[Live-devel] Reception Packet Information

[Dixon Siu]

Hi Ross and everyone,

Just received an request from another engineer that packet loss and received
packet are needed. The client side will implicitly send a leave group
message to the multicast group if network is congested. So I implemented a
public method in RTCPInstance.

Ross, please advise if it is the correct way. Hope that you can implement a
better way so that I can use your method for later release.

In RTCP.hh added the following method definition:
void getCurrentReceiverPacketInfo(long* numPacketReceived, long*
numPacketLost);
	 // hack to allow application that creates RTCPInstance to retrieve
 	// packet information since last reset.

Then in RTCP.cpp:
// Implemented by MGC to retrieve receiver packet loss information.
void RTCPInstance::getCurrentReceiverPacketInfo(long* numPacketReceived,
long* numPacketLost) {
	if (fSource != NULL) {
		RTPReceptionStatsDB& allReceptionStats = fSource->receptionStatsDB();
		RTPReceptionStatsDB::Iterator iterator(allReceptionStats);
		RTPReceptionStats* receptionStats = iterator.next();
		if (receptionStats == NULL) {
			fprintf(stderr, "Reception Statistics is not available!\n");
			*numPacketReceived = -1; // invalid value checked by the caller
			*numPacketLost = -1; // invalid value checked by the caller
			return;
		}
		*numPacketReceived =
(long)receptionStats->numPacketsReceivedSinceLastReset();
		*numPacketLost = (long)(receptionStats->highestExtSeqNumReceived() -
								receptionStats->lastResetExtSeqNumReceived() -
								receptionStats->numPacketsReceivedSinceLastReset());
	}
}

The way to use is to create an RTCPInstance within your application and then
call the method anytime you want. For example, I created a thread for
testing:
DWORD WINAPI thread_proc(LPVOID lpParameter) {
	long x = 0;
	long y = 0;
	while (1){
		sessionState.rtcpInstance->getCurrentReceiverPacketInfo(&x, &y);
		Sleep(5000); // For testing.
	}
}