Well, James explained that to me a while ago (ok, actually he explained it to me several times by now
), and he'd be better in explaining this, but I'll give it a try (after all, I'm more the crypto-guy, and James is the video genius).
It's a bit of a mind-twister...
There is no re-synchronizing being done - the audio and video already has to be synchronized.
What it actually does, is speed up or slow down the whole thing a bit, to better match the refresh-rate of the display.
If you're watching a movie, that comes with a certain framerate and your monitor does not refresh at exactly that rate (or a multiple of that), some frames will show up for a less longer time, than others.
For example, when viewing a stream with 25 fps and your monitor refreshes at 60Hz, most frames will be on the screen for 2 refresh-periods, but quite a few will be on for 3.
And this results in moving sequences looking a little "skippy".
The same happens with a movie with 29.97 fps on a 60HZ-Monitor, just with a different rate (should skip apx. every 8 seconds, if I did that calculating right?).
So ReClock will - in the latter case - speed up the movie just a bit to 30fps (unnoticably). And with PAL you might better readjust the monitor frequency to 50Hz and ReClock will "lock on" the video to that rate.
I hope, I got that right, James don't yell at me.
Well, I guess, the problem with ReClock is rather, that most people think that they don't need it, while they actually do? It would require some hardcore marketing, to get that to the people...