[Asterisk-Users] Offtopic: improving softphone latency on Linux?

Bruno Hertz
Mon, 17 Jan 2005 13:49:28 -0000

Hi folks

last weekend, I tried Windows Messenger first time and was stunned by
the little latency it gives. Until now, I've been using softphones on
Linux exclusively, like iaxcomm, linphone and sjphone, and they all give
me about 1, at times even 2 secs delay. Whereas Messenger really seems
to be in the millisec range.

Of course, I'm now curious why there is that difference. Clearly,
Messenger is more tightly integrated with the OS and accordingly tuned.

So where does this time go? Kernel? Application level? Web searches seem
to suggest that sound latency generally is a problem on Linux, so I
tried the low latency kernel from
http://ccrma.stanford.edu/planetccrma/software/planetccrma.html
(there are two kernels, actually, where I only got the stable version to
boot - bleeding edge didn't do on my machine).

Still, that kernel did not really improve things in a noticeable way.

Question hence: did some of you guys experience and investigate this
same issue? Any recommendations or hints how to make VoIP even more
enjoyable on linux?

I wouldn't care that much if I was the only affected party, but of
course whomever I call will also suffer from those delays, so as the
staunch Linux advocate I've been so far I'd really like to show better
performance ...

Thanks, Bruno.