[Asterisk-Users] Avoiding transcoding

[George Pajari]

Dr. Murphey:

> How can one specify that codec selection should avoid transcoding if
> possible?

Asterisk only transcodes if the original audio stream needs to be connected
either to (a) another audio stream or (b) an internal Asterisk function -- 
and the original audio stream is encoded in a format that is not compatible
with the other audio stream or Asterisk function.

> The reason I ask is that when enum lookup succeeds and the destination
only
> accepts ULAW, the various transcodings seems to garble the audio if GSM,
> ILBC, etc. are allowed.

To illustrate the point above further, if you have a destination that only
accepts ULAW, and an audio stream in GSM or ILBC, you must transcode. It is
simply not an option since ULAW is not GSM, Asterisk has to convert
("transcode") the ULAW samples into GSM samples and vice versa.

Either I've misunderstood your question, or you have a different
understanding of "transcoding" than most.

Hope the above helps and apologies if I've completely missed your point.

George Pajari
www.netvoice.ca
www.ip-centrex.ca