Exploiting inter-frame correlations in compound video coding
Compound images/videos are a mixture of text, graphics and natural images/video. Despite extensive research on compound image coding, rare research on compound video coding has been reported in the literature. This paper proposes three approaches to exploit inter-frame correlations in compound video. One is the motion compensation aided base color (MCA-BC) approach, which handles a special type of motion on text/graphics parts: foreground/background color change. The other two are motion-compensated residue base color and index map (MC-BCIM) and the motion-compensated residue scalar quantization (MC-RSQ) approach, both of which exploit spatial correlations among motion compensated residues. Experiments based on the High-Efficiency Video Coding (HEVC) reference software HM0.9 show that the proposed scheme largely improves the coding efficiency for more than 3dB on compound video with text/graphics and still keep a comparable performance on natural video content.