Distributed video codec (DVC) has been developed to construct a simple encoder that utilizes information theory for distributed sources in the circumstance of mobile multimedia communication. In the DVC codec, an efficient algorithm to generate side information (SI) is one of the most important techniques to improve the coding performance. We propose a scheme to increase the quality of SI frame, where the proposed scheme consists of three steps. In the first step, SI frame is constructed by motion estimation and motion compensation in the DVC decoder. Then, in the second step, the blocks in the temporary SI frame are classified into reli- able or unreliable ones. The unreliable blocks are updated by block boun- dary matching algorithm in the third step. Simulation results show that the proposed algorithm outperforms the conventional methods significantly. In addition, the proposed scheme can be combined with the conventional schemes generating SI frame to increase the coding performance of the DVC codec. © The Authors. Published by SPIE under a Creative Commons Attribution 3.0 Unported License. Distribution or reproduction of this work in whole or in part requires full attribution of the original publication, including its DOI. (DOI: 10.1117/1.OE.52 .10.103111)