【作者】 陈小敬；

【导师】 傅丰林；

【作者基本信息】 西安电子科技大学 ， 通信与信息系统， 2002， 硕士

【摘要】 为了在窄带信道上实现视频通信，本文对基于ITU-T的低比特率视频通信编码标准H．263的视频编码器的原理和实现方法作了深入的研究。主要讨论了基于H．263协议的视频编码器的实现，以及提高编码效率的H．263可选模式的实现。这些可选模式的选用提高了编码性能，但同时也增加了运算的复杂度，影响了编码的实时性。为了解决质量和实时性的矛盾，本方案在保证质量的前提下，针对运算时间较长的运动估计模块，给出了零运动矢量提前判断的方法，从而省去了约50％的匹配块搜索运算，提高了H．263编码器的编码速率；对运算量较大的DCT给出了快速算法，并对全零DCT系数块采用提前判断的方法，从而省去了约40％的DCT运算，进一步提高了H．263编码器的编码速率。更多还原

【Abstract】 In this paper, the theory and implementing method of video encoder based on the ITU-T H.263 video coding for low bit rate communication standard are studied deeply in order to satisfy the demand of narrow-band video communication. The implementing of video encoder based on H.263 standard is discussed, and three negotiable coding options are also discussed to improve performance of encoder. The three options can improve coding efficiency, but they also enhance the complexity of operation of encoder, so they affect the real time operation of encoder. On condition that quality of picture restructured is insured, with a view to the motion estimation algorithms that costs the longest coding time, the method of prejudgment of zero motion vector is adopted in this paper, which makes about 50 percent motion estimation computation left out, so the encoding speed of encoder can be further increased. With a view to DCT that costs the longer computing time, fast DCT is proposed, and the method of prejudgment of an macro-block of all zero coefficient of DCT is adopted in this paper, which makes about 40 percent DCT computation reduced, consequently, the encoding speed of H.263 encoder can be further increased.更多还原