A New Spatial Downsampling Algorithm for DCT-Domain Video Transcoder

Spatial resolution reduction of compressed video is highly desirable in video transcoding. Many studies have addressed this problem, but they either cause drift error or have high computation complexity. A new spatial downsampling algorithm for DCT-Domain video transcoder is proposed in this paper, in which LxM sub-blocks of NxN are combined into a LxN rows and MxN columns blocks in DCT-Domain firstly, by extracting the left-top NxN low-frequency coefficients from this block, the new NxN downsampled block is the obtained. Experimental results confirm that the proposed algorithm performs better than other algorithms in terms of PNSR of reconstructed video sequences, furthermore, the computation complexity reduced greatly. sheet, as illustrated by the portions given in this document.