Dialogic 05-2239-009 User Manual

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Dialogic Corporation

IPPARM_RX_RECVONLY – Media streaming has been initiated for a half-duplex 
receive-only connection. The parameter value is an IP_CAPABILITY structure containing 
the coder configuration that resulted from the capability exchange with the remote peer. 

IPPARM_TX_INACTIVE – Media streaming in the transmit direction has been 
suspended. The parameter value is an IP_CAPABILITY structure containing the coder 
configuration that resulted from the capability exchange with the remote peer. 

IPPARM_RX_INACTIVE – Media streaming in the receive direction has been 
suspended. The parameter value is an IP_CAPABILITY structure containing the coder 
configuration that resulted from the capability exchange with the remote peer. 

When the parameter value in the GC_PARM_BLK structure is IPPARM_TX_CONNECTED, 
indicating that a transmit media stream connection has occurred, the GC_PARM_BLK structure 
will also contain the local and remote RTP addresses. These addresses are handled as an 

 data structure, which contains both the port number and the IP address. The parameter 

set ID used for the RTP addresses is IPSET_RTP_ADDRESS, and the parameter IDs are 
IPPARM_LOCAL and IPPARM_REMOTE. 

The following code snippet illustrates how to retrieve the RTP addresses and negotiated coder 
information from a media stream connection event:

//When the event is an extension event:

GC_PARM_BLKP     gcParmBlk;
EXTENSIONEVTBLK  *pextensionBlk;
GC_PARM_DATA     *parmp = NULL;
RTP_ADDR         l_RTA1,l_RTA2;
pextensionBlk = (EXTENSIONEVTBLK *)(m_pMetaEvent->extevtdatap);
gcParmBlk = (&(pextensionBlk->parmblk));

GC_PARM_DATAP l_pParmData;
IP_CAPABILITYl_IPCap;

switch(pextensionBlk->ext_id)
{
   case IPEXTID_MEDIAINFO:

   //get the coder info:
   l_pParmData = gc_util_find_parm(gcParmBlk, IPSET_MEDIA_STATE, IPPARM_TX_CONNECTED);

   if(l_pParmData != NULL)
   {
      memcpy(&l_IPCap, l_pParmData->value_buf, l_pParmData->value_size);

      // get the local RTP address:
      l_pParmData= gc_util_find_parm(gcParmBlk, IPSET_RTP_ADDRESS, IPPARM_LOCAL);
      if(l_pParmData!= NULL)
      {
         memcpy(&l_RTA1,l_pParmData->value_buf,l_pParmData->value_size);
      }

      //get the remote RTP address:
      l_pParmData =gc_util_find_parm(gcParmBlk, IPSET_RTP_ADDRESS, IPPARM_REMOTE);
      if(l_pParmData != NULL)
      {
         memcpy(&l_RTA2, l_pParmData->value_buf, l_pParmData->value_size);
      }
   }