[Live-devel] Bad performance with 4 or more clients at proxy server

[Ross Finlayson]

>    i have the some problem too and i don't think the problem is caused by vlc.  when I start multiple VLC players and have them playing the stream of a ip camera source, it is working fine . if i start and play them for the remote proxyServer, I will get a bad performance . i try to increase the socket buffer size but could not fix it. i also use ffplay.exe to test proxyServer, then i find some information maybe , the players' frame have a serious time delay, and vlc always discard the delay frames so why we get the bad performance .

Scalability problems like this are almost always caused by the combined bitrate of the multiple-unicast streams (from the proxy server) approaching or exceeding the capacity of your network.  (Note that when you had multiple VLC players playing a stream from an IP camera, that this was probably a *multicast* stream (because few network cameras support unicast streaming to more than one simultaneous client).  The proxy server, on the other hand, streams to each of its clients via unicast; if it has N concurrent clients, then the stream will be multiplied N times (not counting the additional stream that came from the back-end server).)

People tend to greatly overestimate the capacity of their LANs.  They may see a 100 Mbps or 1 Gbps Ethernet interface on the back of their server computers, and assume that that’s the capacity of their LAN.  Usually not even close.  The actual capacity of a network depends on many factors, including OS and network interface buffering, virtualization (if any), network interface issues, the presence of routers (and even worse, firewalls).

In any case, I’m not planning on responding to any more reports like this unless they can also identify a specific problem with our software that might be responsible.


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

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