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mpeg coding performance improvement by jointly optimizing coding mode decisions and rate control

IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 1997年第3期7卷 449-458页

作者： Sun, HF Kwok, W Chien, M Ju, CHJ DAVID SARNOFF RES CTR PRINCETONNJ 08543 C CUBE MICROSYST MILPITASCA 95053

This paper presents a new algorithm for determining the optimal mpeg [1] coding strategy in terms of the selection of macroblock coding modes and quantizer scales. In the algorithm proposed in the Test Model [2] the rate control operates independently from the coding mode selection for each macroblock, The coding mode is decided based only upon the energy of predictive residues. Actually, the two processes of coding mode decision and rate control are intimately related to each other and should be determined jointly in order to achieve optimal coding performance, We formulate the constrained optimization problem and present solutions based upon rate-distortion characteristics, or R(D) curves, for all the macroblocks that compose the picture being coded, Distortion for the entire picture is assumed to be decomposable and expressible as a function of individual macroblock distortions, with this being the objective function to minimize. The determination of the optimal solution is complicated by the mpeg differential encoding of motion vectors and de coefficients, which introduce dependencies that carry over from macroblock to macroblock for a duration equal to the slice length. As an approximation, a near-optimum greedy algorithm is proposed, Once the upper bound in performance is calculated, it can be used to assess how well practical suboptimum methods perform. Finally, such a practical suboptimum algorithm is proposed and evaluated.

关键词： mpeg coding video compression

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Computational-complexity scalable motion estimation for mobile mpeg encoding

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IEEE TRANSACTIONS ON CONSUMER ELECTRONICS 2004年第1期50卷 281-291页

作者： Mietens, S de With, PHN Hentschel, C Philips Res Labs NL-5656 AA Eindhoven Netherlands Eindhoven Univ Technol LogicaCMG NL-5600 MB Eindhoven Netherlands Cottbus Univ Technol D-03044 Cottbus Germany

Complexity scalability algorithms are important for mobile consumer devices using mpeg video coding, because they offer a trade-off between picture quality and the embedded available computational performance. This paper presents a new scalable three-stage motion estimation technique, which includes preprocessing of frames in display order and approximation of motion-vector fields using multiple temporal references. A quality refinement of the approximation is added as an optional stage. Furthermore, we present a new scalable motion-estimation algorithm, based on simple edge detection, for integration into the above-mentioned new three-stage motion estimation technique. The complete system provides a flexible framework with a large scalability range in computational effort, resulting in an output quality that scales up smoothly with the number of operations spent on the motion estimation process. Experiments show a scalable computational effort from below one SAD (sum of absolute difference) computation per macroblock up to 15 SAD computations, resulting in a global variation of 7.4 dB PSNR in picture quality (with the "Stefan" sequence). In high-quality operation, the new algorithm is comparable to (Or even outperforms) a full-search motion estimation with a search window of 32x32 pixels.

关键词： complexity scalable motion estimation mpeg coding mobile

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Adaptive anisotropic filtering (AAF) for real-time visual enhancement of mpeg-Coded video sequences

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 2002年第5期12卷 285-298页

作者： Atzori, L De Natale, GB Granelli, F Univ Cagliari Dept Elect & Elect Engn I-09123 Cagliari Italy Univ Trent DIT Dept Informat & Commun Technol I-38050 Trent Italy

Current standards for video compression achieve good performances in decoded signal. Nevertheless, there are some known problems concerning the visual quality of reconstructed images, which can be partially solved using appropriate post-processing algorithms. The paper proposes a new adaptive anisotropic filter (AAF) that aims to unify the treatment of different sources of perceptive distortion in mpeg sequences. The process is driven by a local classification of blocks and single pixels of decoded frames, taking into account several parameters (distribution of DCT coefficient energy, presence of sharp variations, spatial position of DCT block boundaries). Experimental results show that the proposed algorithm outperforms existing enhancement approaches, in particular when constraints on complexity and real-time processing are compelling.

关键词： compression artifacts FIR filtering mpeg coding video post-processing

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Near-lossless complexity-scalable embedded compression algorithm for cost reduction in DTV receivers

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IEEE TRANSACTIONS ON CONSUMER ELECTRONICS 2000年第4期46卷 923-933页

作者： van der Schaar, M de With, PHN Philips Res Briarcliff Briarcliff Manor NY 10510 USA Univ Mannheim Fac Comp Engn Mannheim Germany

This paper presents a novel complexity-scalable technique to reduce the memory costs of an mpeg-P decoder by a factor of four to six, by recompressing the I- and P-reference pictures prior to motion-compensated reconstruction. The proposed scheme features some unique characteristics, like robustness for multiple encodings and high memory and memory-bandwidth reduction factors. At the same time, the near-lossless quality obtained is preserved, independently of the ratio between the input and display resolution and transmission/storage bit-rates, because no interference between the memory reduction algorithm and the mpeg-2 decoder occurs. Due to the inherent scalability of the presented algorithm, trade-offs between memory, silicon costs or over-all system costs, and image quality can be easily made. The proposed embedded compression algorithm can also be used for memory and memory-bandwidth reduction in alternative systems, like video coding ICs (e.g. mpeg-4) and memory intensive image processing ICs (e.g. de-interlacing and 100-Hz conversion).

关键词： video compression mpeg coding memory reduction memory-bandwidth reduction DTV receivers embedded memory compression scalable complexity compression techniques

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Error concealment algorithms for robust decoding of mpeg compressed video

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SIGNAL PROCESSING-IMAGE COMMUNICATION 1997年第4期10卷 249-268页

作者： Sun, HF Zdepski, JW Kwok, W Raychaudhuri, D THOMSON SUN INTERACT ALLIANCE MT VIEWCA 94043 C CUBE MICROELECT SAN JOSECA NEC USA C&C RES LABSPRINCETONNJ 08540

This paper provides some research results on the topic of error resilience for robust decoding of mpeg (Moving Picture Experts Group) compressed video. It introduces and characterizes the performance of a general class of error concealment algorithms. Such receiver-based error concealment techniques are essential for many practical video transmission scenarios such as terrestrial HDTV broadcasting, packet network based teleconferencing/multimedia, and digital SDTV/HDTV delivery via ATM (asynchronous transfer mode). Error concealment is intended to ameliorate the impact of channel impairments (i.e., bit-errors in noisy channels, or cell-loss in ATM networks) by utilizing available picture redundancy to provide a subjectively acceptable rendition of affected picture regions. The concealment process must be supported by an appropriate transport format which helps to identify image pixel regions which correspond to lost or damaged data. Once the image regions (i.e., macroblocks, slices, etc.) to be concealed are identified, a combination of spatial and temporal replacement techniques may be applied to fill in lost picture elements. A specific class of spatio-temporal error concealment algorithms for mpeg video is described and alternative realizations are compared via detailed end-to-end simulations for both one-or two-tier transmission media. Several algorithm enhancements based on directional interpolation, 'I-picture motion vectors', and use of mpeg-2 'scalability' features are also presented. In each case, achievable performance improvements are estimated via simulation. Overall, these results demonstrate that the proposed class of error concealment algorithms provides significant robustness for mpeg video delivery in the presence of channel impairments, permitting useful operation at ATM cell-loss rates in the region of 10(-4) to 10(-3) and 10(-2) to 10(-1) for one-and two-tier transmission scenarios, respectively. (C) 1997 Elsevier Science B.V.

关键词： mpeg coding mpeg compressed video error resilience error concealment

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A bandwidth assignment algorithm on a satellite channel for VBR traffic

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INTERNATIONAL JOURNAL OF SATELLITE COMMUNICATIONS 1997年第6期15卷 237-246页

作者： Celandroni, N Conti, M Ferro, E Gregori, E Potorti, F CNR CNUCE Inst I-56126 Pisa Italy

Variable bit rate (VBR) video is currently by far the most interesting and challenging real-time application. A VER encoder attempts to keep the quality of video output constant and at the same time reduces bandwidth requirements, since only a minimum amount of information has to be transferred. On the other hand, as VER video traffic is both highly variable and delay-sensitive, high-speed networks (e.g. ATM) are generally implemented by assigning peak rate bandwidths to VER video applications. This approach may, however, be inefficient in a satellite network based on a TDMA scheme. To overcome this problem, we have designed a demand assignment satellite bandwidth allocation algorithm in TDMA, named V2L-DA (VBR 2-Level Demand Assignment), which manages the VER video traffic according to a dynamic bandwidth allocation algorithm. In this paper we discuss how to tune the proposed algorithm in order to optimize network utilization when mpeg-1 VER video traffic is being transmitted. Our results indicate that most of the time only 40% of the peak rate bandwidth is needed to satisfy the VER source, so the remaining 60% of the peak rate bandwidth can be used to transmit the datagram traffic queued in the network stations. (C) 1997 John Wiley & Sons, Ltd.

关键词： satellite TDMA assignment real-time traffic non-real-time traffic VBR traffic mpeg coding traffic model

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Measuring blocking artefacts using harmonic analysis

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ELECTRONICS LETTERS 1999年第16期35卷 1322-1323页

作者： Tan, KT Ghanbari, M Univ Essex Dept Elect Syst Engn Colchester CO4 3SQ Essex England

A novel method for estimating blockiness in mpeg-coded pictures is introduced. By measuring the harmonics generated by blocking artefacts in the frequency domain, an accurate and offset-insensitive estimation of block... 详细信息

关键词： Image and video coding data compression frequency domain blocking artefact mpeg coding blockiness harmonic analysis video coding frequency-domain analysis picture processing

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SHAPE-ADAPTIVE DCT FOR GENERIC coding OF VIDEO

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR VIDEO TECHNOLOGY 1995年第1期5卷 59-62页

作者： SIKORA, T MAKAI, B Department of Digital Image Processing Heinrich-Hertz Institute for Communications Engineering Berlin Germany

In this paper, a low complexity shape-adaptive DCT algorithm suitable for coding pels in arbitrarily shaped image segments is introduced. In contrast to other techniques described in literature the proposed algorithm is based on predefined orthogonal sets of DCT basis functions and does not require more computations than a normal block DCT. It is shown that the shape-adaptive DCT algorithm can be easily incorporated into existing block-based JPEG, H.261, or mpeg coding schemes. Thus segment or object based coding of images and video can be provided with backward compatibility to existing coding standards. As an important feature, with the proposed technique additional content based functionalities currently discussed in the mpeg-4 standardization phase can be readily achieved.

关键词： discrete cosine transforms image segmentation video coding DCT basis functions H.261 JPEG mpeg coding mpeg-4 standardization backward compatibility block-based coding coding standards image segments shape-adaptive DCT algorithm Video coding JPEG code standards discrete cosine transforms image segmentation Videotapes backward compatibility

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Data Hiding in mpeg Video Files Using Multivariate Regression and Flexible Macroblock Ordering

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IEEE TRANSACTIONS ON INFORMATION FORENSICS AND SECURITY 2012年第2期7卷 455-464页

作者： Shanableh, Tamer Amer Univ Sharjah Dept Comp Sci & Engn Sharjah U Arab Emirates

This paper proposes two data hiding approaches using compressed mpeg video. The first approach hides message bits by modulating the quantization scale of a constant bitrate video. A payload of one message bit per macroblock is achieved. A second order multivariate regression is used to find an association between macroblock-level feature variables and the values of a hidden message bit. The regression model is then used by the decoder to predict the values of the hidden message bits with very high prediction accuracy. The second approach uses the flexible macroblock ordering feature of H.264/AVC to hide message bits. Macroblocks are assigned to arbitrary slice groups according to the content of the message bits to be hidden. A maximum payload of three message bits per macroblock is achieved. The proposed solutions are analyzed in terms of message extraction accuracy, message payload, excessive bitrate and quality distortion. Comparisons with previous work reveal that the proposed solutions are superior in terms of message payload while causing less distortion and compression overhead.

关键词： Data hiding flexible macroblock ordering mpeg coding multivariate regression steganography

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Watermarking compressed video stream over Internet 9

Watermarking compressed video stream over Internet

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9th Asia-Pacific Conference on Communications held in conjunction with the 6th Malaysia International Conference on Communications (MICC 2003)

作者： Ghosh, D Ramakrishna, K Indian Inst Technol Dept Elect & Commun Engn Gauhati India

ISBN: (纸本)0780381149

As Internet is gaining popularity day by day throughout the globe, it has become necessary to protect the copyright ownership of multimedia data distributing in Internet. The technique generally used for the purpose is watermarking. This has motivated the ongoing research in watermarking. In this paper, we develop an oblivious scheme for watermarking mpeg coded video stream over Internet. The inter-frame similarity present in a video sequence is exploited to calculate the watermark to be embedded. Watermark corresponding to a region in the current frame is obtained from its best match in the previous frame. The watermark is embedded during the coding. process thereby keeping the overall computational overhead minimum. The algorithm has been tested in terms of the watermarked video quality and its capability in extracting the author's signature (watermark bits). We have also tested the robustness of the proposed scheme against noise attack. Results obtained demonstrate the efficiency of the proposed method.

关键词： oblivious watermarking mpeg coding motion estimation/compensation prediction error watermark embedding/extraction

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