Hardware for Streaming Video

Dennis has a second question about hardware for video streaming. “�one of my friends is involved in web-casting streaming video for Discovery Church in Orlando and was asking if I could build them a computer that could handle the stream better.”

Without knowing more about the church budget and exactly which part of the streaming process the particular PC in question planning to handle, I’m taking a bit of a stab in the dark here. In general, streaming a live video is going to require a machine that’s processing the live video feed and sending it on to a server for distribution. You’re really talking about at least two computers. Unless the church has a data center quality Internet connection, the server actually handling the streaming portion of the process should probably be located with a service specializing in hosting live streaming, like Limelight Networks or Akamai. Since the church is talking about building a streaming server, it’s quite possible that bandwidth is the limiting factor here, not the computer.

If you’re looking at a computer specifically for rendering the video on the fly and outputting it to a server hosted somewhere online, I recommend getting a dual Xeon system with as much memory as they can afford. This machine’s sole purpose is to take an inbound video signal and broadcast to one other computer somewhere online. If they are attempting to stream the video from the machine that’s doing the rendering to multiple viewers that may be a big portion of any streaming problems they might be having.

A second potential bottleneck is the connection the rendering machine has to the Internet. Most churches are likely connecting to the Internet via either DSL or possibly a T-1, giving them somewhere between 256kbps and 1.5Mbps upstream transfer. Without knowing how the setup is configured, I can only speculate about potential problems. If the church has an upstream capability of 256kbps, for instance, and the video stream is 128kbps with the rendering server passing the video stream to the public, no more than two people could connect at any given time under ideal conditions. At 512kbps, up to 4 people could connect, and so on. If the server that’s feeding the video from the church is connecting to a server on the Web, the choke point becomes the Web server’s bandwidth, which is allocated by their hosting provider.

To better scale the stream to accommodate more viewers it makes more sense to use a service specializing in video streaming, like Limelight or Akamai. These services are expensive, but they spread the streaming load over multiple servers and are optimized to make sure each connection by a new viewer is possible. Before jumping to the conclusion that new hardware is required to solve the streaming problems, it would be better to look at the big picture of how the church is currently addressing it’s streaming to determine where the real limitations in their system lie.