A couple weeks ago, I sat down with Kaleb Plamondon as part of our Tech Talks series, where HARMAN experts share their insights on how to address common customer technology problems. Kaleb is the Manager of North America Sales Engineering for HARMAN Professional Solutions, and we discussed how churches go about streaming the video of their services to the worldwide web.

This time, we’re bringing Kaleb back for a related, though more specialized, issue: streaming video to satellite churches. In evangelical churches, especially in the U.S., it is not uncommon for a single congregation to have multiple locations, all lead by the same pastor. In these instances, you might have services going on at the same time at different locations. Each location has their own live music, and then the pastor is “beamed in” virtually through a simulcast to the other locations when it is time for the sermon. This brings up an interesting technological challenge, and I wanted to ask Kaleb how it is addressed.

[SKD]: One of the trends that continues to grow in houses of worship, especially in the U.S., is the concept of multi-campus churches or satellite churches. How do you handle that, technologically speaking? What are some of the challenges there?

[KP]: By and away, the largest challenge we encounter with multi-campus churches is how the wide area network (WAN) that connects the buildings together is setup. Most WANs, by default, do not allow for multicast traffic. By nature, what we’d be trying to do—having one source going to multiple destinations—is best handled by multicast. I send out one piece of information and multiple end points view that information. What we run into is that WANs are infrequently able to support multicast.

If that can be overcome and the church has a savvy IT department that allows multicast over the WAN, then the application is quite simple. We place an encoder at the originating location and corresponding decoders at each remote location that are specifically tuned to receive the multicast stream that is coming from the encoder at the originating campus.

Multicast on a WAN is becoming more and more prevalent, but a lot of churches that are growing rapidly and expanding to multiple campuses haven’t had the time or experience to invest the required money and resources into their infrastructure to support a fluid system like this.

[SKD]: If they don’t have multicast available on their WAN, what other options do they have?

[KP]: There are two potential alternatives. First, they can do multiple unicast transmissions—that is, multiple instances of a unicast transmission. They setup a dedicated path through a virtual private network (VPN) tunnel from an encoder at one location to a decoder at another location. That VPN path allows that stream to traverse the worldwide web and arrive at the remote campus location.

The challenge is that only allows for a single one-way transmission from one campus to another. If I’ve got three satellite locations, I have to take that same setup (encoder, decoder and VPN tunnel) and multiply it by three. I would need three encoders and three decoders (one at each location). The cost goes up exponentially, because with each new location, you need a new encoder at the source and another decoder at the new destination. The other alternative, if that setup is cost-prohibitive, is to look at a content delivery network (CDN), like we spoke about previously. You would broadcast to the CDN, and each remote location would tap into that system via a PC at each location.

[SKD]: One of the issues with streaming a sermon from one location to another is the fact that the worship portion of the service might not end at exactly the same time. Is there a way to time-delay the video of the sermon, so they can start it when they are ready for it without needing to work from a recording of last week’s message, etc.?

[KP]: Absolutely, and that’s incredibly common. That’s actually the reason why we created our Networked Video Recorder (NVR). It gives us the ability to create a buffer that records an event and plays it back in a time-slip format, just like your DVR at home. You record the stream on the NVR, and the remote site can play back the stream whenever they’re ready.

It’s hard when you’re dealing with a multisite church like this. You’re trying to juggle schedules for multiple locations, you don’t know if announcements are going to go a little long, so it’s very common for the remote campus to be ready when their ready. They press “play” and initiate the playback of the recorded stream. The AMX NMX-NVR-N6123 gives you the ability to have nine independent multicast AV streams coming in or out at any point, allowing each site to start the transmission whenever they’re ready.

[SKD]: What about situations where you might be using a format such as JPEG2000 to distribute video within a building? Is there a way to leverage the system to distribute to other campuses as well?

[KP]: Absolutely. We have a number of house of worship clients that started with a JPEG2000 infrastructure, using the AMX N2000 Series to distribute video throughout the facility, and then later made the decision to take their sermon and broadcast video out to other facilities or to the worldwide web (as we discussed last time). What you can do in that case is take an N2000 Series decoder, take the raw audio and video outputs from that decoder and route them into an N3000 Series H.264 encoder. That allows the customer to take any N2000 Series source, point it at that decoder, and I can then use the N3000 Series encoder to distribute that video over the WAN.

We need to use the N2000 Series decoder into an N3000 Series because, while there are several reasons why JPEG2000 is a better video format for distributing video within buildings, H.264 is the preferred format for distributing video over a WAN. The only way I would recommend anything other than H.264 for distributing video between worship centers is if I had multiple sanctuaries on the same piece of property. Say, for example, you have a traditional worship service in one building and a more contemporary worship service in another building, but you want the pastor to preach simultaneously in both locations. As long as everything is on the same physical LAN, I would say absolutely, we should look at JPEG2000. But once you need to traverse a WAN, even if it’s using multicast, I’m going to be dealing with very little available bandwidth, so H.264 is the best available solution at that point. So, we need to convert JPEG2000 into H.264, thus the need for the crossover.

The benefit to that, though, is that it is a pay-as-you-grow system. You’re never locked into a single encoder series or video format. You can add additional inputs and outputs as you need them, and add crossover points to move between formats as needed.

Once again, I’d like to thank Kaleb for taking the time to speak with us. Do you have insights on how to distribute AV between church campuses? Share them in the comments.