[asterisk-dev] RxFax, SpanDSP & Asterisk possible bug?

[Sebastian]

Hi,

For some time now, I've been fighting with RxFax and Asterisk.
I had it working for some time, however, for some reason it just stopped 
working, I guess someone updated Asterisk or something, don't know exactly.

At the moment I keep getting errors while entering the RxFax stage of a 
call.
But due to the fact RxFax does not contain any code to directly interact 
with an RTP stream, it uses SpanDSP, I guess the problem is somewhere in 
SpanDSP.

 From my logs, I get:
   -- Goto (macro-faxreceive,s,7)
   -- Executing RxFAX("SIP/<faxnumber removed>-ff83", 
"/var/spool/asterisk/fax/fax/asterisk-8558-1149842081.2.tif") in new stack
Jun  9 10:34:56 WARNING[8558]: chan_sip.c:1829 sip_write: Asked to 
transmit frame type 64, while native formats is 4 (read/write = 64/4)
Jun  9 10:34:56 WARNING[8558]: chan_sip.c:1829 sip_write: Asked to 
transmit frame type 64, while native formats is 4 (read/write = 64/4)
Jun  9 10:34:56 WARNING[8558]: chan_sip.c:1829 sip_write: Asked to 
transmit frame type 64, while native formats is 4 (read/write = 64/4)

The basic call setup works perfectly, but whenever I try to enter a fax 
stage, I get this error.
According to the SIP call initialisation, there are no problems with 
formats, and the agreed upon format is 4 (aka ulaw).
At the moment I get these errors, there aren't any SIP transmissions, so 
were in mid-session...

I guess the problem is somewhere in SpanDSP or a transcoding error 
between slin and ulaw in chan_sip.

I've confirmed this problem on 2 servers so far.
The first server is our fax receiver (production), where this problem 
started. But it also appeared when I tried to directly connect a fax 
transmission from a PSTN line with an Sipura 3000 as FXO (forwarding the 
audio stream over our NAT to our local Asterisk server, with the ulaw 
codec).
Both servers are Debian Sarge servers.

Confirmed this problem in:
Asterisk 1.0.7 (default .deb packages, being with SpanDSP 0.0.2pre10-3)
Asterisk 1.0.11 (after reading 
http://lists.digium.com/pipermail/asterisk-users/2006-May/151843.html, 
SpanDSP 0.0.2pre26)
Asterisk 1.2.8 (from source, with SpanDSP 0.0.2pre26)
Asterisk 1.2.7.1 (from source, with SpanDSP 0.0.2pre25)

Does anyone know of a way to get it working again?

It has worked before, so I know it's perfectly possible with Debian Sarge.
Furthermore I've set this up on Red Hat Enterprise servers without this 
problem (with Asterisk 1.0.9). So I don't believe this is an error 
caused by myself.

-- 
With kind regards,
Sebastian Berm