Transcoding even after pass-thru settings

Hi guys, I’ve an asterisk server that the load averages are crazy high with only 350 calls.
The LA is around 80-100, no other process run on this server, I’m pretty sure that the problem is the transcoding.

What happen is I have a trunk setup and it accepts only g729, I’ve g729 installed into asterisk too

I tried with ulaw too, same thing happens.


what should i do? is there a way to make sure that asterisk is in fact transcoding it?


On the Asterisk CLI find the channel you are interested in using:

core show channels

Then use it to get more information about the channel by executing:

core show channel

You can then see what read/write formats the channel is using and whether or not it is transcoding. For instance, are “WriteTranscode” and/or “ReadTranscode” blank or have values.

For example, you might see something similar to the following:

NativeFormats: (ulaw)
WriteFormat: slin48
ReadFormat: slin48
WriteTranscode: Yes (slin@48000)->(slin@8000)->(ulaw@8000)
ReadTranscode: Yes (ulaw@8000)->(slin@8000)->(slin@48000)
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Thank you, and I’m wrong I think… I have no idea what is causing the load average then llook:

State: Up (6)
NativeFormats: (g729)
WriteFormat: g729
ReadFormat: g729
WriteTranscode: No
ReadTranscode: No

Do you have any idea?

You can tell if it is transcoding by looking at the licence use counts for the codec.

Lots of things will force the conversion to signed linear format, e.g,: inband DTMF, call recording, conferences, generated tones, Originate/call files if you don’t specify a codec.