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Spatial correlation-based side information refinement for distributed video coding

EURASIP JOURNAL ON ADVANCES IN SIGNAL PROCESSING 2013年第1期2013卷 1-19页

作者： Taieb, Mohamed Haj Chouinard, Jean-Yves Wang, Demin Univ Laval Quebec City PQ G1V 0A8 Canada Commun Res Ctr Canada Ottawa ON K2H 8S2 Canada

distributed video coding (DVC) architecture designs, based on distributed source coding principles, have benefitted from significant progresses lately, notably in terms of achievable rate-distortion performances. However, a significant performance gap still remains when compared to prediction-based video coding schemes such as H.264/AVC. This is mainly due to the non-ideal exploitation of the video sequence temporal correlation properties during the generation of side information (SI). In fact, the decoder side motion estimation provides only an approximation of the true motion. In this paper, a progressive DVC architecture is proposed, which exploits the spatial correlation of the video frames to improve the motion-compensated temporal interpolation (MCTI). Specifically, Wyner-Ziv (WZ) frames are divided into several spatially correlated groups that are then sent progressively to the receiver. SI refinement (SIR) is performed as long as these groups are being decoded, thus providing more accurate SI for the next groups. It is shown that the proposed progressive SIR method leads to significant improvements over the Discover DVC codec as well as other SIR schemes recently introduced in the literature.

关键词： distributed video coding Side information refinement (SIR) Motion estimation Spatial correlation

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Suppressing feedback in a distributed video coding system by employing real field codes

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EURASIP JOURNAL ON ADVANCES IN SIGNAL PROCESSING 2013年第1期2013卷 1页

作者： Louw, Daniel J. Kaneko, Haruhiko Tokyo Inst Technol Dept Comp Sci Tokyo 2268552 Japan

Single-view distributed video coding (DVC) is a video compression method that allows for the computational complexity of the system to be shifted from the encoder to the decoder. The reduced encoding complexity makes DVC attractive for use in systems where processing power or energy use at the encoder is constrained, for example, in wireless devices and surveillance systems. One of the biggest challenges in implementing DVC systems is that the required rate must be known at the encoder. The conventional approach is to use a feedback channel from the decoder to control the rate. Feedback channels introduce their own difficulties such as increased latency and buffering requirements, which makes the resultant system unsuitable for some applications. Alternative approaches, which do not employ feedback, suffer from either increased encoder complexity due to performing motion estimation at the encoder, or an inaccurate rate estimate. Inaccurate rate estimates can result in a reduced average rate-distortion performance, as well as unpleasant visual artifacts. In this paper, the authors propose a single-view DVC system that does not require a feedback channel. The consequences of inaccuracies in the rate estimate are addressed by using codes defined over the real field and a decoder employing successive refinement. The result is a codec with performance that is comparable to that of a feedback-based system at low rates without the use of motion estimation at the encoder or a feedback path. The disadvantage of the approach is a reduction in average rate-distortion performance in the high-rate regime for sequences with significant motion.

关键词： distributed video coding Feedback suppression Real field coding Compressive sensing Multi-hypothesis

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Improved signal reconstruction and return channel suppression in distributed video coding systems

Improved signal reconstruction and return channel suppressio...

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47th International Symposium ELMAR-2005 on Multimedia Systems and Applications

作者： Artigas, X Torres, L Univ Politecn Catalunya Dept Signal Theory & Commun ES-08034 Barcelona Spain

ISBN: (纸本)9537044041

distributed video coding (DVC) is a coding paradigm that gives the decoder the task to exploit the source statistics to achieve efficient compression. Current approaches to DVC rely on motion-compensated interpolation to generate at the decoder an estimation of the frame being decoded. This paper presents an iterative motion-compensated interpolation technique that takes advantage of all available information about the frame being estimated, not only the previous and posterior frames as is common practice. Simulation results show that the addition of this estimation technique to an existing D VC codec produces a 0.15 dB improvement in the PSNR of the rate-distortion plots. Furthermore, a method to avoid using the return channel existing in some D VC implementations is presented that only incurs in a penalty of 10 to 100 kbit/s.

关键词： distributed video coding Wyner-Ziv coding motion-compensated temporal interpolation iterative motion compensation return channel suppression

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Inverse bit plane decoding order for turbo code based distributed video coding

Inverse bit plane decoding order for turbo code based distri...

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IEEE International Conference on Image Processing (ICIP 2007)

作者： Vatis, Yuri Klomp, Sven Ostermann, Joern Leibniz Univ Hannover Inst Informatwerarbeitung D-30167 Hannover Germany

ISBN: (纸本)9781424414369

For Turbo Code based Wyner-Ziv codecs, we propose to use an inverse bit plane decoding order. The investigations have shown that the knowledge about MSB's has only a marginal influence on LSB's, which can be regarded as noise, while the influence of LSB's on MSB's tends to be higher. As a results, we obtain a coding gain of up to 0.3 dB, especially for the sequences, which can only be decoded with a coding efficiency lower than H.264/AVC intra. Furthermore, the distribution of the requests for additional parity bits over the back channel is different compared to the conventional decoding order, resulting in a high number of requests for the last bit plane and a low number of requests for the other bit planes. Therefore, the decoder can request several puncturing levels for LSB's in one step, reducing the number of turbo decoding loops. Hence, transmitting the LSB's first, we can obtain a decoding speedup of 30%, thus making DVC more attractive for real-time applications.

关键词： distributed video coding Slepian-Wolf Wyner-Ziv

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A realization of transform domain distributed video coding on Raspberry Pi

A realization of transform domain distributed video coding o...

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International Symposium on Computer, Consumer and Control (IS3C)

作者： Lin, Yih-Chuan Deng, Bang-Yao Natl Formosa Univ Comp Sci & Informat Engn Huwei Yunlin Taiwan

ISBN: (纸本)9781728193625

Compared with conventional encoding methods, distributed video coding (DVC) has superiority in encoding speed. However, DVC is difficult to exhibit its advantages in fast video encoding in practical applications because it has the problem of insufficient compression ratio and no hardware accelerated chip support. In practical applications, how to effectively use general hardware resources with improved compression ratio is a significant challenge. By implementation, we realized an DVC encoder on Raspberry Pi device. In order to improve the compression ratio of DVC, we used a transform-domain DVC coding method based on frame difference, which can employ the correlation between neighboring frames to reduce the encoding cost of Discrete Cosine Transform (DCT) for those blocks with low motion amplitude, thereby reducing the bandwidth required for transmission of them. This method can improve the compression ratio without increasing excessive calculation in the encoding operation. In the implementation, we try to use video Core (VC) chip of Raspberry Pi and OpenCV4 library for DCT calculation to speed up the DVC encoding process.

关键词： distributed video coding low-density parity-check low-complexity video coding

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An enhanced reconstruction algorithm for unidirectional distributed video coding

An enhanced reconstruction algorithm for unidirectional dist...

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IEEE International Symposium on Consumer Electronics

作者： Weerakkody, W. A. R. J. Fernando, W. A. C. Kondoz, A. M. Univ Surrey Guildford GU2 7XH Surrey England

ISBN: (纸本)9781424424221

distributed video coding (DVC) is an emerging video coding technology that utilizes the distributed source coding principles to build very low cost video encoders, yet with remarkable error resilience. In the common DVC framework, the reconstruction function plays a vital role that has a direct impact on the output video quality. In this paper, a novel algorithm is proposed for the reconstruction function, particularly focusing on the unidirectional DVC architecture. The proposed technique exploits the variations of the bit error rate of the Wyner-Ziv decoded bit stream and the side information stream. The simulation results show that the proposed algorithm yields a significant improvement of the objective and subjective video quality at no additional bit rate cost.

关键词： distributed video coding Wyner-Ziv coding

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ANALYSIS OF PERFORMANCE LOSSES IN distributed video coding

ANALYSIS OF PERFORMANCE LOSSES IN DISTRIBUTED VIDEO CODING

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Picture coding Symposium 2009

作者： Borchert, S. Westerlaken, R. P. Gunnewiek, R. Klein Lagendijk, R. L. Delft Univ Technol Fac EEMCS Informat & Commun Theory Grp POB 5031 NL-2600 GA Delft Netherlands Video Proc Syst Grp Philips Res NL-5656 AA Eindhoven Netherlands

ISBN: (纸本)9781424445936

In this paper we analyze the substantial performance gap between distributed video coding (DVC) and well known state-of-the-art coders. We take a modular approach towards analyzing the performance loss in DVC and investigate 3 key components. These are quantization, bit stream generation and motion estimation. Their respective contributions to the total performance loss varies with the video properties. For low motion sequences the first two components dominate. For more difficult sequences the motion estimation alone is responsible for more than half the loss. We show that it is possible to reduce this loss by repeating the motion estimation after partial decoding. Finally, we discuss advances in recent literature.

关键词： distributed video coding video compression Performance analysis

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Modeling Correlation Noise Statistics at Decoder for Multi-view distributed video coding

Modeling Correlation Noise Statistics at Decoder for Multi-v...

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IEEE International Symposium on Circuits and Systems (ISCAS 2009)

作者： Li, Yongpeng Ma, Siwei Zhao, Debin Gao, Wen Chinese Acad Sci Grad Univ Beijing 100039 Peoples R China Peking Univ Sch Elect Engn & Comp Sci Beijing Peoples R China

ISBN: (纸本)9781424438273

Recently, multi-view distributed video coding (MDVC) receives more and more attention, as its low-complexity encoder and high-complexity decoder coding paradigm suits for many applications such as sensor networks, in which several view sequences are required to be coded by a few power-constraint encoders. Modeling the correlation noises between original frame and side information frame is a hot research issue in distributed video coding (DVC), since it is a vital factor affecting the coding efficiency. This paper firstly proposes a novel method to model the correlation noises in MDVC. And an algorithm to online estimate the model at decoder using the knowledge of adjacent views is also presented. Experiment results show that the proposed correlation model can significantly improve coding efficiency.

关键词： Multi-view video coding distributed video coding correlation model

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Enabling privacy for distributed video coding by transform domain scrambling - art. no. 68222E

Enabling privacy for Distributed Video Coding by transform d...

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Conference on Visual Communications and Image Processing 2008

作者： Ouaret, Mourad Dufaux, Frederic Ebrahimi, Toutadj Ecole Polytech Fed Lausanne Inst Traitement Signaux CH-1015 Lausanne Switzerland

ISBN: (纸本)9780819469946

In this paper, a novel video scrambling scheme is introduced for distributed video coding. The goal is to conceal video information to preserve privacy in several applications such as video surveillance and anonymous video communications. This is achieved by performing a transform domain scrambling on both Key and Wyner-Ziv frames. More specifically, the sign of the scrambled transform coefficient is inverted at the encoder side. The scrambling pattern is-defined-by a secret key and the latter is required at the decoder for descrambling. The scheme is proven to pro vide a good level of security in addition to a flexible scrambling, level (i.e the amount of distortion introduced). Finally, it is shown that the original DVC scheme and the one with scrambling have a similar rate distortion performance. In other words, the DVC compression efficiency is not negatively impacted by the introduction of the scrambling.

关键词： media security privacy scrambling transform domain distributed video coding

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A sequential motion compensation refinement technique for distributed video coding of Wyner-Ziv frames

A sequential motion compensation refinement technique for di...

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IEEE International Conference on Image Processing (ICIP 2006)

作者： Adikari, A. B. B. Fernando, W. A. C. Weerakkody, W. A. R. J. Arachchi, H. K. Brunel Univ Sch Engn & Design Uxbridge UB8 3PH Middx England

ISBN: (纸本)9781424404810

distributed video coding (DVC) is one of the fastest growing coding techniques in the current signal processing world. It has its outstanding low complex encoder which is essential for some applications in the consumer market. Driven by the above motive, in this paper we propose a novel side information refinement technique for Wyner-Ziv video frames in DVC. When a bit plane is decoded, it is used to replace the corresponding bit plane in the side information and used for motion estimation and compensation to up date the side information. Then the information for the next bit plane is extracted from the updated side information and is sent to the turbo decoder as in a conventional DVC decoder. This process is repeated until all bit planes are extracted. This technique can be employed with almost all the side information generation techniques from simplest conventional pixel interpolation to advanced techniques such as bi-directional motion estimation and spatial motion smoothing (BiMESS) [8]. Simulation results show that over 1.4dB PSNR gain can be obtained with the proposed algorithm over the BiMESS smoothing algorithm at the same bit rate.

关键词： distributed video coding video coding signal processing video codecs

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