Detecting corrupted intra macroblocks in H.263 video

Abstract

Corrupted low frequency data of intra coded macroblocks can significantly degrade quality of video in error prone wireless networks. Therefore, a new method for detecting the corrupted blocks is presented. The method exploits temporal smoothness of video by computing the absolute difference between subsequent video frames. A threshold function is used to highlight the block differences, and a heuristic is developed to detect the corrupted blocks. The proposed method is evaluated with our wireless video simulator, which shows that the method substantially improves image quality of video conferencing sequences in presence of transmission errors. In addition, the method is compared to average intersample difference across the block boundaries (AIDB) algorithm whose performance is shown to be more sensitive to selection of correct threshold values than the proposed method.