This paper describes the background, design and application of a new SEI message – the Multiplane Image Information SEI message, which has recently been adopted into the Technology under Consideration (TuC) document of the JVET committee for potential inclusion in the VSEI standard (ITU-T H.274 and ISO/IEC 23002-7). The paper also provides preliminary compression experiment results and analysis on the implications of the coding efficiency and functionality of the different packing options supported in the SEI message.

This paper describes a new video coding tool in the Versatile Video Coding standard (VVC) named as luma mapping with chroma scaling (LMCS). Experimental compression performance results for LMCS and non-normative examples for deriving LMCS parameter values are also provided. LMCS has two main components: 1) a process for mapping input luma code values to a new set of code values for use inside the coding loop; and 2) a luma-dependent process for scaling chroma residue values. The first process, luma mapping, aims at improving the coding efficiency for standard and high dynamic range video signals by making better use of the range of luma code values allowed at a specified bit depth. The second process, chroma scaling, manages relative compression efficiency for the luma and chroma components of the video signal. The luma mapping process of LMCS is applied at the pixel sample level, and is implemented using a piecewise linear model. The chroma scaling process is applied at the chroma block level, and is implemented using a scaling factor derived from reconstructed neighboring luma samples of the chroma block.

This paper describes a video coding scheme submitted in response to the joint call for proposals (CfP) on video compression for capability beyond HEVC issued by ITU-T SG16 Q.6 (VCEG) and ISO/IEC JTC1/SC29/WG11(MPEG) in October 2017. It includes video coding techniques for the standard dynamic range (SDR) and high dynamic range (HDR) categories. Design of the core SDR codec in the response is based on the joint exploration model (JEM) reference software developed by the joint video exploration team (JVET). Some of key coding tools in the JEM are significantly simplified to reduce both average and worst-case complexity for hardware design with negligible coding performance loss. Furthermore, two additional coding technologies, namely multi-type tree (MTT) and decoder-side intra mode derivation (DIMD), are used to further improve coding efficiency. For the HDR category, besides the tools used in SDR category, two additional coding tools: an in-loop reshaper and a luma-based QP prediction method are used to further improve HDR coding efficiency. Simulation results demonstrate the high coding efficiency achieved by the proposed video codec at the expense of moderate coding complexity over HEVC. For random access configuration, it achieves average bit rate savings of 35.7% and 4.00% over the HM and JEM anchors with decoding time of 263% and 33%, respectively, for the SDR sequences. For the HDR sequences, the proposed in-loop reshaper is configured to maximize HDR objective metrics, it achieves average bit rate savings of 31.3% and 4.6% over the HM and JEM for wPSNRY metrics for the HDR PQ content.

ICTCP is a colour difference signal representation recently standardized in Rec. ITU-R BT.2100. One design criteria of ICTCP for HDR/WCG imagery is to address issues in Non-Constant Luminance (NCL) Y'CbCr with HDR/WCG signals. In this paper, the superior performance of ICTCP in preserving constant luminance over the NCL Y'CbCr is analyzed in detail. The fundamental limitations of Y'CbCr luma adjustment algorithm which aims at fixing chroma subsampling artifact of Y'CbCr is discussed as well. This paper also provides guidance on signaling of ICTCP and feasible encoder settings with HEVC Main 10 codec. Experimental results suggest that for HDR content with real BT. 2100 (BT. 2020) colour gamut, to perform chroma subsampling and compression in ICTCP have significant value.