Efficient algorithm for reverse playback in MPEG video streaming

Abstract

Reverse playback is the most common video cassette recording (VCR) functions in many digital video players. However, the predictive processing techniques employed in MPEG severely complicate the reverse-play operation. Previously. we have proposed a compressed-domain algorithm for the MPEG video streaming system to provide efficient reverse playback. In the proposed video streaming server, it classifies macroblocks in the requested frame into two categories - a backward macroblock (BMB) and a forward macroblock (FMB). For BMB, a sign inversion technique has been proposed to reduce the number of macroblocks that need to be decoded by the decoder. However, the required number of macroblocks for reconstructing FMBs is still very high. In this paper, the server identifies the related previous macroblocks of FMBs and reduces the redundancies of those related macroblocks to further reduce the computational complexity of the client decoder. Experimental results show that, as compared to the conventional and the previously proposed algorithms, the new streaming algorithm reduces the required network bandwidth and the decoding complexity significantly.