From 1931761f18cda3756a27087c366270c38160c754 Mon Sep 17 00:00:00 2001 From: Jan Ekström Date: Thu, 26 Jul 2018 02:51:38 +0300 Subject: avformat/movenc: implicitly enable negative CTS offsets for ismv ISMV lacks any sort of edit list support, as well as tfxd is effectively the PTS of the fragment for most intents and purposes. Thus, if b-frames are requested without negative CTS offsets you end up with N frames' worth of delay (tfxd PTS plus the CTS offset of the first sample). Negative CTS offsets enable the first sample to have CTS=DTS, and thus a/v desync due to b-frame reorder delay is avoided. --- doc/muxers.texi | 2 ++ 1 file changed, 2 insertions(+) (limited to 'doc') diff --git a/doc/muxers.texi b/doc/muxers.texi index 33f1f7bbaf..268c152023 100644 --- a/doc/muxers.texi +++ b/doc/muxers.texi @@ -1344,6 +1344,8 @@ be negative. This enables the initial sample to have DTS/CTS of zero, and reduces the need for edit lists for some cases such as video tracks with B-frames. Additionally, eases conformance with the DASH-IF interoperability guidelines. + +This option is implicitly set when writing ismv (Smooth Streaming) files. @item -write_prft Write producer time reference box (PRFT) with a specified time source for the NTP field in the PRFT box. Set value as @samp{wallclock} to specify timesource -- cgit v1.2.3