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path: root/libavformat/hlsproto.c (plain)
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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 "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
48struct segment {
49 int64_t duration;
50 char url[MAX_URL_SIZE];
51};
52
53struct variant {
54 int bandwidth;
55 char url[MAX_URL_SIZE];
56};
57
58typedef 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
72static int read_chomp_line(AVIOContext *s, char *buf, int maxlen)
73{
74 int len = ff_get_line(s, buf, maxlen);
75 while (len > 0 && av_isspace(buf[len - 1]))
76 buf[--len] = '\0';
77 return len;
78}
79
80static void free_segment_list(HLSContext *s)
81{
82 int i;
83 for (i = 0; i < s->n_segments; i++)
84 av_freep(&s->segments[i]);
85 av_freep(&s->segments);
86 s->n_segments = 0;
87}
88
89static void free_variant_list(HLSContext *s)
90{
91 int i;
92 for (i = 0; i < s->n_variants; i++)
93 av_freep(&s->variants[i]);
94 av_freep(&s->variants);
95 s->n_variants = 0;
96}
97
98struct variant_info {
99 char bandwidth[20];
100};
101
102static void handle_variant_args(struct variant_info *info, const char *key,
103 int key_len, char **dest, int *dest_len)
104{
105 if (!strncmp(key, "BANDWIDTH=", key_len)) {
106 *dest = info->bandwidth;
107 *dest_len = sizeof(info->bandwidth);
108 }
109}
110
111static int parse_playlist(URLContext *h, const char *url)
112{
113 HLSContext *s = h->priv_data;
114 AVIOContext *in;
115 int ret = 0, is_segment = 0, is_variant = 0, bandwidth = 0;
116 int64_t duration = 0;
117 char line[1024];
118 const char *ptr;
119
120 if ((ret = ffio_open_whitelist(&in, url, AVIO_FLAG_READ,
121 &h->interrupt_callback, NULL,
122 h->protocol_whitelist, h->protocol_blacklist)) < 0)
123 return ret;
124
125 read_chomp_line(in, line, sizeof(line));
126 if (strcmp(line, "#EXTM3U")) {
127 ret = AVERROR_INVALIDDATA;
128 goto fail;
129 }
130
131 free_segment_list(s);
132 s->finished = 0;
133 while (!avio_feof(in)) {
134 read_chomp_line(in, line, sizeof(line));
135 if (av_strstart(line, "#EXT-X-STREAM-INF:", &ptr)) {
136 struct variant_info info = {{0}};
137 is_variant = 1;
138 ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_variant_args,
139 &info);
140 bandwidth = atoi(info.bandwidth);
141 } else if (av_strstart(line, "#EXT-X-TARGETDURATION:", &ptr)) {
142 s->target_duration = atoi(ptr) * AV_TIME_BASE;
143 } else if (av_strstart(line, "#EXT-X-MEDIA-SEQUENCE:", &ptr)) {
144 s->start_seq_no = atoi(ptr);
145 } else if (av_strstart(line, "#EXT-X-ENDLIST", &ptr)) {
146 s->finished = 1;
147 } else if (av_strstart(line, "#EXTINF:", &ptr)) {
148 is_segment = 1;
149 duration = atof(ptr) * AV_TIME_BASE;
150 } else if (av_strstart(line, "#", NULL)) {
151 continue;
152 } else if (line[0]) {
153 if (is_segment) {
154 struct segment *seg = av_malloc(sizeof(struct segment));
155 if (!seg) {
156 ret = AVERROR(ENOMEM);
157 goto fail;
158 }
159 seg->duration = duration;
160 ff_make_absolute_url(seg->url, sizeof(seg->url), url, line);
161 dynarray_add(&s->segments, &s->n_segments, seg);
162 is_segment = 0;
163 } else if (is_variant) {
164 struct variant *var = av_malloc(sizeof(struct variant));
165 if (!var) {
166 ret = AVERROR(ENOMEM);
167 goto fail;
168 }
169 var->bandwidth = bandwidth;
170 ff_make_absolute_url(var->url, sizeof(var->url), url, line);
171 dynarray_add(&s->variants, &s->n_variants, var);
172 is_variant = 0;
173 }
174 }
175 }
176 s->last_load_time = av_gettime_relative();
177
178fail:
179 avio_close(in);
180 return ret;
181}
182
183static int hls_close(URLContext *h)
184{
185 HLSContext *s = h->priv_data;
186
187 free_segment_list(s);
188 free_variant_list(s);
189 ffurl_close(s->seg_hd);
190 return 0;
191}
192
193static int hls_open(URLContext *h, const char *uri, int flags)
194{
195 HLSContext *s = h->priv_data;
196 int ret, i;
197 const char *nested_url;
198
199 if (flags & AVIO_FLAG_WRITE)
200 return AVERROR(ENOSYS);
201
202 h->is_streamed = 1;
203
204 if (av_strstart(uri, "hls+", &nested_url)) {
205 av_strlcpy(s->playlisturl, nested_url, sizeof(s->playlisturl));
206 } else if (av_strstart(uri, "hls://", &nested_url)) {
207 av_log(h, AV_LOG_ERROR,
208 "No nested protocol specified. Specify e.g. hls+http://%s\n",
209 nested_url);
210 ret = AVERROR(EINVAL);
211 goto fail;
212 } else {
213 av_log(h, AV_LOG_ERROR, "Unsupported url %s\n", uri);
214 ret = AVERROR(EINVAL);
215 goto fail;
216 }
217 av_log(h, AV_LOG_WARNING,
218 "Using the hls protocol is discouraged, please try using the "
219 "hls demuxer instead. The hls demuxer should be more complete "
220 "and work as well as the protocol implementation. (If not, "
221 "please report it.) To use the demuxer, simply use %s as url.\n",
222 s->playlisturl);
223
224 if ((ret = parse_playlist(h, s->playlisturl)) < 0)
225 goto fail;
226
227 if (s->n_segments == 0 && s->n_variants > 0) {
228 int max_bandwidth = 0, maxvar = -1;
229 for (i = 0; i < s->n_variants; i++) {
230 if (s->variants[i]->bandwidth > max_bandwidth || i == 0) {
231 max_bandwidth = s->variants[i]->bandwidth;
232 maxvar = i;
233 }
234 }
235 av_strlcpy(s->playlisturl, s->variants[maxvar]->url,
236 sizeof(s->playlisturl));
237 if ((ret = parse_playlist(h, s->playlisturl)) < 0)
238 goto fail;
239 }
240
241 if (s->n_segments == 0) {
242 av_log(h, AV_LOG_WARNING, "Empty playlist\n");
243 ret = AVERROR(EIO);
244 goto fail;
245 }
246 s->cur_seq_no = s->start_seq_no;
247 if (!s->finished && s->n_segments >= 3)
248 s->cur_seq_no = s->start_seq_no + s->n_segments - 3;
249
250 return 0;
251
252fail:
253 hls_close(h);
254 return ret;
255}
256
257static int hls_read(URLContext *h, uint8_t *buf, int size)
258{
259 HLSContext *s = h->priv_data;
260 const char *url;
261 int ret;
262 int64_t reload_interval;
263
264start:
265 if (s->seg_hd) {
266 ret = ffurl_read(s->seg_hd, buf, size);
267 if (ret > 0)
268 return ret;
269 }
270 if (s->seg_hd) {
271 ffurl_close(s->seg_hd);
272 s->seg_hd = NULL;
273 s->cur_seq_no++;
274 }
275 reload_interval = s->n_segments > 0 ?
276 s->segments[s->n_segments - 1]->duration :
277 s->target_duration;
278retry:
279 if (!s->finished) {
280 int64_t now = av_gettime_relative();
281 if (now - s->last_load_time >= reload_interval) {
282 if ((ret = parse_playlist(h, s->playlisturl)) < 0)
283 return ret;
284 /* If we need to reload the playlist again below (if
285 * there's still no more segments), switch to a reload
286 * interval of half the target duration. */
287 reload_interval = s->target_duration / 2;
288 }
289 }
290 if (s->cur_seq_no < s->start_seq_no) {
291 av_log(h, AV_LOG_WARNING,
292 "skipping %d segments ahead, expired from playlist\n",
293 s->start_seq_no - s->cur_seq_no);
294 s->cur_seq_no = s->start_seq_no;
295 }
296 if (s->cur_seq_no - s->start_seq_no >= s->n_segments) {
297 if (s->finished)
298 return AVERROR_EOF;
299 while (av_gettime_relative() - s->last_load_time < reload_interval) {
300 if (ff_check_interrupt(&h->interrupt_callback))
301 return AVERROR_EXIT;
302 av_usleep(100*1000);
303 }
304 goto retry;
305 }
306 url = s->segments[s->cur_seq_no - s->start_seq_no]->url,
307 av_log(h, AV_LOG_DEBUG, "opening %s\n", url);
308 ret = ffurl_open_whitelist(&s->seg_hd, url, AVIO_FLAG_READ,
309 &h->interrupt_callback, NULL,
310 h->protocol_whitelist, h->protocol_blacklist, h);
311 if (ret < 0) {
312 if (ff_check_interrupt(&h->interrupt_callback))
313 return AVERROR_EXIT;
314 av_log(h, AV_LOG_WARNING, "Unable to open %s\n", url);
315 s->cur_seq_no++;
316 goto retry;
317 }
318 goto start;
319}
320
321const URLProtocol ff_hls_protocol = {
322 .name = "hls",
323 .url_open = hls_open,
324 .url_read = hls_read,
325 .url_close = hls_close,
326 .flags = URL_PROTOCOL_FLAG_NESTED_SCHEME,
327 .priv_data_size = sizeof(HLSContext),
328};
329
generated by cgit at 2024-05-17 03:08:01 (GMT)