Hello,
I have to use a Video SoftPhone in fullscreen mode, I have bought the zoiper communicator license but it doesn´t support h264. The counterpath soft phones are not fullscreen. Is there a softphone that have this features:
-fullscreen video
-h264
Thanks in advance
Have you tried Jitsi?
Zoiper guy here, a new version of zoiper is about to be released, with h264 support (and vp8 and h263+).
Send your details to support AT zoiper.com and we will hook you up with the beta.
Cheers,
Zoa
That’s awesome 
Check your email malcolm
Just did!
With h323+ zoiper comunicator fails, I tried with grandstream 3140, 3175 and with xlite bria and eyebeam.
I have tried using asterisk, and with openser where the media is between endpoints and the video is not working. Without h264 it is not operable, for example yealink phones uses h263 and h264, zoiper just support h263+ 
Send us your contact details and we will send you a version with better h263+ interop, h264 and vp8.
Zoa
I have send you a MP