Marratech client 6.0 has added H.264 MPEG4 support allowing better video quality with lower bit rates. To turn on H.264 on Windows platform go to Tools -> Options -> Video tab -> select "H.264 software encoding" from the drop down under Compression section, click OK. On OS X 10.4 go to Marratech menu -> Preferences -> Video tab -> select "H.264 software encoding" from the drop down under Compression section, click OK.

Please note: while using H.264 software encoding and dialing H.323 IP endpoints - Polycom, Tandberg, Sony, etc, you may experience some codec capability problems. If this happens just use "H.261 software encoding" for those connections involving these endpoints.