> And in this case, I actually know about the problem and I need to ask for someone's help…Everything was in sync before I posted the video onto YouTube, but once it was on YouTube, the sound starts 18 seconds too late, as you report, which is not good ….

I might be able to help if you can put the original to download
somewhere.  I know now what the problem is: different rate on
audio/video.  So, if you want me to give a try just write to me with the
link and I'll do my best.

> I hope you could watch the video anyway for now -

I finally opened two players, one for the sound, one for the video.
It's not the best way to go about it and pausing is complicated ... but
it works :).

> I am happy to know you are visiting our SignWriting on YouTube site:

Yes, I love it!  And the books.  I need to learn more before I can add
more signs and the videos help a lot.