How to control what movie formates download from piratebay?

well, i’ve downloaded the identical movie coming from like, HALF A DOZEN or SEVEN different links on piratebay.each time they help you save as.flv.when will i save them like a different sort of file a person said i can do it being a.avi.when will i do this

You can use a converter, including WinAVI All In a Converter, transform any models to other popular models or units directly.
this is the information:
http://www.winavi.com/flv-to-avi.htm.