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A very low bit rate video coder based on vector quantization

IEEE TRANSACTIONS ON IMAGE PROCESSING 1996年第2期5卷 263-273页

作者： CorteReal, L Alves, AP Departamento de Engenharia ElectrotCcnica e de Computadores Faculdade de Engenharia Universidade do Porto Porto Portugal

This work describes a video coder based on a hybrid DPCM-vector quantization algorithm that is suited for bit rates ranging from 8-16 kb/s, The proposed approach involves segmenting difference images into variable-size and variable-shape blocks and performing segmentation and motion compensation simultaneously, The purpose of obtaining motion vectors for variable-size and variable-shape blocks is to improve the quality of motion estimation, particularly in those areas where the edges of moving objects are situated, For the larger blocks, decimation takes place in order to simplify vector quantization, For very active blocks, which are always of small dimension, a specific vector quantizer has been applied, the fuzzy classified vector quantizer (FCVQ), The coding algorithm described displays good performance in the compression of test sequences at the rates of 8 and 16 kb/s;the signal-to-noise ratios obtained are good in both cases, The complexity of the coder implementation is comparable to that of conventional hybrid coders, while the decoder is much simpler in this proposal.

关键词： video coder motion estimation difference image ENcoder Vector quantization Motion compensation quantizer decoders motion vector VARIABLE SIZE

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A MONOLITHIC TRIPLE 8 BIT CMOS video coder

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IEEE TRANSACTIONS ON CONSUMER ELECTRONICS 1990年第3期36卷 722-729页

作者： HAAS, M DRAXELMAYR, D KUTTNER, F ZOJER, B Siemens-Entwicklungszentrum für Microelektronik Villach Austria

A monolithic video coder, including a triple 8-bit ADC (analog-to-digital converter), DSP function, and standard output coding with direct coupling capability to digital video processing units, is presented. This mixed analog-digital video coder is fabricated in advanced 1- mu CMOS with a die size of 18 mm/sup 2/ and 68 pins. The complete chip for a triple 8-bit 30-MHz bus system has a power dissipation of less than 1 W. Advanced circuitry was used to obtain good analog performance.

关键词： video coder 8-bit MONOLITHIC Power dissipation Treble

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A Rate Control Method for Reducing Quality Fluctuation in the 3D Embedded Wavelet video coder 6th

A Rate Control Method for Reducing Quality Fluctuation in th...

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6th International Conference on Communications, Signal Processing, and Systems (ICCSPS)

作者： Jin, Xuesong Harbin Univ Commerce Harbin 150028 Heilongjiang Peoples R China

ISBN: (纸本)9789811065712;9789811065705

Current rate control schemes in MCTF-based wavelet video coding lack efficient GOP-level bit allocation due to the shortage of GOP rate-distortion (R-D) information and the limitations of real-time encoding. Exploiting the advantage of offline video encoding, a GOP-level bit allocation scheme based on GOP R-D data estimated from the wavelet decomposed temporal-spatial sub-band R-D is described. Each video sequence is encoded twice. In the first pass, the R-D information of the GOP is generated, and this is utilised in the second pass to implement GOP-level bit allocation appropriate for the available bandwidth and such that the video sequence is coded with near-constant quality. Experimental results demonstrate that the proposed technique achieves a smoother, and hence more visually acceptable, quality than existing methods.

关键词： Wavelet transform video coder Rate-distortion

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A LOW-COMPLEXITY MULTIPLE DESCRIPTION video coder BASED ON 3D-TRANSFORMS

A LOW-COMPLEXITY MULTIPLE DESCRIPTION VIDEO CODER BASED ON 3...

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European Signal Processing Conference

作者： Andrey Norkin Atanas Gotchev Karen Egiazarian Jaakko Astola University of Pisa

The paper presents a multiple description (MD) video coder based on three-dimensional (3D) transforms. The coder has low computa- tional complexity and high robustness to transmission errors and is targeted to mobile devices. The encoder represents video sequence in a form of coarse sequence approximation (shaper) included in both descriptions and residual sequence (details) split between two descriptions. The shaper is obtained by block-wise pruned 3D- DCT. The residual sequence is coded by 3D-DCT or hybrid 3D- transform. The coding scheme is simple and yet outperforms some MD coders based on motion-compensated prediction, especially in the low-redundancy region.

关键词： Transmission errors labeling scheme video sequences Shapers video coder Transform

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A SWITCHED MODEL-BASED coder FOR video SIGNALS

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR video TECHNOLOGY 1994年第3期4卷 216-227页

作者： CHOWDHURY, MF CLARK, AF DOWNTON, AC MORIMATSU, E PEARSON, DE FUJITSU LABS LTD NAKAHARA KUKAWASAKIKANAGAWA 211JAPAN

The algorithmic architecture and performance of a video coder are described that switches between model-based and and H.261 modes, depending on image content. The switching criterion incorporates measures of both picture quality and bit rate. The model-based mode uses generalized cylindrical models and a 3D matching technique to estimate motion. The coder was tested with four different image sequences in CBR and VBR operational modes: the performance was generally superior, and in some cases significantly superior, to that of a free-running H.261 coder operating on the same sequences. The switched architecture represents a possible route for the integration of model-based coding with H.261 to give improved performance at very low bit rates.

关键词： video coder Switches video signals videotapes ENcoder

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Hierarchical motion estimator (HME) for block-based video coders

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IEEE TRANSACTIONS ON CONSUMER ELECTRONICS 1997年第4期43卷 1320-1330页

作者： Accame, M De Natale, FGB Giusto, DD Univ Genoa Dept Biophys & Elect Engn I-16145 Genoa Italy Univ Cagliari Dept Elect & Elect Engn I-09123 Cagliari Italy

A hierarchical block-based motion estimation strategy for video sequence coding is proposed, which allows to reduce both the computational load and the number of transmitted motion vectors, The estimation is performed by first computing a coarse motion field at the lowest resolution of a Gaussian pyramid and then propagating and refining it till the maximum resolution, Main innovations concern the adaptive vector propagation and updating strategy, which allow an efficient recovery from wrong estimates while maintaining a low computational load, The advantages of the proposed method are manifold: first, it is able to decrease the computation of even two orders magnitude for an equivalent compensation;second, it generates a lower number of motion vectors, resulting in a lower information rate;third, it produces a more homogeneous motion field, thus easing a successive segmentation.

关键词： video coder MMP12 gene Hierarchical Information rates motion vector Propagating

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BIT ALLOCATION FOR DEPENDENT QUANTIZATION WITH APPLICATIONS TO MULTIRESOLUTION AND MPEG video coderS

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IEEE TRANSACTIONS ON IMAGE PROCESSING 1994年第5期3卷 533-545页

作者： RAMCHANDRAN, K ORTEGA, A VETTERLI, M COLUMBIA UNIV DEPT ELECT & COMP ENGN NEW YORK NY 10027 USA COLUMBIA UNIV CTR TELECOMMUN RES NEW YORK NY 10027 USA UNIV CALIF BERKELEY DEPT ELECT ENGN & COMP SCI BERKELEY CA 94720 USA

We address the problem of efficient bit allocation in a dependent coding environment. While optimal bit allocation for independently coded signal blocks has been studied in the literature, we extend these techniques to the more general temporally and spatially dependent coding scenarios. Of particular interest are the topical MPEG video coder and multiresolution coders. Our approach uses an operational rate-distortion (RD) framework for arbitrary quantizer sets. We show how a certain monotonicity property of the dependent R-D curves can be exploited in formulating fast ways to obtain optimal and near-optimal solutions. We illustrate the application of this property in specifying intelligent pruning conditions to eliminate suboptimal operating paints for the MPEG allocation problem, for which we also point out fast nearly-optimal heuristics. Additionally, we formulate an efficient allocation strategy for multiresolution coders, using the spatial pyramid coder as an example. We then extend this analysis to a spatio-temporal 3-D pyramidal coding scheme. We tackle the compatibility problem of optimizing full-resolution quality while simultaneously catering to subresolution bit rate or quality constraints. We show how to obtain fast solutions that provide nearly optimal (typically within 0.3 dB) full resolution quality while providing much better performance for the subresolution layer (typically 2-3 dB better than the full-resolution optimal solution).

关键词： video coder optimal solution Moving Pictures Experts Group ENcoder Optimal

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THE EFFECT OF A LOOP FILTER ON CIRCULATING NOISE IN INTERFRAME video coderS

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR video TECHNOLOGY 1994年第4期4卷 442-446页

作者： HOLLIER, CJ ARNOLD, JF CAVENOR, MC Department of Electrical Engineering University CollegeAustralian Defence Force Academy University of New South Wales Canberra ACT Australia University of New South Wales Sydney NSW AU Dept. of Electr. Eng. New South Wales Univ. Canberra ACT Australia

An examination of the distribution of signals within the prediction loop of an interframe video codec reveals that small random fluctuations caused by the quantizer build up over a period of time. This quantization noise circulates within the prediction loop causing a gradual decrease in the signal to noise ratio of the reconstructed sequence and an increase in the required data rate. In general, both of these effects can be nullified by the inclusion of a tow pass loop filter.

关键词： video coder interframe random fluctuations quantization noise Loop Filter

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On the computation of warping-based motion compensation in video sequence coding

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SIGNAL PROCESSING-IMAGE COMMUNICATION 1998年第2期13卷 155-160页

作者： Neri, A Colonnese, S Univ Rome 3 Dept Elect Engn I-00146 Rome Italy Fdn Ugo Bordoni I-00142 Rome Italy

The paper illustrates a method for affine warping-based motion compensation using the computing architecture of H263 advanced prediction (AP) mode, namely, changing the (constant) weighting matrices in the H263 AP algorithm. In particular, we analytically derive a realization of affine image prediction based on a regular mesh in presence of linear resampling. The work shows, by means of analytical derivation and simulation results, an intrinsic similarity relationship between the affine motion model and the H.263 advanced prediction technique. The analysis offers a rational basis to explain the performance of H.263 AP as a coarse approximation of affine prediction. (C) 1998 Elsevier Science B.V. All rights reserved.

关键词： affine prediction video coder H.263 advanced prediction motion compensation

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Intra-Frame Coding Using a Conditional Autoencoder

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IEEE JOURNAL OF SELECTED TOPICS IN SIGNAL PROCESSING 2021年第2期15卷 354-365页

作者： Brand, Fabian Seiler, Juergen Kaup, Andre Friedrich Alexander Univ Erlangen Nurnberg Multimedia Commun & Signal Proc D-91058 Erlangen Germany

Exploiting spatial redundancy in images is responsible for a large gain in the performance of image and video compression. The main tool to achieve this is called intra-frame prediction. In most state-of-the-art video coders, intra prediction is applied in a block-wise fashion. Up to now angular prediction was dominant, providing a low-complexity method covering a large variety of content. With deep learning, however, it is possible to create prediction methods covering a wider range of content, being able to predict structures which traditional modes can not predict accurately. Using the conditional autoencoder structure, we are able to train a single artificial neural network which is able to perform multi-mode prediction. In this paper, we derive the approach from the general formulation of the intra-prediction problem and introduce two extensions for spatial mode prediction and for chroma prediction support. Moreover, we propose a novel latent-space-based cross component prediction. We show the power of our prediction scheme with visual examples and report average gains of 1.13% in Bjontegaard delta rate in the luma component and 1.21% in the chroma component compared to VTM using only traditional modes.

关键词： Neural networks Encoding Image coding Training Tools Decoding Prediction methods video coder intra prediction conditional autoencoder deep learning

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