@rrianham : I know I could use device detection for serving them what they need, but I’m not a partisan of this kind of techniques, which are not really trustable. This is just my own point of view.
So I prefer to search for an easy and “standard-maybe-in-near-future” 
HLS seems to be the solution for me.
@tavius : yep, thx for the reply, I saw that, but I prefer the way FlowPlayer is managing videos. As I said, there seems to be a nice plugin taking HLS into account.
By curiosity, and if you want, could you expose here the configuration you choose on Wowza and for your JW player ?