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IEEE International Conference on Multimedia and Expo (ICME)

作者： Yang, Jing An, Bowen Shanghai Maritime Univ Coll Informat Engn Shanghai Peoples R China

ISBN: (纸本)9781612843490

In this paper, the conventional H.264 Rate Distortion (rd) optimization algorithm is extended to improve error resilience for video transmission over error-prone channels. Novel rd cost functions are derived for both motion estimation and mode decision by separating the end-to-end distortion into independent items. The modified cost functions involve additional items which are very simple and can be easily computed in a recursive way, hence low computation complexity can be achieved. Moreover, the proposed scheme maintains complete decoder compatibility and high rd performance. Extensive simulation results show that significant performance improvements are gained over compared algorithms. The computation complexity issue is also discussed.

关键词： rd optimization H.264 error resilient coding motion-compensated prediction

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HEVC Encoder optimization and Decoding Complexity-Aware Video Encoding

HEVC Encoder Optimization and Decoding Complexity-Aware Vide...

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作者： Thanuja Mallikarachchi University of Surrey

学位级别：博士

The increased demand for high quality video evidently elevates the bandwidth require- ments of the communication channels being used, which in return demands for more efficient video coding algorithms within the media distribution tool chain. As such, High Efficiency Video Coding (HEVC) video coding standard is a potential solution that demonstrates a significant coding efficiency improvement over its predecessors. HEVC constitutes an assortment of novel coding tools and features that contribute towards its superior coding performance, yet at the same time demand more compu- tational, processing and energy resources; a crucial bottleneck, especially in the case of resource constrained Consumer Electronic (CE) devices. In this context, the first contribution in this thesis presents a novel content adaptive Coding Unit (CU) size prediction algorithm for HEVC-based low-delay video encoding. In this case, two in- dependent content adaptive CU size selection models are introduced while adopting a moving window-based feature selection process to ensure that the framework remains robust and dynamically adapts to any varying video content. The experimental results demonstrate a consistent average encoding time reduction ranging from 55% – 58% and 57% – 61% with average Bjontegaard Delta Bit Rate (BDBR) increases of 1.93% – 2.26% and 2.14% – 2.33% compared to the HEVC 16.0 reference software for the low delay P and low delay B configurations, respectively, across a wide range of content types and bit rates. The video decoding complexity and the associated energy consumption are tightly coupled with the complexity of the codec as well as the content being decoded. Hence, video content adaptation is extensively considered as an application layer solution to reduce the decoding complexity and thereby the associated energy consumption. In this context, the second contribution in this thesis introduces a decoding complexity- aware video encoding algorithm for HEVC using a novel d

关键词： Video Coding HEVC CU Size Motion Classification rd optimization Decoding Complexity Decoding Energy Decoding Complexity–Rate–Distortion optimization Decoding Complexity Control Rate Control

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Steerable Discrete Cosine Transform

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IEEE TRANSACTIONS ON IMAGE PROCESSING 2017年第1期26卷 303-314页

作者： Fracastoro, Giulia Fosson, Sophie M. Magli, Enrico Politecn Torino Dept Elect & Telecommun I-10129 Turin Italy

In image compression, classical block-based separable transforms tend to be inefficient when image blocks contain arbitrarily shaped discontinuities. For this reason, transforms incorporating directional information are an appealing alternative. In this paper, we propose a new approach to this problem, namely, a discrete cosine transform (DCT) that can be steered in any chosen direction. Such transform, called steerable DCT (SDCT), allows to rotate in a flexible way pairs of basis vectors, and enables precise matching of directionality in each image block, achieving improved coding efficiency. The optimal rotation angles for SDCT can be represented as solution of a suitable rate-distortion (rd) problem. We propose iterative methods to search such solution, and we develop a fully fledged image encoder to practically compare our techniques with other competing transforms. Analytical and numerical results prove that SDCT outperforms both DCT and state-of-the-art directional transforms.

关键词： Image compression DCT graph signal processing rd optimization

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Intra Coding with Prediction Mode Information Inference

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2010年第12期20卷 1786-1796页

作者： Laroche, Guillaume Jung, Joel Pesquet-Popescu, Beatrice Canon Res Ctr France F-35517 Cesson Sevigne France Orange Labs F-92794 Issy Les Moulineaux France Telecom ParisTech F-75634 Paris France

In a typical competition-based coding, the pertinence of a prediction mode does not only depend on its own efficiency but also on the fact that it is complementary with the other modes. The method proposed in this paper to improve the intra coding of the H.264/AVC standard relies on this remark;it shows how the cost of signaling predictors that are quite similar can be avoided. Indeed, at low bitrates, the information related to the predictor signaling in intra coding reaches up to 25% of the total bitrate for the whole set of standard VCEG test sequences. In order to reduce this cost, a method reproducible at the decoder side is proposed to eliminate some predictors from the intra predictor set. The proposed method exploits the proximity of the predictors in the transform domain in order to obtain a representative and non-redundant set of predictors.

关键词： Competition-based scheme H.264/AVC intra prediction intra-1-D rd optimization

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Error Detection Scheme for the H.264/AVC using the rd Optimized Motion Vector Constraints

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IEEE TRANSACTIONS ON CONSUMER ELECTRONICS 2012年第3期58卷 955-962页

作者： Ko, Man-Geun Hong, Jang-Eui Suh, Jae-Won Chungbuk Natl Univ Dept Elect Engn Chonju South Korea Chungbuk Natl Univ Coll Elect & Comp Engn Chonju South Korea

The corruption of compressed video bitstreams during their transmission over error-prone communication channels leads to degradation in the visual quality at the decoder. In order to effectively conceal the corrupted video data an exact error detection scheme is of utmost importance. In this paper, we present a new error detection scheme for the H.264/AVC using the rd optimized motion vector constraints to improve the error detection rate. The simulation results show that the detection rate of the proposed algorithm is about 86%, although the proposed scheme brings about a small amount of bitrate increment and causes a slight decrement in the PSNR during the encoding(1).

关键词： Error detection rd optimization Motion vector constraints

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Rate-distortion-optimized predictive compression of dynamic 3D mesh sequences

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SIGNAL PROCESSING-IMAGE COMMUNICATION 2006年第9期21卷 812-828页

作者： Mueller, Karsten Smolic, Aljoscha Kautzner, Matthias Eisert, Peter Wiegand, Thomas Fraunhofer Inst Telecommun Heinrich Hertz Inst Image Proc Dept D-10587 Berlin Germany

Compression of computer graphics data such as static and dynamic 3D meshes has received significant attention in recent years, since new applications require transmission over channels and storage on media with limited capacity. This includes pure graphics applications (virtual reality, games) as well as 3DTV and free viewpoint video. Efficient compression algorithms have been developed first for static 3D meshes, and later for dynamic 3D meshes and animations. Standard formats are available for instance in MPEG-4 3D mesh compression for static meshes, and Interpolator Compression for the animation part. For some important types of 3D objects, e.g. human head or body models, facial and body animation parameters have been introduced. Recent results for compression of general dynamic meshes have shown that the statistical dependencies within a mesh sequence can be exploited well by predictive coding approaches. Coders introduced so far use experimentally determined or heuristic thresholds for tuning the algorithms. In video coding, rate-distortion (rd) optimization is often used to avoid fixed thresholds and to select the optimum prediction mode. We applied these ideas and present here an rd-optimized dynamic 3D mesh coder. It includes different prediction modes as well as an rd cost computation that controls the mode selection across all possible spatial partitions of a mesh to find the clustering structure together with the associated prediction modes. The general coding structure is derived from statistical analysis of mesh sequences and exploits temporal as well as spatial mesh dependencies. To evaluate the coding efficiency of the developed coder, comparative coding results for mesh sequences at different resolutions were carried out. (C) 2006 Elsevier B.V. All rights reserved.

关键词： 3D mesh dynamic mesh coding animation coding DPCM spatial clustering rd optimization

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Speeding up the optimisation of the Rate Distortion performance in MPEG-2 video coding through quantizer loop parametrisation

Speeding up the optimisation of the Rate Distortion performa...

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Conference on Image and Video Communications and Processing

作者： Grecos, C Saparon, A Loughborough Univ Technol Dept Elect Engn Elect Loughborough LE11 3TU Leics England

ISBN: (纸本)0819448222

A simple scheme for fast Rate Distortion optimisation based on Lagrange multipliers is presented in this paper. It's based on the observation that for accurate target rates, the change of the multiplier alone may not have an effect for small step sizes. However, a combination of small step sizes along with appropriate quantizer loop parameterisation may solve this problem thus resulting in significant computational savings since only a portion of the Rate distortion characteristics need to be considered for optimisation. Extensive experiments using quantizer loop parametrisation reveal savings between 60.14 and 92.94% for the rate bounding case and between 56.48 and 91.01% for the bisection search for a wide variety of video sequences exhibiting different characteristics.

关键词： MPEG-2 rate control rd optimization

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Dynamic Redundancy Allocation for Video Streaming using Sub-GOP based FEC Code

Dynamic Redundancy Allocation for Video Streaming using Sub-...

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IEEE Visual Communications and Image Processing Conference

作者： Yu, Li Xiao, Jimin Tillo, Tammam Xian Jiaotong Liverpool Univ Dept Elect & Elect Engn Suzhou Peoples R China

ISBN: (纸本)9781479961399

Reed-Solomon erasure code is one of the most studied protection methods for video streaming over unreliable networks. As a block-based error correcting code, large block size and increased number of parity packets will enhance its protection performance. However, for video applications this enhancement is sacrificed by the error propagation and the increased bitrate. So, to tackle this paradox, we propose a rate-distortion optimized redundancy allocation scheme, which takes into consideration the distortion caused by losing each slice and the propagated error. Different from other approaches, the amount of introduced redundancy and the way it is introduced are automatically selected without human interventions based on the network condition and video characteristics. The redundancy allocation problem is formulated as a constraint optimization problem, which allows to have more flexibility in setting the block-wise redundancy. The proposed scheme is implemented in JM14.0 for H.264, and it achieves an average gain of 1dB over the state-of-the-art approach.

关键词： RS erasure code rd optimization dynamic redundancy rate dynamic Sub-GOP allocation video streaming

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Fast intra prediction decision algorithm for the QTBT structure

Fast intra prediction decision algorithm for the QTBT struct...

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IEEE International Conference on Design and Test of Integrated Micro and Nano-Systems (DTS)

作者： Zouidi, Naima Belghith, Fatma Kessentini, Amina Masmoudi, Nouri Univ Sfax Natl Sch Engineers Elect & Informat Technol Lab Sfax Tunisia

ISBN: (纸本)9781728111285

The Joint Exploration Team JVET, created in October 2015, between ITU-T and ISO, is currently preparing the next video coding standard called Versatile Video Coding (VVC). This proposition, which is expected to be finalized by the end of 2020, is designed to address high-resolution 8k video applications and emerging applications such as 360-degree omnidirectional and High Dynamic Range (HDR) videos. The new proposition comes with different improvements, especially for the intra prediction module. An increased set of angular modes IPM (Intra Prediction Modes) was proposed to model angular textures more accurately. In addition, a new partition structure called Quadtree plus Binary Tree (QTBT) replaced the quadtree structure. These enhancements aiming at increasing the coding efficiency have led to burden coding complexity particularly in terms of coding time. In this paper, a fast intra prediction mode decision algorithm was proposed for the different QTBT binary depths. Experimental results show the effectiveness of the proposed method, which allows a complexity reduction of 56.32% with a negligible loss in video quality of -0.02 dB on average and a bite rate increase between 1% and 3%.

关键词： VVC Intra prediction rd optimization fast algorithm Complexity reduction

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Efficient rate control scheme for low bit rate H.264/AVC video coding

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The Journal of China Universities of Posts and Telecommunications 2009年第2期16卷 103-107页

作者： LI Zhi-cheng ZHANG Yong-jun LIU Tao GU Wan-yi Beijing University of Posts and Telecommunications Key Laboratory of Optical Communication and Lightwave Technologies Ministry of Education 北京 100876

This article presents an efficient rate control scheme for H.264/AVC video coding in low bit rate environment. In the proposed scheme, an improved rate-distortion (rd) model by both analytical and empirical approaches is developed. It involves an enhanced mean absolute difference estimating method and a more rate-robust distortion model. Based on this rd model, an efficient macroblock-layer rate control scheme for H.264/AVC video coding is proposed. Experimental results show that this model encodes video sequences with higher peak signal-to-noise ratio gains and generates bit stream closer to the target rate.

关键词： H.264/AVC rate control rd optimization

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