Low bit rate videophone codec for ISDN applications

摘要

This article presents the performance results of a low-bit rate image codec for videophone and B/2B channel ISDN applications. The codec at the encoder skips two frames over three images and encodes every one image over three using DCT-Huffman coding and sends together with the motion vectors computed over overlapped blocks. At the receiver, the missing frames are constructed by linear interpolation using coded frames and respective motion vectors. The effectiveness of the codec is evaluated by employing two video sequences as input. The resulting video sequences indicate that for videophone applications, an acceptable quality of image is obtained. Therefore, this codec can be a good candidate for a videophone in ISDN network. Finally, the implementation considerations of this codec are also given.