We have devices that we control which are using Opus but we are looking to remove transcoding and just use ulaw as a passthrough. I have configured both peers to allow ulaw only (plus disallow all) and added ulaw to any originate calls.
Currently our sound files are in sln format. We created ulaw sound files but asterisk is still choosing to use the sln codec files even though the channels are using ulaw based on channelstats.
Does all of the codecs have to align to do a passthrough for ulaw? This would be recordings, music on hold, sound files, and of course any channels for us.
You are probably doing an originate operation. That won’t know the codec in time so will use an slin type one, unless you explicitly select the codec. Not all options for originate allow you to do that.
Is there any documentation for originate and transcodings? Are there any logs that I can turn on to view the transcoder and whats it doing or why its making certain decisions? Edit: Only asking from an ignorant perspective.
We are doing an originate through ARI. It calls an endpoint with disallow all and allow ulaw. We also specify the formats query param as ulaw.
channels?endpoint=myTrunkEndpoint
&app=myStasisAppName
&appArgs=dialed
&callerId=myCallerId
&formats=ulaw
Then later on we add it to a mixing bridge.