I want to capture browser display to video, compress with x265 and stream over the network for display to another machine.
I was considering berkelium but they don't update binaries nearly often enough with new chromium releases, and building that oneself is far too much work.
I also looked at chromiumembedded but offscreen rendering only seems to work on Windows.

So my question is, can I somehow make the X window of a browser render to an offscreen buffer without modifying the browser source? I want to be able to update browser as new security updates come out without having to worry about rebuilding it every time.