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ffmpeg/libavformat/applehttpproto.c

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/*
* Apple HTTP Live Streaming Protocol Handler
* Copyright (c) 2010 Martin Storsjo
*
* This file is part of FFmpeg.
*
* FFmpeg is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* FFmpeg is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with FFmpeg; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
/**
* @file
* Apple HTTP Live Streaming Protocol Handler
* http://tools.ietf.org/html/draft-pantos-http-live-streaming
*/
#include "libavutil/avstring.h"
#include "avformat.h"
#include "internal.h"
#include "url.h"
#include <unistd.h>
/*
* An apple http stream consists of a playlist with media segment files,
* played sequentially. There may be several playlists with the same
* video content, in different bandwidth variants, that are played in
* parallel (preferrably only one bandwidth variant at a time). In this case,
* the user supplied the url to a main playlist that only lists the variant
* playlists.
*
* If the main playlist doesn't point at any variants, we still create
* one anonymous toplevel variant for this, to maintain the structure.
*/
struct segment {
int duration;
char url[MAX_URL_SIZE];
};
struct variant {
int bandwidth;
char url[MAX_URL_SIZE];
};
typedef struct AppleHTTPContext {
char playlisturl[MAX_URL_SIZE];
int target_duration;
int start_seq_no;
int finished;
int n_segments;
struct segment **segments;
int n_variants;
struct variant **variants;
int cur_seq_no;
URLContext *seg_hd;
int64_t last_load_time;
} AppleHTTPContext;
static int read_chomp_line(AVIOContext *s, char *buf, int maxlen)
{
int len = ff_get_line(s, buf, maxlen);
while (len > 0 && isspace(buf[len - 1]))
buf[--len] = '\0';
return len;
}
static void free_segment_list(AppleHTTPContext *s)
{
int i;
for (i = 0; i < s->n_segments; i++)
av_free(s->segments[i]);
av_freep(&s->segments);
s->n_segments = 0;
}
static void free_variant_list(AppleHTTPContext *s)
{
int i;
for (i = 0; i < s->n_variants; i++)
av_free(s->variants[i]);
av_freep(&s->variants);
s->n_variants = 0;
}
struct variant_info {
char bandwidth[20];
};
static void handle_variant_args(struct variant_info *info, const char *key,
int key_len, char **dest, int *dest_len)
{
if (!strncmp(key, "BANDWIDTH=", key_len)) {
*dest = info->bandwidth;
*dest_len = sizeof(info->bandwidth);
}
}
static int parse_playlist(URLContext *h, const char *url)
{
AppleHTTPContext *s = h->priv_data;
AVIOContext *in;
int ret = 0, duration = 0, is_segment = 0, is_variant = 0, bandwidth = 0;
char line[1024];
const char *ptr;
if ((ret = avio_open2(&in, url, AVIO_FLAG_READ,
&h->interrupt_callback, NULL)) < 0)
return ret;
read_chomp_line(in, line, sizeof(line));
if (strcmp(line, "#EXTM3U"))
return AVERROR_INVALIDDATA;
free_segment_list(s);
s->finished = 0;
while (!url_feof(in)) {
read_chomp_line(in, line, sizeof(line));
if (av_strstart(line, "#EXT-X-STREAM-INF:", &ptr)) {
struct variant_info info = {{0}};
is_variant = 1;
ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_variant_args,
&info);
bandwidth = atoi(info.bandwidth);
} else if (av_strstart(line, "#EXT-X-TARGETDURATION:", &ptr)) {
s->target_duration = atoi(ptr);
} else if (av_strstart(line, "#EXT-X-MEDIA-SEQUENCE:", &ptr)) {
s->start_seq_no = atoi(ptr);
} else if (av_strstart(line, "#EXT-X-ENDLIST", &ptr)) {
s->finished = 1;
} else if (av_strstart(line, "#EXTINF:", &ptr)) {
is_segment = 1;
duration = atoi(ptr);
} else if (av_strstart(line, "#", NULL)) {
continue;
} else if (line[0]) {
if (is_segment) {
struct segment *seg = av_malloc(sizeof(struct segment));
if (!seg) {
ret = AVERROR(ENOMEM);
goto fail;
}
seg->duration = duration;
ff_make_absolute_url(seg->url, sizeof(seg->url), url, line);
dynarray_add(&s->segments, &s->n_segments, seg);
is_segment = 0;
} else if (is_variant) {
struct variant *var = av_malloc(sizeof(struct variant));
if (!var) {
ret = AVERROR(ENOMEM);
goto fail;
}
var->bandwidth = bandwidth;
ff_make_absolute_url(var->url, sizeof(var->url), url, line);
dynarray_add(&s->variants, &s->n_variants, var);
is_variant = 0;
}
}
}
s->last_load_time = av_gettime();
fail:
avio_close(in);
return ret;
}
static int applehttp_close(URLContext *h)
{
AppleHTTPContext *s = h->priv_data;
free_segment_list(s);
free_variant_list(s);
ffurl_close(s->seg_hd);
return 0;
}
static int applehttp_open(URLContext *h, const char *uri, int flags)
{
AppleHTTPContext *s = h->priv_data;
int ret, i;
const char *nested_url;
if (flags & AVIO_FLAG_WRITE)
return AVERROR(ENOSYS);
h->is_streamed = 1;
if (av_strstart(uri, "applehttp+", &nested_url)) {
av_strlcpy(s->playlisturl, nested_url, sizeof(s->playlisturl));
} else if (av_strstart(uri, "applehttp://", &nested_url)) {
av_strlcpy(s->playlisturl, "http://", sizeof(s->playlisturl));
av_strlcat(s->playlisturl, nested_url, sizeof(s->playlisturl));
} else {
av_log(h, AV_LOG_ERROR, "Unsupported url %s\n", uri);
ret = AVERROR(EINVAL);
goto fail;
}
if ((ret = parse_playlist(h, s->playlisturl)) < 0)
goto fail;
if (s->n_segments == 0 && s->n_variants > 0) {
int max_bandwidth = 0, maxvar = -1;
for (i = 0; i < s->n_variants; i++) {
if (s->variants[i]->bandwidth > max_bandwidth || i == 0) {
max_bandwidth = s->variants[i]->bandwidth;
maxvar = i;
}
}
av_strlcpy(s->playlisturl, s->variants[maxvar]->url,
sizeof(s->playlisturl));
if ((ret = parse_playlist(h, s->playlisturl)) < 0)
goto fail;
}
if (s->n_segments == 0) {
av_log(h, AV_LOG_WARNING, "Empty playlist\n");
ret = AVERROR(EIO);
goto fail;
}
s->cur_seq_no = s->start_seq_no;
if (!s->finished && s->n_segments >= 3)
s->cur_seq_no = s->start_seq_no + s->n_segments - 3;
return 0;
fail:
applehttp_close(h);
return ret;
}
static int applehttp_read(URLContext *h, uint8_t *buf, int size)
{
AppleHTTPContext *s = h->priv_data;
const char *url;
int ret;
start:
if (s->seg_hd) {
ret = ffurl_read(s->seg_hd, buf, size);
if (ret > 0)
return ret;
}
if (s->seg_hd) {
ffurl_close(s->seg_hd);
s->seg_hd = NULL;
s->cur_seq_no++;
}
retry:
if (!s->finished) {
int64_t now = av_gettime();
if (now - s->last_load_time >= s->target_duration*1000000)
if ((ret = parse_playlist(h, s->playlisturl)) < 0)
return ret;
}
if (s->cur_seq_no < s->start_seq_no) {
av_log(h, AV_LOG_WARNING,
"skipping %d segments ahead, expired from playlist\n",
s->start_seq_no - s->cur_seq_no);
s->cur_seq_no = s->start_seq_no;
}
if (s->cur_seq_no - s->start_seq_no >= s->n_segments) {
if (s->finished)
return AVERROR_EOF;
while (av_gettime() - s->last_load_time < s->target_duration*1000000) {
if (ff_check_interrupt(&h->interrupt_callback))
return AVERROR_EXIT;
usleep(100*1000);
}
goto retry;
}
url = s->segments[s->cur_seq_no - s->start_seq_no]->url,
av_log(h, AV_LOG_DEBUG, "opening %s\n", url);
ret = ffurl_open(&s->seg_hd, url, AVIO_FLAG_READ,
&h->interrupt_callback, NULL);
if (ret < 0) {
if (ff_check_interrupt(&h->interrupt_callback))
return AVERROR_EXIT;
av_log(h, AV_LOG_WARNING, "Unable to open %s\n", url);
s->cur_seq_no++;
goto retry;
}
goto start;
}
URLProtocol ff_applehttp_protocol = {
.name = "applehttp",
.url_open = applehttp_open,
.url_read = applehttp_read,
.url_close = applehttp_close,
.flags = URL_PROTOCOL_FLAG_NESTED_SCHEME,
.priv_data_size = sizeof(AppleHTTPContext),
};
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