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https://git.ffmpeg.org/ffmpeg.git
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185a155e57
This fixes roundup issue 2583. Signed-off-by: Ronald S. Bultje <rsbultje@gmail.com>
606 lines
19 KiB
C
606 lines
19 KiB
C
/*
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* Apple HTTP Live Streaming demuxer
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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 demuxer
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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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/*
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* Each variant has its own demuxer. If it currently is active,
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* it has an open ByteIOContext too, and potentially an AVPacket
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* containing the next packet from this stream.
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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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ByteIOContext *pb;
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AVFormatContext *ctx;
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AVPacket pkt;
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int stream_offset;
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int start_seq_no;
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int n_segments;
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struct segment **segments;
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int needed;
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};
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typedef struct AppleHTTPContext {
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int target_duration;
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int finished;
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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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int64_t last_load_time;
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int64_t last_packet_dts;
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int max_start_seq, min_end_seq;
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} AppleHTTPContext;
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static int read_chomp_line(ByteIOContext *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(struct variant *var)
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{
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int i;
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for (i = 0; i < var->n_segments; i++)
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av_free(var->segments[i]);
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av_freep(&var->segments);
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var->n_segments = 0;
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}
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static void free_variant_list(AppleHTTPContext *c)
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{
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int i;
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for (i = 0; i < c->n_variants; i++) {
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struct variant *var = c->variants[i];
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free_segment_list(var);
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av_free_packet(&var->pkt);
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if (var->pb)
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url_fclose(var->pb);
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if (var->ctx) {
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var->ctx->pb = NULL;
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av_close_input_file(var->ctx);
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}
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av_free(var);
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}
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av_freep(&c->variants);
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c->n_variants = 0;
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}
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/*
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* Used to reset a statically allocated AVPacket to a clean slate,
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* containing no data.
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*/
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static void reset_packet(AVPacket *pkt)
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{
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av_init_packet(pkt);
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pkt->data = NULL;
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}
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static struct variant *new_variant(AppleHTTPContext *c, int bandwidth,
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const char *url, const char *base)
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{
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struct variant *var = av_mallocz(sizeof(struct variant));
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if (!var)
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return NULL;
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reset_packet(&var->pkt);
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var->bandwidth = bandwidth;
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make_absolute_url(var->url, sizeof(var->url), base, url);
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dynarray_add(&c->variants, &c->n_variants, var);
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return var;
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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(AppleHTTPContext *c, const char *url,
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struct variant *var, ByteIOContext *in)
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{
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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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int close_in = 0;
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if (!in) {
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close_in = 1;
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if ((ret = url_fopen(&in, url, URL_RDONLY)) < 0)
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return ret;
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}
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read_chomp_line(in, line, sizeof(line));
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if (strcmp(line, "#EXTM3U")) {
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ret = AVERROR_INVALIDDATA;
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goto fail;
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}
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if (var)
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free_segment_list(var);
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c->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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c->target_duration = atoi(ptr);
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} else if (av_strstart(line, "#EXT-X-MEDIA-SEQUENCE:", &ptr)) {
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if (!var) {
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var = new_variant(c, 0, url, NULL);
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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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}
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var->start_seq_no = atoi(ptr);
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} else if (av_strstart(line, "#EXT-X-ENDLIST", &ptr)) {
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c->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_variant) {
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if (!new_variant(c, bandwidth, line, url)) {
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ret = AVERROR(ENOMEM);
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goto fail;
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}
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is_variant = 0;
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bandwidth = 0;
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}
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if (is_segment) {
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struct segment *seg;
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if (!var) {
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var = new_variant(c, 0, url, NULL);
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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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}
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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(&var->segments, &var->n_segments, seg);
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is_segment = 0;
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}
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}
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}
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c->last_load_time = av_gettime();
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fail:
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if (close_in)
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url_fclose(in);
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return ret;
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}
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static int applehttp_read_header(AVFormatContext *s, AVFormatParameters *ap)
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{
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AppleHTTPContext *c = s->priv_data;
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int ret = 0, i, j, stream_offset = 0;
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if ((ret = parse_playlist(c, s->filename, NULL, s->pb)) < 0)
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goto fail;
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if (c->n_variants == 0) {
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av_log(NULL, AV_LOG_WARNING, "Empty playlist\n");
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ret = AVERROR_EOF;
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goto fail;
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}
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/* If the playlist only contained variants, parse each individual
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* variant playlist. */
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if (c->n_variants > 1 || c->variants[0]->n_segments == 0) {
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for (i = 0; i < c->n_variants; i++) {
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struct variant *v = c->variants[i];
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if ((ret = parse_playlist(c, v->url, v, NULL)) < 0)
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goto fail;
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}
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}
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if (c->variants[0]->n_segments == 0) {
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av_log(NULL, AV_LOG_WARNING, "Empty playlist\n");
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ret = AVERROR_EOF;
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goto fail;
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}
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/* If this isn't a live stream, calculate the total duration of the
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* stream. */
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if (c->finished) {
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int64_t duration = 0;
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for (i = 0; i < c->variants[0]->n_segments; i++)
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duration += c->variants[0]->segments[i]->duration;
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s->duration = duration * AV_TIME_BASE;
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}
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c->min_end_seq = INT_MAX;
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/* Open the demuxer for each variant */
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for (i = 0; i < c->n_variants; i++) {
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struct variant *v = c->variants[i];
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if (v->n_segments == 0)
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continue;
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c->max_start_seq = FFMAX(c->max_start_seq, v->start_seq_no);
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c->min_end_seq = FFMIN(c->min_end_seq, v->start_seq_no +
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v->n_segments);
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ret = av_open_input_file(&v->ctx, v->segments[0]->url, NULL, 0, NULL);
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if (ret < 0)
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goto fail;
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url_fclose(v->ctx->pb);
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v->ctx->pb = NULL;
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v->stream_offset = stream_offset;
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/* Create new AVStreams for each stream in this variant */
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for (j = 0; j < v->ctx->nb_streams; j++) {
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AVStream *st = av_new_stream(s, i);
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if (!st) {
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ret = AVERROR(ENOMEM);
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goto fail;
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}
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avcodec_copy_context(st->codec, v->ctx->streams[j]->codec);
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}
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stream_offset += v->ctx->nb_streams;
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}
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c->last_packet_dts = AV_NOPTS_VALUE;
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c->cur_seq_no = c->max_start_seq;
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/* If this is a live stream with more than 3 segments, start at the
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* third last segment. */
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if (!c->finished && c->min_end_seq - c->max_start_seq > 3)
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c->cur_seq_no = c->min_end_seq - 2;
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return 0;
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fail:
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free_variant_list(c);
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return ret;
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}
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static int open_variant(AppleHTTPContext *c, struct variant *var, int skip)
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{
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int ret;
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if (c->cur_seq_no < var->start_seq_no) {
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av_log(NULL, AV_LOG_WARNING,
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"seq %d not available in variant %s, skipping\n",
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var->start_seq_no, var->url);
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return 0;
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}
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if (c->cur_seq_no - var->start_seq_no >= var->n_segments)
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return c->finished ? AVERROR_EOF : 0;
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ret = url_fopen(&var->pb,
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var->segments[c->cur_seq_no - var->start_seq_no]->url,
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URL_RDONLY);
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if (ret < 0)
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return ret;
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var->ctx->pb = var->pb;
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/* If this is a new segment in parallel with another one already opened,
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* skip ahead so they're all at the same dts. */
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if (skip && c->last_packet_dts != AV_NOPTS_VALUE) {
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while (1) {
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ret = av_read_frame(var->ctx, &var->pkt);
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if (ret < 0) {
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if (ret == AVERROR_EOF) {
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reset_packet(&var->pkt);
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return 0;
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}
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return ret;
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}
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if (var->pkt.dts >= c->last_packet_dts)
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break;
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av_free_packet(&var->pkt);
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}
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}
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return 0;
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}
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static int applehttp_read_packet(AVFormatContext *s, AVPacket *pkt)
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{
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AppleHTTPContext *c = s->priv_data;
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int ret, i, minvariant = -1, first = 1, needed = 0, changed = 0,
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variants = 0;
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/* Recheck the discard flags - which streams are desired at the moment */
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for (i = 0; i < c->n_variants; i++)
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c->variants[i]->needed = 0;
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for (i = 0; i < s->nb_streams; i++) {
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AVStream *st = s->streams[i];
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struct variant *var = c->variants[s->streams[i]->id];
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if (st->discard < AVDISCARD_ALL) {
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var->needed = 1;
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needed++;
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}
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/* Copy the discard flag to the chained demuxer, to indicate which
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* streams are desired. */
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var->ctx->streams[i - var->stream_offset]->discard = st->discard;
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}
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if (!needed)
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return AVERROR_EOF;
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start:
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for (i = 0; i < c->n_variants; i++) {
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struct variant *var = c->variants[i];
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/* Close unneeded streams, open newly requested streams */
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if (var->pb && !var->needed) {
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av_log(s, AV_LOG_DEBUG,
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"Closing variant stream %d, no longer needed\n", i);
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av_free_packet(&var->pkt);
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reset_packet(&var->pkt);
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url_fclose(var->pb);
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var->pb = NULL;
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changed = 1;
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} else if (!var->pb && var->needed) {
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if (first)
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av_log(s, AV_LOG_DEBUG, "Opening variant stream %d\n", i);
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if (first && !c->finished)
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if ((ret = parse_playlist(c, var->url, var, NULL)) < 0)
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return ret;
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ret = open_variant(c, var, first);
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if (ret < 0)
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return ret;
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changed = 1;
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}
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/* Count the number of open variants */
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if (var->pb)
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variants++;
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/* Make sure we've got one buffered packet from each open variant
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* stream */
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if (var->pb && !var->pkt.data) {
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ret = av_read_frame(var->ctx, &var->pkt);
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if (ret < 0) {
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if (!url_feof(var->pb))
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return ret;
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reset_packet(&var->pkt);
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}
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}
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/* Check if this stream has the packet with the lowest dts */
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if (var->pkt.data) {
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if (minvariant < 0 ||
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var->pkt.dts < c->variants[minvariant]->pkt.dts)
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minvariant = i;
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}
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}
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if (first && changed)
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av_log(s, AV_LOG_INFO, "Receiving %d variant streams\n", variants);
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/* If we got a packet, return it */
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if (minvariant >= 0) {
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*pkt = c->variants[minvariant]->pkt;
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pkt->stream_index += c->variants[minvariant]->stream_offset;
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reset_packet(&c->variants[minvariant]->pkt);
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c->last_packet_dts = pkt->dts;
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return 0;
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}
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/* No more packets - eof reached in all variant streams, close the
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* current segments. */
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for (i = 0; i < c->n_variants; i++) {
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struct variant *var = c->variants[i];
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if (var->pb) {
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url_fclose(var->pb);
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var->pb = NULL;
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}
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}
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/* Indicate that we're opening the next segment, not opening a new
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* variant stream in parallel, so we shouldn't try to skip ahead. */
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first = 0;
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c->cur_seq_no++;
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reload:
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if (!c->finished) {
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/* If this is a live stream and target_duration has elapsed since
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* the last playlist reload, reload the variant playlists now. */
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int64_t now = av_gettime();
|
|
if (now - c->last_load_time >= c->target_duration*1000000) {
|
|
c->max_start_seq = 0;
|
|
c->min_end_seq = INT_MAX;
|
|
for (i = 0; i < c->n_variants; i++) {
|
|
struct variant *var = c->variants[i];
|
|
if (var->needed) {
|
|
if ((ret = parse_playlist(c, var->url, var, NULL)) < 0)
|
|
return ret;
|
|
c->max_start_seq = FFMAX(c->max_start_seq,
|
|
var->start_seq_no);
|
|
c->min_end_seq = FFMIN(c->min_end_seq,
|
|
var->start_seq_no + var->n_segments);
|
|
}
|
|
}
|
|
}
|
|
}
|
|
if (c->cur_seq_no < c->max_start_seq) {
|
|
av_log(NULL, AV_LOG_WARNING,
|
|
"skipping %d segments ahead, expired from playlists\n",
|
|
c->max_start_seq - c->cur_seq_no);
|
|
c->cur_seq_no = c->max_start_seq;
|
|
}
|
|
/* If more segments exit, open the next one */
|
|
if (c->cur_seq_no < c->min_end_seq)
|
|
goto start;
|
|
/* We've reached the end of the playlists - return eof if this is a
|
|
* non-live stream, wait until the next playlist reload if it is live. */
|
|
if (c->finished)
|
|
return AVERROR_EOF;
|
|
while (av_gettime() - c->last_load_time < c->target_duration*1000000) {
|
|
if (url_interrupt_cb())
|
|
return AVERROR(EINTR);
|
|
usleep(100*1000);
|
|
}
|
|
/* Enough time has elapsed since the last reload */
|
|
goto reload;
|
|
}
|
|
|
|
static int applehttp_close(AVFormatContext *s)
|
|
{
|
|
AppleHTTPContext *c = s->priv_data;
|
|
|
|
free_variant_list(c);
|
|
return 0;
|
|
}
|
|
|
|
static int applehttp_read_seek(AVFormatContext *s, int stream_index,
|
|
int64_t timestamp, int flags)
|
|
{
|
|
AppleHTTPContext *c = s->priv_data;
|
|
int pos = 0, i;
|
|
struct variant *var = c->variants[0];
|
|
|
|
if ((flags & AVSEEK_FLAG_BYTE) || !c->finished)
|
|
return AVERROR(ENOSYS);
|
|
|
|
/* Reset the variants */
|
|
c->last_packet_dts = AV_NOPTS_VALUE;
|
|
for (i = 0; i < c->n_variants; i++) {
|
|
struct variant *var = c->variants[i];
|
|
if (var->pb) {
|
|
url_fclose(var->pb);
|
|
var->pb = NULL;
|
|
}
|
|
av_free_packet(&var->pkt);
|
|
reset_packet(&var->pkt);
|
|
}
|
|
|
|
timestamp = av_rescale_rnd(timestamp, 1, stream_index >= 0 ?
|
|
s->streams[stream_index]->time_base.den :
|
|
AV_TIME_BASE, flags & AVSEEK_FLAG_BACKWARD ?
|
|
AV_ROUND_DOWN : AV_ROUND_UP);
|
|
/* Locate the segment that contains the target timestamp */
|
|
for (i = 0; i < var->n_segments; i++) {
|
|
if (timestamp >= pos && timestamp < pos + var->segments[i]->duration) {
|
|
c->cur_seq_no = var->start_seq_no + i;
|
|
return 0;
|
|
}
|
|
pos += var->segments[i]->duration;
|
|
}
|
|
return AVERROR(EIO);
|
|
}
|
|
|
|
static int applehttp_probe(AVProbeData *p)
|
|
{
|
|
/* Require #EXTM3U at the start, and either one of the ones below
|
|
* somewhere for a proper match. */
|
|
if (strncmp(p->buf, "#EXTM3U", 7))
|
|
return 0;
|
|
if (strstr(p->buf, "#EXT-X-STREAM-INF:") ||
|
|
strstr(p->buf, "#EXT-X-TARGETDURATION:") ||
|
|
strstr(p->buf, "#EXT-X-MEDIA-SEQUENCE:"))
|
|
return AVPROBE_SCORE_MAX;
|
|
return 0;
|
|
}
|
|
|
|
AVInputFormat ff_applehttp_demuxer = {
|
|
"applehttp",
|
|
NULL_IF_CONFIG_SMALL("Apple HTTP Live Streaming format"),
|
|
sizeof(AppleHTTPContext),
|
|
applehttp_probe,
|
|
applehttp_read_header,
|
|
applehttp_read_packet,
|
|
applehttp_close,
|
|
applehttp_read_seek,
|
|
};
|