359 lines
10 KiB
C
359 lines
10 KiB
C
/*
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* Apple HTTP Live Streaming Protocol Handler
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* Copyright (c) 2010 Martin Storsjo
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*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* Apple HTTP Live Streaming Protocol Handler
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* http://tools.ietf.org/html/draft-pantos-http-live-streaming
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*/
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#define _XOPEN_SOURCE 600
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#include "libavutil/avstring.h"
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#include "avformat.h"
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#include "internal.h"
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#include <unistd.h>
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/*
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* An apple http stream consists of a playlist with media segment files,
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* played sequentially. There may be several playlists with the same
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* video content, in different bandwidth variants, that are played in
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* parallel (preferrably only one bandwidth variant at a time). In this case,
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* the user supplied the url to a main playlist that only lists the variant
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* playlists.
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*
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* If the main playlist doesn't point at any variants, we still create
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* one anonymous toplevel variant for this, to maintain the structure.
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*/
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struct segment {
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int duration;
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char url[MAX_URL_SIZE];
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};
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struct variant {
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int bandwidth;
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char url[MAX_URL_SIZE];
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};
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typedef struct AppleHTTPContext {
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char playlisturl[MAX_URL_SIZE];
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int target_duration;
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int start_seq_no;
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int finished;
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int n_segments;
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struct segment **segments;
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int n_variants;
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struct variant **variants;
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int cur_seq_no;
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URLContext *seg_hd;
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int64_t last_load_time;
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} AppleHTTPContext;
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static int read_chomp_line(AVIOContext *s, char *buf, int maxlen)
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{
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int len = ff_get_line(s, buf, maxlen);
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while (len > 0 && isspace(buf[len - 1]))
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buf[--len] = '\0';
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return len;
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}
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static void make_absolute_url(char *buf, int size, const char *base,
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const char *rel)
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{
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char *sep;
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/* Absolute path, relative to the current server */
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if (base && strstr(base, "://") && rel[0] == '/') {
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if (base != buf)
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av_strlcpy(buf, base, size);
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sep = strstr(buf, "://");
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if (sep) {
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sep += 3;
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sep = strchr(sep, '/');
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if (sep)
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*sep = '\0';
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}
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av_strlcat(buf, rel, size);
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return;
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}
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/* If rel actually is an absolute url, just copy it */
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if (!base || strstr(rel, "://") || rel[0] == '/') {
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av_strlcpy(buf, rel, size);
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return;
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}
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if (base != buf)
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av_strlcpy(buf, base, size);
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/* Remove the file name from the base url */
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sep = strrchr(buf, '/');
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if (sep)
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sep[1] = '\0';
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else
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buf[0] = '\0';
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while (av_strstart(rel, "../", NULL) && sep) {
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/* Remove the path delimiter at the end */
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sep[0] = '\0';
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sep = strrchr(buf, '/');
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/* If the next directory name to pop off is "..", break here */
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if (!strcmp(sep ? &sep[1] : buf, "..")) {
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/* Readd the slash we just removed */
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av_strlcat(buf, "/", size);
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break;
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}
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/* Cut off the directory name */
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if (sep)
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sep[1] = '\0';
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else
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buf[0] = '\0';
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rel += 3;
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}
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av_strlcat(buf, rel, size);
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}
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static void free_segment_list(AppleHTTPContext *s)
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{
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int i;
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for (i = 0; i < s->n_segments; i++)
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av_free(s->segments[i]);
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av_freep(&s->segments);
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s->n_segments = 0;
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}
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static void free_variant_list(AppleHTTPContext *s)
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{
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int i;
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for (i = 0; i < s->n_variants; i++)
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av_free(s->variants[i]);
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av_freep(&s->variants);
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s->n_variants = 0;
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}
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struct variant_info {
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char bandwidth[20];
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};
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static void handle_variant_args(struct variant_info *info, const char *key,
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int key_len, char **dest, int *dest_len)
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{
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if (!strncmp(key, "BANDWIDTH=", key_len)) {
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*dest = info->bandwidth;
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*dest_len = sizeof(info->bandwidth);
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}
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}
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static int parse_playlist(URLContext *h, const char *url)
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{
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AppleHTTPContext *s = h->priv_data;
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AVIOContext *in;
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int ret = 0, duration = 0, is_segment = 0, is_variant = 0, bandwidth = 0;
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char line[1024];
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const char *ptr;
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if ((ret = avio_open(&in, url, URL_RDONLY)) < 0)
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return ret;
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read_chomp_line(in, line, sizeof(line));
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if (strcmp(line, "#EXTM3U"))
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return AVERROR_INVALIDDATA;
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free_segment_list(s);
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s->finished = 0;
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while (!url_feof(in)) {
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read_chomp_line(in, line, sizeof(line));
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if (av_strstart(line, "#EXT-X-STREAM-INF:", &ptr)) {
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struct variant_info info = {{0}};
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is_variant = 1;
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ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_variant_args,
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&info);
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bandwidth = atoi(info.bandwidth);
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} else if (av_strstart(line, "#EXT-X-TARGETDURATION:", &ptr)) {
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s->target_duration = atoi(ptr);
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} else if (av_strstart(line, "#EXT-X-MEDIA-SEQUENCE:", &ptr)) {
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s->start_seq_no = atoi(ptr);
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} else if (av_strstart(line, "#EXT-X-ENDLIST", &ptr)) {
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s->finished = 1;
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} else if (av_strstart(line, "#EXTINF:", &ptr)) {
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is_segment = 1;
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duration = atoi(ptr);
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} else if (av_strstart(line, "#", NULL)) {
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continue;
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} else if (line[0]) {
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if (is_segment) {
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struct segment *seg = av_malloc(sizeof(struct segment));
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if (!seg) {
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ret = AVERROR(ENOMEM);
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goto fail;
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}
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seg->duration = duration;
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make_absolute_url(seg->url, sizeof(seg->url), url, line);
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dynarray_add(&s->segments, &s->n_segments, seg);
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is_segment = 0;
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} else if (is_variant) {
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struct variant *var = av_malloc(sizeof(struct variant));
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if (!var) {
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ret = AVERROR(ENOMEM);
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goto fail;
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}
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var->bandwidth = bandwidth;
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make_absolute_url(var->url, sizeof(var->url), url, line);
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dynarray_add(&s->variants, &s->n_variants, var);
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is_variant = 0;
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}
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}
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}
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s->last_load_time = av_gettime();
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fail:
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avio_close(in);
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return ret;
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}
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static int applehttp_open(URLContext *h, const char *uri, int flags)
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{
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AppleHTTPContext *s;
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int ret, i;
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const char *nested_url;
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if (flags & (URL_WRONLY | URL_RDWR))
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return AVERROR_NOTSUPP;
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s = av_mallocz(sizeof(AppleHTTPContext));
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if (!s)
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return AVERROR(ENOMEM);
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h->priv_data = s;
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h->is_streamed = 1;
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if (av_strstart(uri, "applehttp+", &nested_url)) {
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av_strlcpy(s->playlisturl, nested_url, sizeof(s->playlisturl));
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} else if (av_strstart(uri, "applehttp://", &nested_url)) {
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av_strlcpy(s->playlisturl, "http://", sizeof(s->playlisturl));
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av_strlcat(s->playlisturl, nested_url, sizeof(s->playlisturl));
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} else {
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av_log(NULL, AV_LOG_ERROR, "Unsupported url %s\n", uri);
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ret = AVERROR(EINVAL);
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goto fail;
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}
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if ((ret = parse_playlist(h, s->playlisturl)) < 0)
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goto fail;
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if (s->n_segments == 0 && s->n_variants > 0) {
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int max_bandwidth = 0, maxvar = -1;
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for (i = 0; i < s->n_variants; i++) {
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if (s->variants[i]->bandwidth > max_bandwidth || i == 0) {
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max_bandwidth = s->variants[i]->bandwidth;
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maxvar = i;
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}
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}
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av_strlcpy(s->playlisturl, s->variants[maxvar]->url,
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sizeof(s->playlisturl));
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if ((ret = parse_playlist(h, s->playlisturl)) < 0)
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goto fail;
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}
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if (s->n_segments == 0) {
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av_log(NULL, AV_LOG_WARNING, "Empty playlist\n");
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ret = AVERROR(EIO);
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goto fail;
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}
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s->cur_seq_no = s->start_seq_no;
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if (!s->finished && s->n_segments >= 3)
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s->cur_seq_no = s->start_seq_no + s->n_segments - 3;
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return 0;
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fail:
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av_free(s);
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return ret;
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}
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static int applehttp_read(URLContext *h, uint8_t *buf, int size)
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{
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AppleHTTPContext *s = h->priv_data;
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const char *url;
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int ret;
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start:
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if (s->seg_hd) {
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ret = url_read(s->seg_hd, buf, size);
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if (ret > 0)
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return ret;
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}
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if (s->seg_hd) {
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url_close(s->seg_hd);
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s->seg_hd = NULL;
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s->cur_seq_no++;
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}
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retry:
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if (!s->finished) {
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int64_t now = av_gettime();
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if (now - s->last_load_time >= s->target_duration*1000000)
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if ((ret = parse_playlist(h, s->playlisturl)) < 0)
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return ret;
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}
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if (s->cur_seq_no < s->start_seq_no) {
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av_log(NULL, AV_LOG_WARNING,
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"skipping %d segments ahead, expired from playlist\n",
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s->start_seq_no - s->cur_seq_no);
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s->cur_seq_no = s->start_seq_no;
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}
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if (s->cur_seq_no - s->start_seq_no >= s->n_segments) {
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if (s->finished)
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return AVERROR_EOF;
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while (av_gettime() - s->last_load_time < s->target_duration*1000000) {
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if (url_interrupt_cb())
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return AVERROR(EINTR);
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usleep(100*1000);
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}
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goto retry;
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}
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url = s->segments[s->cur_seq_no - s->start_seq_no]->url,
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av_log(NULL, AV_LOG_DEBUG, "opening %s\n", url);
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ret = url_open(&s->seg_hd, url, URL_RDONLY);
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if (ret < 0) {
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if (url_interrupt_cb())
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return AVERROR(EINTR);
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av_log(NULL, AV_LOG_WARNING, "Unable to open %s\n", url);
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s->cur_seq_no++;
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goto retry;
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}
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goto start;
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}
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static int applehttp_close(URLContext *h)
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{
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AppleHTTPContext *s = h->priv_data;
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free_segment_list(s);
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free_variant_list(s);
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url_close(s->seg_hd);
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av_free(s);
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return 0;
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}
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URLProtocol ff_applehttp_protocol = {
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"applehttp",
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applehttp_open,
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applehttp_read,
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NULL, /* write */
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NULL, /* seek */
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applehttp_close,
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.flags = URL_PROTOCOL_FLAG_NESTED_SCHEME,
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};
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