The transmission of video information through a narrowband channel requires a significant degree of image compression. In addition to the actual coding procedure, the frame rate is reduced, the spatial sample rate is lowered, and the color components are further filtered. Through a review of a practical and flexible image compression configuration, the important technical aspects of video coding are presented. The complexity of the currently developed system is discussed for operation over a 64 kbit/s communication channel. The specific and primary considerations include the following: After a reduction of temporal and spatial resolution, the luminance and color difference signals are divided in pixel blocks of 16 x 16 and 8 x 8, respectively. Then they are passed on to a motion-compensated differential pulse-code modulation coding system with a subsequent discrete cosine transform of the prediction error. The appropriate quantization in performed by means of several Huffman tables.