A method and system are provided for controlling a bit rate of an encoded video that includes a plurality of pictures. In the method, each of the plurality of pictures is one of a plurality of picture types. For the method, the number of bits required to encode a current picture as well as other pictures in a window is determined, and the fullness of a buffer storing the current picture and other picture data is estimated and compared to buffer fullness limits. This process is repeated for different quantization values to determine a suitable quantization value.