Strange audio issue with playback

andy

Whenever I play an avi file through winamp or mediaplayer10...the file will play fine but eventually the audio will gradually start to delay by small frations and get worse.  But if I stop the file and then restart it back at the time stamp it delayed at the file will regain sync.  This is happening on files that a month or so ago played fine without this issue.  My system has not changed in anyway regarding software or hardware.

Does this have something to do with the divx decoder settings themselves?

Thanks for any help.