[Asterisk-Dev] Missing RTP header in iLBC

[Jan Saell]

Hi all!

We have a software company changing their iLBC codec so its working with 
asterisk - they had on 20ms and asterisk aparently is using the 30ms 
version.

They are complaning that the RTP

I have just tested our new client in 30ms iLBC mode and it works against
your PBX.  I just have one quick question, I'm not sure if you are the
correct person to be asking, but do you know why the PBX does not specify
the iLBC configuration fully in the SDP sent?  As per the iLBC
specification, an extra "fmtp" attribute is needed to describe the mode you
are working in, so that the other endpoint can negotiate or match it.  The
media part of your SDP message looks like this:

....
m=audio 16040 RTP/AVP 97 8 3 0 101
a=rtpmap:97 iLBC/8000
a=rtpmap:8 PCMA/8000
a=rtpmap:3 GSM/8000
a=rtpmap:0 PCMU/8000
a=rtpmap:101 telephone-event/8000
a=fmtp:101 0-16
...

But it should have an extra a=fmtp line like this:

a=fmtp:97 mode=30

as you are operating in 30ms mode.

Is this someting anyone knows about, or is it fiexed in 1.2?

Best regards
jan

-- 
+-------------------------------------------------------------------
! Irial / YASK AB
! Att: Jan Saell
! Box 59, S-692 21 KUMLA, SWEDEN
! Tel: 019-58 25 15     Int +46-19 58 25 15     Fax +46-19 58 38 05
! E-mail: jan at irial.com
! PGP Fingerprint: E957 23C8 9F51 0958 B9AD  7F18 404A 5DA1 F944 A08B
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 189 bytes
Desc: not available
Url : http://lists.digium.com/pipermail/asterisk-dev/attachments/20051130/b4cdb10a/attachment.pgp