Further questions
Posted: Sun Jan 28, 2007 6:57 am
Okay, do we know the characteristics of the DSL lines at the stake centers? Most DSL implementations are not symmetrical, ie different upload bandwidth vs. download. With a DSL connection available already the problem may be simplified somewhat. An MPEG4 or h.264 encoder can render compressed video stream that is usable for a large projection at about 1 Mb. Not that many DSL implementations have that much upload bandwidth but with the answer on the size of these lines we'll know for sure whether upload via the existing DSL is practical.
It was also mentioned earlier that people aren't that attracted to a solution with grainy video and they are right, poor video quality links often reduce the likelihood that the system will be listened to again. So implementing something that is compressed any lower than 1 Mb is probably not a good use of church resources. Given that, for a large multi-site meeting where there would be contributors or speakers present at multiple sites may be impractical with the current infrastructure list, we'll have to see once we get a few more answers.
The downlink side of that same DSL line is likely to be more capacious and could easily be in the 2-4 Mb/s range. Do we know who the carrier for these lines is? I'd assume that they are all purchased through some centralized deal so that a good price is obtained for the services. Some of the carriers have IGMP v.3 multicast enabled in their core and edge routers which would enable multicast of content via the DSL lines. Others don't have this available at all and multisite flows are treated as unicasts requiring more bandwidth at the origin server.
It still feels that the satellite interconnection system will need to be involved in this to have a good professional quality projection-size display at the receive sites. Does anyone know what the characteristics at the uplink site are? How much bandwidth is there in total? There are probably several compressed streams across a larger chunk of transponder bandwidth. Do we know of these are individually modulated and fed in SCPC fashion or if they are aggregated into a larger stream with a stat mux in MCPC mode? These questions would tell us what it would take in the way of equipment to feed a stream from a stake center out through the satellite system. Also what video compression formats are supported by the satellite recevers? My understanding is that the satellite receivers are from Wegener Corp but I don't know the model # to be able to look up the features available on the receive end. Does anyone know that info (or are they all different models)?
Sorry to ask so many questions but with a few answers we may be able to outline a practical implementation for at least one of these meeting scenarios, if not more.
It was also mentioned earlier that people aren't that attracted to a solution with grainy video and they are right, poor video quality links often reduce the likelihood that the system will be listened to again. So implementing something that is compressed any lower than 1 Mb is probably not a good use of church resources. Given that, for a large multi-site meeting where there would be contributors or speakers present at multiple sites may be impractical with the current infrastructure list, we'll have to see once we get a few more answers.
The downlink side of that same DSL line is likely to be more capacious and could easily be in the 2-4 Mb/s range. Do we know who the carrier for these lines is? I'd assume that they are all purchased through some centralized deal so that a good price is obtained for the services. Some of the carriers have IGMP v.3 multicast enabled in their core and edge routers which would enable multicast of content via the DSL lines. Others don't have this available at all and multisite flows are treated as unicasts requiring more bandwidth at the origin server.
It still feels that the satellite interconnection system will need to be involved in this to have a good professional quality projection-size display at the receive sites. Does anyone know what the characteristics at the uplink site are? How much bandwidth is there in total? There are probably several compressed streams across a larger chunk of transponder bandwidth. Do we know of these are individually modulated and fed in SCPC fashion or if they are aggregated into a larger stream with a stat mux in MCPC mode? These questions would tell us what it would take in the way of equipment to feed a stream from a stake center out through the satellite system. Also what video compression formats are supported by the satellite recevers? My understanding is that the satellite receivers are from Wegener Corp but I don't know the model # to be able to look up the features available on the receive end. Does anyone know that info (or are they all different models)?
Sorry to ask so many questions but with a few answers we may be able to outline a practical implementation for at least one of these meeting scenarios, if not more.