Python pycall works like a champ

import sys
from pycall import CallFile, Call, Application

def call(number):
        c = Call('SIP/%s' % number)
        a = Application('Playback', 'hello-world')
        cf = CallFile(c, a, user='asterisk')
        cf.spool()

if __name__ == '__main__':
        call(sys.argv[1])

Zoiper 1.3 for Android video with Asterisk/FreePBX

vp8 does not seem to work, but h263p does work.  Zoiper crashed if fps or size were different settings on each endpoint.

Had to add the following to the sip_general_additional.conf:

allow=h263p
videosupport=yes

15fps struggled sometimes, but seems to work.  30fps can setup initial call, but then frames freeze for long periods.

Devices:

Samsung S5
Samsung S3