How long should conversion take?

I am trying to convert a simple 2min youtube song to an mp3 file (128kb/s). The file is just converting for a lot of time - more then 10 minutes. How long should a conversion take? Also I got a pop-up saying, that the site failed to download a TV player - which I thought is related if one wants to download videos - but I also found that a bit weird? Any explanations?