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Decoder-driven mode decision in a block-based distributed video codec

MULTIMEDIA TOOLS AND APPLICATIONS 2012年第1期58卷 239-266页

作者： Mys, Stefaan Slowack, Juergen Skorupa, Jozef Deligiannis, Nikos Lambert, Peter Munteanu, Adrian Van de Walle, Rik Ghent Univ IBBT Multimedia Lab Dept Elect & Informat Syst ELIS Gaston Crommenlaan 8 Bus 201 B-9050 Ghent Belgium Vrije Univ Brussel IBBT Elect & Informat Dept ETRO B-1050 Brussels Belgium

distributed video coding (DVC) is a video coding paradigm in which the computational complexity is shifted from the encoder to the decoder. DVC is based on information theoretic results suggesting that, under ideal conditions, the same rate-distortion performance can be achieved as for traditional video codecs. In practice however, there is still a significant performance gap between the two coding architectures. One of the main reasons for this gap is the lack of multiple coding modes in current DVC solutions. In this paper, we propose a block-based distributed video codec that supports three coding modes: Wyner-Ziv, skip, and intra. The mode decision process is entirely decoder-driven. Skip blocks are selected based on the estimated accuracy of the side information. The choice between intra and Wyner-Ziv coding modes is made on a rate-distortion basis, by selecting the coding mode with the lowest rate while assuring equal distortion for both modes. Experimental results illustrate that the proposed block-based architecture has some advantages over classical bitplane-based approaches. Introducing skip and intra coded blocks yields average bitrate gains of up to 33.7% over our basic configuration supporting Wyner-Ziv mode only, and up to 29.7% over the reference bitplane-based DISCOVER codec.

关键词： Skip mode Intra mode Mode decision distributed video coding Wyner-Ziv coding

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An Error Resilient video coding Scheme Using Embedded Wyner-Ziv Description with Decoder Side Non-Stationary Distortion Modeling

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR video TECHNOLOGY 2011年第4期21卷 498-512页

作者： Zhang, Yongsheng Xiong, Hongkai He, Zhihai Yu, Songyu Chen, Chang Wen Shanghai Jiao Tong Univ Dept Elect Engn Shanghai 200240 Peoples R China Univ Missouri Dept Elect & Comp Engn Columbia MO 65211 USA SUNY Buffalo Dept Comp Sci & Engn Buffalo NY 14260 USA

In this paper, we propose a generic error resilient video coding (ERVC) scheme using embedded Wyner-Ziv (WZ) description. At the encoder side, a joint source-channel R-D optimized mode selection (JSC-RDO-MS) algorithm with WZ-coded anchor frames is statistically studied and developed. Given a stationary first-order Markov Gaussian source, the proposed mode optimization is justified by an analysis of the RD impact on the WZ bit-rate. JSC-RDO-MS involves in the estimation of expected rate and distortion of WZ coding with the unavailable side information, and the WZ bit-rate of each coding mode is determined based on the error correction capability of the specific WZ codec. At the decoder side, an online correlation noise model between the source and the side-information is proposed with a mixture of Laplacians whose parameters are attained to reflect the coherence of the motion field of successive frames and the energy of prediction residual. Each mixture component represents the statistical distribution of prediction residuals, and the mixing coefficients represent the amount of errors in motion compensation. The proposed scheme achieves the so-called classification gain by exploiting the spatially non-stationary characteristics of the motion field and texture. Extensive experimental results show that the proposed WZ-ERVC scheme achieves a better overall RD performance than existing ERVC schemes, and the proposed modeling algorithm also significantly outperforms the conventional Laplacian model by up to 2 dB.

关键词： Correlation noise modeling distributed video coding error resilient video coding non-stationary Wyner-Ziv coding

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Progressive Side Information Refinement Algorithm for Wyner-Ziv Codec

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IEICE TRANSACTIONS ON INFORMATION AND SYSTEMS 2011年第8期E94D卷 1641-1652页

作者： Han, Chan-Hee Lee, Si-Woong Gholamhosseini, Hamid Ko, Yun-Ho Chungnam Natl Univ Dept Mechatron Engn Taejon South Korea Auckland Univ Technol Sch Engn Auckland 1142 New Zealand Hanbat Natl Univ Div Informat Commun & Comp Engn Taejon South Korea

In this paper, side information refinement methods for Wyner-Ziv video codec are presented. In the proposed method, each block of a Wyner-Ziv frame is separated into a predefined number of groups, and these groups are interleaved to be coded. The side information for the first group is generated by the motion compensated temporal interpolation using adjacent key frames only. Then, the side information for remaining groups is gradually refined using the knowledge of the already decoded signal of the current Wyner-Ziv frame. Based on this basic concept, two progressive side information refinement methods are proposed. One is the band-wise side information refinement (BW-SIR) method which is based on transform domain interleaving, while the other is the field-wise side information refinement (FW-SIR) method which is based on pixel domain interleaving. Simulation results show that the proposed methods improve the quality of the side information and rate-distortion performance compared to the conventional side information refinement methods.

关键词： Wyner-Ziv video codec distributed video coding side information refinement band-wise side information refinement field-wise side information refinement

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Side information hybrid generation based on improved motion vector field

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MULTIMEDIA TOOLS AND APPLICATIONS 2021年第17期80卷 26713-26730页

作者： Wang, Wei Li, Jingjian Mo, Hong Chen, Jianhua Yunnan Univ Sch Informat Sci & Engn Kunming 650504 Yunnan Peoples R China

The quality of side information has an important impact on the performance of a distributed video coding system. At present, the generation of side information is mainly based on the translational motion model using the inter-frame correlation for motion estimation. Considering that the generated side information is prone to block effect and ghosting, as well as the situation that the nonlinear motion is not fully considered and the intra-frame correlation is not fully utilized, a side information hybrid generation algorithm based on an improvement model for the motion vector field is proposed. The side information frame to be generated for the current Wyner-Ziv frame is divided into easy-to-estimate and difficult-to-estimate macroblocks. For difficult-to-estimate macroblocks, the Horn and Schunck dense optical flow method is used to generate reliable motion vectors, for easy-to-estimate macroblocks, the block matching method is used to generate unreliable motion vectors which are modified by the proposed scheme, and then, the improved motion vectors are used for motion compensation to produce the final side information frame. Experiment results show that the quality of side information obtained by using the improved motion vector field for motion compensation has been significantly improved, thus the overall performance of the distributed video coding system has been effectively improved.

关键词： distributed video coding Side information Motion estimation Optical flow method Improvement model Motion vector field Block matching

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Real-time low-bitrate multimedia communication for smart spaces and wireless sensor networks

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IET COMMUNICATIONS 2011年第17期5卷 2482-2490页

作者： Vijayanagar, K. R. Kim, J. IIT Dept Elect & Comp Engn Chicago IL 60616 USA

Smart spaces is a scenario that is ideal for the application of wireless communication technology to benefit non-expert users. A prime example of such an application would be low-cost and real-time video surveillance of hallways or video conferencing. Traditional solutions for these scenarios use state-of-the-art video codecs like H.264/AVC in order to achieve the low bitrate which is essential in wireless communication. On the flip side, such encoders are computationally complex and need expensive hardware to run on thus making them inefficient choices for being deployed in clusters. Recent research has resulted in distributed video coding (DVC) being proposed as a solution for applications that have limited battery resources and low hardware complexity, thus necessitating a low-complexity encoder. It is now a popular topic in the research community and the past years have seen several implementations. However, current DVC solutions use iteratively decodable channel codes like low-density parity check - accumulate (LDPCA) codes or Turbo codes that have large latencies. In order to make real-time communication possible, the proposed architecture makes efficient use of skip blocks to reduce the bitrate, eliminates the iterative decoding nature of the Wyner-Ziv (WZ) channel and uses a simple data-hiding-based compression algorithm. This drastically cuts down on the time complexity of the decoding procedure while still maintaining a rate-distortion performance better than that of H.264/AVC intra-coding and other current DVC solutions.

关键词： Image and video coding LDPCA code video codecs WZ channel smart space real-time low-bitrate multimedia communication simple data-hiding-based compression algorithm H.264-AVC intracoding video coding Wireless sensor networks decoding DVC channel coding wireless sensor network multimedia communication iterative decoding nature distributed video coding video codec wireless sensor networks video conferencing low-complexity encoder decodable channel code video surveillance Wyner-Ziv channel Image recognition Multimedia communications wireless communication technology turbo code rate-distortion performance low-density parity check-accumulate code

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Toward fast Wyner-Ziv video decoding on multicore processors

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MULTIMEDIA TOOLS AND APPLICATIONS 2014年第3期68卷 717-745页

作者： Corrales-Garcia, Alberto Luis Martinez, Jose Fernandez-Escribano, Gerardo Quiles, Francisco J. Univ Castilla La Mancha Inst Invest Informat Albacete Albacete 02071 Spain

The Wyner-Ziv video coding paradigm provides a framework where most of the complexity is moved from the encoder to the decoder. In this way, Wyner-Ziv coding efficiently supports multimedia services for mobile devices which have to capture, encode and send video. However, the complexity of the decoder is quite high and it should be reduced. This work presents several parallel Wyner-Ziv decoding algorithms aimed at reducing this high complexity. Considering the fact that technological advances provide us new hardware which supports parallel data processing, these algorithms efficiently distribute the burden of the complexity over the number of cores which are available in the architecture. Particularly four parallel approaches have been proposed and analyzed. In the first parallel approach, the each bitplane of a frame could be decoded in a parallel way by a different core, achieving a time reduction of 33.21 % in average, although it depends on the number of bitplanes used. The second approach proposes a spatial distribution of each frame, avoiding dependences between bitplanes and then obtaining a time reduction of 67 % in average. The third approach executes each GOP in a parallel way, avoiding all synchronization dependences and achieving 71 % of time reduction in average, although the maximum performance is reached when the key frame buffer is full. Finally, the last approach distributes the burden of complexity over two levels, namely GOP and frame, in order to obtain the advantages of both: a negligible rate distortion penalty based on the GOP approach, and a low delay introduced by the spatial distribution approach. By using this parallel approach, the decoding time is reduced up to 76 %. In addition, by using parallel decoding, 60 % of the energy consumption is saved. The proposed methods are scalable for any multicore processor architecture and adaptable for different Wyner-Ziv decoding schemes.

关键词： Wyner-Ziv distributed video coding Parallel computing OpenMP Multicore processors

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A frame-level encoder rate control scheme for transform domain Wyner-Ziv video coding

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MULTIMEDIA TOOLS AND APPLICATIONS 2017年第20期76卷 20567-20585页

作者： Chen, Jian Zheng, Shuai Hu, Qing Kuo, Yonghong Xidian Univ Sch Telecommun Engn Xian 710071 Shaanxi Peoples R China

Available distributed video coding codecs are mostly based on decoder rate control scheme where the parity bits for decoding can be achieved over a feedback channel. Meanwhile, the frequent requests over feedback channel increase the transmission delay. The feedback-free distributed video coding, relying on encoder rate control in literatures, has overcome the aforementioned shortcoming. However, when performing parity bitrate estimation and other operations, the feedback-free distributed video coding systems based on bit-plane usually require high precision of bitrate estimation and high quality of side information at the encoder. In this paper, we propose a frame-level distributed video coding system based on encoder rate control. The innovations include three parts: 1) an adaptive coding mode selection algorithm is proposed, which utilizes both temporal and spatial correlation and reduces the complexity of encoder;2) a bit-plane rearrangement method is adopted, which makes the coding rate on each bit-plane homogeneous and effectively reduces the accuracy requirement of the parity bitrate prediction and improves the efficiency of rate estimation;3) a frame-level parity bitrate estimation scheme is presented to enhance the efficiency of rate estimation on the basis of a look-up table. Numerical results verify that the proposed scheme remarkably improves the rate distortion performance of distributed video coding at low bitrate.

关键词： distributed video coding Encoder rate control Adaptive coding mode selection Bit-plane rearrangement Frame-level rate estimation

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A mixed framework for transform domain Wyner-Ziv video coding

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OPTIK 2013年第21期124卷 4929-4938页

作者： Rup, Suvendu Majhi, Banshidhar Int Inst Informat Technol Dept Comp Sci & Engn Bhubaneswar Orissa India Natl Inst Technol Dept Comp Sci & Engn Rourkela India

This paper presents a mixed framework based on an efficient intra key frame coding and an improved side information (SI) generation scheme in transform domain Wyner-Ziv (WZ) video coding. The performance of the WZ video coding strongly depends on the quality of the SI. The SI can be generated from the decoded key frames resulted from intra key frame video coding. The better the decoded key frames are the better would be the SI generation. In this paper, a Burrows-Wheeler transform (BWT) based intra-frame video coding is proposed to generate improved decoded key frames. Furthermore, an improved SI generation scheme with multilayer perceptron (MLP) is proposed. Comparative analysis with other standard techniques of WZ video coding reveals that the proposed scheme has better standing as compared to its counterparts in terms of both coding efficiency and improved perceptual quality. (C) 2013 Elsevier GmbH. All rights reserved.

关键词： distributed video coding Wyner-Ziv video coding Side information Burrows-Wheeler transform Multilayer perceptron

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Systematic Lossy Error Protection of video Signals

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IEEE TRANSACTIONS ON CIRCUITS AND SYSTEMS FOR video TECHNOLOGY 2008年第10期18卷 1347-1360页

作者： Rane, Shantanu Baccichet, Pierpaolo Girod, Bernd Mitsubishi Elect Res Labs Cambridge MA 02139 USA Stanford Univ Max Planck Ctr Visual Comp & Commun Stanford CA 94035 USA Stanford Univ Informat Syst Lab Stanford CA 94035 USA

This paper proposes a scheme called Systematic Lossy Error Protection (SLEP) for robust transmission of video signals over packet erasure channels. The systematic portion of the transmission consists of a conventionally encoded video bit stream which is transmitted without channel coding. An additional bit stream generated by Wyner-Ziv encoding of the video signal is transmitted for error resilience. In the event of packet loss, this supplementary bit stream is decoded and allows the recovery of a coarsely quantized video signal, which is displayed in lieu of the lost portions of the primary video signal, The quantization mismatch results in a small, controlled loss in picture quality, but a drastic reduction in picture quality is avoided. An implementation of the SLEP system using the state-of-the-art H.264/AVC standard codec is described. Specifically, H.264/AVC redundant slices are used in conjunction with Reed-Solomon coding to generate the Wyner-Ziv bit stream. The received video quality is modeled as a function of the bit rates of the primary and redundant descriptions and the error resilience bit rate. The model is used to optimize the video quality delivered by SLEP. Via theoretical analysis and experimental simulation, it is shown that SLEP provides a flexible tradeoff between error resilience and decoded picture quality. By allowing the quality to degrade gracefully over a wider range of packet loss rates, SLEP mitigates the precipitous drop in picture quality suffered by traditional FEC-based systems.

关键词： distributed video coding H264/AVC redundant slices side information systematic lossy source/channel coding Wyner-Ziv coding

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PRISM: A video coding paradigm with motion estimation at the decoder

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IEEE TRANSACTIONS ON IMAGE PROCESSING 2007年第10期16卷 2436-2448页

作者： Puri, Rohit Majumdar, Abhik Ramchandran, Karman Univ Calif Berkeley Dept Elect Engn & Comp Sci Berkeley CA 94720 USA

We describe PRISM,(1) a video coding paradigm based on the principles of lossy distributed compression (also called source coding with side information or Wyner-Ziv coding) from multiuser information theory. PRISM represents a major departure from conventional video coding architectures (e.g., the MPEGx, H.26x families) that are based on motion-compensated predictive coding, with the goal of addressing some of their architectural limitations. PRISM allows for two key architectural enhancements: 1) inbuilt robustness to "drift" between encoder and decoder and 2) the feasibility of a flexible distribution of computational complexity between encoder and decoder. Specifically, PRISM enables transfer of the computationally expensive video encoder motion-search module to the video decoder. Based on this capability, we consider an instance of PRISM corresponding to a near reversal in codec complexities with respect to today's codecs (leading to a novel light encoder and heavy decoder paradigm), in this paper. We present encouraging preliminary results on real-world video sequences, particularly in the realm of transmission losses, where PRISM exhibits the characteristic of rapid recovery, in contrast to contemporary codecs. This renders PRISM as an attractive candidate for wireless video applications.

关键词： distributed source coding distributed video coding robust video coding wireless video

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