Low Bit Rate Video Coding Using DCT-Based Fast Decimation/Interpolation and Embedded Zerotree Coding

Abstract

In this paper, we propose a low bit rate video coding procedure in the discrete cosine transform (DCT) domain that is based in an embedded zerotree algorithm and uses decimation and interpolation. Theory for decimation/interpolation in the DCT domain is presented, and its implementation with fast algorithms is shown. Motivated by the compositing of several video sources in multipoint video conferencing, we propose a new method for single streams that uses the proposed DCT-decimation in the encoder and the corresponding DCT-interpolation in the decoder. Decimated video frames are encoded using an embedded zerotree and an adaptive arithmetic coder to improve the quality of the decoded videos. Zerotree coding is a progressive coding method that quantizes amplitudes of DCT coefficients of video frames into bit streams with increasing precision. Embedded coding scheme depends on coding a symbol by an adaptive arithmetic encoder as soon as the symbol is obtained by the zerotree coding. Zerotree coder gives flexibility of controlling the bit rate precisely at given target bit rate. Compared to conventional coding our proposed algorithm achieves peak signal-to-noise ratio improvements at low bit rate video coding.