GerryK wrote: > RE: > Kon's comment > We're not talking about ad insertion, and we're not talking about IPTV. > > you are talking about targeted advertising, > ( Targeted TV Advertising Catches Interest) > that is "ad insertion" To switch ads into a system for targeted advertising you either splice, target, or insert. These are all very different things depending on how they are deployed. Stream switching for IPTV has its own set of complexities that is nothing like MPEG, even though they share common properties. > and we ARE talking about IP TV for both digital Cable TV and > for the telephone companies Actually the topic of the discussion has been how to do this to OTS OTA boxes that have no PVR functionality, no IPTV capability, no backchannel, and no CA. > for the IP TV folks they simply switch the correct stream onto the > selected ADSL twisted pair, and they can send each subscriber a unique > stream, that would include the video of the program being watched, > which is taken from one multicast stream coming off one of the four > Gigabit Ethernet streams that feeds into the Central Office, > and then, in real time, they can switch one-of-many selected ads into the > stream that feeds that ADSL twisted pair You're doing a lot of hand-waving and not making too much sense. IPTV is not quite that simple. BTW there's no need to send each subscriber a unique stream, since now you need a hefty box at the POP. It is easier to relay the multicast, do unicast CA authentication, receive the SDP or other descriptor file for the stream, and then do an IGMP join on the stream and decrypt/view. At least, thats the model most of the IPTV systems seem to use, from my limited experience. Ad-splicing has to be unicast though. If you're storing content at the POP it makes no sense since you run into buffering issues and the server load can get out of control. Its easier for the ad server to push the ads in a rotating FIFO queue to the receivers and let them (since they have enough CPU power) filter the content and handle the switch-over. Cheers Kon ---------------------------------------------------------------------- You can UNSUBSCRIBE from the OpenDTV list in two ways: - Using the UNSUBSCRIBE command in your user configuration settings at FreeLists.org - By sending a message to: opendtv-request@xxxxxxxxxxxxx with the word unsubscribe in the subject line.