Video compression using integer DCT

Abstract

This paper describes the implementation of the integer discrete cosine transform (IntDCT) using the Walsh-Hadamard transform and the lifting scheme. The implementation is in the forms of shifts and adds, and all internal nodes have finite precision. A general-purpose scheme of 8-pt IntDCT with complexity of 45 adds and 18 shifts is proposed which gives comparable performance to the floating-point DCT (FloatDCT). For this particular scheme with 8-bit input, perfect reconstruction (PR) is preserved even when all the internal nodes are limited to 16-bit words, rendering the Pentium MMX optimization possible. Implementation has been done to incorporate the proposed IntDCT into the H.263+ coder, and the resulting system performs equally well as the original. Further extension to the MPEG coder is straightforward. The proposed IntDCT is reversible, with a low level of power consumption, and is very suitable for source coding, and communication, etc. in a mobile environment.