To support efficient multimedia retrieval, multimedia server usually store a large size of multimedia data in a compressed form, such as MPEG format for video and audio data. However, variable bit rate (VBR) of MPEG movies is a serious problem for a system supporting video-on-demand services (VOD). In this paper, we propose a Smoothing by Block Adjustment (SBA) scheme to deal with the VBR problem based on physical storage of multimedia data by a block. If we reduce the frequence of rate adjustment for all movies in a VOD system, we can eliminate much useless overhead of the server or network resource adjustment in a VOD system. We show that our SBA scheme can solve VBR problems without incurring much complexity and efficiently reduce frequent rate adjustment for a movie playback.