My video is lagging behind real-time? How do I fix this?


Regarding video delays - It can be complex!  Sometimes when your live video lags farther and farther behind real-time it has to do with you pushing too much bandwidth for your connection, sometimes it has to do with your encoder settings.

 

The first thing to do is look at your live stats to ensure you aren't bumping up against your upload bandwidth limits (the limits of your ISP's upload speeds.  We have no limits on our end).

Second, start lowering your encoders Frame Rate and Bitrate until the delay goes away:

  • Frame Rate: 20 fps (no need for greater than 20 with online video)
  • Bit Rate:  500Kps is a good place to start but can be adjusted up or down.
    • If video is choppy or lags more than a few seconds behind real-time lower the Frame Rate and Bit Rate until problems go away. 

See these recommendations as well.

More details on this subject:

In theory a higher bitrate on a large connection would work fine.  However, its more complex than that.  Things that factor into a delay:

Frame Rate:  We've found that there is no need to have more than 20fps with online video.  It just doesn't make a difference to the human eye, especially if the video isn't motion video (i.e. sports).

Audio:  We've seen situations where having to high an audio sample rate or audio bit rate can cause delays.   Not sure why but I've seen numerous reports of this online with other video providers as well.  Since audio characteristics of must computers isn't very good we recommend setting your audio settings fairly low.

The quality of your internet connection and the CPU power of your encoder:  Here at our offices we have a 100MB fiber connection.  Our streaming servers are in Albuquerque by the way.  I can stream at 2000Kbps without a delays or issues (I also use a recent Mac laptop as my encoder.)  So if your encoder doesn't have a strong CPU, or your connection has packet loss, I can image that would result in delays and the need to lower your bitrate (Kbps) until the delay goes away.

You can test packet loss during your broadcasts by pinging and running traceroutes "live1.brownrice.com" during your video presentation from your encoder machine.  If you have packet loss or slow ping times (i.e.  Slow is greater than 250millenseconds or so) during the broadcast I'd be concerned that your big connection isn't as quality as you are being led to believe.  I'd also be happy to look at your results as well.