I've got a gigabit switch. I tried compressing with your block, and while it works fine on osx, for whatever reason it gets scrambled on windows. It must not be sending through the same number of bytes when you compress it, so when it comes through on the receiving end, it's all interlaced looking.
NDI looks cool, though potentially a bit tricky to set up. I also briefly looked at libx264, but i'm not sure it's it's applicable here.