[Live-devel] Assistance

[Ross Finlayson]

(Sorry for the delay; I’m catching up on a big backlog of email.)


> Could you point me to some tools or forums to help resolve a problem I’m having with freezing video?  We are using Live555 as a proxy server to serve up 10 -15 clients a live camera feed.  If my clients connect directly to the camera there is no problem and the picture is clear.  However, when my clients are connected to Live555 they freeze regularly for 3 - 4 seconds.  This includes when the client is running both connections simultaneously (one to the camera and one to the Live55 server).  The clients are using VLC media player 2.2.6.
>  
> Do you have any suggestions for us to try?

First, it wasn’t totally clear from your email whether or not you are running two (or more) copies of VLC on the same computer, but I’d be wary of doing this; this has known performance problems.  But assuming that you’re not doing this:

In my experience, scalability issues with a reasonably small number of clients (e.g., 10-15) are often caused by running up against network bandwidth limits.  Note that if you are running the “LIVE555 Proxy Server” on a host, serving a single ‘back end’ stream to N ‘front-end’ clients, then the bitrate on your host’s network interface will be N+1 times the bitrate of the ‘back-end’ stream.  You may be approaching the capacity of your network (which is usually a lot less than the nominal bit rate of your network adaptor(s)).

Another (related) possibility: People also run into problems if they have very large ‘key frames', because that makes them very vulnerable to network packet loss.  If you have large ‘key frames’, I suggest reconfiguring your ‘back-end’ stream so that it generates a sequence of ‘slice’ H.264 NAL units for each key frame, rather than a single (extremely large) NAL unit for each key frame. (This assumes that your stream is H.264)  This is something that I have commented on numerous times; see, for example:
	http://lists.live555.com/pipermail/live-devel/2011-December/014190.html
	http://lists.live555.com/pipermail/live-devel/2012-August/015615.html
	http://lists.live555.com/pipermail/live-devel/2013-May/016994.html
	http://lists.live555.com/pipermail/live-devel/2014-June/018426.html
	http://lists.live555.com/pipermail/live-devel/2014-June/018432.html
	http://lists.live555.com/pipermail/live-devel/2014-June/018433.html
	http://lists.live555.com/pipermail/live-devel/2014-June/018434.html
	http://lists.live555.com/pipermail/live-devel/2015-March/019135.html
	http://lists.live555.com/pipermail/live-devel/2015-April/019228.html


Ross Finlayson
Live Networks, Inc.
http://www.live555.com/