YouTube video popup

I got a strange message from a YouTube video popup suggesting that I install an "HD converter".   The message was not an advert served in the usual YouTube format.   I was given the following reference as a possible description of the problem:     http://labs.bromium.com/2014/02/21/the-wild-wild-web-youtube-ads-serving-malware/ .   I do not have Java on my PC.   At the time of the hit, I was using FireFox and NoScript.   I am running Windows 7 (current), NIS 2014 and FireFox 27.0.1.