Yong-jin Cho

Inter-layer filtering for scalable extension of HEVC

This paper introduces inter-layer filters for the scalable extension of High Efficiency Video Coding (SHVC) standard, which is being developed by the Joint Collaborative Team on Video Coding (JCT-VC). The major new coding tool in SHVC is inter-layer texture prediction. It provides about 18% average BD-rate reduction compared with HEVC two-layer simulcast. In the case of spatial scalability, base layer reconstructed pictures are up-sampled to the enhancement layer resolution to generate inter-layer texture prediction. A set of 2D separable 8 taps (luma) and 4 taps (chroma) DCT based interpolation filters, which follow the design principles of HEVC motion compensation interpolation filter, are used in the up-sampling process. In the case of SNR scalability, the up-sampling process is not needed since the reference layer has the same spatial resolution as the current layer but encoded with lower quality. This paper proposes a novel inter-layer filter with denoising effect for SNR scalability to improve enhancement layer coding efficiency and equalize the number of stages in inter-layer processing between SNR and spatial scalabilities. Experimental results show that the usage of inter-layer de-noising filter in SNR scalability provides up to 7.5% BD-rate reduction and has observable improvement on subjective visual quality.

Region based inter-layer cross-color filtering for scalable extension of HEVC

Inter-layer filtering is a key module of the emerging Scalable Extension of High Efficiency Video Coding Standard (SHVC). In SHVC, up-sampled based layer reconstructed pictures are used as inter-layer references to predict enhancement layer frames such that inter-layer redundancy is reduced. To improve the coding performance of inter-layer filtering, luma plane based chroma plane enhancement was proposed at picture level. However, the efficiency of the picture level adaptation is not very promising when picture resolution is high. To address this issue, region based inter-layer cross-color filtering is proposed in this paper. Simulations under the common test conditions defined by Joint Collaborative Team on Video Coding (JCT-VC) showed that significant chroma coding gain and moderate luma improvement were achieved by the proposed method. When compared to the luma plane based chroma plane enhancement method, the coding gain over SHVC reference software SHM-2.0 is about doubled while the decoding complexity is kept even lower. Moreover, the proposed method outperforms other tools studied in SHVC core experiment on inter-layer filtering.