High Dynamic Range Video Coding Research Articles

A NOVEL METHOD FOR HDR VIDEO ENCODING, COMPRESSION AND QUALITY EVALUATION

The high dynamic range imaging/video has become more prominent in the consumer electronic realm as the it allows the human to view a picture e or a video at a minimum eye adaption. The high dynamic ranging is capable enough to capture a full range light from the scene unlike the traditional methods that captures only 8-f-stops. Though the high dynamic range video are produced using more standard methodologies, it still needs continuous developments in the distribution phase. so the paper discourses the shortcomings in the present method of high dynamic range video coding and puts forth the novel method of two layered backward compatible video encoding methods accompanied by the Chroma subsampling and the luminance masking to improve the color accuracy and remove the nonvisible portion respectively of the video content. The performance measurement of the novel method HDR video encoding compression (N-HVEC) in term of mean opinion source, bit rate savings and he HDR-VQM metric is compared with the HDR10 and HDR-HLG

High Dynamic Range Video Coding Technology in Responses to the Joint Call for Proposals on Video Compression With Capability Beyond HEVC

The ITU-T Video Coding Experts Group and the ISO/IEC Moving Picture Experts Group issued a Call for Proposals (CfP) on video compression with capability beyond HEVC in October 2017. The CfP considered three categories of content – Standard Dynamic Range, High Dynamic Range and Wide Colour Gamut (HDR/WCG), and 360° Omni-directional video. As a result of the CfP process, the development of a new video coding standard, named Versatile Video Coding (VVC), was initiated. The goal of this paper is to provide an overview of the CfP responses for the HDR/WCG category. The paper includes a summary of work leading to the development of the CfP, a presentation of the CfP results for the HDR/WCG category, and a description of the specific HDR/WCG technologies submitted to the CfP.

Pipelines for HDR Video Coding Based on Luminance Independent Chromaticity Preprocessing

We consider the chromaticity in high dynamic range (HDR) video coding and show the advantages of a constant luminance color space for encoding. For this, we introduce two constant luminance HDR video coding pipelines, which convert the source video to linear $Y u^\prime v^\prime $ . A content dependent scaling of the chromaticity components serves as color quality parameter. This reduces perceivable color artifacts while remaining fully compatible with core High Efficiency Video Coding or other video coding standards. One of the pipelines further combines the scaling with a dedicated chromaticity transform to optimize the representation of the chromaticity components for encoding. We validate both pipelines with subjective user studies in addition to an objective comparison to the other state-of-the-art methods. The user studies show a significant improvement in perceived color quality at medium to high compression rates without sacrificing luminance quality compared with current standard coding pipelines. The objective evaluation suggests that both pipelines perform at least comparable to the current state-of-the-art methods.

A 4K/60p HEVC Real-Time Encoding System With High Quality HDR Color Representations

This paper describes a 4K/60p high efficiency video coding (HEVC, the latest coding standard) real-time encoding system with high quality high dynamic range (HDR) color representations. The HDR technology provides attractive video contents with a wider dynamic range of luminance, which can make shadows and brighter details appear clearly without any blown out highlights or blocked up shadows. We propose a new rate control method for HDR video coding. The method consists of two algorithms for improving perceptual quality by reducing degradation of HDR-specific color artifacts. The first one, adaptive block size and prediction mode decision, is conducted to suppress perceptual degradation due to prediction error in high chroma areas. The second, local quantization parameter control, is carried out to improve the visual quality with appropriate bit allocation in low chroma areas. The method was implemented in an HEVC real-time encoding system and its performance was assessed by measuring the color difference metrics by 3.86% at the most degraded frame, while peak signal-to-noise ratio remained almost the same. The subjective quality of the decoded HDR images was improved by reducing color artifacts.

Visual perception based rate distortion optimization method for high dynamic range video coding

In view of the drastic increase of storage resources and transmission bandwidth requirement for high dynamic range (HDR) video compared to the traditional low dynamic range (LDR) video, we propose a dynamic rate distortion optimization algorithm based on visual perception for HDR Video encoding to improve the performance of high efficiency video coding (HEVC) Main 10 for coding HDR video. With the information of visual selective attention, we design a non-uniform distortion weight distribution strategy to different regions of interest and improve the conventional method of distortion calculation. At the same time, in order to further eliminate the perceptive redundancy in HDR video coding, the texture characteristics of video content are used to adjust Lagrange multipliers adaptively, which is applied to the encoder to dynamically adjust the quantization parameters to realize reasonably the trade-off between coded bits and distortion perception. The experimental results show that the proposed algorithm can save an average of 7.46% and 6.53% bitrate with the same HDR-visible difference predictor-2.2(HDR-VDP-2.2) and PSNR_DE compared with HEVC Main 10, saving the maximum of 18.52 % and 11.49% respectively. The proposed algorithm can effectively reduce the consumption of the overall bitrates and still maintain the visual quality of the reconstructed HDR video.

Improved High Dynamic Range Video Coding with a Nonlinearity Based on Natural Image Statistics

Improved High Dynamic Range Video Coding with a Nonlinearity Based on Natural Image Statistics

Visual assessment of HDR video

The future of Multimedia can be depicted in a scenario where almost all the fruition of audiovisual content will be delivered to the final user by means of streaming over any kind of transmission media. This migration towards streaming will change drastically most of today's scenarios, ranging from TV receivers down to any kind of mobile terminals, including 5G devices. On the other side the content itself will be of better quality; in fact it will be in HD and UHD format, it will be scalable and it will also use a Wider Color Gamut (WCG) and High Dynamic Range (HDR), to improve the User Experience. Furthermore the users will be able to access the Broadcasting services (i.e. TV) also through the new generation 4G/5G networks. This paper deals with the formal subjective assessment evaluation of WCG and HDR video content, and it is located in the framework of the standardization activities of MPEG (ISO-JEC/SC29/WG11) that, together with ITU-T (through the joint committee JCTVC) is active in the definition of new technologies for WCG and HDR video coding. Here the results of the comparison between a new test method designed to evaluate HDR video content, i.e. the HDR-Side By Side (HDRSBS), and a classic subjective video test method, the DCR (Degradation Category Rating), are described. The new HDR-SBS test method, was designed to evaluate HDR and WCG video material produces by the Submissions made in response to the Call for Evidence (CfE) recently issued by MPEG [1]; the HDR-SBS method is basically a category rating method based on a side-byside approach. The paper demonstrates that, despite the effort made by MPEG to design a new test method devoted to the assessment of HDR content, and despite what suggested in other papers describing similar tests [2] [3] [6], the DCR method shows better performances. Furthermore the DCR test method results to be less stressing for the human subjects participating to a formal subjective assessment experiment.

Methods for improving the tone mapping for backward compatible high dynamic range image and video coding

Backward compatibility for high dynamic range image and video compression forms one of the essential requirements in the transition phase from low dynamic range (LDR) displays to high dynamic range (HDR) displays. In a recent work [1], the problems of tone mapping and HDR video coding are originally fused together in the same mathematical framework, and an optimized solution for tone mapping is achieved in terms of the mean square error (MSE) of the logarithm of luminance values. In this paper, we improve this pioneer study in three aspects by considering its three shortcomings. First, the proposed method [1] works over the logarithms of luminance values which are not uniform with respect to Human Visual System (HVS) sensitivity. We propose to use the perceptually uniform luminance values as an alternative for the optimization of tone mapping curve. Second, the proposed method [1] does not take the quality of the resulting tone mapped images into account during the formulation in contrary to the main goal of tone mapping research. We include the LDR image quality as a constraint to the optimization problem and develop a generic methodology to compromise the trade-off between HDR and LDR image qualities for coding. Third, the proposed method [1] simply applies a low-pass filter to the generated tone curves for video frames to avoid flickering during the adaptation of the method to the video. We instead include an HVS based flickering constraint to the optimization and derive a methodology to compromise the trade-off between the rate-distortion performance and flickering distortion. The superiority of the proposed methodologies is verified with experiments on HDR images and video sequences.