Ouput as WebM or HEVC

A client asked me to output project as WebM or HEVC. What is the best way to do it ?

FCP7 (neither FCPX , Compressor ) don't support these formats yet. By the way, someone can tell me if Apple will (and when) support

WebM and HEVC?

I tried using MPEG Streamclip, but as FCP, it doesn't export as WebM and HEVC. I know firefogg, but I can't install firefox here.

What third-party software I could use to do this?

Thank you.

Jennifer