Live Streaming Basics
Oct 19, 2011 4:22 PM, Provided by Digital Rapids
Expanding a ministry’s reach through live video streaming.
Technical Considerations for Success
One of the first considerations is ensuring an adequate Internet connection to send your live stream from your church. As discussed above, the bandwidth requirements for the Internet connection will depend on the deployment model, specifically whether an inhouse distribution server is being used (to reach a small number of affiliated sites) or a CDN (to reach a virtually unlimited number of viewers). To recap, in the case of the in house server, the amount of sustained upload bandwidth needed by the church is essentially the bit rate of the stream times the number of locations being streamed to. When using a CDN, there’s essentially only one location being streamed to (the CDN), with the CDN effectively replicating the stream for distribution to an almost unlimited number of viewers. Please see the examples above.
In either case, the bit rate you choose for streaming is an important factor. As above, a higher bit rate enables potentially higher quality, but requires more bandwidth on both the sending and viewing sides. A 3Mbps stream at 1280x720 high definition resolution will have higher perceived quality than a 1.5Mbps stream at the same resolution, but it requires each viewer to have 3Mbps receiving bandwidth—not unreasonable for tech-savvy viewers, but likely too high for the broad audience that you’ll probably want to reach—and the church to have at least 3Mbps sending bandwidth even if using a CDN.
If you’re streaming between gathering sites, a high bit rate and resolution will probably be worthwhile, as it’s likely that the stream will be viewed on a large monitor by multiple people. Low resolution, low bit-rate streams that look fine at small size in a window on a PC may look horrible when viewed full-screen on a large monitor or TV.
Note that it’s very important to distinguish the upload (outgoing) speed of the church’s Internet connection from the download (incoming) speed. When Internet Service Providers promote the speed of their service, the number they’re citing is generally the download speed—and on all but the highest-end offerings, the upload speed is significantly less. For example, a service provider local to us offers a service package with 12Mbps download speed, but the upload speed is only 1Mbps. While download speed is important to the viewers, it’s the upload speed that is important to the church when choosing an Internet connection, since the video is being sent out. Such a 1Mbps upload speed would be insufficient for the HD or high-bitrate systems mentioned above, but quite adequate for 640x480 standard-definition stream. (Note that since computer monitors use square pixels, NTSC video at 720x480 non-square pixels becomes 640x480 for streaming).
Ideally, the Internet connection used for sending the streaming video should be separate from the general Internet connection that the church uses for other tasks such as e-mail, web browsing and other uses. Sharing an Internet connection between the outgoing streaming and other tasks can result in unexpected performance drops as the various tasks contend for bandwidth. A dedicated line ensures that the outgoing stream isn’t affected by any other Internet activity at the church.
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