在DCT域中，通过裁减高频分量，或者增加高频分量的方式，对图像视频序列的尺寸进行上/下变换，变换过程中其他的低频DCT系数也要做相应的调整，否则处理后图像亮度会与原图不一致-resizing the video/image in dct domain .Adding or removing the high frequency components will realize the up-resizing or down-resizing. extra attention need to on the orignal low frequency. because the luminance have connection with the low frequency components.