Adaptive colour-space selection in high efficiency video coding

Abstract

Abstract-Recent developments in the standardisation of High Efficiency Video Coding (HEVC) have shown that the block-wise activation/deactivation of a colour transform can significantly improve the compression performance. This coding tool is based on a fixed colour space which is either YCgCo in lossy compression mode or YCgCo-R in the lossless mode.The proposed method shows that the performance can be increased even more when the colour space is not fixed but selected dependent on the image characteristic. Improvements of more than 2% can be achieved in lossless intra coding if the colour space is automatically chosen once for the entire image. In lossy intra compression, the performance can also be increased if a proper colour space is chosen.

On the Utilization of Reversible Colour Transforms for Lossless 2-D Data Compression

“…Telagarapu et al in [33] employed Discrete Cosine Transform (DCT) and Discrete Wavelet Transform (DWT) showing that the DWT outperformed the DCT in terms of lossless compression. Strutz et al in [34] used automatic selection of colour transforms for efficient coding, either lossy or lossless. It was 2 percent more efficient in the case of lossless coding.…”

Adaptive color space model based on dominant colors for image and video compression performance improvement

“…For example, an image is divided into 9 blocks (p = q = 3), in each block the same components can be applied, or may also be different, according to their entropy calculation result. Both adaptive color space and macro block models have been developed in [14,15] and implemented in 4: 4: 4 video coding.…”