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author | Martin Storsjö <martin@martin.st> | 2010-08-19 14:54:37 +0000 |
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committer | Martin Storsjö <martin@martin.st> | 2010-08-19 14:54:37 +0000 |
commit | cd223e0b4e1371d12d6cbb36bb66afdc40fd6281 (patch) | |
tree | 6c9f36285217f78b9d90133e981263fbea9abbc0 /libavformat/applehttp.c | |
parent | e55ebcc3f6cf1f00ffd56ef0f357dc8010c6e046 (diff) | |
download | ffmpeg-streaming-cd223e0b4e1371d12d6cbb36bb66afdc40fd6281.zip ffmpeg-streaming-cd223e0b4e1371d12d6cbb36bb66afdc40fd6281.tar.gz |
Add Apple HTTP Live Streaming demuxer
Originally committed as revision 24834 to svn://svn.ffmpeg.org/ffmpeg/trunk
Diffstat (limited to 'libavformat/applehttp.c')
-rw-r--r-- | libavformat/applehttp.c | 578 |
1 files changed, 578 insertions, 0 deletions
diff --git a/libavformat/applehttp.c b/libavformat/applehttp.c new file mode 100644 index 0000000..3d8b61d --- /dev/null +++ b/libavformat/applehttp.c @@ -0,0 +1,578 @@ +/* + * Apple HTTP Live Streaming demuxer + * Copyright (c) 2010 Martin Storsjo + * + * This file is part of FFmpeg. + * + * FFmpeg 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. + * + * FFmpeg 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 FFmpeg; 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 "avformat.h" +#include "internal.h" +#include <unistd.h> + +/* + * 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. + */ + +struct segment { + int duration; + char url[MAX_URL_SIZE]; +}; + +/* + * Each variant has its own demuxer. If it currently is active, + * it has an open ByteIOContext too, and potentially an AVPacket + * containing the next packet from this stream. + */ +struct variant { + int bandwidth; + char url[MAX_URL_SIZE]; + ByteIOContext *pb; + AVFormatContext *ctx; + AVPacket pkt; + int stream_offset; + + int start_seq_no; + int n_segments; + struct segment **segments; + int needed; +}; + +typedef struct AppleHTTPContext { + int target_duration; + int finished; + int n_variants; + struct variant **variants; + int cur_seq_no; + int64_t last_load_time; + int64_t last_packet_dts; + int max_start_seq, min_end_seq; +} AppleHTTPContext; + +static int read_chomp_line(ByteIOContext *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 make_absolute_url(char *buf, int size, const char *base, + const char *rel) +{ + char *sep; + if (!base || strstr(rel, "://")) { + av_strlcpy(buf, rel, size); + return; + } + if (base != buf) + av_strlcpy(buf, base, size); + sep = strrchr(buf, '/'); + if (sep) + sep[1] = '\0'; + while (av_strstart(rel, "../", NULL)) { + if (sep) { + sep[0] = '\0'; + sep = strrchr(buf, '/'); + if (sep) + sep[1] = '\0'; + } + rel += 3; + } + av_strlcat(buf, rel, size); +} + +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); + if (var->pb) + url_fclose(var->pb); + if (var->ctx) { + var->ctx->pb = NULL; + av_close_input_file(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; + 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); + } +} + +static int parse_playlist(AppleHTTPContext *c, const char *url, + struct variant *var, ByteIOContext *in) +{ + int ret = 0, duration = 0, is_segment = 0, is_variant = 0, bandwidth = 0; + char line[1024]; + const char *ptr; + int close_in = 0; + + if (!in) { + close_in = 1; + if ((ret = url_fopen(&in, url, URL_RDONLY)) < 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); + c->finished = 0; + while (!url_feof(in)) { + 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-TARGETDURATION:", &ptr)) { + c->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)) { + c->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; + make_absolute_url(seg->url, sizeof(seg->url), url, line); + dynarray_add(&var->segments, &var->n_segments, seg); + is_segment = 0; + } + } + } + c->last_load_time = av_gettime(); + +fail: + if (close_in) + url_fclose(in); + return ret; +} + +static int applehttp_read_header(AVFormatContext *s, AVFormatParameters *ap) +{ + AppleHTTPContext *c = s->priv_data; + int ret = 0, i, j, stream_offset = 0; + + 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->finished) { + int 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; + } + + c->min_end_seq = INT_MAX; + /* Open the demuxer for each variant */ + for (i = 0; i < c->n_variants; i++) { + struct variant *v = c->variants[i]; + if (v->n_segments == 0) + continue; + c->max_start_seq = FFMAX(c->max_start_seq, v->start_seq_no); + c->min_end_seq = FFMIN(c->min_end_seq, v->start_seq_no + + v->n_segments); + ret = av_open_input_file(&v->ctx, v->segments[0]->url, NULL, 0, NULL); + if (ret < 0) + goto fail; + url_fclose(v->ctx->pb); + v->ctx->pb = NULL; + v->stream_offset = stream_offset; + /* Create new AVStreams for each stream in this variant */ + for (j = 0; j < v->ctx->nb_streams; j++) { + AVStream *st = av_new_stream(s, i); + if (!st) { + ret = AVERROR(ENOMEM); + goto fail; + } + avcodec_copy_context(st->codec, v->ctx->streams[j]->codec); + } + stream_offset += v->ctx->nb_streams; + } + c->last_packet_dts = AV_NOPTS_VALUE; + + c->cur_seq_no = c->max_start_seq; + /* If this is a live stream with more than 3 segments, start at the + * third last segment. */ + if (!c->finished && c->min_end_seq - c->max_start_seq > 3) + c->cur_seq_no = c->min_end_seq - 2; + + return 0; +fail: + free_variant_list(c); + return ret; +} + +static int open_variant(AppleHTTPContext *c, struct variant *var, int skip) +{ + int ret; + + if (c->cur_seq_no < var->start_seq_no) { + av_log(NULL, AV_LOG_WARNING, + "seq %d not available in variant %s, skipping\n", + var->start_seq_no, var->url); + return 0; + } + if (c->cur_seq_no - var->start_seq_no >= var->n_segments) + return c->finished ? AVERROR_EOF : 0; + ret = url_fopen(&var->pb, + var->segments[c->cur_seq_no - var->start_seq_no]->url, + URL_RDONLY); + if (ret < 0) + return ret; + var->ctx->pb = var->pb; + /* If this is a new segment in parallel with another one already opened, + * skip ahead so they're all at the same dts. */ + if (skip && c->last_packet_dts != AV_NOPTS_VALUE) { + while (1) { + ret = av_read_frame(var->ctx, &var->pkt); + if (ret < 0) { + if (ret == AVERROR_EOF) { + reset_packet(&var->pkt); + return 0; + } + return ret; + } + if (var->pkt.dts >= c->last_packet_dts) + break; + av_free_packet(&var->pkt); + } + } + return 0; +} + +static int applehttp_read_packet(AVFormatContext *s, AVPacket *pkt) +{ + AppleHTTPContext *c = s->priv_data; + int ret, i, minvariant = -1, first = 1, needed = 0, changed = 0, + variants = 0; + + /* Recheck the discard flags - which streams are desired at the moment */ + for (i = 0; i < c->n_variants; i++) + c->variants[i]->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->needed = 1; + needed++; + } + /* Copy the discard flag to the chained demuxer, to indicate which + * streams are desired. */ + var->ctx->streams[i - var->stream_offset]->discard = st->discard; + } + if (!needed) + return AVERROR_EOF; +start: + for (i = 0; i < c->n_variants; i++) { + struct variant *var = c->variants[i]; + /* Close unneeded streams, open newly requested streams */ + if (var->pb && !var->needed) { + av_log(s, AV_LOG_DEBUG, + "Closing variant stream %d, no longer needed\n", i); + av_free_packet(&var->pkt); + reset_packet(&var->pkt); + url_fclose(var->pb); + var->pb = NULL; + changed = 1; + } else if (!var->pb && var->needed) { + if (first) + av_log(s, AV_LOG_DEBUG, "Opening variant stream %d\n", i); + if (first && !c->finished) + if ((ret = parse_playlist(c, var->url, var, NULL)) < 0) + return ret; + ret = open_variant(c, var, first); + if (ret < 0) + return ret; + changed = 1; + } + /* Count the number of open variants */ + if (var->pb) + variants++; + /* Make sure we've got one buffered packet from each open variant + * stream */ + if (var->pb && !var->pkt.data) { + ret = av_read_frame(var->ctx, &var->pkt); + if (ret < 0) { + if (!url_feof(var->pb)) + return ret; + reset_packet(&var->pkt); + } + } + /* 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 (first && changed) + av_log(s, AV_LOG_INFO, "Receiving %d variant streams\n", variants); + /* 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); + c->last_packet_dts = pkt->dts; + return 0; + } + /* No more packets - eof reached in all variant streams, close the + * current segments. */ + for (i = 0; i < c->n_variants; i++) { + struct variant *var = c->variants[i]; + if (var->pb) { + url_fclose(var->pb); + var->pb = NULL; + } + } + /* Indicate that we're opening the next segment, not opening a new + * variant stream in parallel, so we shouldn't try to skip ahead. */ + first = 0; + c->cur_seq_no++; +reload: + if (!c->finished) { + /* If this is a live stream and target_duration has elapsed since + * the last playlist reload, reload the variant playlists now. */ + 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 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, +}; |