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 coefficients entirely in the transform domain. We show that the conversion is essentially a 2D transform. We derive the ... [Show full abstract] transform kernel matrix; provide a fast algorithm and an integer approx- imation 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.