[asterisk-users] Monitor problem, Asterisk 1.2.13

[Nikhil Nair]

Hi guys,

I'm running Asterisk 1.2.13 on a Debian Linux system (that was just the 
version that was packaged for it).  I've been using monitor() to record 
calls, with fairly satisfactory results - at least until the last few 
months.

I've been recording VoIP calls, and using monitor() with no arguments, so 
I'm getting separate wav files for each leg (both use ALAW, BTW), and 
combining them with soxmix, which apparently does support ALAW (if I'm 
right in presuming the wav files would be in this format - I'm no expert 
on such things).  I'm then using mplayer to listen to them.

However, I'm finding that the two legs of the call often get quite badly 
out of sync, so much so that I've often heard the answer to a question 
come before the question itself in a recording, when it certainly didn't 
happen like that at the time!  In one such instance, the in-file and 
out-file also differed in length by some 30 seconds, while being nearly an 
hour long each; they were perfectly in sync right at the beginning of the 
call, but already quite badly out by only 6 minutes in.

I'm pretty stumped here; I can only imagine that, for some reason, not all 
silence is being recorded in the sound files, so that, when there's 
silence on one leg and voice on the other, they become uncoordinated.  I'm 
puzzled as to why this wasn't a problem previously, though; I suspect it 
was before I was using SIP for VoIP, so, in that case, in the previous 
(working) case, one leg was IAX while the other was SIP, while now, both 
are SIP.  Canreinvite is set to no, however, so I didn't think this would 
be an issue.  It is possible, however, that it was a problem before, but 
that I failed to notice it, or perhaps it triggered less often for some 
other reason.

any thoughts appreciated!

BTW, I'm blind, which partly limits my choice of applications (I've been 
using console based ones, as I haven't worked out how to use X).

Best wishes,

Nikhil.