[asterisk-users] Why doesn't Asterisk try to prevent transcoding

[jg]

I see, you do want something like picking g722 provided there is no transcoding. Because 
Asterisk is a B2BUA it can transcode, so it would choose g722 where the other party is doing g711.

For known parties, maybe one could change the SIP configuration on the fly using the Asterisk 
realtime engine, or modify the settings of the phone with an http request. Generally, an 
Asterisk configuration option like "prioritize_matching_codecs" would be needed, but I don't 
think this is very useful. In this case there should also be all sound files available in g722. 
Even if you have them, some channels might still be silent as sometimes users choose to get MOH, 
for example, from the phone itself. Phones usually store sound files in a single format assuming 
that somebody else is able to transcode if necessary.

Please correct me, if my description is incorrect.

jg