Improving SHVC performance with a joint layer coding mode
The growing need for a powerful scalable video coding engine targeting the heterogeneous landscape of network, devices, and consumption environments has led to the development of the Scalable High Efficiency Video Coding (SHVC) standard, an extension of the High Efficiency Video Coding (HEVC) standard. To improve the SHVC compression efficiency, this paper proposes a novel joint layer coding mode to be integrated in the SHVC codec. In the proposed coding mode, the base layer (BL) and enhancement layer (EL) decoded information are linearly combined at the pixel level to create an additional coding mode. To fuse the BL and EL driven predictions, a weighting term is defined to indicate the contributions of each of them for the final joint layer prediction. To reach high adaptability, these weights are computed at pixel level in the prediction unit. Moreover, to achieve the highest compression efficiency, the proposed joint layer coding mode is adaptively selected using a rate distortion optimization (RDO) mechanism. Experiments conducted for a rich set of test conditions have shown that significant compression efficiency gains can be achieved with the proposed joint layer coding mode, notably up to 4.3 % in BD-Rate savings regarding the standard SHVC quality scalable codec.