Low Bit-rate Video Coding Algorithms Based On Wavelet Transform

Digital video has large amount of data which makes video storage and transportation difficult. Digital video coding is one of the key technologies to resolve this problem. The several international standards of H.26x and MPEG are promulgated by ITU-T and MPEG(Moving Picture Experts Group) based on summarizing the latest and efficient research achievements in the world, which based on DCT transform. But this scheme is obsessed with block effect in the instance of low bit rate transmission.While wavelet transform is suitable in image compression due to its multi-resolution and multi-scale analysis property, and is used in the standards of image compression. This paper futher analyzed the advance of image processing using wavelet transform. The basic concept of lifting wavelet transform is presented with the introduction of programs. The embedded coding is introduced in order to control the data rate accurately, then the principle of EZW(Embedded Zerotree Wavelet)is analyzed. The priciples of the improved algorithms such as SPIHT(Set Partitioning in Hierarchical Trees), SPECK(Set Partitioned Embedded Block Coder)are discussed then. The comparing result of these algorithms is given.An algorithm of video coding based on wavelet transform and block-based motion estimation is proposed after the discussing of motion estimation and motion compensation, and the coefficients are resorted using SPIHT. The motion estimation is improved using diamond searching method. A solution using DSP chip is provided with its hardware-realization in the end. The experimental results indicate that the method has higher PSNR and better subjective sense compared to the algorithms using DCT.