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Multimedia selective encryption by means of randomized arithmetic coding

IEEE TRANSACTIONS ON MULTIMEDIA 2006年第5期8卷 905-917页

作者： Grangetto, Marco Magli, Enrico Olmo, Gabriella CERCOM Dipartimento Elettr Politecn Torino I-10129 Turin Italy

We propose a novel multimedia security framework based on a modification of the arithmetic coder, which is used by most international image and video coding standards as entropy coding stage. In particular, we introduce a randomized arithmetic coding paradigm, which achieves encryption by inserting some randomization in the arithmetic coding procedure;notably, and unlike previous works on encryption by arithmetic coding, this is done at no expense in terms of coding efficiency. The proposed technique can be applied to any multimedia coder employing arithmetic coding;in this paper we describe an implementation tailored to the JPEG 2000 standard. The proposed approach turns out to be robust towards attempts to estimating the image or discovering the key, and allows very flexible protection procedures at the code-block level, allowing to perform total and selective encryption, as well as conditional access.

关键词： arithmetic coding conditional access JPEG 2000 selective encryption

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Concurrency techniques for arithmetic coding in JPEG2000

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS I-REGULAR PAPERS 2006年第6期53卷 1203-1213页

作者： Dyer, Michael Taubman, David Nooshabadi, Saeid Gupta, Amit Kumar Univ New S Wales Sydney NSW 2052 Australia

JPEG2000 is a recently standardized image compression algorithm. The heart of this algorithm is the coding scheme known as embedded block coding with optimal truncation (EBCOT). This contributes the majority of processing time to the compression algorithm. The EBCOT scheme consists of a bit-plane coder coupled to a MQ arithmetic coder. Recent bit-plane coder architectures are capable of producing symbols at a higher rate than the existing MQ arithmetic coders can absorb. Thus, there is a requirement for a high throughput MQ arithmetic coder. We examine the existing MQ arithmetic coder architectures and develop novel techniques capable of absorbing the high symbol rate from high performance bit-plane coders, as well as providing flexible design choices.

关键词： arithmetic coding image compression JPEG2000

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An optimized context-based adaptive binary arithmetic coding algorithm in progressive H.264 encoder

An optimized context-based adaptive binary arithmetic coding...

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Conference on Visual Information Processing XV

作者： Xiao, guang Shi, xu-li An, ping yang-Zhang, zhao Gao, ge Teng, guo-wei Shanghai Univ Sch Commun & Informat Engn Shanghai 200072 Peoples R China Minist Educ Key Lab Adv Displays & Syst Applicat Shanghai 200072 Peoples R China Shanghai Municipal Educ Examinat Author 500 South Qinzhou Rd Shanghai 200235 Peoples R China Shanghai Univ Engn Sci Shanghai Peoples R China SVA GRP Co Ltd Cent Res Acad Shanghai Peoples R China

ISBN: (纸本)0819463027

Context-based Adaptive Binary arithmetic coding (CABAC) is a new entropy coding method presented in H.264/AVC that is highly efficient in video coding. In the method, the probability of current symbol is estimated by using the wisely designed context model, which is adaptive and can approach to the statistic characteristic. Then an arithmetic coding mechanism largely reduces the redundancy in inter-symbol. Compared with UVLC method in the prior standard, CABAC is complicated but efficiently reduce the bit rate. Based on thorough analysis of coding and decoding methods of CABAC, This paper proposed two methods, sub-table method and stream-reuse methods, to improve the encoding efficiency implemented in H.264 JM code. In JM, the CABAC function produces bits one by one of every syntactic element. Multiplication operating times after times in the CABAC function lead to it inefficient. The proposed algorithm creates tables beforehand and then produce every bits of syntactic element. In JM, intra-prediction and inter-prediction mode selection algorithm with different criterion is based on RDO(rate distortion optimization) model. One of the parameter of the RDO model is bit rate that is produced by CABAC operator. After intra-prediction or inter-prediction mode selection, the CABAC stream is discard and is recalculated to output stream. The proposed Stream-reuse algorithm puts the stream in memory that is created in mode selection algorithm and reuses it in encoding function. Experiment results show that our proposed algorithm can averagely speed up 17 to 78 MSEL higher speed for QCIF and CIF sequences individually compared with the original algorithm of JM at the cost of only a little memory space. The CABAC was realized in our progressive h.264 encoder.

关键词： arithmetic coding video coding context modeling H.264 CABAC

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Parameter Selection for Wyner-Ziv coding of Laplacian Sources with Additive Laplacian or Gaussian Innovation

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IEEE TRANSACTIONS ON SIGNAL PROCESSING 2009年第8期57卷 3208-3225页

作者： Mukherjee, Debargha Hewlett Packard Labs Palo Alto CA 94304 USA

A large number of practical coding scenarios deal with sources such as transform coefficients that can be well modeled as Laplacians. For regular coding of such sources, samples are often quantized by a family of uniform quantizers possibly with a dead-zone, and then entropy coded. For the Wyner-Ziv coding problem when correlated side-information is available at the decoder, the side-information can be modeled as obtained by independent additive Laplacian or Gaussian innovation on the source. This paper deals with optimal choice of parameters for practical Wyner-Ziv coding in such scenarios, using the same quantizer family as in the regular codec to cover a range of rate-distortion tradeoffs, given the variances of the source and additive noise. We propose and analyze a general encoding model based on multilevel coset codes that combines source coding and channel coding and show that at practical block lengths and code complexities, not pure channel coding but a hybrid combination of source coding and channel coding with right parameters provide optimal rate-distortion performance. We also provide a framework for on-the-fly parameter choice based on non-parametric representation of a set of seed functions, for use in scenarios where variances are estimated during encoding. A good insight in the optimal parameter selection mechanism is essential for building practical distributed codecs.

关键词： arithmetic coding channel coding distributed source coding Laplacian distribution optimal reconstruction rate-distortion analysis systematic repeat accumulate codes

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coding theory

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WILEY INTERDISCIPLINARY REVIEWS-COMPUTATIONAL STATISTICS 2009年第3期1卷 261-270页

作者： Stine, Robert A. Univ Penn Dept Stat Philadelphia PA 19104 USA

coding theory is a portion of information theory concerned with the explicit representation of data as a sequence of symbols, usually a sequence of bits. The entropy of a probability distribution measures the information content of data, giving a lower bound on the number of bits necessary to encode data. Source coding also defines a measure, the divergence, of the cost of using a suboptimal representation. Channel coding describes representations that maximize the rate at which information can be communicated through a noisy medium. Important applications of coding theory include data compression, signal processing, and the comparison of statistical models. (C) 2009 John Wiley & Sons, Inc.

关键词： arithmetic coding divergence entropy mutual information universal code

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Context-based entropy coding in AVS video coding standard

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SIGNAL PROCESSING-IMAGE COMMUNICATION 2009年第4期24卷 263-276页

作者： Zhang, Li Wang, Qiang Zhang, Ning Zhao, Debin Wu, Xiaolin Gao, Wen Chinese Acad Sci Inst Comp Technol Key Lab Intelligent Informat Proc Beijing Peoples R China Harbin Inst Technol Dept Comp Sci & Engn Harbin 150006 Peoples R China McMaster Univ Dept Elect & Comp Engn Hamilton ON L8S 4L8 Canada Peking Univ Sch Elect Engn & Comp Sci Inst Digital Media Beijing 100871 Peoples R China

In this paper, two context-based entropy coding schemes for AVS Part-2 video coding standard are presented. One is Context-based 2D Variable Length coding (C2DVLC) as a low complexity entropy coding scheme for AVS Part-2 Jizhun profile. C2DVLC uses Multiple 2D-VLC tables to exploit the statistical features of DCT coefficients for higher coding efficiency. Exponential-Golomb codes are applied in C2DVLC to code the pairs of the run-length of zero coefficients and the non-zero coefficients for lower storage requirement. The other is Context-based Binary arithmetic coding (CBAC) as an enhanced entropy coding scheme for AVS Part-2 Jiaqiang profile. CBAC utilizes all previously coded coefficient magnitudes in a DCT block for context modeling. This enables adaptive arithmetic coding to exploit the redundancy of the high-order Markov process in DCT domain with a few contexts. In addition, a context weighting technique is used to further improve CBAC's coding efficiency. Moreover, CBAC is designed to be compatible to C2DVLC in coding elements which simplifies the implementations. The experimental results demonstrate that both C2DVLC and CBAC can achieve comparable or even slightly higher coding performance when compared to Context-Adaptive Variable Length coding (CAVLC) in H.264/AVC baseline profile and Context-Based Adaptive Binary arithmetic coding (CABAC) in H.264/AVC main profile respectively. (C) 2009 Elsevier B.V. All rights reserved.

关键词： AVS DCT video coding Entropy coding Context modeling Variable length coding arithmetic coding

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Single-rate near lossless compression of animated geometry

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COMPUTER-AIDED DESIGN 2009年第10期41卷 711-718页

作者： Amjoun, Rachida Strasser, Wolfgang Univ Tubingen WSI GRIS Tubingen Germany

Representing mesh geometry in local rather than the world coordinate systems is very useful in many 3D animation processing applications. One can investigate the representation of vertex locations relative to a local coordinate frame (LCF) in the compression of dynamic 3D meshes. Unlike the world coordinates, which scatter in a wide range and show non-linear behavior of the vertices, the local coordinates exhibit a large clustering behavior of the vertex over time. This property is very useful for exploiting a large coherence over the vertex trajectory and between neighboring vertices. In this paper, we discuss the use of the LCF in static and animated mesh encoding and we introduce a new connectivity-guided predictive scheme for single-rate compression for animated meshes. The proposed geometry encoding strategy is based on a region growing encoding order, and only the differences between original and predicted locations are encoded in a local coordinate system, which splits into two tangential and one normal components. The approach is simple, efficient, and well-suited for real time applications. (C) 2009 Elsevier Ltd. All rights reserved.

关键词： 3D mesh Animation Local coordinates Quantization arithmetic coding

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Lossless Compression of Microarray Images Using Image-Dependent Finite-Context Models

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IEEE TRANSACTIONS ON MEDICAL IMAGING 2009年第2期28卷 194-201页

作者： Neves, Antonio J. R. Pinho, Armando J. Univ Aveiro Signal Proc Lab DETI IEETA P-3810193 Aveiro Portugal

The use of microarray expression data in state-of-the-art biology has been well established. The widespread adoption of this technology, coupled with the significant volume of data generated per experiment, in the form of images, has led to significant challenges in storage and query retrieval. In this paper, we present a lossless bitplane-based method for efficient compression of microarray images. This method is based on arithmetic coding driven by image-dependent multibitplane finite-context models. It produces an embedded bitstream that allows progressive, lossy-to-lossless decoding. We compare the compression efficiency of the proposed method with three image compression standards (JPEG2000, JPEG-LS, and JBIG) and also with the two most recent specialized methods for microarray image coding. The proposed method gives better results for all images of the test sets and confirms the effectiveness of bitplane-based methods and finite-context modeling for the lossless compression of microarray images.

关键词： arithmetic coding finite-context modeling image coding standards lossless image compression microarray images

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Improved Sequential MAP Estimation of CABAC Encoded Data with Objective Adjustment of the Complexity/Efficiency Tradeoff

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IEEE TRANSACTIONS ON COMMUNICATIONS 2009年第7期57卷 2014-2023页

作者： Jamaa, Salma Ben Kieffer, Michel Duhamel, Pierre Univ Paris Sud Supelec CNRS LSS F-91192 Gif Sur Yvette France

This paper presents an improved sequential MAP estimator to be used as a joint source-channel decoding technique for CABAC encoded data. The decoding process is compatible with realistic implementations of CABAC in standards like H.264, Le, handling adaptive probabilities, context modeling and integer arithmetic coding. Soft-input decoding is obtained using an improved sequential decoding technique, which allows to obtain a tradeoff between complexity and efficiency. The algorithms are simulated in a context reminiscent of H264. Error detection is realized by exploiting on one side the properties of the binarization scheme and on the other side the redundancy left in the code string. As a result, the CABAC compression efficiency is preserved and no additional redundancy is introduced in the bit stream. Simulation results outline the efficiency of the proposed techniques for encoded data sent over AWGN and UMTS-OFDM channels.

关键词： arithmetic coding joint source-channel decoding MAP estimation sequential decoding

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Simple lossless preprocessing algorithms for text compression

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IET SOFTWARE 2009年第1期3卷 37-45页

作者： Robert, L. Nadarajan, R. Govt Arts Coll Dept Comp Sci Coimbatore Tamil Nadu India PSG Coll Technol Dept Comp Applicat Coimbatore Tamil Nadu India

Lossless data compression researchers have developed highly sophisticated approaches, such as Huffman encoding, arithmetic coding, the Lempel-Ziv family, prediction by partial matching and Burrow-Wheeler transform based algorithms. One approach for attaining better compression is to develop generic, reversible transformation that can be applied to a source text that improves an existing compression algorithm's ability to compress. A few reversible transformation techniques that give better compression ratios are presented. A method, which transforms a text file into intermediate file with minimum possible byte values, is proposed. An attempt has been made to reduce the number of possible bytes that appear after every byte in the source file. This increases backend algorithm's compression performance.

关键词： lossless data compression Lempel-Ziv family text compression data compression arithmetic coding arithmetic codes transform coding Huffman codes lossless preprocessing algorithms text analysis Burrow-Wheeler transform Document processing techniques Huffman encoding

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