Rickard Sjöberg

High Performance, Low Complexity Video Coding and the Emerging HEVC Standard

This paper describes a low complexity video codec with high coding efficiency. It was proposed to the high efficiency video coding (HEVC) standardization effort of moving picture experts group and video coding experts group, and has been partially adopted into the initial HEVC test model under consideration design. The proposal utilizes a quadtree-based coding structure with support for macroblocks of size 64 × 64, 32 × 32, and 16 × 16 pixels. Entropy coding is performed using a low complexity variable length coding scheme with improved context adaptation compared to the context adaptive variable length coding design in H.264/AVC. The proposals interpolation and deblocking filter designs improve coding efficiency, yet have low complexity. Finally, intra-picture coding methods have been improved to provide better subjective quality than H.264/AVC. The subjective quality of the proposed codec has been evaluated extensively within the HEVC project, with results indicating that similar visual quality to H.264/AVC High Profile anchors is achieved, measured by mean opinion score, using significantly fewer bits. Coding efficiency improvements are achieved with lower complexity than the H.264/AVC Baseline Profile, particularly suiting the proposal for high resolution, high quality applications in resource-constrained environments.

Overview of HEVC High-Level Syntax and Reference Picture Management

The increasing proportion of video traffic in telecommunication networks puts an emphasis on efficient video compression technology. High Efficiency Video Coding (HEVC) is the forthcoming video coding standard that provides substantial bit rate reductions compared to its predecessors. In the HEVC standardization process, technologies such as picture partitioning, reference picture management, and parameter sets are categorized as “high-level syntax.” The design of the high-level syntax impacts the interface to systems and error resilience, and provides new functionalities. This paper presents an overview of the HEVC high-level syntax, including network abstraction layer unit headers, parameter sets, picture partitioning schemes, reference picture management, and supplemental enhancement information messages.

Low complexity video coding and the emerging HEVC standard

This paper describes a low complexity video codec with high coding efficiency. It was proposed to the High Efficiency Video Coding (HEVC) standardization effort of MPEG and VCEG, and has been partially adopted into the initial HEVC Test Model under Consideration design. The proposal utilizes a quad-tree structure with a support of large macroblocks of size 64×64 and 32×32, in addition to macroblocks of size 16×16. The entropy coding is done using a low complexity variable length coding based scheme with improved context adaptation over the H.264/AVC design. In addition, the proposal includes improved interpolation and deblocking filters, giving better coding efficiency while having low complexity. Finally, an improved intra coding method is presented. The subjective quality of the proposal is evaluated extensively and the results show that the proposed method achieves similar visual quality as H.264/AVC High Profile anchors with around 50% and 35% bit rate reduction for low delay and random-access experiments respectively at high definition sequences. This is achieved with less complexity than H.264/AVC Baseline Profile, making the proposal especially suitable for resource constrained environments.

Dependent random access point pictures in HEVC

This paper describes the concept and a number of system aspects for the Dependent Random Access Point (DRAP) picture, a new feature that was recently introduced in the High-Efficiency Video Coding (HEVC) standard. A DRAP picture is an inter-coded picture that may only reference the previous Intra Random Access Point (IRAP) picture and provides a random access point in the bitstream at the DRAP picture given that the IRAP picture is available. The DRAP picture is indicated in the HEVC bitstream by a supplementary enhancement indication (SEI) message. DRAP pictures could increase coding efficiency for random access configured bitstreams for video services like adaptive video streaming, video conferencing, and may also provide faster channel switching for broadcasted TV for a certain bitrate.

Guided Transcoding Using Deflation and Inflation

This paper analyzes and improves an existing guided transcoding scheme called deflation and inflation. By adding three new coding tools, required storage is reduced by 4.2 percentage points on a test set defined by the Moving Picture Experts Group. The first tool predicts coefficient signs, the second tool reorders coefficients using a dynamic scanning order, and the third tool uses new contexts for the binary coder to encode whether coefficients are non-zero or not. All three tools are based on a new method for estimating the likelihood of a coefficient being non-zero. Furthermore, the paper introduces a modified test configuration using a fast transcoder based on the x265 encoder for comparisons. Using this configuration, the three proposed tools provide a storage reduction of 4.4 percentage points with a transcoding complexity of around 5% of a transcoder based on x265.

Analysis of H.264/AVC Scalable Video Coding for Video Delivery to Heterogeneous Terminals

In 2007, the ITU-T H.264 | ISO/IEC MPEG-4 AVC standard was extended to support temporal, spatial and fidelity (SNR) scalability in a framework that is referred to as Scalable Video Coding (SVC). Since the development of this SVC extension, its use has been proposed for several applications. It seems however there is not yet a broadly agreed understanding about the benefits of SVC compared to non-scalable coding. In this paper, we describe coding efficiency gain and cost measures for scalable video against non-scalable simulcast, and single layer non-scalable coding, respectively, in the context of video delivery to heterogeneous terminals. Our results show that the cost and gain from SVC are strongly dependent on the application and conditions. Specifically, it is shown that while SVC can theoretically provide promising gain in some applications, its cost is not negligible and in some cases this cost can outweigh the gain.