Any option to stablize the varying video bitrate ?

[viveky-rf]

Hi,
I am trying to encode a incoming TS udp stream of 2mbps using your ffmpeg bindings, i have kept the output video bitrate to 1.2mbps with a 128kbps audio bitrate. But the issue is that the video bitrate is varying in between 400 kbps to 3500kbps(approx), which i think is due to the amount of redundancy in a particular video frame, looking to keep the quality at the same level. Can we control the video bitrate of the output stream.