On Wed, 16 Nov 2016 10:31:10 +0000 Franklin Phillips <franklinphill...@gmx.com> wrote:
> This patch is a fix for ticket #2833. > > Each subtitle segment is its own WebVTT file and has to demuxed individually. > The timing of the subtitles are not perfect but it is the best I could What does this mean? > do and it also does not take into account the X-TIMESTAMP-MAP header > in the WebVTT files which is needed to conform to the specification > (https://tools.ietf.org/html/draft-pantos-http-live-streaming-20#section-3.5). I'm not entirely familiar how HLS works. Shouldn't this be fine as long as the webvtt events have the correct "final" timestamp? > > Signed-off-by: Franklin Phillips <franklinphill...@gmx.com> > --- > libavformat/hls.c | 178 > ++++++++++++++++++++++++++++++++++++++++++++++++------ > 1 file changed, 159 insertions(+), 19 deletions(-) > > diff --git a/libavformat/hls.c b/libavformat/hls.c > index 3ae3c7c..bf13be4 100644 > --- a/libavformat/hls.c > +++ b/libavformat/hls.c > @@ -153,6 +153,8 @@ struct playlist { > * playlist, if any. */ > int n_init_sections; > struct segment **init_sections; > + > + int is_subtitle; /* Indicates if the playlist is for subtitles */ > }; > > /* > @@ -312,6 +314,8 @@ static struct playlist *new_playlist(HLSContext *c, const > char *url, > pls->is_id3_timestamped = -1; > pls->id3_mpegts_timestamp = AV_NOPTS_VALUE; > > + pls->is_subtitle = 0; > + > dynarray_add(&c->playlists, &c->n_playlists, pls); > return pls; > } > @@ -482,11 +486,6 @@ static struct rendition *new_rendition(HLSContext *c, > struct rendition_info *inf > if (type == AVMEDIA_TYPE_SUBTITLE && !info->uri[0]) > return NULL; > > - /* TODO: handle subtitles (each segment has to parsed separately) */ > - if (c->strict_std_compliance > FF_COMPLIANCE_EXPERIMENTAL) > - if (type == AVMEDIA_TYPE_SUBTITLE) > - return NULL; > - > rend = av_mallocz(sizeof(struct rendition)); > if (!rend) > return NULL; > @@ -501,9 +500,14 @@ static struct rendition *new_rendition(HLSContext *c, > struct rendition_info *inf > /* add the playlist if this is an external rendition */ > if (info->uri[0]) { > rend->playlist = new_playlist(c, info->uri, url_base); > - if (rend->playlist) > + if (rend->playlist) { > dynarray_add(&rend->playlist->renditions, > &rend->playlist->n_renditions, rend); > + if (type == AVMEDIA_TYPE_SUBTITLE) { > + rend->playlist->is_subtitle = 1; > + rend->playlist->is_id3_timestamped = 0; > + } > + } > } > > if (info->assoc_language[0]) { > @@ -1349,6 +1353,136 @@ reload: > goto restart; > } > > +static int nested_io_open(AVFormatContext *s, AVIOContext **pb, const char > *url, > + int flags, AVDictionary **opts) > +{ > + av_log(s, AV_LOG_ERROR, > + "A HLS playlist item '%s' referred to an external file '%s'. " > + "Opening this file was forbidden for security reasons\n", > + s->filename, url); > + return AVERROR(EPERM); > +} > + > +static int read_data_simple(void *opaque, uint8_t *buf, int buf_size) > +{ > + struct playlist *v = opaque; > + HLSContext *c = v->parent->priv_data; > + struct segment *seg; > + > + if (v->cur_seq_no >= v->start_seq_no + v->n_segments) { > + return AVERROR_EOF; > + } else { > + seg = current_segment(v); > + } > + > + if (!v->input) { > + open_input(c, v, seg); > + } > + > + return read_from_url(v, seg, buf, buf_size, READ_NORMAL); > +} > + > +static int read_packet_subtitle(struct playlist *v, AVPacket *pkt) > +{ > + HLSContext *c = v->parent->priv_data; > + int ret, i; > + > +restart: > + if (!v->needed) > + return AVERROR_EOF; > + > + if (!v->input) { > + int64_t reload_interval; > + > + /* Check that the playlist is still needed before opening a new > + * segment. */ > + if (v->ctx && v->ctx->nb_streams) { > + v->needed = 0; > + for (i = 0; i < v->n_main_streams; i++) { > + if (v->main_streams[i]->discard < AVDISCARD_ALL) { > + v->needed = 1; > + break; > + } > + } > + } > + if (!v->needed) { > + av_log(v->parent, AV_LOG_INFO, "No longer receiving playlist > %d\n", > + v->index); > + return AVERROR_EOF; > + } > + > + /* If this is a live stream and the reload interval has elapsed since > + * the last playlist reload, reload the playlists now. */ > + reload_interval = default_reload_interval(v); > + > + if (!v->finished && > + av_gettime_relative() - v->last_load_time >= reload_interval) { > + if ((ret = parse_playlist(c, v->url, v, NULL)) < 0) { > + av_log(v->parent, AV_LOG_WARNING, "Failed to reload playlist > %d\n", > + v->index); > + 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 / 2; > + } > + if (v->cur_seq_no < v->start_seq_no) { > + av_log(NULL, AV_LOG_WARNING, > + "skipping %d segments ahead, expired from subtitle > 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) { > + return AVERROR_EOF; > + } > + } > + > + if (v->ctx == NULL) { > + AVInputFormat *in_fmt; > + > + if (!(v->ctx = avformat_alloc_context())) { > + return AVERROR(ENOMEM); > + } > + > + v->read_buffer = av_malloc(INITIAL_BUFFER_SIZE); > + if (!v->read_buffer){ > + avformat_free_context(v->ctx); > + v->ctx = NULL; > + return AVERROR(ENOMEM); > + } > + > + ffio_init_context(&v->pb, v->read_buffer, INITIAL_BUFFER_SIZE, 0, v, > + read_data_simple, NULL, NULL); > + v->pb.seekable = 0; > + v->ctx->pb = &v->pb; > + v->ctx->io_open = nested_io_open; > + > + ret = ff_copy_whiteblacklists(v->ctx, v->parent); > + if (ret < 0) { > + return ret; > + } > + > + in_fmt = av_find_input_format("webvtt"); > + ret = avformat_open_input(&v->ctx, current_segment(v)->url, in_fmt, > NULL); > + if (ret < 0) { > + return ret; > + } > + } > + > + ret = av_read_frame(v->ctx, pkt); > + if (ret < 0) { > + ff_format_io_close(v->parent, &v->input); > + avformat_close_input(&v->ctx); > + if (ret == AVERROR_EOF) { > + v->cur_seq_no++; > + goto restart; > + } > + } > + > + return ret; > +} > + That seems to duplicate a lot of code from the normal read path... > static void add_renditions_to_variant(HLSContext *c, struct variant *var, > enum AVMediaType type, const char > *group_id) > { > @@ -1492,16 +1626,6 @@ static int save_avio_options(AVFormatContext *s) > return ret; > } > > -static int nested_io_open(AVFormatContext *s, AVIOContext **pb, const char > *url, > - int flags, AVDictionary **opts) > -{ > - av_log(s, AV_LOG_ERROR, > - "A HLS playlist item '%s' referred to an external file '%s'. " > - "Opening this file was forbidden for security reasons\n", > - s->filename, url); > - return AVERROR(EPERM); > -} > - > static void add_stream_to_programs(AVFormatContext *s, struct playlist *pls, > AVStream *stream) > { > HLSContext *c = s->priv_data; > @@ -1744,8 +1868,14 @@ static int hls_read_header(AVFormatContext *s) > pls->ctx = NULL; > goto fail; > } > - ffio_init_context(&pls->pb, pls->read_buffer, INITIAL_BUFFER_SIZE, > 0, pls, > - read_data, NULL, NULL); > + > + if (pls->is_subtitle) { > + ffio_init_context(&pls->pb, pls->read_buffer, > INITIAL_BUFFER_SIZE, 0, pls, > + read_data_simple, NULL, NULL); > + } else { > + ffio_init_context(&pls->pb, pls->read_buffer, > INITIAL_BUFFER_SIZE, 0, pls, > + read_data, NULL, NULL); > + } > pls->pb.seekable = 0; > ret = av_probe_input_buffer(&pls->pb, &in_fmt, pls->segments[0]->url, > NULL, 0, 0); > @@ -1843,6 +1973,8 @@ static int recheck_discard_flags(AVFormatContext *s, > int first) > } else if (first && !pls->cur_needed && pls->needed) { > if (pls->input) > ff_format_io_close(pls->parent, &pls->input); > + if (pls->is_subtitle) > + avformat_close_input(&pls->ctx); > pls->needed = 0; > changed = 1; > av_log(s, AV_LOG_INFO, "No longer receiving playlist %d\n", i); > @@ -1909,7 +2041,12 @@ static int hls_read_packet(AVFormatContext *s, > AVPacket *pkt) > while (1) { > int64_t ts_diff; > AVRational tb; > - ret = av_read_frame(pls->ctx, &pls->pkt); > + if (pls->is_subtitle) { > + ret = read_packet_subtitle(pls, &pls->pkt); > + } else { > + ret = av_read_frame(pls->ctx, &pls->pkt); > + } > + > if (ret < 0) { > if (!avio_feof(&pls->pb) && ret != AVERROR_EOF) > return ret; > @@ -2087,6 +2224,9 @@ static int hls_read_seek(AVFormatContext *s, int > stream_index, > /* Flush the packet queue of the subdemuxer. */ > ff_read_frame_flush(pls->ctx); > > + if (pls->is_subtitle) > + avformat_close_input(&pls->ctx); > + > pls->seek_timestamp = seek_timestamp; > pls->seek_flags = flags; > _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org http://ffmpeg.org/mailman/listinfo/ffmpeg-devel
