If you are doing satellite webcasting, you may be wondering, “Is my connection fast enough?” The beauty of satellite is that you can get Internet connectivity just about anyplace to deliver your webcast event. Figuring out how much satellite bandwidth you really need can be a little tricky though.
The truth is that satellite internet can’t quite achieve the same speeds as terrestrial internet. We can however, achieve the same throughput.
Why? There is an natural delay in every satellite connection of about 500- 600 milliseconds resulting from the time it takes for a radio signal to travel the 46,000 mile round trip from the earth, to the satellite and back again. So, a traditional “speed test” that you run on your home or office computer, will never give a true report of the amount of data passed in one second.
The throughput is the amount of data that can be sent in a one second period. So for a 1 Mb/s satellite connection, the “speed test” may show a lower data rate, but 1 Mb/s of data can still be transmitted in a one second period. The second just begins 500 milliseconds later.
Ok, so now that we’ve defined the difference between speed and throughput, let’s answer the question. Is my connection fast enough?
The great news is that your viewers will never notice that 500 millisecond delay. The buffering of the video takes much longer than that and will be imperceptible to the end user.
What matters most when you are webcasting over satellite is the throughput. How much do you need?
Your encoding software or hardware lets you choose an encoding data rate for your live webstream. If you are using multiple streams, add up the streams. Then you need to plan for overhead. Overhead is additional bandwidth which is required to send the various commands used to communicate between devices and to provide error correction (error correction ensures that the data arrives accurately and complete at its destination.) A couple of rules generally apply. 1) larger encoding streams require more overhead and 2) shorter buffering times require more overhead than longer buffering times. Your satellite engineering team can help you determine how much you need.
We just can’t overstate how important this step is. There are so many variables going into every webcast stream that settings can change, including the amount of total bandwidth required for a successful satellite webcast.
Test by setting up the actual stream sizes you plan to use for the event. Use a similar video content (ie; if you will stream high action video, test with high action video) and run an end to end test. Its so much easier to make adjustments to bandwidth, settings and other variables before you get out into the field. And you can feel confident in the performance of all equipment and services working together.
Here’s to successful satellite webcasting!