AOM Video 1 (AV1) and Versatile Video Coding (VVC) are the outcome of two recent independent video coding technology developments. Although VVC is the successor of High Efficiency Video Coding (HEVC) in the lineage of international video coding standards jointly developed by ITU-T and ISO/IEC within an open and public standardization process, AV1 is a video coding scheme that was developed by the industry consortium Alliance for Open Media (AOM) and that has its technological roots in Google's proprietary VP9 codec. This paper presents a compression efficiency evaluation for the AV1, VVC, and HEVC video coding schemes in a typical video compression application requiring random access. The latter is an important property, without which essential functionalities in digital video broadcasting or streaming could not be provided. For the evaluation, we employed a controlled experimental environment that basically follows the guidelines specified in the Common Test Conditions of the Joint Video Experts Team. As representatives of the corresponding video coding schemes, we selected their freely available reference software implementations. Depending on the application-specific frequency of random access points, the experimental results show averaged bit-rate savings of about 10–15% for AV1 and 36–37% for the VVC reference encoder implementation (VTM), both relative to the HEVC reference encoder implementation (HM) and by using a test set of video sequences with different characteristics regarding content and resolution. A direct comparison between VTM and AV1 reveals averaged bit-rate savings of about 25–29% for VTM, while the averaged encoding and decoding run times of VTM relative to those of AV1 are around 300% and 270%, respectively.

In this paper, we compare the video codecs AV1 (version 1.0.0-2242 from August 2019), HEVC (HM and x265), AVC (x264), the exploration software JEM which is based on HEVC, and the VVC (successor of HEVC) test model VTM (version 4.0 from February 2019) under two fair and balanced configurations: All Intra for the assessment of intra coding and Maximum Coding Efficiency with all codecs being tuned for their best coding efficiency settings. VTM achieves the highest coding efficiency in both configurations, followed by JEM and AV1. The worst coding efficiency is achieved by x264 and x265, even in the placebo preset for highest coding efficiency. AV1 gained a lot in terms of coding efficiency compared to previous versions and now outperforms HM by 24% BD-Rate gains. VTM gains 5% over AV1 in terms of BD-Rates. By reporting separate numbers for JVET and AOM test sequences, it is ensured that no bias in the test sequences exists. When comparing only intra coding tools, it is observed that the complexity increases exponentially for linearly increasing coding efficiency.

The standardization process for Versatile Video Coding (VVC), the next generation video coding standard, was launched in 2018, after several recent advances in video coding technologies had been investigated under the Joint Video Experts Team (JVET) of ITU-T VCEG and ISO/IEC MPEG experts. The recent standard development status (up to VVC working draft 2) shows that the VTM software, the test model for this VVC standard, can achieve over 23% average coding gain under random access configuration when compared to the HM software, the test model of HEVC standard. This paper gives a review of recently developed video coding technologies that have been either adopted into the VVC working draft as part of the standard or under further evaluation for potential inclusions.

Intra coding is an essential part of all video coding algorithms and applications. Additionally, intra coding algorithms are predestined for an efficient still image coding. To overcome limitations in existing intra coding algorithms (such as linear directional extrapolation, only one direction per block, small reference area), we propose non-linear Contour-based Multidirectional Intra Coding. This coding mode is based on four different non-linear contour models, on the connection of intersecting contours and on a boundary recall-based contour model selection algorithm. The different contour models address robustness against outliers for the detected contours and evasive curvature changes. Additionally, the information for the prediction is derived from already reconstructed pixels in neighboring blocks. The achieved coding efficiency is superior to those of related works from the literature. Compared with the closest related work, BD rate gains of 2.16% are achieved on average.

Technologies for coding non-camera-captured video contents have received great interests lately due to the rapid growth of application areas such as wireless display and screen sharing, etc. In response to the market demands, the ITU-T Video Coding Expert Group and ISO/IEC Motion Picture Expert Group have jointly launched a new standardization project, i.e. the High-Efficiency Video Coding (HEVC) extensions on screen content coding (HEVC SCC). Several new video coding tools, including intra block copy, palette coding, adaptive color transform, and adaptive motion resolution, have been developed and adopted into HEVC SCC draft standard. This paper reviews the main features and coding technologies in the current HEVC SCC draft standard, with discussions about the performance and complexity aspects compared with prior arts.

Being connected “anywhere anytime” has become a way of life for much of the world's population. Thanks to major technological advances in internet, wireless communication, video technology, silicon manufacturing, etc., our mobile devices have become not only faster and more powerful, but also smaller and sleeker. With the popularity of rich media on the rise, the no. 1 data traffic over the mobile network is attributed to video. That is the reason why we depict the Freeman Dyson's book title “From Eros to Gaia.” Equipped with rich media capabilities, our mobile devices enable a completely different storytelling experience unlike anything the human race has experienced before. In this paper, we review the latest technological evolutions in the wireless space and in the video space, namely long-term evolution and high-efficiency video coding, respectively. We then discuss how these advanced technologies impact our way of life at present and in years to come.

This paper presents a novel rate control scheme designed for the newest high efficiency video coding (HEVC) standard, and aimed at enhancing the quality of regions of interest (ROI) for a videoconferencing system. It is designed to consider the different regions at both frame level and coding tree unit (CTU) level. The proposed approach allocates a higher bit rate to the region of interest while keeping the global bit rate close to the assigned target value. The ROIs, typically faces in this application, are automatically detected and each CTU is classified in a region of interest map. This binary map is given as input to the rate control algorithm and the bit allocation is made accordingly. The algorithm is tested, first, using the initial version of the controller introduced in HEVC test model (HM.10), then, extended in HM.13. In this work, we first investigate the impact of differentiated bit allocation between the two regions using a fixed bit rate ratio in intra-coded frames (I-frames) and Bidirectionally predicted frames (B-frames). Then, unit quantization parameters (QPs) are computed independently for CTUs of different regions. The proposed approach has been compared to the reference controller implemented in HM and to a ROI-based rate control algorithm initially proposed for H.264 that we adopted to HEVC and implemented in HM.9. Experimental results show that our scheme has comparable performances with the ROI-based controller proposed for H.264. It achieves accurate target bit rates and provides an improvement in region of interest quality, both in objective metrics (up to 2 dB in PSNR) and based on subjective quality evaluation.

The new High Efficiency Video Coding (HEVC) standard achieves higher encoding efficiency when compared to its predecessors such as H.264/AVC. One of the factors responsible for this improvement is the new intra prediction method, which introduces a larger number of prediction directions resulting in an enhanced rate-distortion (RD) performance obtained at the cost of higher computational complexity. This paper proposes an algorithm to accelerate the intra mode decision, reducing the complexity of intra coding. The acceleration procedure takes into account the texture local directionality information and explores the correlation of intra modes across levels of the hierarchical tree structure used in HEVC. Experimental results show that the proposed algorithm provides a decrease of 39.22 and 43.88% in the HEVC intra prediction processing time on average, for all-intra high efficiency (AI-HE) and low complexity (AI-LC) configurations, respectively, with a small degradation in encoding efficiency (BD-PSNR loss of 0.1 dB for AI-HE and 0.8 dB for AI-LC on average).