[asterisk-users] can't transcode ilbc

[James Harper]

I'm getting messages like 'WARNING[10263]: chan_sip.c:2552 sip_write:
Asked to transmit frame type 8, while native formats is 1024 (read/write
= 1024/1024)', where 8 = alaw and 1024 = ilbc.

If I do show translation I get this:
*CLI> show translation
         Translation times between formats (in milliseconds)
          Source Format (Rows) Destination Format(Columns)

         g723   gsm  ulaw  alaw  g726 adpcm  slin lpc10  g729 speex
ilbc
   g723     -     -     -     -     -     -     -     -     -     -
-
    gsm     -     -     7     7    14     7     6    19     -    93
-
   ulaw     -    17     -     1     9     2     1    14     -    88
-
   alaw     -    17     1     -     9     2     1    14     -    88
-
   g726     -    23     8     8     -     8     7    20     -    94
-
  adpcm     -    17     2     2     9     -     1    14     -    88
-
   slin     -    16     1     1     8     1     -    13     -    87
-
  lpc10     -    24     9     9    16     9     8     -     -    95
-
   g729     -     -     -     -     -     -     -     -     -     -
-
  speex     -    27    12    12    19    12    11    24     -     -
-
   ilbc     -     -     -     -     -     -     -     -     -     -
-

which I think means that there is no translation/transcoding path
between ilbc and anything else.

Is there some configuration option I need to set somewhere to allow this
transcoding to take place or is there something about the ilbc protocol
which makes transcoding a bad idea?

The call in question is:

SJphoneA -> AsteriskA -> mynetfone -> AsteriskB -> SJphoneB

SJphoneA and SJphoneB both have a clear path to each other (tunnel), but
when AsteriskA calls mynetfone, it uses nat. I don't think nat is a
problem in this case though.

Any suggestions? I'm also seeing the same thing when I try to make a
call like:
SJphone -> Asterisk -> PBX (via mISDN)

SJphone is talking ilbc to Asterisk, but obviously Asterisk talks alaw
to the PBX, and Asterisk refuses to transcode.

James