System-Wide Audio/Video Syncing

I'm aware of VLC's capability to sync the audio to the video in milliseconds. It's really useful.
However, I've run into an issue where there is a lengthy video online (Flash) that is out of sync. Are there any solutions to syncing the two system-wide (as I doubt there are any browser extensions to do this)?
Now, the tough part is, the video is ahead of the audio. Would this require caching the video for a few milliseconds to allow the audio to catch up?