yading@11: /*
yading@11:  * Apple HTTP Live Streaming Protocol Handler
yading@11:  * Copyright (c) 2010 Martin Storsjo
yading@11:  *
yading@11:  * This file is part of FFmpeg.
yading@11:  *
yading@11:  * FFmpeg is free software; you can redistribute it and/or
yading@11:  * modify it under the terms of the GNU Lesser General Public
yading@11:  * License as published by the Free Software Foundation; either
yading@11:  * version 2.1 of the License, or (at your option) any later version.
yading@11:  *
yading@11:  * FFmpeg is distributed in the hope that it will be useful,
yading@11:  * but WITHOUT ANY WARRANTY; without even the implied warranty of
yading@11:  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
yading@11:  * Lesser General Public License for more details.
yading@11:  *
yading@11:  * You should have received a copy of the GNU Lesser General Public
yading@11:  * License along with FFmpeg; if not, write to the Free Software
yading@11:  * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
yading@11:  */
yading@11: 
yading@11: /**
yading@11:  * @file
yading@11:  * Apple HTTP Live Streaming Protocol Handler
yading@11:  * http://tools.ietf.org/html/draft-pantos-http-live-streaming
yading@11:  */
yading@11: 
yading@11: #include "libavutil/avstring.h"
yading@11: #include "libavutil/time.h"
yading@11: #include "avformat.h"
yading@11: #include "internal.h"
yading@11: #include "url.h"
yading@11: #include "version.h"
yading@11: 
yading@11: /*
yading@11:  * An apple http stream consists of a playlist with media segment files,
yading@11:  * played sequentially. There may be several playlists with the same
yading@11:  * video content, in different bandwidth variants, that are played in
yading@11:  * parallel (preferably only one bandwidth variant at a time). In this case,
yading@11:  * the user supplied the url to a main playlist that only lists the variant
yading@11:  * playlists.
yading@11:  *
yading@11:  * If the main playlist doesn't point at any variants, we still create
yading@11:  * one anonymous toplevel variant for this, to maintain the structure.
yading@11:  */
yading@11: 
yading@11: struct segment {
yading@11:     int duration;
yading@11:     char url[MAX_URL_SIZE];
yading@11: };
yading@11: 
yading@11: struct variant {
yading@11:     int bandwidth;
yading@11:     char url[MAX_URL_SIZE];
yading@11: };
yading@11: 
yading@11: typedef struct HLSContext {
yading@11:     char playlisturl[MAX_URL_SIZE];
yading@11:     int target_duration;
yading@11:     int start_seq_no;
yading@11:     int finished;
yading@11:     int n_segments;
yading@11:     struct segment **segments;
yading@11:     int n_variants;
yading@11:     struct variant **variants;
yading@11:     int cur_seq_no;
yading@11:     URLContext *seg_hd;
yading@11:     int64_t last_load_time;
yading@11: } HLSContext;
yading@11: 
yading@11: static int read_chomp_line(AVIOContext *s, char *buf, int maxlen)
yading@11: {
yading@11:     int len = ff_get_line(s, buf, maxlen);
yading@11:     while (len > 0 && av_isspace(buf[len - 1]))
yading@11:         buf[--len] = '\0';
yading@11:     return len;
yading@11: }
yading@11: 
yading@11: static void free_segment_list(HLSContext *s)
yading@11: {
yading@11:     int i;
yading@11:     for (i = 0; i < s->n_segments; i++)
yading@11:         av_free(s->segments[i]);
yading@11:     av_freep(&s->segments);
yading@11:     s->n_segments = 0;
yading@11: }
yading@11: 
yading@11: static void free_variant_list(HLSContext *s)
yading@11: {
yading@11:     int i;
yading@11:     for (i = 0; i < s->n_variants; i++)
yading@11:         av_free(s->variants[i]);
yading@11:     av_freep(&s->variants);
yading@11:     s->n_variants = 0;
yading@11: }
yading@11: 
yading@11: struct variant_info {
yading@11:     char bandwidth[20];
yading@11: };
yading@11: 
yading@11: static void handle_variant_args(struct variant_info *info, const char *key,
yading@11:                                 int key_len, char **dest, int *dest_len)
yading@11: {
yading@11:     if (!strncmp(key, "BANDWIDTH=", key_len)) {
yading@11:         *dest     =        info->bandwidth;
yading@11:         *dest_len = sizeof(info->bandwidth);
yading@11:     }
yading@11: }
yading@11: 
yading@11: static int parse_playlist(URLContext *h, const char *url)
yading@11: {
yading@11:     HLSContext *s = h->priv_data;
yading@11:     AVIOContext *in;
yading@11:     int ret = 0, duration = 0, is_segment = 0, is_variant = 0, bandwidth = 0;
yading@11:     char line[1024];
yading@11:     const char *ptr;
yading@11: 
yading@11:     if ((ret = avio_open2(&in, url, AVIO_FLAG_READ,
yading@11:                           &h->interrupt_callback, NULL)) < 0)
yading@11:         return ret;
yading@11: 
yading@11:     read_chomp_line(in, line, sizeof(line));
yading@11:     if (strcmp(line, "#EXTM3U"))
yading@11:         return AVERROR_INVALIDDATA;
yading@11: 
yading@11:     free_segment_list(s);
yading@11:     s->finished = 0;
yading@11:     while (!url_feof(in)) {
yading@11:         read_chomp_line(in, line, sizeof(line));
yading@11:         if (av_strstart(line, "#EXT-X-STREAM-INF:", &ptr)) {
yading@11:             struct variant_info info = {{0}};
yading@11:             is_variant = 1;
yading@11:             ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_variant_args,
yading@11:                                &info);
yading@11:             bandwidth = atoi(info.bandwidth);
yading@11:         } else if (av_strstart(line, "#EXT-X-TARGETDURATION:", &ptr)) {
yading@11:             s->target_duration = atoi(ptr);
yading@11:         } else if (av_strstart(line, "#EXT-X-MEDIA-SEQUENCE:", &ptr)) {
yading@11:             s->start_seq_no = atoi(ptr);
yading@11:         } else if (av_strstart(line, "#EXT-X-ENDLIST", &ptr)) {
yading@11:             s->finished = 1;
yading@11:         } else if (av_strstart(line, "#EXTINF:", &ptr)) {
yading@11:             is_segment = 1;
yading@11:             duration = atoi(ptr);
yading@11:         } else if (av_strstart(line, "#", NULL)) {
yading@11:             continue;
yading@11:         } else if (line[0]) {
yading@11:             if (is_segment) {
yading@11:                 struct segment *seg = av_malloc(sizeof(struct segment));
yading@11:                 if (!seg) {
yading@11:                     ret = AVERROR(ENOMEM);
yading@11:                     goto fail;
yading@11:                 }
yading@11:                 seg->duration = duration;
yading@11:                 ff_make_absolute_url(seg->url, sizeof(seg->url), url, line);
yading@11:                 dynarray_add(&s->segments, &s->n_segments, seg);
yading@11:                 is_segment = 0;
yading@11:             } else if (is_variant) {
yading@11:                 struct variant *var = av_malloc(sizeof(struct variant));
yading@11:                 if (!var) {
yading@11:                     ret = AVERROR(ENOMEM);
yading@11:                     goto fail;
yading@11:                 }
yading@11:                 var->bandwidth = bandwidth;
yading@11:                 ff_make_absolute_url(var->url, sizeof(var->url), url, line);
yading@11:                 dynarray_add(&s->variants, &s->n_variants, var);
yading@11:                 is_variant = 0;
yading@11:             }
yading@11:         }
yading@11:     }
yading@11:     s->last_load_time = av_gettime();
yading@11: 
yading@11: fail:
yading@11:     avio_close(in);
yading@11:     return ret;
yading@11: }
yading@11: 
yading@11: static int hls_close(URLContext *h)
yading@11: {
yading@11:     HLSContext *s = h->priv_data;
yading@11: 
yading@11:     free_segment_list(s);
yading@11:     free_variant_list(s);
yading@11:     ffurl_close(s->seg_hd);
yading@11:     return 0;
yading@11: }
yading@11: 
yading@11: static int hls_open(URLContext *h, const char *uri, int flags)
yading@11: {
yading@11:     HLSContext *s = h->priv_data;
yading@11:     int ret, i;
yading@11:     const char *nested_url;
yading@11: 
yading@11:     if (flags & AVIO_FLAG_WRITE)
yading@11:         return AVERROR(ENOSYS);
yading@11: 
yading@11:     h->is_streamed = 1;
yading@11: 
yading@11:     if (av_strstart(uri, "hls+", &nested_url)) {
yading@11:         av_strlcpy(s->playlisturl, nested_url, sizeof(s->playlisturl));
yading@11:     } else if (av_strstart(uri, "hls://", &nested_url)) {
yading@11:         av_log(h, AV_LOG_ERROR,
yading@11:                "No nested protocol specified. Specify e.g. hls+http://%s\n",
yading@11:                nested_url);
yading@11:         ret = AVERROR(EINVAL);
yading@11:         goto fail;
yading@11:     } else {
yading@11:         av_log(h, AV_LOG_ERROR, "Unsupported url %s\n", uri);
yading@11:         ret = AVERROR(EINVAL);
yading@11:         goto fail;
yading@11:     }
yading@11:     av_log(h, AV_LOG_WARNING,
yading@11:            "Using the hls protocol is discouraged, please try using the "
yading@11:            "hls demuxer instead. The hls demuxer should be more complete "
yading@11:            "and work as well as the protocol implementation. (If not, "
yading@11:            "please report it.) To use the demuxer, simply use %s as url.\n",
yading@11:            s->playlisturl);
yading@11: 
yading@11:     if ((ret = parse_playlist(h, s->playlisturl)) < 0)
yading@11:         goto fail;
yading@11: 
yading@11:     if (s->n_segments == 0 && s->n_variants > 0) {
yading@11:         int max_bandwidth = 0, maxvar = -1;
yading@11:         for (i = 0; i < s->n_variants; i++) {
yading@11:             if (s->variants[i]->bandwidth > max_bandwidth || i == 0) {
yading@11:                 max_bandwidth = s->variants[i]->bandwidth;
yading@11:                 maxvar = i;
yading@11:             }
yading@11:         }
yading@11:         av_strlcpy(s->playlisturl, s->variants[maxvar]->url,
yading@11:                    sizeof(s->playlisturl));
yading@11:         if ((ret = parse_playlist(h, s->playlisturl)) < 0)
yading@11:             goto fail;
yading@11:     }
yading@11: 
yading@11:     if (s->n_segments == 0) {
yading@11:         av_log(h, AV_LOG_WARNING, "Empty playlist\n");
yading@11:         ret = AVERROR(EIO);
yading@11:         goto fail;
yading@11:     }
yading@11:     s->cur_seq_no = s->start_seq_no;
yading@11:     if (!s->finished && s->n_segments >= 3)
yading@11:         s->cur_seq_no = s->start_seq_no + s->n_segments - 3;
yading@11: 
yading@11:     return 0;
yading@11: 
yading@11: fail:
yading@11:     hls_close(h);
yading@11:     return ret;
yading@11: }
yading@11: 
yading@11: static int hls_read(URLContext *h, uint8_t *buf, int size)
yading@11: {
yading@11:     HLSContext *s = h->priv_data;
yading@11:     const char *url;
yading@11:     int ret;
yading@11:     int64_t reload_interval;
yading@11: 
yading@11: start:
yading@11:     if (s->seg_hd) {
yading@11:         ret = ffurl_read(s->seg_hd, buf, size);
yading@11:         if (ret > 0)
yading@11:             return ret;
yading@11:     }
yading@11:     if (s->seg_hd) {
yading@11:         ffurl_close(s->seg_hd);
yading@11:         s->seg_hd = NULL;
yading@11:         s->cur_seq_no++;
yading@11:     }
yading@11:     reload_interval = s->n_segments > 0 ?
yading@11:                       s->segments[s->n_segments - 1]->duration :
yading@11:                       s->target_duration;
yading@11:     reload_interval *= 1000000;
yading@11: retry:
yading@11:     if (!s->finished) {
yading@11:         int64_t now = av_gettime();
yading@11:         if (now - s->last_load_time >= reload_interval) {
yading@11:             if ((ret = parse_playlist(h, s->playlisturl)) < 0)
yading@11:                 return ret;
yading@11:             /* If we need to reload the playlist again below (if
yading@11:              * there's still no more segments), switch to a reload
yading@11:              * interval of half the target duration. */
yading@11:             reload_interval = s->target_duration * 500000LL;
yading@11:         }
yading@11:     }
yading@11:     if (s->cur_seq_no < s->start_seq_no) {
yading@11:         av_log(h, AV_LOG_WARNING,
yading@11:                "skipping %d segments ahead, expired from playlist\n",
yading@11:                s->start_seq_no - s->cur_seq_no);
yading@11:         s->cur_seq_no = s->start_seq_no;
yading@11:     }
yading@11:     if (s->cur_seq_no - s->start_seq_no >= s->n_segments) {
yading@11:         if (s->finished)
yading@11:             return AVERROR_EOF;
yading@11:         while (av_gettime() - s->last_load_time < reload_interval) {
yading@11:             if (ff_check_interrupt(&h->interrupt_callback))
yading@11:                 return AVERROR_EXIT;
yading@11:             av_usleep(100*1000);
yading@11:         }
yading@11:         goto retry;
yading@11:     }
yading@11:     url = s->segments[s->cur_seq_no - s->start_seq_no]->url,
yading@11:     av_log(h, AV_LOG_DEBUG, "opening %s\n", url);
yading@11:     ret = ffurl_open(&s->seg_hd, url, AVIO_FLAG_READ,
yading@11:                      &h->interrupt_callback, NULL);
yading@11:     if (ret < 0) {
yading@11:         if (ff_check_interrupt(&h->interrupt_callback))
yading@11:             return AVERROR_EXIT;
yading@11:         av_log(h, AV_LOG_WARNING, "Unable to open %s\n", url);
yading@11:         s->cur_seq_no++;
yading@11:         goto retry;
yading@11:     }
yading@11:     goto start;
yading@11: }
yading@11: 
yading@11: URLProtocol ff_hls_protocol = {
yading@11:     .name           = "hls",
yading@11:     .url_open       = hls_open,
yading@11:     .url_read       = hls_read,
yading@11:     .url_close      = hls_close,
yading@11:     .flags          = URL_PROTOCOL_FLAG_NESTED_SCHEME,
yading@11:     .priv_data_size = sizeof(HLSContext),
yading@11: };