Try this URL
http://www.geocities.com/kryst0ph/nasavideo2.html
and click on the "Apollo Footage" link. I personally don't favor Geocities. Their free web service comes at the price of being able to view some content only in a browser and its plugins and not to save it to disk for analysis by other tools.
Some source comfirm that the video is a real footage from Apollo 12 mission ...
I see no reason to doubt that this is authentic footage from Apollo 12, however in the future confirmation cannot come from "some source". It's not confirmation unless we know the identity of the comfirmer.
... and no one was able to find an explanation.
My, this sounds ominous. What do you think it is, and why?