libavformat/hlsproto.c

   1 /*
   2  * Apple HTTP Live Streaming Protocol Handler
   3  * Copyright (c) 2010 Martin Storsjo
   4  *
   5  * This file is part of Libav.
   6  *
   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.
  11  *
  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.
  16  *
  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
  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 {
  58     char playlisturl[MAX_URL_SIZE];
  59     int 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, 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
 126     free_segment_list(s);
 127     s->finished = 0;
 128     while (!in->eof_reached) {
 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;
 133             ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_variant_args,
 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
 182     free_segment_list(s);
 183     free_variant_list(s);
 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));
 210         av_log(h, AV_LOG_WARNING,
 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));
 216         av_log(h, AV_LOG_WARNING,
 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     }
 225     av_log(h, AV_LOG_WARNING,
 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 * 500000;
 297         }
 298     }
 299     if (s->cur_seq_no < s->start_seq_no) {
 300         av_log(h, AV_LOG_WARNING,
 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) {
 309             if (ff_check_interrupt(&h->interrupt_callback))
 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) {
 320         if (ff_check_interrupt(&h->interrupt_callback))
 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,
 335     .flags          = URL_PROTOCOL_FLAG_NESTED_SCHEME,
 336     .priv_data_size = sizeof(HLSContext),
 337 };
 338 #endif
 339
 340 URLProtocol ff_hls_protocol = {
 341     .name           = "hls",
 342     .url_open       = hls_open,
 343     .url_read       = hls_read,
 344     .url_close      = hls_close,
 345     .flags          = URL_PROTOCOL_FLAG_NESTED_SCHEME,
 346     .priv_data_size = sizeof(HLSContext),
 347 };