Codec Negotiation Issue

Asterisk Asterisk Support
1

Hi,

I have a codec negotiation problem. I’m using version 1.6.2.18-rc1

Here is the scenario

A leg INVITE codecs: g729,g711
Asterisk chooses g729
B leg invite codecs: g729

but B endpoint only accepts g711 so it rejects the call.

none of the “peers” is on sip conf, i.e. global values are used which are:

disallow=all ; First disallow all codecs allow=g729 allow=alaw

I have found this patch for 1.4 that it seems that adresses the issue.
Is there anything I can do to make it work on 1.6?

2

You are using an expired release candidate, for an old release of an end of life version. You should, at least, go to 1.6.2.24.

Asterisk doesn’t choose a codec at that point. It should offer all the codecs that are in common between its list and the callers.

Note that a-law will not match the mu-law variant of G.711.

3

Thanks for your fast reply. all g711 codecs are alaw.

I will try the version you suggested. Anyway it seems that asterisk does some sort of codec choosing at the beginning on the call (function is sip_new in channel_sip.c) Then that codec information seems to be used when creating the second channel. I’ll post the logs soon

4

For the record. It is an issue on how Asterisk negotiate codecs. For versions 1.4 this seems to fix it