[Linphone-developers] DTMF issues with oRTP

[Mike]

Hello,

 

I’ve developed a custom SIP application (using my own SIP library), and oRTP for the media channel.

 

Everything seems to work great, other than some occasional DTMF issues (RFC2833 using the rtp_session_send_dtmf() function in oRTP).

 

If I run wireshark (ethereal) on the interface, and I send out a DTMF tone, normally I see five packets (three packets, then the third repeated two more times for reliability)- which correlates exactly with the code in telephonyevents.c. The maximum duration gets to 480.

 

But, occasionally, I’ll send a DTMF tone, and see hundreds of packets (the last test I did, sent out 200 packets), and the duration keeps incrementing (the last test incremented up to 32160). It does also send the last packet three times as in the first case for reliability.

 

Because of  the long duration, this obviously translates into a long tone on the receiving end, which is causing me some issues with some termination providers (some deal with it fine).

 

Does anybody have any thoughts on where these extra packets are coming from?

 

I’ve downloaded the CVS version of oRTP from the linphone distribution; I saw there was some changes related to the sequence number and timestamp, but it didn’t seem to resolve this issue.

 

Any help would be greatly appreciated,

 

Mike