Converting DCT Coefficients to H.264/AVC Transform Coefficients

Many video coding schemes, including MPEG-2, use a Discrete Cosine Transform (DCT). The recently completed video coding standard, H.264/AVC, uses an integer transform, which will be referred to as HT in this paper. We propose an ecient method to convert DCT coefficients to HT coeffients entirely in the transform domain. We show that the conversion is essentially a 2D transform.We derive the transform kernel matrix, provide a fast algorithm and an integer approximation of the transform. We show that the proposed transform domain conversion outperforms the conventional pixel domain approach. It is expected to have applications in transform domain video transcoding. This work may not be copied or reproduced in whole or in part for any commercial purpose. Permission to copy in whole or in part without payment of fee is granted for nonprofit educational and research purposes provided that all such whole or partial copies include the following: a notice that such copying is by permission of Mitsubishi Electric Research Laboratories, Inc.; an acknowledgment of the authors and individual contributions to the work; and all applicable portions of the copyright notice. Copying, reproduction, or republishing for any other purpose shall require a license with payment of fee to Mitsubishi Electric Research Laboratories, Inc. All rights reserved. Copyright c ©Mitsubishi Electric Research Laboratories, Inc., 2004 201 Broadway, Cambridge, Massachusetts 02139 Publication History: 1. First printing, TR-2004-058, June 2004 Converting DCT Coefficients to H.264/AVC Transform Coefficients Jun Xin, Anthony Vetro, and Huifang Sun Mitsubishi Electric Research Laboratories, Cambridge MA 02139, USA jxin,avetro,[email protected] Abstract. Many video coding schemes, including MPEG-2, use a Discrete Cosine Transform (DCT). The recently completed video coding standard, H.264/AVC, uses an integer transform, which will be referred to as HT in this paper. We propose an efficient method to convert DCT coefficients to HT coefficients entirely in the transform domain. We show that the conversion is essentially a 2D transform. We derive the transform kernel matrix, provide a fast algorithm and an integer approximation of the transform. We show that the proposed transform domain conversion outperforms the conventional pixel domain approach. It is expected to have applications in transform domain video transcoding.