A few weeks ago I followed with interest a Megaconference listserv discussion about LifeSize and it’s support of video protocols. Here is a comment by John S. Martin, from the JANET Videoconferencing Management Centre, University of Edinburgh.
When multipointing in a multi-user environment we have found several incompatibility issues which are only resolved when one, or all, of the connected codecs connected at H.261. This is the base standard for H.323 videoconferencing. Yes, a video protocol transcoded conference will overcome this issue, but this uses more resource on an MCU such as a Polycom MGC. I
have spoken to lifesize about this and apparently it was a commercial decision not to implement H.261, but something they may look at in the future, depending on demand.
I just find it bizarre that a company have developed a system which doesn’t connect to H.261/3/4 video protocols.
Usually I’m not thinking much about video protocols, but I was very interested in this conversation. The Megaconference listserv has many international higher ed technicians and I learn a lot just by reading the messages. It was intriguing because some people thought it didn’t matter. Why would a high definition VC product want to connect to a low end legacy product that could only do H.261?
This conversation concerned me, coming from a K12 VC environment where usually there is much less tech support. Some districts have a teacher who is responsible for the videoconferencing equipment, and that’s it! That teacher or media specialist expects the connection to work if it’s IP or ISDN and they usually don’t know anything about the video protocols. It’s enough to remember H.323 or H.320! As K12 endusers, we just want it to work! You want to be able to talk to someone, find out if they have videoconferencing, and have it work!
So I have a few thoughts and reflections based on this experience.
Learn From Others! If you participate in Megaconference or Megaconference Jr., stay on the listserv after the event is over! Even if the conversation seems like it’s way over your head! That’s how I felt when I first participated in Megaconference a few years ago. But I’ve stayed on the listserv and “lurked” and learned a lot about the technical back end details of videoconferencing that I wouldn’t have learned otherwise. Another good place to learn about technical details is the VTC Talk Forums.
Talking To Your Vendor. If you’re new to videoconferencing and are talking to your vendor, there are some things you should consider. Some of this advice is based on experiences with connecting to other schools for MysteryQuest, Read Across America, and similar projects. 9 times out of 10 your vendor will not have imagined these types of uses of videoconferencing and so may try to convince you otherwise.
1. You definitely need to be able to dial out to an IP address. And if possible, you need a way to get to ISDN sites as well. Not all of the providers have switched to IP yet. And some schools that you might want to connect to are also ISDN. Sometimes your educational service agency (ISD, BOCES, ESC, etc.) can provide this service for you. Or your vendor may have ideas of how you can get access to ISDN if needed. ISDN usage in K12 videoconferencing has diminished greatly in the last year or so, but if you truly want to be able to connect to anyone, you’ll need a way to convert to ISDN occasionally.
2. Second, you really need to be able to receive calls, preferably to an external IP address. There are a few content providers who prefer to call the school they are connecting to. There are also many great projects you can do with other schools. But if you partner up with a school that can only call out, and you can only call out, then you are stuck! This is a big problem in the Read Across America project and spin off projects that use the same format. There are new firewall traversal units coming out to help schools with the challenges of IP videoconferencing. However, sometimes these tools create an environment where you have to dial an extension to get to the right unit. Some schools connect through a bridge, and the bridge can’t dial an extension. All these things complicate projects that should be able to happen easily! So if at all possible, design your system so that you can receive calls to an external IP address. Otherwise, you may need your educational service agency to help you make connections with other schools.
3. Have as little as possible in between your VC unit and the rest of the world. In my experience with IP calls, the more “boxes” (firewalls, gateways, bridges, & stuff) are between two units, the lower the quality of the call. If you are in a consortium, design your system so you can make calls with or without the assistance of a central bridge. It’s good to be independent of that bridge if at all possible. I’m finding that my calls work better and have clearer pictures when connected directly. Some of the newer units can do beautiful H.264 calls that look great! But not all the bridges and gateways and stuff in between allow that protocol through.
H.323 has made videoconferencing cheaper and more accessible to schools, but it has also added a level of complexity to connections that is sometimes hard to navigate. But that’s the nature of the beast these days it seems.
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