Hi Robert,

The H2250LogicalChannelAckParameters in src/asn/h245.asn has sessionID constraints set to 1..255:
sessionID   INTEGER(1..255) OPTIONAL

Due to this the OLC Ack to the extendedVideo OLC from Polycom with SessionID=0 is responded with sessionID=1.
The gatekeeper between the Polycom and opal on seeing this Ack starts sending the audio Session 1 RTP to the new destination that was actually meant for the extendedVideo.

Here is a hack that I applied to force setting the sessionID to a value other than 1, ensuring the audio continued with the original OLC Ack port. This hack fixes the problem. I tried changing the constraints but that leads to some Ack failures.

+++ opal-3.14/src/h323/channels.cxx 2014-07-09 19:02:32.236630005 +0530
@@ -563,6 +563,8 @@
   const H245_H2250LogicalChannelParameters & openparam =
                           open.m_forwardLogicalChannelParameters.m_multiplexParameters;
   unsigned sessionID = openparam.m_sessionID;
+  if(sessionID == 0)
+      sessionID = 100;
   param.m_sessionID = sessionID;
 
   OnSendOpenAck(param);

Thanks,
-Satya