From 2772258a986fb2da3ca5c6eb423a5024b9e9df27 Mon Sep 17 00:00:00 2001 From: Martin Storsjö Date: Tue, 14 Feb 2012 11:47:31 +0200 Subject: libavformat: Rename the applehttp demuxer to hls MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit When this demuxer was created, there didn't seem to be any consensus of a common short name for this protocol. Now the consensus seems to be to call it hls. Signed-off-by: Martin Storsjö --- libavformat/hls.c | 711 ++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 711 insertions(+) create mode 100644 libavformat/hls.c (limited to 'libavformat/hls.c') diff --git a/libavformat/hls.c b/libavformat/hls.c new file mode 100644 index 0000000000..13b9b27378 --- /dev/null +++ b/libavformat/hls.c @@ -0,0 +1,711 @@ +/* + * 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) { + /* If this is a live stream and the reload interval has elapsed since + * the last playlist reload, reload the variant playlists now. */ + int64_t reload_interval = v->n_segments > 0 ? + v->segments[v->n_segments - 1]->duration : + v->target_duration; + reload_interval *= 1000000; + +reload: + if (!v->finished && + av_gettime() - v->last_load_time >= reload_interval) { + if ((ret = parse_playlist(c, v->url, v, NULL)) < 0) + return ret; + /* If we need to reload the playlist again below (if + * there's still no more segments), switch to a reload + * interval of half the target duration. */ + reload_interval = v->target_duration * 500000; + } + 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 < reload_interval) { + 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) +{ + 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) { + /* Free the ctx - it isn't initialized properly at this point, + * so avformat_close_input shouldn't be called. If + * avformat_open_input fails below, it frees and zeros the + * context, so it doesn't need any special treatment like this. */ + avformat_free_context(v->ctx); + v->ctx = NULL; + 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_hls_demuxer = { + .name = "hls", + .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, +}; -- cgit v1.2.3