[asterisk-bugs] [Asterisk 0012575]: IAX forcejitterbuffer + maxjitterbuffer

[noreply at bugs.digium.com]

A NOTE has been added to this issue. 
====================================================================== 
http://bugs.digium.com/view.php?id=12575 
====================================================================== 
Reported By:                nvrpunk
Assigned To:                
====================================================================== 
Project:                    Asterisk
Issue ID:                   12575
Category:                   Core/Jitterbuffer
Reproducibility:            always
Severity:                   minor
Priority:                   normal
Status:                     new
Asterisk Version:           1.4.19 
SVN Branch (only for SVN checkouts, not tarball releases): N/A 
SVN Revision (number only!):  
Disclaimer on File?:        N/A 
Request Review:              
====================================================================== 
Date Submitted:             05-02-2008 14:36 CDT
Last Modified:              07-01-2008 10:25 CDT
====================================================================== 
Summary:                    IAX forcejitterbuffer + maxjitterbuffer
Description: 
When creating a jitterbuffer via IAX not trunked or trunked and then force
jitterbuffer, the maxjitterbuffer size does not seem to actually *stick* as
core debug messages state it is attempting to exceed the max time slots of
600 even though maxjitterbuffer is set to 400 with a maxexcess of 80.  

At some point this will either disconnect the call or the audio will stop.
 It varies on length of time but as the call duration lengthens the more
often it seems to happen until the buffer seems to just overflow and stop
the call.
====================================================================== 

---------------------------------------------------------------------- 
 stevedavies - 07-01-08 10:25  
---------------------------------------------------------------------- 
OK - 

I disabled the "dropem" logic and retested.

My conclusion is that the existing code (which "clamps" the jitter buffer
size to the max_jitterbuf figure) works fine except that the jitterbuffer
can briefly grow larger than the max size.

I set a very small max_jitterbuffer and saw lots of "clamping" messages
and audio evidence of the missing packets (that arrived too late for the
configured jitter buffer size), but there were no big blank spots, just
jittery audio.  I much prefer that is users will understand that as network
issues, but a big blank spot sounds like a system problem.

My conclusion is that the jitterbuffer.c code works better as Steve Kann
originally wrote it and without this change from jdixon and I'd recommend
that the change be reverted.

Regards,
Steve 

Issue History 
Date Modified   Username       Field                    Change               
====================================================================== 
07-01-08 10:25  stevedavies    Note Added: 0089526                          
======================================================================