A low-cost desktop videoconferencing codec: an adaptive Motion-JPEG design

摘要

An adaptive Motion-JPEG coding scheme is proposed for desktop videoconferencing. The H.261 and Motion-JPEG are two commonly used codecs for videoconferencing. But, they have their own drawbacks. The problem of the H.261 is that it is computation intensive, and a special hardware is required as a result. The cost of an H.261 codec is so far too expensive to be accepted by desktop users. The Motion-JPEG is a low-cost choice for videoconferencing. But, its coding efficiency is not as good as the H.261 because temporal redundancy is not removed. In the proposed design, we try to take advantage of both H.261 and Motion-JPEG. The blocks are classified into two categories: the background and the motion. The motion blocks are coded in the same way as Motion-JPEG. The method of coding the background blocks is basically similar to the H.261 except that two techniques are employed such that its computation has the same order as that of the Motion-JPEG. The performance of the Motion-JPEG and adaptive Motion-JPEG was investigated by conducting several experiments. It is shown that the presented scheme improved the picture quality by about 2 dB for a bit rate of 1.15 Mbps.