> I am having a problem with the video / audio sync when recording from an
> RTSP stream with ffmpeg.


> The result seems leave the video and audio out of sync in Windows Media
> Player (which unfortunately is the application I need to use for this), where
> as VLC seems to be able to cope with this and rectifies the problem.

Andy,

I have a similar (if not exact same) problem when copying an RTSP stream.  I've 
also verified the different behavior in Windows Media Player and VLC.  The 
workaround I found was to run the resultant video through an ffmpeg process 
using -ss 0 -i input -c copy which seems to bring the audio and video back into 
sync.  It's a quick "copy" process.  No need to find the exact offset as -ss 0 
seemed to work no matter what amount of offset there was.  My theory is that 
ffmpeg waits until a keyframe before copying video, but audio starts copying 
right away which causes audio to lag video (video is pulled forward to fill the 
non-keyframe gap).  The -copyinkf (copy initial non-keyframe) parameter didn't 
have any affect for me.  Again, only a theory.  I'm just a user, not a 
developer.

Dave

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