[Asterisk-Users] Codec passthrough patch for IAX

[Michael Giagnocavo]

Hi there,

	I had a problem, basically, I have 4 different types of end users
(gsm, ilbc, g729, ulaw). However, I only have one user with my DID provider.
My provider supports all 4 codecs. The issue is then: When an incoming call
comes in, a codec is negotiated (usually ULAW), later on, when the extension
is dialed, we'll see we're doing GSM, and thus transcode. Here's an example
dialplan:

[incoming]
exten => 123,1,Dial(IAX2/gsmUser)
exten => 456,2,Dial(IAX2/ilbcUser)
exten => 789,3,Dial(IAX2/g729User)

	You're pretty much forced to accept ULAW, and then transcode. Not
fun if your provider does it for you (that's what you pay them for, right?).

So, with this patch, just add a new config file.
codec_passthrough.conf:
[iax_my-did-provider]
123=gsm
456=ilbc
789=g729

	Now, when an incoming call comes in, the user/extension will be
found, and your preferred codec changed. No more transcoding. 

	http://bugs.digium.com/bug_view_page.php?bug_id=0003553

	My main question is: Can this be done without this patch? I've heard
it's impossible, and it sure seems that way. Any suggestions?

-Michael