From 1b60d647a7ca6c1c502c821265b689b847f7255a Mon Sep 17 00:00:00 2001 From: Sebastian Zeller Date: Tue, 5 Jan 2021 07:09:34 +0100 Subject: [PATCH 3/3] avformat/webvttdec: Calculate hls_ts_offset relative to first fragment --- libavformat/webvttdec.c | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-) diff --git a/libavformat/webvttdec.c b/libavformat/webvttdec.c index c6acf8e5bb..cf56f0c232 100644 --- a/libavformat/webvttdec.c +++ b/libavformat/webvttdec.c @@ -71,6 +71,7 @@ static int webvtt_read_header(AVFormatContext *s) AVStream *st = avformat_new_stream(s, NULL); int has_hls_timestamp_map = 0; int64_t hls_ts_offset; + int64_t hls_ts_offset_global = -1; if (!st) return AVERROR(ENOMEM); @@ -121,7 +122,14 @@ static int webvtt_read_header(AVFormatContext *s) int64_t mpegts_ts = strtoll(mpegts_str + 7, NULL, 10); if (native_ts != AV_NOPTS_VALUE) { - hls_ts_offset = mpegts_ts - native_ts * 90; + /* + * In livestreams the timestamp map can start at any mpegts time. + * Consequently, everything should be treated relative to the first timestamp. + */ + if (hls_ts_offset_global == -1) { + hls_ts_offset_global = mpegts_ts; + } + hls_ts_offset = mpegts_ts - native_ts * 90 - hls_ts_offset_global; has_hls_timestamp_map = 1; avpriv_set_pts_info(st, 33, 1, 90000); } -- 2.29.2