In the multi-view video coding, both temporal and inter-view redundancies can be exploited by using standard block-based motion estimation (BBME) technique. In this paper, an extensive review of BBME algorithms proposed within the last three decades is presented. Algorithms are divided into five categories: 1) based on the search position number reduction; 2) multiresolution; 3) based on the simplification of matching criterion; 4) fast full search; 5) computation-aware. Algorithms are compared in terms of their efficiency and computational complexity.

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Block-based motion estimation algorithms — a survey

The emerging international standard for multiview video coding (MVC) is an extension of H.264/advanced video coding. In the joint mode of MVC, both motion estimation (ME) and disparity estimation (DE) are included in the encoding process. This achieves the highest coding efficiency but requires a very high computational complexity. In this letter, we propose a fast ME and DE algorithm that adaptively utilizes the inter-view correlation. The coding mode complexity and the motion homogeneity of a macroblock (MB) are first analyzed according to the coding modes and motion vectors from the corresponding MBs in the neighbor views, which are located by means of global disparity vector. According to the coding mode complexity and the motion homogeneity, the proposed algorithm adjusts the search strategies for different types of MBs in order to perform a precise search according to video content. Experimental results demonstrate that the proposed algorithm can save 85% computational complexity on average, with negligible loss of coding efficiency.

View-Adaptive Motion Estimation and Disparity Estimation for Low Complexity Multiview Video Coding

Multi-view video coding (MVC) is an ongoing standard in which variable size disparity estimation (DE) and motion estimation (ME) are both employed to select the best coding mode for each macroblock (MB). This technique achieves the highest possible coding efficiency, but it results in extremely large encoding time which obstructs it from practical use. In this paper, a fast DE and ME algorithm based on motion homogeneity is proposed to reduce MVC computational complexity. The basic idea of the method is to utilize the spatial property of motion field in prediction where DE and variable size ME are needed, and only in these regions DE and variable size ME are enabled. The motion field is generated by the corresponding motion vectors (MVs) in spatial window. Simulation results show that the proposed algorithm can save 63% average computational complexity, with negligible loss of coding efficiency.

Selective Disparity Estimation and Variable Size Motion Estimation Based on Motion Homogeneity for Multi-View Coding

Recently, multiview video coding has attracted great attention from industries and research institutes. However, the heavy computational complexity limits its practical applications. In this paper, a fast disparity and motion estimation for multiview video coding is presented, based on the correlations between the neighboring cameras and between the motion and the disparity. In the proposed approach, first, a search region estimation is proposed to reduce the disparity estimation complexity according to that the camera set is usually fixed and therefore the disparity between the two neighboring views can be limited to an estimable range. Second, a motion vector derivation is given based on the geometric relationship between the motion and the disparity. In addition, an early termination scheme is provided to further reduce the number of reference frames. The experimental results show that roughly 50% time saving for disparity and motion computing can be reached when compared to the anchor in multiview video coding test model JSVM only with negligible coding efficiency loss.

Fast disparity and motion estimation based on correlations for multiview video coding

The finalized international standard for multiview video coding (MVC) is an extension of H.264. In the joint model of MVC, variable size motion estimation (ME) and disparity estimation (DE) are introduced to achieve the highest coding efficiency with the cost of very high computational complexity. A low complexity mode decision algorithm is proposed to reduce complexity of ME and DE. An experimental analysis is performed to study inter-view correlation in the coding information such as the prediction mode and rate-distortion (RD) cost. Based on the correlation, we propose four efficient mode decision techniques, including early SKIP mode decision, adaptive early termination, fast mode size decision, and selective intra coding in inter frame. Experimental results show that the proposed algorithm can significantly reduce computational complexity of MVC while maintaining almost the same RD performance.

Low-Complexity Mode Decision for MVC

The multi-view video coding improves the coding efficiency by utilizing motion-compensated prediction (MCP) and disparity-compensated prediction (DCP). However, the complexity of the inter frame prediction is very high, especially when the rate-distortion optimization is used. This paper presents a fast inter frame prediction algorithm to reduce the complexity. Firstly the prediction type is decided according to reference frames. Then some unuseful search regions in view direction are removed. Finally a fast inter mode decision strategy is proposed based on the relationship between MCP and DCP. Experimental results verify that the proposed algorithm can greatly increase the speed of prediction with negligible loss of coding efficiency.

A Fast Inter Frame Prediction Algorithm for Multi-View Video Coding

Recently multiview video coding (MVC) standard has been finalized as an extension of H.264/AVC by Joint Video Team (JVT). In the project Joint Multiview Video Model (JMVM) for the standardization, illumination compensation (IC) is adopted as a useful tool. In this paper, a novel illumination compensation algorithm based on template is proposed. The basic idea of the algorithm is that the illumination of the current block has a strong correlation with its adjacent template. Based on this idea, firstly a template based illumination compensation method is presented, and then a template models selection strategy is devised to improve the illumination compensation performance. The experimental results show that the proposed algorithm can improve the coding efficiency significantly.

http://www.jdl.ac.cn/doc/2010/VCIP10_Template%20based%20illumination%20compensation%20algorithm%20for%20multiview%20video%20coding_xmli.pdf

Template based illumination compensation algorithm for multiview video coding

The invention provides a method for intra-frame prediction of a three-dimensional video and coding and decoding methods. Therefore, technical problems of improvement of a method for intra-frame prediction of a three-dimensional video under a traditional mixing coding framework and compression efficiency of three-dimensional video/image coding can be solved according to the invention. The invention brings forward a novel intra-frame difference compensation prediction method, which is applied to a three-dimensional video in an interleaved mode. The method comprises the following steps that: coding is carried out on image contents of other viewpoints; and when a current view point is coded, inter-view difference estimation and difference compensation are carried out by utilizing reconstructed images of other viewpoints as reference images; therefore, prediction redundancy is reduced and coding efficiency is improved. According to the invention, compression efficiency of three-dimensional video/image coding in a common code rate range can be obviously improved; and moreover, the computation complexity is relatively reduced; therefore, the methods are suitable for practical application.

Method for intra-frame prediction of three-dimensional video and coding and decoding methods

Multiview video coding (MVC) improves the coding efficiency by motion estimation (ME) and disparity estimation (DE). ME and DE at encoder side involve in heavy computation, which needs to be further reduced for practical applications. This paper presents fast disparity estimation by utilizing depth information to reduce DE's computational complexity. First, the coordinate offset of the encoding block is calculated by 3D warping in the reference view frame utilizing depth map. Then the search region for DE is adjusted according to the coordinate offset. Experimental results verify that the proposed algorithm can save roughly 50% coding time with negligible loss of coding efficiency.

Xiaoming Li

Papers

Fast disparity and motion estimation based on correlations for multiview video coding

A Fast Inter Frame Prediction Algorithm for Multi-View Video Coding

Template based illumination compensation algorithm for multiview video coding

Method for intra-frame prediction of three-dimensional video and coding and decoding methods

Fast disparity estimation utilizing depth information for multiview video coding