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On the efficiency of the shortened error correcting codes

INTERNATIONAL JOURNAL OF ELECTRICAL ENGINEERING EDUCATION 2013年第2期50卷 201-212页

作者： Liaperdos, I. Paraskevas, I. Potirakis, S. M. Technol Educ Inst Kalamata Dept Technol Informat & Telecommun Branch Sparta Sparta Greece Technol Educ Inst Piraeus Dept Elect Athens Greece

Shortening is a widely used technique aiming mainly to reduce the block size of an error correcting code and at the same time to enhance its efficiency. However, due to a common misapprehension, students tend to believe that maximum shortening retains maximum coding efficiency. In this work, an educational approach is presented which eliminates the aforementioned misapprehension. Specifically, the efficiency of the shortened error correcting codes is examined both theoretically and experimentally via simulations.

关键词： coding efficiency error control coding shortened codes

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Alternating asymmetric search range assignment for bidirectional motion estimation in H.265/HEVC and H.264/AVC

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JOURNAL OF VISUAL COMMUNICATION AND IMAGE REPRESENTATION 2014年第5期25卷 1275-1286页

作者： Zhou, Jinjia Zhou, Dajiang Goto, Satoshi Waseda Univ Grad Sch Informat Prod & Syst Kitakyushu Fukuoka 8080135 Japan

Bidirectional motion estimation (ME) significantly enhances video coding efficiency, whereas its huge complexity is also a critical problem for implementation. This paper presents alternating asymmetric search range assignment (AASRA) schemes to reduce the complexity by switching the use of a large and a small search ranges (SR.L and SR.S). A temporal AASRA (T-AASRA) scheme performs search range switching between past and future reference directions. A temporal-spatial AASRA (TS-AASRA) scheme performs more aggressive switching on the two dimensions of reference direction and MB/CTB index. T-AASRA and TS-AASRA achieve 43.5% and 65.2% complexity reduction, respectively, with small coding efficiency drop. Even after removing the factor of coding efficiency drop, the two schemes still show 38.4% and 54.7% equivalent complexity reduction. AASRA can also be combined with existing fast algorithms for further complexity saving, which has been demonstrated on hierarchical ME and dynamic search range selection algorithms. (C) 2014 Elsevier Inc. All rights reserved.

关键词： Motion estimation Bidirectional prediction Hardware implementation Search range Complexity reduction coding efficiency H.264/AVC HEVC

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Optimal Huffman coding Performance of Ad-Hoc Networks Based on Cross-Layer Design

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JOURNAL OF INFORMATION SCIENCE AND ENGINEERING 2020年第6期36卷 1375-1386页

作者： Mehta, Ridhima Jawaharlal Nehru Univ Sch Comp & Syst Sci New Delhi 110067 India

Effective data compression and sustainable management of limited bandwidth are the fundamental challenges in the design of current ad-hoc wireless networks. Dynamic Huffman coding protocol with optimal prefix-free codewords assigned to network parameters through cross-layer methodology can considerably address these issues for performance enhancement in these networks. In this paper, the entropy based Huffman binary and ternary coding schemes are implemented with cross-layer design in mobile ad-hoc networks. This cross-layer approach for achieving higher adaptivity incorporated four layers of the traditional networking stack. The simulation results demonstrated the performance trade-off between throughput and coding metrics for the proposed cross-layer architecture. Moreover, our proposed model exhibits substantially higher compression ratio and coding efficiency than the other existing methods through the integration of this lossless coding protocol in the developed cross-layer framework.

关键词： ad-hoc network cross-layer design Huffman coding information rate coding efficiency

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Memory Efficient Set Partitioning in Hierarchical Tree (MESH) for Wavelet Image Compression

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IEICE TRANSACTIONS ON COMMUNICATIONS 2012年第9期E95B卷 2906-2913页

作者： Ghani, Farid Kader, Abdul Khan, Ekram Ahmad, Badlishah Univ Malaysia Perlis Sch Comp & Commun Engn Kuala Perlis 02000 Perlis Malaysia Aligarh Muslim Univ Dept Elect Engn Aligarh 202002 Uttar Pradesh India

This paper presents a memory efficient version of set partitioning in hierarchical tree (SPIHT). The proposed coder called Memory Efficient SPIHT (MESH) uses a single re-usable list instead of three continuously growing linked lists as in conventional SPIHT. The list is re-initialized at the beginning of each bit-plane (coding pass) and is exhausted within the same bit-plane. Another feature of the proposed coder is that it uses a single pass for each bit-plane by merging the sorting and refinement passes of the conventional version of SPIHT. The performance of the proposed coder is measured in terms of coding efficiency, and the worst case dynamic memory requirements due to the list entries in each bit-plane. Performance comparison with SPIHT shows that the proposed coder reduces the dynamic memory requirement by about 50-70% compared to the SPIHT while retaining its coding efficiency.

关键词： coding efficiency image coding reduced memory SPIHT wavelet transform

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Efficient Parallel Framework for HEVC Motion Estimation on Many-Core Processors

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2014年第12期24卷 2077-2089页

作者： Yan, Chenggang Zhang, Yongdong Xu, Jizheng Dai, Feng Zhang, Jun Dai, Qionghai Wu, Feng Chinese Acad Sci Inst Comp Technol Key Lab Intelligent Informat Proc Beijing 100190 Peoples R China Tsinghua Univ Dept Automat Beijing 100084 Peoples R China Microsoft Res Asia Beijing 100190 Peoples R China

High efficiency Video coding (HEVC) provides superior coding efficiency than previous video coding standards at the cost of increasing encoding complexity. The complexity increase of motion estimation (ME) procedure is rather significant, especially when considering the complicated partitioning structure of HEVC. To fully exploit the coding efficiency brought by HEVC requires a huge amount of computations. In this paper, we analyze the ME structure in HEVC and propose a parallel framework to decouple ME for different partitions on many-core processors. Based on local parallel method (LPM), we first use the directed acyclic graph (DAG)-based order to parallelize coding tree units (CTUs) and adopt improved LPM (ILPM) within each CTU (DAGILPM), which exploits the CTU-level and prediction unit (PU)-level parallelism. Then, we find that there exist completely independent PUs (CIPUs) and partially independent PUs (PIPUs). When the degree of parallelism (DP) is smaller than the maximum DP of DAGILPM, we process the CIPUs and PIPUs, which further increases the DP. The data dependencies and coding efficiency stay the same as LPM. Experiments show that on a 64-core system, compared with serial execution, our proposed scheme achieves more than 30 and 40 times speedup for 1920 x 1080 and 2560 x 1600 video sequences, respectively.

关键词： coding efficiency degree of parallelism (DP) efficient parallel framework High efficiency Video coding (HEVC) many-core processors motion estimation (ME)

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Theoretical Analysis of Various Software-Defined Multiplexing Codes

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IEEE-ACM TRANSACTIONS ON NETWORKING 2019年第6期27卷 2444-2457页

作者： Sun, Elaine Y. -N. Wu, Hsiao-Chun Huang, Scott C. -H. Natl Tsing Hua Univ Dept Elect Engn Hsinchu 30013 Taiwan Louisiana State Univ Sch Elect Engn & Comp Sci Baton Rouge LA 70803 USA

How to combine multiple data-streams for transmission in aggregate is a very interesting problem, especially for the emerging software-defined networks nowadays. The conventional packet-based protocols cannot provide the flexibility for combining data-streams in the ad hoc nature. If the number of data-streams changes over time, the existing packet formats cannot handle the transmission of multiple data-streams effectively. The effectiveness is measured by two performance metrics, namely coding efficiency and data-transmission intermittency. We propose a new software-defined multiplexing code (SDMC) approach, which can combine (multiplex) multiple data-streams easily and is much more effective than the conventional packet-based method. Three SDMC schemes (distributed, hierarchical, and hybrid) are compared theoretically and by simulation. A trade-off between these two performance metrics can be found when one selects one of the three SDMC schemes for combining multiple data-streams. The hierarchical SDMC scheme brings about the highest coding efficiency while the hybrid SDMC scheme suffers from the smallest overall intermittency.

关键词： Software defined networking Encoding Data transmission Multiplexing Software-defined multiplexing code (SDMC) software-defined network (SDN) coding efficiency data-transmission intermittency

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Adaptive Intra Prediction Mode Signaling Approach in H.264/AVC

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IEICE TRANSACTIONS ON COMMUNICATIONS 2014年第9期E97B卷 1990-1999页

作者： Kim, Kibaek Jeon, Gwanggil Jeong, Jechang Hanyang Univ Dept Elect & Comp Engn Seoul 133791 South Korea Incheon Natl Univ Dept Embedded Syst Engn Inchon South Korea

H.264/AVC estimates the prediction mode from the modes of neighboring blocks in order to reduce the quantity of bits needed to represent the best mode. The estimated mode is known as Most Probable Mode (MPM). When QP changes, the probability of MPM increases. In this paper, we propose an adaptive mode signaling method based on the probability of MPM. According to the probability of MPM, a conventional MPM method and the proposed merging method are adaptively used to signal the intra prediction mode. Experimental results show that the proposed method achieves an average bit savings of 0.727% and an average PSNR gain of 0.041 dB. In the low bit rate condition, the proposed method achieves an average bit savings of 1.795%, and a PSNR gain of 0.103 dB, compared to H.264/AVC.

关键词： H.264/AVC intra prediction coding efficiency most probable mode

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Performance analysis of inter-layer prediction module for H.264/SVC

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AEU-INTERNATIONAL JOURNAL OF ELECTRONICS AND COMMUNICATIONS 2015年第1期69卷 344-350页

作者： Kessentini, Amina Samet, Amine Ben Ayed, Mohamed Ali Masmoudi, Nouri ENIS Dept Elect Engn Sfax Tunisia ISECS Dept Commun Sfax Tunisia

With the introduction of diverse variety of display resolutions and transmission channel capacities, the Joint Video Team (JVT) has developed a new scalable video coding standard (H264/SVC) as an extension of H.264/AVC. The SVC can compress numerous video sequences of various resolutions as a single bit-stream. The spatial scalability is mainly based on coding tools such as inter-layer predictions that offer a better coding efficiency. Consequently, for the enhancement layer, a thorough mode decision process based on the base layer mode predictions is performed on the Joint Scalable Video Model software implementation. In order to highlight the inter-layer's coding efficiency, several analyses were made using numerous HD sequences with different motion characteristics. In fact, in this paper we present the efficiency of different inter-layer prediction modes for spatial scalability. As a first step, analysis results show the significant role of inter-layer prediction process for coding efficiency. As a second step, role of each inter-layer prediction type is investigated. Simulations results show the important role of inter-layer intra prediction and inter-layer residual prediction when targeting a better coding efficiency. (C) 2014 Elsevier GmbH. All rights reserved.

关键词： Scalable video coding Inter-layer prediction coding efficiency

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Low-complexity feedback-channel-free distributed video coding using local rank transform

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IET IMAGE PROCESSING 2017年第2期11卷 126-134页

作者： Bhagath, Pudi Raj Mallick, Kallol Mukherjee, Jayanta Mukopadhayay, Sudipta Indian Inst Technol Dept Elect & Elect Commun Engn Kharagpur W Bengal India Azure Software Syst Ltd Kolkata India Indian Inst Technol Dept Comp Sci & Engn Kharagpur W Bengal India

In this study, the authors propose a new feedback-channel-free distributed video coding algorithm using local rank transform (LRT). The encoder computes LRT by considering selected neighbourhood pixels of Wyner-Ziv (WZ) frame. These LRT values are merged, and their positions are entropy coded and sent to the decoder. In addition, means of each block of WZ frame are also transmitted to assist motion estimation (ME). Using these measurements, the decoder generates side information (SI) by implementing ME and compensation in LRT domain. An iterative algorithm is executed on SI using LRT to reconstruct the WZ frame. Experimental results show that the coding efficiency of the authors' codec is close to the efficiency of pixel domain distributed video coders based on low-density parity check and accumulate or turbo codes, with less encoder and decoder complexity.

关键词： video coding entropy codes turbo codes transforms motion estimation image resolution image reconstruction parity check codes turbo code accumulate code low-density parity check code pixel domain distributed video coders coding efficiency side information generation motion estimation WZ frame reconstruction Wyner-Ziv frame neighbourhood pixels LRT computation local rank transform low-complexity feedback-channel-free distributed video coding algorithm

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Highly Efficient Video Codec for Entertainment-Quality

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ETRI JOURNAL 2011年第2期33卷 145-154页

作者： Jeong, Seyoon Lim, Sung-Chang Lee, Hahyun Kim, Jongho Choi, Jin Soo Choi, Haechul Hanbat Natl Univ Div Informat Commun & Comp Engn Taejon South Korea ETRI Broadcasting & Telecommun Convergence Res Lab Broadcasting & Telecommun Media Res Dept Taejon South Korea

We present a novel video codec for supporting entertainment-quality video. It has new coding tools such as an intra prediction with offset, integer sine transform, and enhanced block-based adaptive loop filter. These tools are used adaptively in the processing of intra prediction, transform, and loop filtering. In our experiments, the proposed codec achieved an average reduction of 13.35% in BD-rate relative to H.264/AVC for 720p sequences.

关键词： Video coding H.264/AVC coding efficiency

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