2 * Apple HTTP Live Streaming demuxer
3 * Copyright (c) 2010 Martin Storsjo
5 * This file is part of Libav.
7 * Libav is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU Lesser General Public
9 * License as published by the Free Software Foundation; either
10 * version 2.1 of the License, or (at your option) any later version.
12 * Libav is distributed in the hope that it will be useful,
13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
15 * Lesser General Public License for more details.
17 * You should have received a copy of the GNU Lesser General Public
18 * License along with Libav; if not, write to the Free Software
19 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
24 * Apple HTTP Live Streaming demuxer
25 * http://tools.ietf.org/html/draft-pantos-http-live-streaming
28 #include "libavutil/avstring.h"
29 #include "libavutil/intreadwrite.h"
30 #include "libavutil/opt.h"
34 #include "avio_internal.h"
37 #define INITIAL_BUFFER_SIZE 32768
40 * An apple http stream consists of a playlist with media segment files,
41 * played sequentially. There may be several playlists with the same
42 * video content, in different bandwidth variants, that are played in
43 * parallel (preferrably only one bandwidth variant at a time). In this case,
44 * the user supplied the url to a main playlist that only lists the variant
47 * If the main playlist doesn't point at any variants, we still create
48 * one anonymous toplevel variant for this, to maintain the structure.
58 char url[MAX_URL_SIZE];
59 char key[MAX_URL_SIZE];
60 enum KeyType key_type;
65 * Each variant has its own demuxer. If it currently is active,
66 * it has an open AVIOContext too, and potentially an AVPacket
67 * containing the next packet from this stream.
71 char url[MAX_URL_SIZE];
75 AVFormatContext *parent;
85 struct segment **segments;
86 int needed, cur_needed;
88 int64_t last_load_time;
90 char key_url[MAX_URL_SIZE];
94 typedef struct AppleHTTPContext {
96 struct variant **variants;
102 static int read_chomp_line(AVIOContext *s, char *buf, int maxlen)
104 int len = ff_get_line(s, buf, maxlen);
105 while (len > 0 && isspace(buf[len - 1]))
110 static void free_segment_list(struct variant *var)
113 for (i = 0; i < var->n_segments; i++)
114 av_free(var->segments[i]);
115 av_freep(&var->segments);
119 static void free_variant_list(AppleHTTPContext *c)
122 for (i = 0; i < c->n_variants; i++) {
123 struct variant *var = c->variants[i];
124 free_segment_list(var);
125 av_free_packet(&var->pkt);
126 av_free(var->pb.buffer);
128 ffurl_close(var->input);
131 av_close_input_file(var->ctx);
135 av_freep(&c->variants);
140 * Used to reset a statically allocated AVPacket to a clean slate,
141 * containing no data.
143 static void reset_packet(AVPacket *pkt)
149 static struct variant *new_variant(AppleHTTPContext *c, int bandwidth,
150 const char *url, const char *base)
152 struct variant *var = av_mallocz(sizeof(struct variant));
155 reset_packet(&var->pkt);
156 var->bandwidth = bandwidth;
157 ff_make_absolute_url(var->url, sizeof(var->url), base, url);
158 dynarray_add(&c->variants, &c->n_variants, var);
162 struct variant_info {
166 static void handle_variant_args(struct variant_info *info, const char *key,
167 int key_len, char **dest, int *dest_len)
169 if (!strncmp(key, "BANDWIDTH=", key_len)) {
170 *dest = info->bandwidth;
171 *dest_len = sizeof(info->bandwidth);
176 char uri[MAX_URL_SIZE];
181 static void handle_key_args(struct key_info *info, const char *key,
182 int key_len, char **dest, int *dest_len)
184 if (!strncmp(key, "METHOD=", key_len)) {
185 *dest = info->method;
186 *dest_len = sizeof(info->method);
187 } else if (!strncmp(key, "URI=", key_len)) {
189 *dest_len = sizeof(info->uri);
190 } else if (!strncmp(key, "IV=", key_len)) {
192 *dest_len = sizeof(info->iv);
196 static int parse_playlist(AppleHTTPContext *c, const char *url,
197 struct variant *var, AVIOContext *in)
199 int ret = 0, duration = 0, is_segment = 0, is_variant = 0, bandwidth = 0;
200 enum KeyType key_type = KEY_NONE;
203 char key[MAX_URL_SIZE];
210 if ((ret = avio_open(&in, url, AVIO_FLAG_READ)) < 0)
214 read_chomp_line(in, line, sizeof(line));
215 if (strcmp(line, "#EXTM3U")) {
216 ret = AVERROR_INVALIDDATA;
221 free_segment_list(var);
224 while (!in->eof_reached) {
225 read_chomp_line(in, line, sizeof(line));
226 if (av_strstart(line, "#EXT-X-STREAM-INF:", &ptr)) {
227 struct variant_info info = {{0}};
229 ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_variant_args,
231 bandwidth = atoi(info.bandwidth);
232 } else if (av_strstart(line, "#EXT-X-KEY:", &ptr)) {
233 struct key_info info = {{0}};
234 ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_key_args,
238 if (!strcmp(info.method, "AES-128"))
239 key_type = KEY_AES_128;
240 if (!strncmp(info.iv, "0x", 2) || !strncmp(info.iv, "0X", 2)) {
241 ff_hex_to_data(iv, info.iv + 2);
244 av_strlcpy(key, info.uri, sizeof(key));
245 } else if (av_strstart(line, "#EXT-X-TARGETDURATION:", &ptr)) {
247 var = new_variant(c, 0, url, NULL);
249 ret = AVERROR(ENOMEM);
253 var->target_duration = atoi(ptr);
254 } else if (av_strstart(line, "#EXT-X-MEDIA-SEQUENCE:", &ptr)) {
256 var = new_variant(c, 0, url, NULL);
258 ret = AVERROR(ENOMEM);
262 var->start_seq_no = atoi(ptr);
263 } else if (av_strstart(line, "#EXT-X-ENDLIST", &ptr)) {
266 } else if (av_strstart(line, "#EXTINF:", &ptr)) {
268 duration = atoi(ptr);
269 } else if (av_strstart(line, "#", NULL)) {
271 } else if (line[0]) {
273 if (!new_variant(c, bandwidth, line, url)) {
274 ret = AVERROR(ENOMEM);
283 var = new_variant(c, 0, url, NULL);
285 ret = AVERROR(ENOMEM);
289 seg = av_malloc(sizeof(struct segment));
291 ret = AVERROR(ENOMEM);
294 seg->duration = duration;
295 seg->key_type = key_type;
297 memcpy(seg->iv, iv, sizeof(iv));
299 int seq = var->start_seq_no + var->n_segments;
300 memset(seg->iv, 0, sizeof(seg->iv));
301 AV_WB32(seg->iv + 12, seq);
303 ff_make_absolute_url(seg->key, sizeof(seg->key), url, key);
304 ff_make_absolute_url(seg->url, sizeof(seg->url), url, line);
305 dynarray_add(&var->segments, &var->n_segments, seg);
311 var->last_load_time = av_gettime();
319 static int open_input(struct variant *var)
321 struct segment *seg = var->segments[var->cur_seq_no - var->start_seq_no];
322 if (seg->key_type == KEY_NONE) {
323 return ffurl_open(&var->input, seg->url, AVIO_FLAG_READ);
324 } else if (seg->key_type == KEY_AES_128) {
325 char iv[33], key[33], url[MAX_URL_SIZE];
327 if (strcmp(seg->key, var->key_url)) {
329 if (ffurl_open(&uc, seg->key, AVIO_FLAG_READ) == 0) {
330 if (ffurl_read_complete(uc, var->key, sizeof(var->key))
331 != sizeof(var->key)) {
332 av_log(NULL, AV_LOG_ERROR, "Unable to read key file %s\n",
337 av_log(NULL, AV_LOG_ERROR, "Unable to open key file %s\n",
340 av_strlcpy(var->key_url, seg->key, sizeof(var->key_url));
342 ff_data_to_hex(iv, seg->iv, sizeof(seg->iv), 0);
343 ff_data_to_hex(key, var->key, sizeof(var->key), 0);
344 iv[32] = key[32] = '\0';
345 if (strstr(seg->url, "://"))
346 snprintf(url, sizeof(url), "crypto+%s", seg->url);
348 snprintf(url, sizeof(url), "crypto:%s", seg->url);
349 if ((ret = ffurl_alloc(&var->input, url, AVIO_FLAG_READ)) < 0)
351 av_set_string3(var->input->priv_data, "key", key, 0, NULL);
352 av_set_string3(var->input->priv_data, "iv", iv, 0, NULL);
353 if ((ret = ffurl_connect(var->input)) < 0) {
354 ffurl_close(var->input);
360 return AVERROR(ENOSYS);
363 static int read_data(void *opaque, uint8_t *buf, int buf_size)
365 struct variant *v = opaque;
366 AppleHTTPContext *c = v->parent->priv_data;
372 /* If this is a live stream and target_duration has elapsed since
373 * the last playlist reload, reload the variant playlists now. */
375 av_gettime() - v->last_load_time >= v->target_duration*1000000 &&
376 (ret = parse_playlist(c, v->url, v, NULL)) < 0)
378 if (v->cur_seq_no < v->start_seq_no) {
379 av_log(NULL, AV_LOG_WARNING,
380 "skipping %d segments ahead, expired from playlists\n",
381 v->start_seq_no - v->cur_seq_no);
382 v->cur_seq_no = v->start_seq_no;
384 if (v->cur_seq_no >= v->start_seq_no + v->n_segments) {
387 while (av_gettime() - v->last_load_time <
388 v->target_duration*1000000) {
389 if (url_interrupt_cb())
393 /* Enough time has elapsed since the last reload */
401 ret = ffurl_read(v->input, buf, buf_size);
404 if (ret < 0 && ret != AVERROR_EOF)
406 ffurl_close(v->input);
410 c->end_of_segment = 1;
411 c->cur_seq_no = v->cur_seq_no;
415 for (i = v->stream_offset; i < v->stream_offset + v->ctx->nb_streams;
417 if (v->parent->streams[i]->discard < AVDISCARD_ALL)
422 av_log(v->parent, AV_LOG_INFO, "No longer receiving variant %d\n",
429 static int applehttp_read_header(AVFormatContext *s, AVFormatParameters *ap)
431 AppleHTTPContext *c = s->priv_data;
432 int ret = 0, i, j, stream_offset = 0;
434 if ((ret = parse_playlist(c, s->filename, NULL, s->pb)) < 0)
437 if (c->n_variants == 0) {
438 av_log(NULL, AV_LOG_WARNING, "Empty playlist\n");
442 /* If the playlist only contained variants, parse each individual
443 * variant playlist. */
444 if (c->n_variants > 1 || c->variants[0]->n_segments == 0) {
445 for (i = 0; i < c->n_variants; i++) {
446 struct variant *v = c->variants[i];
447 if ((ret = parse_playlist(c, v->url, v, NULL)) < 0)
452 if (c->variants[0]->n_segments == 0) {
453 av_log(NULL, AV_LOG_WARNING, "Empty playlist\n");
458 /* If this isn't a live stream, calculate the total duration of the
460 if (c->variants[0]->finished) {
461 int64_t duration = 0;
462 for (i = 0; i < c->variants[0]->n_segments; i++)
463 duration += c->variants[0]->segments[i]->duration;
464 s->duration = duration * AV_TIME_BASE;
467 /* Open the demuxer for each variant */
468 for (i = 0; i < c->n_variants; i++) {
469 struct variant *v = c->variants[i];
470 AVInputFormat *in_fmt = NULL;
471 char bitrate_str[20];
472 if (v->n_segments == 0)
479 /* If this is a live stream with more than 3 segments, start at the
480 * third last segment. */
481 v->cur_seq_no = v->start_seq_no;
482 if (!v->finished && v->n_segments > 3)
483 v->cur_seq_no = v->start_seq_no + v->n_segments - 3;
485 v->read_buffer = av_malloc(INITIAL_BUFFER_SIZE);
486 ffio_init_context(&v->pb, v->read_buffer, INITIAL_BUFFER_SIZE, 0, v,
487 read_data, NULL, NULL);
489 ret = av_probe_input_buffer(&v->pb, &in_fmt, v->segments[0]->url,
493 ret = av_open_input_stream(&v->ctx, &v->pb, v->segments[0]->url,
497 v->stream_offset = stream_offset;
498 snprintf(bitrate_str, sizeof(bitrate_str), "%d", v->bandwidth);
499 /* Create new AVStreams for each stream in this variant */
500 for (j = 0; j < v->ctx->nb_streams; j++) {
501 AVStream *st = av_new_stream(s, i);
503 ret = AVERROR(ENOMEM);
506 avcodec_copy_context(st->codec, v->ctx->streams[j]->codec);
508 av_metadata_set2(&st->metadata, "variant_bitrate", bitrate_str,
511 stream_offset += v->ctx->nb_streams;
518 free_variant_list(c);
522 static int recheck_discard_flags(AVFormatContext *s, int first)
524 AppleHTTPContext *c = s->priv_data;
527 /* Check if any new streams are needed */
528 for (i = 0; i < c->n_variants; i++)
529 c->variants[i]->cur_needed = 0;;
531 for (i = 0; i < s->nb_streams; i++) {
532 AVStream *st = s->streams[i];
533 struct variant *var = c->variants[s->streams[i]->id];
534 if (st->discard < AVDISCARD_ALL)
537 for (i = 0; i < c->n_variants; i++) {
538 struct variant *v = c->variants[i];
539 if (v->cur_needed && !v->needed) {
542 v->cur_seq_no = c->cur_seq_no;
543 v->pb.eof_reached = 0;
544 av_log(s, AV_LOG_INFO, "Now receiving variant %d\n", i);
545 } else if (first && !v->cur_needed && v->needed) {
547 ffurl_close(v->input);
551 av_log(s, AV_LOG_INFO, "No longer receiving variant %d\n", i);
557 static int applehttp_read_packet(AVFormatContext *s, AVPacket *pkt)
559 AppleHTTPContext *c = s->priv_data;
560 int ret, i, minvariant = -1;
562 if (c->first_packet) {
563 recheck_discard_flags(s, 1);
568 c->end_of_segment = 0;
569 for (i = 0; i < c->n_variants; i++) {
570 struct variant *var = c->variants[i];
571 /* Make sure we've got one buffered packet from each open variant
573 if (var->needed && !var->pkt.data) {
574 ret = av_read_frame(var->ctx, &var->pkt);
576 if (!var->pb.eof_reached)
578 reset_packet(&var->pkt);
581 /* Check if this stream has the packet with the lowest dts */
583 if (minvariant < 0 ||
584 var->pkt.dts < c->variants[minvariant]->pkt.dts)
588 if (c->end_of_segment) {
589 if (recheck_discard_flags(s, 0))
592 /* If we got a packet, return it */
593 if (minvariant >= 0) {
594 *pkt = c->variants[minvariant]->pkt;
595 pkt->stream_index += c->variants[minvariant]->stream_offset;
596 reset_packet(&c->variants[minvariant]->pkt);
602 static int applehttp_close(AVFormatContext *s)
604 AppleHTTPContext *c = s->priv_data;
606 free_variant_list(c);
610 static int applehttp_read_seek(AVFormatContext *s, int stream_index,
611 int64_t timestamp, int flags)
613 AppleHTTPContext *c = s->priv_data;
616 if ((flags & AVSEEK_FLAG_BYTE) || !c->variants[0]->finished)
617 return AVERROR(ENOSYS);
619 timestamp = av_rescale_rnd(timestamp, 1, stream_index >= 0 ?
620 s->streams[stream_index]->time_base.den :
621 AV_TIME_BASE, flags & AVSEEK_FLAG_BACKWARD ?
622 AV_ROUND_DOWN : AV_ROUND_UP);
624 for (i = 0; i < c->n_variants; i++) {
626 struct variant *var = c->variants[i];
629 ffurl_close(var->input);
632 av_free_packet(&var->pkt);
633 reset_packet(&var->pkt);
634 var->pb.eof_reached = 0;
636 /* Locate the segment that contains the target timestamp */
637 for (j = 0; j < var->n_segments; j++) {
638 if (timestamp >= pos &&
639 timestamp < pos + var->segments[j]->duration) {
640 var->cur_seq_no = var->start_seq_no + j;
644 pos += var->segments[j]->duration;
650 static int applehttp_probe(AVProbeData *p)
652 /* Require #EXTM3U at the start, and either one of the ones below
653 * somewhere for a proper match. */
654 if (strncmp(p->buf, "#EXTM3U", 7))
656 if (strstr(p->buf, "#EXT-X-STREAM-INF:") ||
657 strstr(p->buf, "#EXT-X-TARGETDURATION:") ||
658 strstr(p->buf, "#EXT-X-MEDIA-SEQUENCE:"))
659 return AVPROBE_SCORE_MAX;
663 AVInputFormat ff_applehttp_demuxer = {
665 NULL_IF_CONFIG_SMALL("Apple HTTP Live Streaming format"),
666 sizeof(AppleHTTPContext),
668 applehttp_read_header,
669 applehttp_read_packet,