[gst-devel] Playbin loss of sync

Scott Watson baudtender1 at comcast.net
Thu Mar 3 23:47:20 CET 2005


I've been fiddling with the cross-platform aspect of gstreamer for the 
last week or two -
looking to get a substantial portion up and running using native Windows 
compile with
Visual C++ 6.0.  My goal is to do a PortAudio plugin to function as a 
cross-platform
audio source/sink and to modify the SDL video sink plugin as necessary.  
Before each
step I do sanity-checks with existing pieces under Linux.

I did a fresh Fedora Core 3 install to use as a reference platform and 
have noticed
some weirdness that I would like to get comments on before proceeding 
further.  What
I'm seeing is with the 0.8.7.2 plugin package, the playbin plugin loses 
A/V sync
after a play/pause/play transition.  The lag doesn't appear to be related to
the amount of time the pipeline was paused - if anything it appears to 
be what I'd
expect for an internal playbin queue or more likely, an ALSA internal 
ringbuffer.
I tried this for both an .avi file wrapping a DIVX codec, and for an 
MPEG-1 file -
I'm just not sure which demuxers/decoders are being selected by 
playbin.  My test
is almost verbatim the test4.c file in the playbin directory, modified only
in the timing to get to a vocals part in my test tracks to make checking 
A/V sync
easier.

I should also mention that the gstreamer-backend Totem installed with 
Fedora does
exactly the same thing, but other players (xine, mplayer) survive this 
procedure
on the same files with flying colors.

Any thoughts?

S.W.





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