Research Of Video Image Coding Technology Based On H.263 Protocol

In the past few years, there has been significant interest in digital video applications.Consequently,academic and industry have worked toward developing video compression techniques, and several successful standards have emerged,e.g.,ITU-T H.261,H.263,ISO/IEC MPEG-1 and MPEG-2.While the demand for digital video communication applications such as video conferencing,video e-mailing,telemedicine,and video telephony has increased considerably,transmission rates over public switched telephone networks (PSTN) and wireless networks are still very limited.This requires compression performance and channel error robustness levels. ITU-T H.263,entitled " Video Coding for Low Bit Rate Communications ", provides better picture quality at low bit rates with little additional complexity.lt also includes four optional modes aimed at improving compression performance,.In this thesis, the H.263 standard specially suitable for low bitrate transmission, is adopted for digital video compression.The goal of this thesis is to develop a efficient video coding-decoding system having good error resilience. Specially,the concrete jobs of the thesis are:Opitimizes motion estimation. The modified motion estimation algorithm use adjacent several frames as reference other than single frame.Simplifies the algorithm of enhanced reference frame mode in H.263+ optinal mode.Therefore, multiframes reference adopt "sliding windows" method.Proposes a new strategy of video transmission aiming at speciality of Internet,which is instable and easily congested.The strategy improves reliability of the error concealment method,and makesbreaking image get correctly recovered.