[Fixed] Unable to find a codec translation path for GSM?

Asterisk Asterisk Support
1

Hey guys,

I finally got my Asterisk system up and running but I am experiencing some choppy audio so I figured I would change the default codec to GSM instead of ULAW. Asterisk starts fine but when a call comes in I get this error in the CLI:

Aug 21 09:54:52 WARNING[2671]: channel.c:2341 set_format: Unable to find a codec translation path from g723 to gsm Aug 21 09:54:52 WARNING[2671]: chan_sip.c:2552 sip_write: Asked to transmit frame type 4, while native formats is 1 (read/write = 4/2)

Now, If you check my modules.conf I AM loading all the GSM modules as well as the g723.

load=codec_gsm.so ; GSM/PCM16 (signed linear) Codec Translate load=format_g723.so ; G.723.1 Simple Timestamp File Format load=format_gsm.so ; Raw GSM data load=format_wav_gsm.so ; Microsoft WAV format (Proprietary GSM)

Is there a codec I am missing to get GSM to work? Any help will be appreciated! Thanks!!

2

do a ‘show translation’ - there is a matrix that shows what can be converted to what, and how much time the conversion takes.

on my box, i do not have g723 installed, so i have a dash in the intersection between gsm and g723. if you have a number, that means the codec translator sees both and can convert - if not, then something is awry.

i know this doesn’t help a lot, but it’s a start.

3

Thanks for the reply, here is my show translation:

[code]LKG7E7916*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 - - 30 - 713 - 29 - - - -
ulaw - 688 - - 686 - 2 - - - -
alaw - - - - - - - - - - -
g726 - 1213 528 - - - 527 - - - -
adpcm - - - - - - - - - - -
slin - 686 1 - 684 - - - - - -
lpc10 - - - - - - - - - - -
g729 - - - - - - - - - - -
speex - - - - - - - - - - -
ilbc - - - - - - - - - - -[/code]

It looks like indeed the system as it stands now cannot translate g723 to GSM. I am running this on a Linksys NSLU2 so I have to be very careful which codecs I use, and I was under the assumption that GSM was the lightest of them all. Is that correct?

Another thing that seems weird to me, is g723 simply a requirement to use GSM? Seems weird that ULAW works OK but GSM won’t…

4

it’s not that you don’t have GSM installed, it’s that your system is trying to translate from g723 to GSM:

Aug 21 09:54:52 WARNING[2671]: channel.c:2341 set_format: Unable to find a codec translation path from g723 to gsm

double check your sip.conf, make sure you don’t have g723 enabled on any of the devices in question.

if you can’t figure it out, post more of your logs and we’ll get it sorted out.

5

Sometimes it that small little kick you need. Got her figured, I had the following in my sip.conf:

disallow=all ;allow=ulaw allow=gsm

D’uh! She now reads:

;allow=ulaw allow=gsm

Man, sometimes…

THANKS!