Use the DSP calculator to size PVDMs based off from your requirements.
A simple search like PVDM3 + video conference or video conference + ISR G2 will give you all you need
Cisco ISR G2 Video Conferencing Services
http://www.cisco.com/en/US/partner/prod/collateral/voicesw/ps6790/gatecont/ps4952/qa_c67-649850.html
No, this is just like an audio conference, just with video.
HTH
java
if this helps, please rate
www.cisco.com/go/pdihelpdesk
HTH
java
if this helps, please rate