Interplane prediction for RGB video coding

This paper presents an efficient video coding method in RGB space. Generally RGB space is regarded as a bad space from a compression point of view. Each RGB component contains the color information along with luminance information. This redundancy degrades the coding efficiency. To exploit the intercolor redundancy, the RGB space is usually converted into another color space. But it inevitably causes color distortion due to the rounding operation involved. For professional applications it is essential to maintain the original color fidelity. To cope with these problems we propose an inter-plane prediction (IPP) that increases the coding efficiency in RGB space while avoiding color distortion. The proposed IPP exploits the redundancy of the residual images, which exists even after intra/inter prediction in MC-DCT based codec. The simulation results show that by applying the IPP to the MPEG-4 AVC/H.264 4:4:4 codec we can achieve up to 40% higher coding efficiency than that of the coding without IPP option. We also show there exists an achievable PSNR limit if color space conversion is involved. In other words, coding in a given space is important to keep the fidelity of the original data for professional applications.