2 * Apple HTTP Live Streaming demuxer
3 * Copyright (c) 2010 Martin Storsjo
5 * This file is part of FFmpeg.
7 * FFmpeg 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 * FFmpeg 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 FFmpeg; 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"
31 #include "libavutil/dict.h"
35 #include "avio_internal.h"
38 #define INITIAL_BUFFER_SIZE 32768
41 * An apple http stream consists of a playlist with media segment files,
42 * played sequentially. There may be several playlists with the same
43 * video content, in different bandwidth variants, that are played in
44 * parallel (preferrably only one bandwidth variant at a time). In this case,
45 * the user supplied the url to a main playlist that only lists the variant
48 * If the main playlist doesn't point at any variants, we still create
49 * one anonymous toplevel variant for this, to maintain the structure.
59 char url[MAX_URL_SIZE];
60 char key[MAX_URL_SIZE];
61 enum KeyType key_type;
66 * Each variant has its own demuxer. If it currently is active,
67 * it has an open AVIOContext too, and potentially an AVPacket
68 * containing the next packet from this stream.
72 char url[MAX_URL_SIZE];
76 AVFormatContext *parent;
86 struct segment **segments;
87 int needed, cur_needed;
89 int64_t last_load_time;
91 char key_url[MAX_URL_SIZE];
95 typedef struct AppleHTTPContext {
97 struct variant **variants;
103 static int read_chomp_line(AVIOContext *s, char *buf, int maxlen)
105 int len = ff_get_line(s, buf, maxlen);
106 while (len > 0 && isspace(buf[len - 1]))
111 static void free_segment_list(struct variant *var)
114 for (i = 0; i < var->n_segments; i++)
115 av_free(var->segments[i]);
116 av_freep(&var->segments);
120 static void free_variant_list(AppleHTTPContext *c)
123 for (i = 0; i < c->n_variants; i++) {
124 struct variant *var = c->variants[i];
125 free_segment_list(var);
126 av_free_packet(&var->pkt);
127 av_free(var->pb.buffer);
129 ffurl_close(var->input);
132 av_close_input_file(var->ctx);
136 av_freep(&c->variants);
141 * Used to reset a statically allocated AVPacket to a clean slate,
142 * containing no data.
144 static void reset_packet(AVPacket *pkt)
150 static struct variant *new_variant(AppleHTTPContext *c, int bandwidth,
151 const char *url, const char *base)
153 struct variant *var = av_mallocz(sizeof(struct variant));
156 reset_packet(&var->pkt);
157 var->bandwidth = bandwidth;
158 ff_make_absolute_url(var->url, sizeof(var->url), base, url);
159 dynarray_add(&c->variants, &c->n_variants, var);
163 struct variant_info {
167 static void handle_variant_args(struct variant_info *info, const char *key,
168 int key_len, char **dest, int *dest_len)
170 if (!strncmp(key, "BANDWIDTH=", key_len)) {
171 *dest = info->bandwidth;
172 *dest_len = sizeof(info->bandwidth);
177 char uri[MAX_URL_SIZE];
182 static void handle_key_args(struct key_info *info, const char *key,
183 int key_len, char **dest, int *dest_len)
185 if (!strncmp(key, "METHOD=", key_len)) {
186 *dest = info->method;
187 *dest_len = sizeof(info->method);
188 } else if (!strncmp(key, "URI=", key_len)) {
190 *dest_len = sizeof(info->uri);
191 } else if (!strncmp(key, "IV=", key_len)) {
193 *dest_len = sizeof(info->iv);
197 static int parse_playlist(AppleHTTPContext *c, const char *url,
198 struct variant *var, AVIOContext *in)
200 int ret = 0, duration = 0, is_segment = 0, is_variant = 0, bandwidth = 0;
201 enum KeyType key_type = KEY_NONE;
204 char key[MAX_URL_SIZE];
211 if ((ret = avio_open(&in, url, AVIO_FLAG_READ)) < 0)
215 read_chomp_line(in, line, sizeof(line));
216 if (strcmp(line, "#EXTM3U")) {
217 ret = AVERROR_INVALIDDATA;
222 free_segment_list(var);
225 while (!url_feof(in)) {
226 read_chomp_line(in, line, sizeof(line));
227 if (av_strstart(line, "#EXT-X-STREAM-INF:", &ptr)) {
228 struct variant_info info = {{0}};
230 ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_variant_args,
232 bandwidth = atoi(info.bandwidth);
233 } else if (av_strstart(line, "#EXT-X-KEY:", &ptr)) {
234 struct key_info info = {{0}};
235 ff_parse_key_value(ptr, (ff_parse_key_val_cb) handle_key_args,
239 if (!strcmp(info.method, "AES-128"))
240 key_type = KEY_AES_128;
241 if (!strncmp(info.iv, "0x", 2) || !strncmp(info.iv, "0X", 2)) {
242 ff_hex_to_data(iv, info.iv + 2);
245 av_strlcpy(key, info.uri, sizeof(key));
246 } else if (av_strstart(line, "#EXT-X-TARGETDURATION:", &ptr)) {
248 var = new_variant(c, 0, url, NULL);
250 ret = AVERROR(ENOMEM);
254 var->target_duration = atoi(ptr);
255 } else if (av_strstart(line, "#EXT-X-MEDIA-SEQUENCE:", &ptr)) {
257 var = new_variant(c, 0, url, NULL);
259 ret = AVERROR(ENOMEM);
263 var->start_seq_no = atoi(ptr);
264 } else if (av_strstart(line, "#EXT-X-ENDLIST", &ptr)) {
267 } else if (av_strstart(line, "#EXTINF:", &ptr)) {
269 duration = atoi(ptr);
270 } else if (av_strstart(line, "#", NULL)) {
272 } else if (line[0]) {
274 if (!new_variant(c, bandwidth, line, url)) {
275 ret = AVERROR(ENOMEM);
284 var = new_variant(c, 0, url, NULL);
286 ret = AVERROR(ENOMEM);
290 seg = av_malloc(sizeof(struct segment));
292 ret = AVERROR(ENOMEM);
295 seg->duration = duration;
296 seg->key_type = key_type;
298 memcpy(seg->iv, iv, sizeof(iv));
300 int seq = var->start_seq_no + var->n_segments;
301 memset(seg->iv, 0, sizeof(seg->iv));
302 AV_WB32(seg->iv + 12, seq);
304 ff_make_absolute_url(seg->key, sizeof(seg->key), url, key);
305 ff_make_absolute_url(seg->url, sizeof(seg->url), url, line);
306 dynarray_add(&var->segments, &var->n_segments, seg);
312 var->last_load_time = av_gettime();
320 static int open_input(struct variant *var)
322 struct segment *seg = var->segments[var->cur_seq_no - var->start_seq_no];
323 if (seg->key_type == KEY_NONE) {
324 return ffurl_open(&var->input, seg->url, AVIO_FLAG_READ);
325 } else if (seg->key_type == KEY_AES_128) {
326 char iv[33], key[33], url[MAX_URL_SIZE];
328 if (strcmp(seg->key, var->key_url)) {
330 if (ffurl_open(&uc, seg->key, AVIO_FLAG_READ) == 0) {
331 if (ffurl_read_complete(uc, var->key, sizeof(var->key))
332 != sizeof(var->key)) {
333 av_log(NULL, AV_LOG_ERROR, "Unable to read key file %s\n",
338 av_log(NULL, AV_LOG_ERROR, "Unable to open key file %s\n",
341 av_strlcpy(var->key_url, seg->key, sizeof(var->key_url));
343 ff_data_to_hex(iv, seg->iv, sizeof(seg->iv), 0);
344 ff_data_to_hex(key, var->key, sizeof(var->key), 0);
345 iv[32] = key[32] = '\0';
346 if (strstr(seg->url, "://"))
347 snprintf(url, sizeof(url), "crypto+%s", seg->url);
349 snprintf(url, sizeof(url), "crypto:%s", seg->url);
350 if ((ret = ffurl_alloc(&var->input, url, AVIO_FLAG_READ)) < 0)
352 av_set_string3(var->input->priv_data, "key", key, 0, NULL);
353 av_set_string3(var->input->priv_data, "iv", iv, 0, NULL);
354 if ((ret = ffurl_connect(var->input)) < 0) {
355 ffurl_close(var->input);
361 return AVERROR(ENOSYS);
364 static int read_data(void *opaque, uint8_t *buf, int buf_size)
366 struct variant *v = opaque;
367 AppleHTTPContext *c = v->parent->priv_data;
373 /* If this is a live stream and target_duration has elapsed since
374 * the last playlist reload, reload the variant playlists now. */
376 av_gettime() - v->last_load_time >= v->target_duration*1000000 &&
377 (ret = parse_playlist(c, v->url, v, NULL)) < 0)
379 if (v->cur_seq_no < v->start_seq_no) {
380 av_log(NULL, AV_LOG_WARNING,
381 "skipping %d segments ahead, expired from playlists\n",
382 v->start_seq_no - v->cur_seq_no);
383 v->cur_seq_no = v->start_seq_no;
385 if (v->cur_seq_no >= v->start_seq_no + v->n_segments) {
388 while (av_gettime() - v->last_load_time <
389 v->target_duration*1000000) {
390 if (url_interrupt_cb())
394 /* Enough time has elapsed since the last reload */
402 ret = ffurl_read(v->input, buf, buf_size);
405 if (ret < 0 && ret != AVERROR_EOF)
407 ffurl_close(v->input);
411 c->end_of_segment = 1;
412 c->cur_seq_no = v->cur_seq_no;
416 for (i = v->stream_offset; i < v->stream_offset + v->ctx->nb_streams;
418 if (v->parent->streams[i]->discard < AVDISCARD_ALL)
423 av_log(v->parent, AV_LOG_INFO, "No longer receiving variant %d\n",
430 static int applehttp_read_header(AVFormatContext *s, AVFormatParameters *ap)
432 AppleHTTPContext *c = s->priv_data;
433 int ret = 0, i, j, stream_offset = 0;
435 if ((ret = parse_playlist(c, s->filename, NULL, s->pb)) < 0)
438 if (c->n_variants == 0) {
439 av_log(NULL, AV_LOG_WARNING, "Empty playlist\n");
443 /* If the playlist only contained variants, parse each individual
444 * variant playlist. */
445 if (c->n_variants > 1 || c->variants[0]->n_segments == 0) {
446 for (i = 0; i < c->n_variants; i++) {
447 struct variant *v = c->variants[i];
448 if ((ret = parse_playlist(c, v->url, v, NULL)) < 0)
453 if (c->variants[0]->n_segments == 0) {
454 av_log(NULL, AV_LOG_WARNING, "Empty playlist\n");
459 /* If this isn't a live stream, calculate the total duration of the
461 if (c->variants[0]->finished) {
462 int64_t duration = 0;
463 for (i = 0; i < c->variants[0]->n_segments; i++)
464 duration += c->variants[0]->segments[i]->duration;
465 s->duration = duration * AV_TIME_BASE;
468 /* Open the demuxer for each variant */
469 for (i = 0; i < c->n_variants; i++) {
470 struct variant *v = c->variants[i];
471 AVInputFormat *in_fmt = NULL;
472 char bitrate_str[20];
473 if (v->n_segments == 0)
480 /* If this is a live stream with more than 3 segments, start at the
481 * third last segment. */
482 v->cur_seq_no = v->start_seq_no;
483 if (!v->finished && v->n_segments > 3)
484 v->cur_seq_no = v->start_seq_no + v->n_segments - 3;
486 v->read_buffer = av_malloc(INITIAL_BUFFER_SIZE);
487 ffio_init_context(&v->pb, v->read_buffer, INITIAL_BUFFER_SIZE, 0, v,
488 read_data, NULL, NULL);
490 ret = av_probe_input_buffer(&v->pb, &in_fmt, v->segments[0]->url,
494 ret = av_open_input_stream(&v->ctx, &v->pb, v->segments[0]->url,
498 v->stream_offset = stream_offset;
499 snprintf(bitrate_str, sizeof(bitrate_str), "%d", v->bandwidth);
500 /* Create new AVStreams for each stream in this variant */
501 for (j = 0; j < v->ctx->nb_streams; j++) {
502 AVStream *st = av_new_stream(s, i);
504 ret = AVERROR(ENOMEM);
507 avcodec_copy_context(st->codec, v->ctx->streams[j]->codec);
509 av_dict_set(&st->metadata, "variant_bitrate", bitrate_str,
512 stream_offset += v->ctx->nb_streams;
519 free_variant_list(c);
523 static int recheck_discard_flags(AVFormatContext *s, int first)
525 AppleHTTPContext *c = s->priv_data;
528 /* Check if any new streams are needed */
529 for (i = 0; i < c->n_variants; i++)
530 c->variants[i]->cur_needed = 0;;
532 for (i = 0; i < s->nb_streams; i++) {
533 AVStream *st = s->streams[i];
534 struct variant *var = c->variants[s->streams[i]->id];
535 if (st->discard < AVDISCARD_ALL)
538 for (i = 0; i < c->n_variants; i++) {
539 struct variant *v = c->variants[i];
540 if (v->cur_needed && !v->needed) {
543 v->cur_seq_no = c->cur_seq_no;
544 v->pb.eof_reached = 0;
545 av_log(s, AV_LOG_INFO, "Now receiving variant %d\n", i);
546 } else if (first && !v->cur_needed && v->needed) {
548 ffurl_close(v->input);
552 av_log(s, AV_LOG_INFO, "No longer receiving variant %d\n", i);
558 static int applehttp_read_packet(AVFormatContext *s, AVPacket *pkt)
560 AppleHTTPContext *c = s->priv_data;
561 int ret, i, minvariant = -1;
563 if (c->first_packet) {
564 recheck_discard_flags(s, 1);
569 c->end_of_segment = 0;
570 for (i = 0; i < c->n_variants; i++) {
571 struct variant *var = c->variants[i];
572 /* Make sure we've got one buffered packet from each open variant
574 if (var->needed && !var->pkt.data) {
575 ret = av_read_frame(var->ctx, &var->pkt);
577 if (!url_feof(&var->pb))
579 reset_packet(&var->pkt);
582 /* Check if this stream has the packet with the lowest dts */
584 if (minvariant < 0 ||
585 var->pkt.dts < c->variants[minvariant]->pkt.dts)
589 if (c->end_of_segment) {
590 if (recheck_discard_flags(s, 0))
593 /* If we got a packet, return it */
594 if (minvariant >= 0) {
595 *pkt = c->variants[minvariant]->pkt;
596 pkt->stream_index += c->variants[minvariant]->stream_offset;
597 reset_packet(&c->variants[minvariant]->pkt);
603 static int applehttp_close(AVFormatContext *s)
605 AppleHTTPContext *c = s->priv_data;
607 free_variant_list(c);
611 static int applehttp_read_seek(AVFormatContext *s, int stream_index,
612 int64_t timestamp, int flags)
614 AppleHTTPContext *c = s->priv_data;
617 if ((flags & AVSEEK_FLAG_BYTE) || !c->variants[0]->finished)
618 return AVERROR(ENOSYS);
620 timestamp = av_rescale_rnd(timestamp, 1, stream_index >= 0 ?
621 s->streams[stream_index]->time_base.den :
622 AV_TIME_BASE, flags & AVSEEK_FLAG_BACKWARD ?
623 AV_ROUND_DOWN : AV_ROUND_UP);
625 for (i = 0; i < c->n_variants; i++) {
627 struct variant *var = c->variants[i];
630 ffurl_close(var->input);
633 av_free_packet(&var->pkt);
634 reset_packet(&var->pkt);
635 var->pb.eof_reached = 0;
637 /* Locate the segment that contains the target timestamp */
638 for (j = 0; j < var->n_segments; j++) {
639 if (timestamp >= pos &&
640 timestamp < pos + var->segments[j]->duration) {
641 var->cur_seq_no = var->start_seq_no + j;
645 pos += var->segments[j]->duration;
651 static int applehttp_probe(AVProbeData *p)
653 /* Require #EXTM3U at the start, and either one of the ones below
654 * somewhere for a proper match. */
655 if (strncmp(p->buf, "#EXTM3U", 7))
657 if (strstr(p->buf, "#EXT-X-STREAM-INF:") ||
658 strstr(p->buf, "#EXT-X-TARGETDURATION:") ||
659 strstr(p->buf, "#EXT-X-MEDIA-SEQUENCE:"))
660 return AVPROBE_SCORE_MAX;
664 AVInputFormat ff_applehttp_demuxer = {
666 NULL_IF_CONFIG_SMALL("Apple HTTP Live Streaming format"),
667 sizeof(AppleHTTPContext),
669 applehttp_read_header,
670 applehttp_read_packet,