_interval) {
310  return AVERROR_EXIT;
311  av_usleep(100*1000);
312  }
313  goto retry;
314  }
315  url = s->segments[s->cur_seq_no - s->start_seq_no]->url,
316  av_log(h, AV_LOG_DEBUG, "opening %s\n", url);
317  ret = ffurl_open(&s->seg_hd, url, AVIO_FLAG_READ,
318  &h->interrupt_callback, NULL);
319  if (ret < 0) {
321  return AVERROR_EXIT;
322  av_log(h, AV_LOG_WARNING, "Unable to open %s\n", url);
323  s->cur_seq_no++;
324  goto retry;
325  }
326  goto start;
327 }
328 
329 #if FF_API_APPLEHTTP_PROTO
330 URLProtocol ff_applehttp_protocol = {
331  .name = "applehttp",
332  .url_open = hls_open,
333  .url_read = hls_read,
334  .url_close = hls_close,
336  .priv_data_size = sizeof(HLSContext),
337 };
338 #endif
339 
341  .name = "hls",
342  .url_open = hls_open,
343  .url_read = hls_read,
344  .url_close = hls_close,
346  .priv_data_size = sizeof(HLSContext),
347 };