The Research Of Technology Of Video Coding For Low Bit Rate Communication

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.