So…. I’m using a client on Mac OS 10.11.5 connecting to Ubuntu 16.04 server that has the xfce4 meta package installed. For the heck of it I also installed cups but I don’t think it matters.
I compiled the libx264 component using the opensource version following directions here: https://www.nomachine.com/DT07M00078
When streaming HTML5 video remotely I get audio but no video. It just shows as a black box. Tested in Chromium.
After installing pepper flash and installing an extension that forces YouTube to use flash (as a test) it played just fine.