ffmpeg rtp and rtcp audio video problem

if I am sending audio and vide thru ffmpeg, I got flickering in the video;
the reason is ffmpeg video 4999 audio 5000
But I am not getting proper audio at client side; I got some glitches .
Reason :
---------------
1.we have to choose the even number of rtp port;rtcp packets will be sent by the ffmpeg ( rtp port + 1) = rtcp port number;
2. rtp video is sent in 4999 and ffmpeg will send the rtcp info at 5000
3.At the same time ffmpeg will sends audio at RTP port 5000 and RTCP at 5001;
4.So FFMPEG is sending the RTP and RTCP packets in a same Port that is 5000;