Adrenaline Garage Blog

Can your internet connection handle your live stream? Are you sure?

Posted by Jeff Harper on Wed, Sep 8, 2010 @ 19:09 PM

This article is the third part of our series, 5 Things you need for a Stutter Free Webcast.

Get a quality internet connection at your event site

Even if you can view high resolution videos using your internet connection, that may not mean that your connection is sufficient for streaming a live webcast.  Here is our process to determine if a connections is "live stream ready" and if not, what alternatives exist for you to consider.

Understanding how a live webcast uses an internet connection.

When you measure connection speed, there are two speeds that you need to keep in mind, download speed and upload speed.  While it might seem logical that both would be the same at any given location, that is rarely the case.  Most often, internet service providers will provide more bandwidth for downloading than uploading simply because that is what most people do most often.

Unfortuatnely, for a live webcast, upload speed is absolutely Speed matters for webcastscritical.  It is what determines the bitrate you can push to your streaming server.  Bandwidth is like a pipe.  As long as you aren't cramming more stuff in the pipe than it's capacity, there's not a problem.  As soon as you do, not all the information can get through.  The result in your webcast is stuttering, dropped frames and all sorts of nastiness that you want to avoid.

Measuring your upload speed

The easiest way to measure your upload speed is by conducting a free speed test.  Select a location nearest to where your origin server exists.  Some CDNs provide multiple origin servers at various locations around the world.  By testing the speed to several locations, you can identify the server that is most likely to perform the best.

It's important to test your connection speed multiple times in conditions similar to the ones you'll be operating under.  Additional users sharing your connection will affect your connection speed.  For example, many ski resorts' POS system use the internet.  During very heavy sales, their system may cause a reduction in the available bandwidth.

Why you need to consider overhead

Even if your results are pretty good, there are number of things that can happen during your webcast that you need to take into account. 

  • All encoders stream's bitrate will spike when there is a lot of action on screen.  Unfortunately, when there is a lot of action is on screen tends to be the most critical point of an action sports event.  This is one of the reasons we suggest a getting a dedicated encoder for your webcast, as they tend to have much smaller spikes.
  • Increased internet traffic at any point along your route can cause a decrease in your connection speed.  Realistically, during events, there is always more demand for internet connections than you've anticipated.
  • Just the way that streaming technology works means that your stream actually will have less effective bandwidth than what you've measured.

To calculate your maximum bitrate, take the worst result from your speed test and divide it by 2.  For example, if you measured your upload speed at 3.2Mbps, that means that 1.6Mbps is the maximum recommended bitrate of your stream.

Alternatives

If you discover that you don't have a sufficient connection for your desired bitrate, there are a couple options available.

  1. Lower the bandwidth of your streams.  While this will cause more compression and therefore a degredation of the quality in your video stream, we consider this far better than stuttering.
  2. Eliminate adaptive streaming.  Each stream takes up bandwidth in your connection.  Eliminating a stream may allow you to have enough bandwidth for the others.
  3. Get a temporary high speed connection.  Some internet service providers are happy to set up a temporary connection.  If that doesn't work, portable satellite uplinks are available for rent, but tend to be very expensive.

Are you looking for other ways to improve your live webcast?  Don't want to miss out on more tips and tricks for producing better, more engaging, higher quality livestreams?  Subscribe to Adrenaline Garage's quarterly report via email today.

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    Topics: Webcast Tips