/* * Apple HTTP Live Streaming demuxer * Copyright (c) 2010 Martin Storsjo * * This file is part of Libav. * * Libav 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. * * Libav 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 Libav; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA */ /** * @file * Apple HTTP Live Streaming demuxer * http://tools.ietf.org/html/draft-pantos-http-live-streaming */ #include "libavutil/avstring.h" #include "libavutil/intreadwrite.h" #include "libavutil/mathematics.h" #include "libavutil/opt.h" #include "libavutil/dict.h" #include "avformat.h" #include "internal.h" #include #include "avio_internal.h" #include "url.h" #define INITIAL_BUFFER_SIZE 32768 /* * 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. */ enum KeyType { KEY_NONE, KEY_AES_128, }; struct segment { int duration; char url[MAX_URL_SIZE]; char key[MAX_URL_SIZE]; enum KeyType key_type; uint8_t iv[16]; }; /* * Each variant has its own demuxer. If it currently is active, * it has an open AVIOContext too, and potentially an AVPacket * containing the next packet from this stream. */ struct variant { int bandwidth; char url[MAX_URL_SIZE]; AVIOContext pb; uint8_t* read_buffer; URLContext *input; AVFormatContext *parent; int index; AVFormatContext *ctx; AVPacket pkt; int stream_offset; int finished; int target_duration; int start_seq_no; int n_segments; struct segment **segments; int needed, cur_needed; int cur_seq_no; int64_t last_load_time; char key_url[MAX_URL_SIZE]; uint8_t key[16]; }; typedef struct AppleHTTPContext { int n_variants; struct variant **variants; int cur_seq_no; int end_of_segment; int first_packet; int64_t first_timestamp; AVIOInterruptCB *interrupt_callback; } 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(struct variant *var) { int i; for (i = 0; i < var->n_segments; i++) av_free(var->segments[i]); av_freep(&var->segments); var->n_segments = 0; } static void free_variant_list(AppleHTTPContext *c) { int i; for (i = 0; i < c->n_variants; i++) { struct variant *var = c->variants[i]; free_segment_list(var); av_free_packet(&var->pkt); av_free(var->pb.buffer); if (var->input) ffurl_close(var->input); if (var->ctx) { var->ctx->pb = NULL; avformat_close_input(&var->ctx); } av_free(var); } av_freep(&c->variants); c->n_variants = 0; } /* * Used to reset a statically allocated AVPacket to a clean slate, * containing no data. */ static void reset_packet(AVPacket *pkt) { av_init_packet(pkt); pkt->data = NULL; } static struct variant *new_variant(AppleHTTPContext *c, int bandwidth, const char *url, const char *base) { struct variant *var = av_mallocz(sizeof(struct variant)); if (!var) return NULL; reset_packet(&var->pkt); var->bandwidth = bandwidth; ff_make_absolute_url(var->url, sizeof(var->url), base, url); dynarray_add(&c->variants, &c->n_variants, var); return var; } 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); } } struct key_info { char uri[MAX_URL_SIZE]; char method[10]; char iv[35]; }; static void handle_key_args(struct key_info *info, const char *key, int key_len, char **dest, int *dest_len) { if (!strncmp(key, "METHOD=", key_len)) { *dest = info->method; *dest_len = sizeof(info->method); } else if (!strncmp(key, "URI=", key_len)) { *dest = info->uri; *dest_len = sizeof(info->uri); } else if (!strncmp(key, "IV=", key_len)) { *dest = info->iv; *dest_len = sizeof(info->iv); } } static int parse_playlist(AppleHTTPContext *c, const char *url, struct variant *var, AVIOContext *in) { int ret = 0, duration = 0, is_segment = 0, is_variant = 0, bandwidth = 0; enum KeyType key_type = KEY_NONE; uint8_t iv[16] = ""; int has_iv = 0; char key[MAX_URL_SIZE] = ""; char line[1024]; const char *ptr; int close_in = 0; if (!in) { close_in = 1; if ((ret = avio_open2(&in, url, AVIO_FLAG_READ, c->interrupt_callback, NULL)) < 0) return ret; } read_chomp_line(in, line, sizeof(line)); if (strcmp(line, "#EXTM3U")) { ret = AVERROR_INVALIDDATA; goto fail; } if (var) { free_segment_list(var); var->finished = 0; } while (!in->eof_reached) { 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-KEY:", &ptr)) { struct key_info info = {{0}}; ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_key_args, &info); key_type = KEY_NONE; has_iv = 0; if (!strcmp(info.method, "AES-128")) key_type = KEY_AES_128; if (!strncmp(info.iv, "0x", 2) || !strncmp(info.iv, "0X", 2)) { ff_hex_to_data(iv, info.iv + 2); has_iv = 1; } av_strlcpy(key, info.uri, sizeof(key)); } else if (av_strstart(line, "#EXT-X-TARGETDURATION:", &ptr)) { if (!var) { var = new_variant(c, 0, url, NULL); if (!var) { ret = AVERROR(ENOMEM); goto fail; } } var->target_duration = atoi(ptr); } else if (av_strstart(line, "#EXT-X-MEDIA-SEQUENCE:", &ptr)) { if (!var) { var = new_variant(c, 0, url, NULL); if (!var) { ret = AVERROR(ENOMEM); goto fail; } } var->start_seq_no = atoi(ptr); } else if (av_strstart(line, "#EXT-X-ENDLIST", &ptr)) { if (var) var->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_variant) { if (!new_variant(c, bandwidth, line, url)) { ret = AVERROR(ENOMEM); goto fail; } is_variant = 0; bandwidth = 0; } if (is_segment) { struct segment *seg; if (!var) { var = new_variant(c, 0, url, NULL); if (!var) { ret = AVERROR(ENOMEM); goto fail; } } seg = av_malloc(sizeof(struct segment)); if (!seg) { ret = AVERROR(ENOMEM); goto fail; } seg->duration = duration; seg->key_type = key_type; if (has_iv) { memcpy(seg->iv, iv, sizeof(iv)); } else { int seq = var->start_seq_no + var->n_segments; memset(seg->iv, 0, sizeof(seg->iv)); AV_WB32(seg->iv + 12, seq); } ff_make_absolute_url(seg->key, sizeof(seg->key), url, key); ff_make_absolute_url(seg->url, sizeof(seg->url), url, line); dynarray_add(&var->segments, &var->n_segments, seg); is_segment = 0; } } } if (var) var->last_load_time = av_gettime(); fail: if (close_in) avio_close(in); return ret; } static int open_input(struct variant *var) { struct segment *seg = var->segments[var->cur_seq_no - var->start_seq_no]; if (seg->key_type == KEY_NONE) { return ffurl_open(&var->input, seg->url, AVIO_FLAG_READ, &var->parent->interrupt_callback, NULL); } else if (seg->key_type == KEY_AES_128) { char iv[33], key[33], url[MAX_URL_SIZE]; int ret; if (strcmp(seg->key, var->key_url)) { URLContext *uc; if (ffurl_open(&uc, seg->key, AVIO_FLAG_READ, &var->parent->interrupt_callback, NULL) == 0) { if (ffurl_read_complete(uc, var->key, sizeof(var->key)) != sizeof(var->key)) { av_log(NULL, AV_LOG_ERROR, "Unable to read key file %s\n", seg->key); } ffurl_close(uc); } else { av_log(NULL, AV_LOG_ERROR, "Unable to open key file %s\n", seg->key); } av_strlcpy(var->key_url, seg->key, sizeof(var->key_url)); } ff_data_to_hex(iv, seg->iv, sizeof(seg->iv), 0); ff_data_to_hex(key, var->key, sizeof(var->key), 0); iv[32] = key[32] = '\0'; if (strstr(seg->url, "://")) snprintf(url, sizeof(url), "crypto+%s", seg->url); else snprintf(url, sizeof(url), "crypto:%s", seg->url); if ((ret = ffurl_alloc(&var->input, url, AVIO_FLAG_READ, &var->parent->interrupt_callback)) < 0) return ret; av_opt_set(var->input->priv_data, "key", key, 0); av_opt_set(var->input->priv_data, "iv", iv, 0); if ((ret = ffurl_connect(var->input, NULL)) < 0) { ffurl_close(var->input); var->input = NULL; return ret; } return 0; } return AVERROR(ENOSYS); } static int read_data(void *opaque, uint8_t *buf, int buf_size) { struct variant *v = opaque; AppleHTTPContext *c = v->parent->priv_data; int ret, i; restart: if (!v->input) { reload: /* If this is a live stream and target_duration has elapsed since * the last playlist reload, reload the variant playlists now. */ if (!v->finished && av_gettime() - v->last_load_time >= v->target_duration*1000000 && (ret = parse_playlist(c, v->url, v, NULL)) < 0) return ret; if (v->cur_seq_no < v->start_seq_no) { av_log(NULL, AV_LOG_WARNING, "skipping %d segments ahead, expired from playlists\n", v->start_seq_no - v->cur_seq_no); v->cur_seq_no = v->start_seq_no; } if (v->cur_seq_no >= v->start_seq_no + v->n_segments) { if (v->finished) return AVERROR_EOF; while (av_gettime() - v->last_load_time < v->target_duration*1000000) { if (ff_check_interrupt(c->interrupt_callback)) return AVERROR_EXIT; usleep(100*1000); } /* Enough time has elapsed since the last reload */ goto reload; } ret = open_input(v); if (ret < 0) return ret; } ret = ffurl_read(v->input, buf, buf_size); if (ret > 0) return ret; if (ret < 0 && ret != AVERROR_EOF) return ret; ffurl_close(v->input); v->input = NULL; v->cur_seq_no++; c->end_of_segment = 1; c->cur_seq_no = v->cur_seq_no; if (v->ctx && v->ctx->nb_streams) { v->needed = 0; for (i = v->stream_offset; i < v->stream_offset + v->ctx->nb_streams; i++) { if (v->parent->streams[i]->discard < AVDISCARD_ALL) v->needed = 1; } } if (!v->needed) { av_log(v->parent, AV_LOG_INFO, "No longer receiving variant %d\n", v->index); return AVERROR_EOF; } goto restart; } static int applehttp_read_header(AVFormatContext *s, AVFormatParameters *ap) { AppleHTTPContext *c = s->priv_data; int ret = 0, i, j, stream_offset = 0; c->interrupt_callback = &s->interrupt_callback; if ((ret = parse_playlist(c, s->filename, NULL, s->pb)) < 0) goto fail; if (c->n_variants == 0) { av_log(NULL, AV_LOG_WARNING, "Empty playlist\n"); ret = AVERROR_EOF; goto fail; } /* If the playlist only contained variants, parse each individual * variant playlist. */ if (c->n_variants > 1 || c->variants[0]->n_segments == 0) { for (i = 0; i < c->n_variants; i++) { struct variant *v = c->variants[i]; if ((ret = parse_playlist(c, v->url, v, NULL)) < 0) goto fail; } } if (c->variants[0]->n_segments == 0) { av_log(NULL, AV_LOG_WARNING, "Empty playlist\n"); ret = AVERROR_EOF; goto fail; } /* If this isn't a live stream, calculate the total duration of the * stream. */ if (c->variants[0]->finished) { int64_t duration = 0; for (i = 0; i < c->variants[0]->n_segments; i++) duration += c->variants[0]->segments[i]->duration; s->duration = duration * AV_TIME_BASE; } /* Open the demuxer for each variant */ for (i = 0; i < c->n_variants; i++) { struct variant *v = c->variants[i]; AVInputFormat *in_fmt = NULL; char bitrate_str[20]; if (v->n_segments == 0) continue; if (!(v->ctx = avformat_alloc_context())) { ret = AVERROR(ENOMEM); goto fail; } v->index = i; v->needed = 1; v->parent = s; /* If this is a live stream with more than 3 segments, start at the * third last segment. */ v->cur_seq_no = v->start_seq_no; if (!v->finished && v->n_segments > 3) v->cur_seq_no = v->start_seq_no + v->n_segments - 3; v->read_buffer = av_malloc(INITIAL_BUFFER_SIZE); ffio_init_context(&v->pb, v->read_buffer, INITIAL_BUFFER_SIZE, 0, v, read_data, NULL, NULL); v->pb.seekable = 0; ret = av_probe_input_buffer(&v->pb, &in_fmt, v->segments[0]->url, NULL, 0, 0); if (ret < 0) goto fail; v->ctx->pb = &v->pb; ret = avformat_open_input(&v->ctx, v->segments[0]->url, in_fmt, NULL); if (ret < 0) goto fail; v->stream_offset = stream_offset; snprintf(bitrate_str, sizeof(bitrate_str), "%d", v->bandwidth); /* Create new AVStreams for each stream in this variant */ for (j = 0; j < v->ctx->nb_streams; j++) { AVStream *st = avformat_new_stream(s, NULL); if (!st) { ret = AVERROR(ENOMEM); goto fail; } st->id = i; avcodec_copy_context(st->codec, v->ctx->streams[j]->codec); if (v->bandwidth) av_dict_set(&st->metadata, "variant_bitrate", bitrate_str, 0); } stream_offset += v->ctx->nb_streams; } c->first_packet = 1; c->first_timestamp = AV_NOPTS_VALUE; return 0; fail: free_variant_list(c); return ret; } static int recheck_discard_flags(AVFormatContext *s, int first) { AppleHTTPContext *c = s->priv_data; int i, changed = 0; /* Check if any new streams are needed */ for (i = 0; i < c->n_variants; i++) c->variants[i]->cur_needed = 0;; for (i = 0; i < s->nb_streams; i++) { AVStream *st = s->streams[i]; struct variant *var = c->variants[s->streams[i]->id]; if (st->discard < AVDISCARD_ALL) var->cur_needed = 1; } for (i = 0; i < c->n_variants; i++) { struct variant *v = c->variants[i]; if (v->cur_needed && !v->needed) { v->needed = 1; changed = 1; v->cur_seq_no = c->cur_seq_no; v->pb.eof_reached = 0; av_log(s, AV_LOG_INFO, "Now receiving variant %d\n", i); } else if (first && !v->cur_needed && v->needed) { if (v->input) ffurl_close(v->input); v->input = NULL; v->needed = 0; changed = 1; av_log(s, AV_LOG_INFO, "No longer receiving variant %d\n", i); } } return changed; } static int applehttp_read_packet(AVFormatContext *s, AVPacket *pkt) { AppleHTTPContext *c = s->priv_data; int ret, i, minvariant = -1; if (c->first_packet) { recheck_discard_flags(s, 1); c->first_packet = 0; } start: c->end_of_segment = 0; for (i = 0; i < c->n_variants; i++) { struct variant *var = c->variants[i]; /* Make sure we've got one buffered packet from each open variant * stream */ if (var->needed && !var->pkt.data) { ret = av_read_frame(var->ctx, &var->pkt); if (ret < 0) { if (!var->pb.eof_reached) return ret; reset_packet(&var->pkt); } else { if (c->first_timestamp == AV_NOPTS_VALUE) c->first_timestamp = var->pkt.dts; } } /* Check if this stream has the packet with the lowest dts */ if (var->pkt.data) { if (minvariant < 0 || var->pkt.dts < c->variants[minvariant]->pkt.dts) minvariant = i; } } if (c->end_of_segment) { if (recheck_discard_flags(s, 0)) goto start; } /* If we got a packet, return it */ if (minvariant >= 0) { *pkt = c->variants[minvariant]->pkt; pkt->stream_index += c->variants[minvariant]->stream_offset; reset_packet(&c->variants[minvariant]->pkt); return 0; } return AVERROR_EOF; } 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 i, j, ret; if ((flags & AVSEEK_FLAG_BYTE) || !c->variants[0]->finished) return AVERROR(ENOSYS); 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); ret = AVERROR(EIO); for (i = 0; i < c->n_variants; i++) { /* Reset reading */ struct variant *var = c->variants[i]; int64_t pos = c->first_timestamp == AV_NOPTS_VALUE ? 0 : av_rescale_rnd(c->first_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); if (var->input) { ffurl_close(var->input); var->input = NULL; } av_free_packet(&var->pkt); reset_packet(&var->pkt); var->pb.eof_reached = 0; /* Locate the segment that contains the target timestamp */ for (j = 0; j < var->n_segments; j++) { if (timestamp >= pos && timestamp < pos + var->segments[j]->duration) { var->cur_seq_no = var->start_seq_no + j; ret = 0; break; } pos += var->segments[j]->duration; } } return ret; } 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 = { .name = "applehttp", .long_name = NULL_IF_CONFIG_SMALL("Apple HTTP Live Streaming format"), .priv_data_size = sizeof(AppleHTTPContext), .read_probe = applehttp_probe, .read_header = applehttp_read_header, .read_packet = applehttp_read_packet, .read_close = applehttp_close, .read_seek = applehttp_read_seek, };