A Fast DCT Domain Based Video Downscaling System

In many multi-media applications DCT based digital video coding standards like MPEG are widely used. In certain applications like video database browsing, picture in picture etc., the video is required to be downscaled before transmitting it over the network. The naive spatial domain approach for video downscaling requires video to be fully decompressed. It requires huge computation time. The computation time greatly be reduced if all the computations are performed in the DCT domain. In this paper, we propose a fast DCT domain based video downscaling system. To reduce computational requirement, we have proposed efficient algorithms for inverse motion compensation. The sparseness of the DCT blocks are also considered for further reduction of computations. We found that our proposed system is 36 times faster than the spatial domain method and PSNR wise produces better quality downscaled video