From 3586c68687035225451f57c4e422673cbe6d4377 Mon Sep 17 00:00:00 2001 From: Anssi Hannula Date: Wed, 27 Jul 2016 22:52:44 +0300 Subject: [PATCH] avformat/hls: Sync starting segment across variants on live streams This will avoid a large time difference between variants in the most common case. (cherry picked from commit 4d85069e5dff37e4a9904767242b47e14cf62a9c) Signed-off-by: Michael Niedermayer --- libavformat/hls.c | 25 ++++++++++++++++++++++++- 1 file changed, 24 insertions(+), 1 deletion(-) diff --git a/libavformat/hls.c b/libavformat/hls.c index 66f4550411..88402c2284 100644 --- a/libavformat/hls.c +++ b/libavformat/hls.c @@ -1520,6 +1520,7 @@ static int hls_read_header(AVFormatContext *s) void *u = (s->flags & AVFMT_FLAG_CUSTOM_IO) ? NULL : s->pb; HLSContext *c = s->priv_data; int ret = 0, i, j, stream_offset = 0; + int highest_cur_seq_no = 0; c->ctx = s; c->interrupt_callback = &s->interrupt_callback; @@ -1594,6 +1595,17 @@ static int hls_read_header(AVFormatContext *s) add_renditions_to_variant(c, var, AVMEDIA_TYPE_SUBTITLE, var->subtitles_group); } + /* Select the starting segments */ + for (i = 0; i < c->n_playlists; i++) { + struct playlist *pls = c->playlists[i]; + + if (pls->n_segments == 0) + continue; + + pls->cur_seq_no = select_cur_seq_no(c, pls); + highest_cur_seq_no = FFMAX(highest_cur_seq_no, pls->cur_seq_no); + } + /* Open the demuxer for each playlist */ for (i = 0; i < c->n_playlists; i++) { struct playlist *pls = c->playlists[i]; @@ -1610,7 +1622,18 @@ static int hls_read_header(AVFormatContext *s) pls->index = i; pls->needed = 1; pls->parent = s; - pls->cur_seq_no = select_cur_seq_no(c, pls); + + /* + * If this is a live stream and this playlist looks like it is one segment + * behind, try to sync it up so that every substream starts at the same + * time position (so e.g. avformat_find_stream_info() will see packets from + * all active streams within the first few seconds). This is not very generic, + * though, as the sequence numbers are technically independent. + */ + if (!pls->finished && pls->cur_seq_no == highest_cur_seq_no - 1 && + highest_cur_seq_no < pls->start_seq_no + pls->n_segments) { + pls->cur_seq_no = highest_cur_seq_no; + } pls->read_buffer = av_malloc(INITIAL_BUFFER_SIZE); if (!pls->read_buffer){