[FFmpeg-user] Warning "Starting new cluster due to timestamp" on muxing two input streams and resulting movie with muted audio at some locations

[Georgi D. Sotirov]

Hello,

I'm having the warning "/Starting new cluster due to timestamp/" when 
trying to mux the video and the audio from two (matroska) input streams 
by just copying the video from the first and the audio from the second 
them (i.e. without re-encoding). The resulting movie is scrambled - the 
video is OK, but the audio is inconsistent - it's muted in random 
locations. It's the same problem explained here 
<http://ffmpeg.gusari.org/viewtopic.php?f=11&t=2713> and I reproduce it 
with Sintel movie <https://durian.blender.org/download/> as given in the 
example. The strange is that I've done the same operation many times in 
the past and I'm not sure why I have this warning just now as in the 
source it seem to have been introduced almost 3 years ago (see commit 
7923aa0fba6b7b55ebbe1af8b7620060f36a1133 
<https://github.com/FFmpeg/FFmpeg/commit/7923aa0fba6b7b55ebbe1af8b7620060f36a1133>). 
Thus, I normally receive the same warning with newly released FFmpeg 3.3 
as well as with previous 3.2.4 version.

So is there any way to solve this problem, avoid the warning and produce 
movie without muted sound?


Best regards,
--
Georgi D. Sotirov