The easiest and cleanest way to do this is to have one of the H.323 endpoints that are in the call decode the video out to NTSC (analog) again, and then feed that video back into an IP/TV Broadcast Server.
The other way is that there are two H.323 endpoints on the market have a "interactive multicast" feature, where they will multicast out the video that they are recieving from the H.323 call. The two vendors are Polycom (only on their FX model), and VCON (on their PCI-based "Escort" and "Cruiser" models). However, there is no standard for doing this, so these endpoints have implemented this in a proprietary way, so that it only works in a like-vendor environment (i.e. You can't have different H.323 clients in the call, AND turn on the multicast feature).
I have not tried this, however I am assured that VCON's product line integrates well with Cisco's IP/TV products. It should be noted that most of these endpoint products (including the core components) are based around RADVision's H.323 stack. This incldues the Zydacron which will apparently include this functionality in it's next release.
One major problem with allowing endpoints to multicast video is the management of the multicast addresses used to multicast a video stream. Protocols such as MASC (RFC2909) attempt to deal with this but you should be aware of the high-maintenance requirements of this setup are.
I'm not able to access my old voice mail messages all of a sudden. The recording says something like 'the message is currently not available'. This has never happened before in all the years I have been using this system. I have t...