In this paper a statistical multiplexing system to encode several video programs in parallel using MPEG-2 compatible video encoders, is presented. Particularly, an external joint rate control algorithm with look- ahead has been developed. It distributes the channel bandwidth dynamically among the encoders according to their relative complexities using picture and coding statistics. The proposed scheme allows, at start of encoding, adaptive distribution of the channel bandwidth among the programs based on their relative scene contents. It also assures quick reaction for scene changes, while a feedback approach requires an unavoidable delay. Experimental results show that the presented look-ahead approach results in improved picture quality in comparison to the feedback approach, which is a special case of the proposed algorithm.