Hi. I've always edited video on a PC using Sony Vegas.
Now I'll be working on a Mac with Adobe Premiere Pro CC.

Many of my jobs will require converting FLV files to editable video files. After editing I will need to convert the rendered final file back to FLV.

I'm not sure what would be the best workflow on a Mac for this. Which would be a good lossless format that is compatible with Mac/Perimiere that I could convert the FLV to and later from?

Which software do you recommend (preferably freeware) to make the conversion?
Or can I do this directly in Premiere?

Thanks!