> -----Original Message----- > From: [EMAIL PROTECTED] > [mailto:[EMAIL PROTECTED] On Behalf Of > George Pajari > Sent: Saturday, July 10, 2004 4:58 PM > To: [EMAIL PROTECTED] > Subject: Re: [Asterisk-Users] Avoiding transcoding > > 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.
Is it possible to configure asterisk to select a codec common to both channels? Per your example, I tested a call from XTEN (sip) that allowed ULAW or GSM, through asterisk, to a destination that accepts only ULAW. XTEN(SIP) -> asterisk -> SIP destination It should be possible to avoid transcoding, but asterisk shows this: Peer User/ANR Call ID Seq (Tx/Rx) Format 216.234.116.184 1800246846 1b07a93b13f 00102/00000 ULAW 172.16.0.100 xten EEE6B555-5B 00101/09156 GSM Because the destination is found by enum lookup, it's not possible to know which protocol or codec in advance. Thank very much for your explanations. Cheers, Rich _______________________________________________ Asterisk-Users mailing list [EMAIL PROTECTED] http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users
