This paper provides a technical overview of palette-based coding that was adopted into the test model for the screen content coding (SCC) extension of High Efficiency Video Coding (HEVC) standard at the 18th JCT-VC meeting. Key techniques that enable the palette mode to deliver significant coding gains for screen contents are highlighted, including palette table generation, palette table coding, and the coding methods for palette indices and escape colors. Proposed and adopted techniques up to the first version of the working draft of HEVC SCC extension and test model SCM-2.0 are presented. Experimental results are provided to evaluate the performance of the palette mode in the SCC extension of HEVC.

This paper presents an inter-layer filtering technique to improve the coding efficiency of the emerging SHVC scalable video coding standard. This filtering method is based on the Sample Adaptive Offset (SAO) tool introduced in the HEVC video coding standard. The original SAO filtering technique is slightly modified and applied to filter the HEVC base layer so as to improve the prediction of the enhancement layer. Based on the testing conditions of the SHVC standardization process, the results of this SAO inter-layer processing compared to the SHVC reference software show a noticeable improvement of the coding efficiency for the enhancement layer.

In this paper, we investigate a new inter-channel coding mode called LM mode proposed for the next generation video coding standard called high efficiency video coding. This mode exploits inter-channel correlation using reconstructed luma to predict chroma linearly with parameters derived from neighboring reconstructed luma and chroma pixels at both encoder and decoder to avoid overhead signaling. In this paper, we analyze the LM mode and prove that the LM parameters for predicting original chroma and reconstructed chroma are statistically the same. We also analyze the error sensitivity of the LM parameters. We identify some LM mode problematic situations and propose three novel LM-like modes called LMA, LML, and LMO to address the situations. To limit the increase in complexity due to the LM-like modes, we propose some fast algorithms with the help of some new cost functions. We further identify some potentially-problematic conditions in the parameter estimation (including regression dilution problem) and introduce a novel model correction technique to detect and correct those conditions. Simulation results suggest that considerable BD-rate reduction can be achieved by the proposed LM-like modes and model correction technique. In addition, the performance gain of the two techniques appears to be essentially additive when combined.

A new inter-channel coding mode named LM mode has been intensively explored in the HEVC standardization project. This mode predicts the chroma signal from the luma signal using a linear model whose parameters are inferred from neighboring reconstructed luma and chroma samples. Although this mode presents very good coding efficiency, it is observed that ill cases in the linear parameters calculation can be detected and fixed. This paper gives an overview of the LM mode and presents a novel model correction scheme to detect and correct those ill cases. Simulation results show significant bit-rate savings by the proposed correction scheme with limited added complexity.

After having issued the version 1 of the new video coding standard HEVC, ISO-MPEG and ITU-T VCEG groups are specifying its scalable extension. The candidate schemes are based on a multi-layer multi-loop coding framework, exploiting inter-layer texture and motion prediction and full base layer picture decoding. Several inter-layer prediction tools have been explored, implemented either using high-level syntax or block-level core HEVC design changes. One of these tools, Generalized Residual Prediction (GRP), has been extensively studied during several meeting cycles. It is based on second order residual prediction, exploiting motion compensation prediction residual in the base layer. This paper is focused on this new mode. The principle of GRP is described with an analysis of several implementation variants completed by a complexity analysis. Performance of these different implementations is provided, showing that noticeable gains can be obtained without significant complexity increase compared to a simple scalable design comprising only texture and motion inter-layer prediction.