[Mp4-tech] [video]Any body knows RTCP?

[lizhengming]

Dear all,
Does anybody know the RTCP(RTP Control Protocol) protocol, which is one part
of the RFC1889? 
I'm working on RTP and RTCP, trying to send media data with RTP and getting
the quality of the data transmission through RTCP feedback. I think I devise
the RTCP packets according to RFC1889,however the packets-loss ratio and
packets-loss counts drawn from RTCP packets are not always reasonable. When
the network conditions are good enough and all media data can be
transmitted, then actual packets-loss ratio and packets-loss counts are all
equall to zero, and packets-loss ratio and packets-loss counts drawn from
RTCP packets are also equal to zero. However, when the network conditions
are not so good, then the actual packets-loss ratio and packets-loss counts
are larger than zero, but those parameters drawn from RTCP packets are
seemingly meaningless, with these two parameters changing rapidly and not
incrementally. 
Though the RTCP applications on the server are devised by myself,I use
Quicktime player as the client player. So I'm not sure whether there is
something wrong with the RTCP applications on the server side.
Who knows where are some example codes of RTP/RTCP applications that can be
my reference? Please tell me if you have any hints. Thanks in advance.
Regards,
Li Zhengming