asterisk users - Sep 2011 - Determine negotiated codec in script

Sorry if this is an obvious question and perhaps my Google foo isn't
right on this one:

I have calls coming into an Asterisk server that may be using 2
different codecs.  I am recording audio in both cases but the
challenge is knowing which codec was negotiated at call setup.  I need
to pass the proper format to the record command as the codecs cannot
be transcoded and are only supported for playback/record/passthru etc.

Is there some global variable present that I can look at for codec
identification?

"Sip show channels" will give you the active codec.  You can get the
information using an AGI or a system command.

-----Original Message-----
From: asterisk-users-bounces at lists.digium.com
[mailto:asterisk-users-bounces at lists.digium.com] On Behalf Of Tom Browning
Sent: Tuesday, September 13, 2011 4:19 PM
To: Asterisk Users Mailing List - Non-Commercial Discussion
Subject: [asterisk-users] Determine negotiated codec in script

Sorry if this is an obvious question and perhaps my Google foo isn't right
on this one:

I have calls coming into an Asterisk server that may be using 2 different
codecs.  I am recording audio in both cases but the challenge is knowing
which codec was negotiated at call setup.  I need to pass the proper format
to the record command as the codecs cannot be transcoded and are only
supported for playback/record/passthru etc.

Is there some global variable present that I can look at for codec
identification?

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So I did a little more digging and found a real simple answer:

${CHANNEL(audionativeformat)}

tells me 'ulaw' or 'siren14' and lets me pick the right file
extension
for the record function.




On Tue, Sep 13, 2011 at 5:19 PM, Tom Browning <ttbrowning at gmail.com>
wrote:
> Sorry if this is an obvious question and perhaps my Google foo isn't
> right on this one:
>
> I have calls coming into an Asterisk server that may be using 2
> different codecs. ?I am recording audio in both cases but the
> challenge is knowing which codec was negotiated at call setup. ?I need
> to pass the proper format to the record command as the codecs cannot
> be transcoded and are only supported for playback/record/passthru etc.
>
> Is there some global variable present that I can look at for codec
> identification?
>