为了在高信噪比条件下获得对彩色视频的高倍压缩，提出了 4维矩阵及 4维矩阵离散余弦变换理论，并将该理论应用于彩色视频编码.基于 4维矩阵离散余弦变换的彩色视频编码方法将彩色视频的多个帧放在一个统一的数学模型 (即，4维矩阵 )中考虑，利用 4维矩阵离散余弦变换去除其间的各种相关性，并通过矢量量化对变换系数进行压缩编码.其方法可以同时全面利用彩色视频图象相邻像素间、彩色空间 Y、U、V 3分量间，以及视频图象相邻帧之间的相关性.实验结果证明，对可视电话和视频会议等应用中的彩色视频序列图象，利用该方法可在高信噪比条件下获得较高压缩比的编码效果

Four-dimensional(4D) matrix and four-dimensional matrix DCT(4D-MDCT) theory are proposed and applied in color video coding, in order to obtain high compression for color video under high signal-to-noise ratio. The four-dimensional matrix (4D Matrix) theory is a new and useful theory for color video processing. The color video coding method based on 4D-MDCT put several frames of color video into a unified mathematical model (i.e., 4D matrix), and various correlations in color video are eliminated utilizing 4D-MDCT. The four dimensions of 4D-MDCT used in the proposed algorithm are image width (row component), image height (column component), three channels (Y, U and V) in a color image (vertical component), and adjacent three frames of the video sequence (depth component) respectively. Similar to the method of 2D-DCT, the whole three frames of a color video sequence are also divided into“4D-blocks”, that is 4D sub-matrices, and the order of each sub-matrix is 3×3×3×3. The transform coefficients are coded by vector quantization further. The method can fully exploit correlations between adjacent pixels of an image, YUV frames of color space, and adjacent frames of video at the same time. Experimental results has proved that for the color video in applications such as videophone and video conferencing, the proposed method can achieve higher compression ratio under high signal-to-noise ratio.