Wyner-Ziv Coding of Video
Wyner-Ziv Coding of Video

Author: Anne Margot Fernandez Aaron

Publisher:

Published: 2011

Total Pages:

ISBN-13:

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For numerous video compression scenarios, encoding is performed on low-power or mobile devices. Examples of such systems include wireless video sensors for surveillance, wireless PC cameras and mobile phones. For these applications, encoding must be implemented at the camera where memory and computation are scarce and low power usage is essential. Current video compression standards, such as MPEG or H.264/AVC, exploit the redundancy among video frames at the encoder. Due to the interframe processing performed at the encoder, these compression schemes are less suitable for applications which require low-complexity encoders. The Slepian-Wolf theorem on distributed source coding and the Wyner-Ziv results on source coding with decoder side information suggest that we can achieve efficient compression by exploiting the source statistics only at the decoder. Motivated by these theoretical results, a Wyner-Ziv video codec is developed. In this compression scheme individual frames are encoded independently, but decoded conditionally on adjacent reconstructed frames. Independently encoding the frames leads to low computation and memory requirements at the encoder, while the interframe processing at the decoder allows for efficient compression. As a building block for the Wyner-Ziv video codec, a practical scheme for compression with decoder side information based on turbo codes is presented. This coding technique performs close to the Slepian-Wolf bound and allows for rate-adaptivity and joint source-channel decoding. The Wyner-Ziv video codec is implemented in the pixel domain and the transform domain. Simulation results show that this video compression scheme achieves better rate-distortion performance than conventional low-complexity encoding schemes. To further improve the performance of the Wyner-Ziv video codec, two extensions are presented. Specifically, we implement hash-based motion estimation at the receiver. This allows the system to effectively estimate the motion at the decoder. We also extend the system to Wyner-Ziv coding of the residual images of a video sequence. With this scheme, the encoder uses a simple reference frame to calculate the residual while the decoder performs more sophisticated motion-compensation to generate side information for conditional decoding.

Layered Wyner-Ziv Video Coding
Layered Wyner-Ziv Video Coding

Author: Qian Xu

Publisher:

Published: 2010

Total Pages:

ISBN-13:

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Following recent theoretical works on successive Wyner-Ziv coding, we propose a practical layered Wyner-Ziv video coder using the DCT, nested scalar quantization, and irregular LDPC code based Slepian-Wolf coding (or lossless source coding with side information at the decoder). Our main novelty is to use the base layer of a standard scalable video coder (e.g., MPEG-4/H.26L FGS or H.263+) as the decoder side information and perform layered Wyner-Ziv coding for quality enhancement. Similar to FGS coding, there is no performance difference between layered and monolithic Wyner-Ziv coding when the enhancement bitstream is generated in our proposed coder. Using an H.26L coded version as the base layer, experiments indicate that Wyner-Ziv coding gives slightly worse performance than FGS coding when the channel (for both the base and enhancement layers) is noiseless. However, when the channel is noisy, extensive simulations of video transmission over wireless networks conforming to the CDMA2000 1X standard show that H.26L base layer coding plus Wyner-Ziv enhancement layer coding are more robust against channel errors than H.26L FGS coding. These results demonstrate that layered Wyner-Ziv video coding is a promising new technique for video streaming over wireless networks. For scalable video transmission over the Internet and 3G wireless networks, we propose a system for receiver-driven layered multicast based on layered Wyner-Ziv video coding and digital fountain coding. Digital fountain codes are near-capacity erasure codes that are ideally suited for multicast applications because of their rate- less property. By combining an error-resilient Wyner-Ziv video coder and rateless fountain codes, our system allows reliable multicast of high-quality video to an arbitrary number of heterogeneous receivers without the requirement of feedback channels. Extending this work on separate source-channel coding, we consider distributed joint source-channel coding by using a single channel code for both video compression (via Slepian-Wolf coding) and packet loss protection. We choose Raptor codes - the best approximation to a digital fountain - and address in detail both encoder and de- coder designs. Simulation results show that, compared to one separate design using Slepian-Wolf compression plus erasure protection and another based on FGS coding plus erasure protection, the proposed joint design provides better video quality at the same number of transmitted packets.

Wyner-Ziv Video Coding
Wyner-Ziv Video Coding

Author: Ghazaleh R. Esmaili

Publisher:

Published: 2011

Total Pages: 82

ISBN-13: 9781267073556

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Wyner Ziv (WZ) video coding is based on the results of the Slepian-Wolf and Wyner-Ziv theorems where the temporal correlation between neighboring frames is exploited at the decoder. This approach enables designing low-cost, low complexity encoders which are essential for some recent applications such as video surveillance and mobile camera phone. Despite recent advances in WZ video coding, the rate distortion performance is still far from that of predictive coding. One of the main factors affecting the WZ coding performance is the accuracy of modeling the dependency (correlation noise) between a frame to be coded and its estimation (side information) at the decoder. In existing transform domain Wyner-Ziv video coding methods, blocks within a frame are treated uniformly to estimate the correlation noise even though the success of generating side information is different for each block. This thesis proposes a method to estimate the correlation noise by differentiating blocks within a frame based on the accuracy of the side information. A second contribution of this dissertation is exploiting the temporal correlation between key frames which are usually simply intra coded. We propose a frequency band coding mode selection for key frames to exploit similarities between adjacent key frames at the decoder to improve the overall performance. Furthermore, the advantage of applying both schemes in a hierarchical order is investigated. Rate control is an important issue in many video applications. In Wyner-Ziv video coding architectures, the available bit budget for each GOP is shared between key frames and Wyner-Ziv frames. In this dissertation, we propose a model to express the relationship between the quantization step size of key and WZ frames based on their motion activity. Then we apply this model to propose an adaptive algorithm adjusting the quantization step size of key and WZ frames to achieve and maintain a target bit rate. The objective and subjective quality of the proposed method is evaluated.

Layered Wyner-Ziv Video Coding for Noisy Channels
Layered Wyner-Ziv Video Coding for Noisy Channels

Author: Qian Xu

Publisher:

Published: 2005

Total Pages:

ISBN-13:

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The growing popularity of video sensor networks and video celluar phones has generated the need for low-complexity and power-efficient multimedia systems that can handle multiple video input and output streams. While standard video coding techniques fail to satisfy these requirements, distributed source coding is a promising technique for "uplink" applications. Wyner-Ziv coding refers to lossy source coding with side information at the decoder. Based on recent theoretical result on successive Wyner-Ziv coding, we propose in this thesis a practical layered Wyner-Ziv video codec using the DCT, nested scalar quantizer, and irregular LDPC code based Slepian-Wolf coding (or lossless source coding with side information) for noiseless channel. The DCT is applied as an approximation to the conditional KLT, which makes the components of the transformed block conditionally independent given the side information. NSQ is a binning scheme that facilitates layered bit-plane coding of the bin indices while reducing the bit rate. LDPC code based Slepian-Wolf coding exploits the correlation between the quantized version of the source and the side information to achieve further compression. Different from previous works, an attractive feature of our proposed system is that video encoding is done only once but decoding allowed at many lower bit rates without quality loss. For Wyner-Ziv coding over discrete noisy channels, we present a Wyner-Ziv video codec using IRA codes for Slepian-Wolf coding based on the idea of two equivalent channels. For video streaming applications where the channel is packet based, we apply unequal error protection scheme to the embedded Wyner-Ziv coded video stream to find the optimal source-channel coding trade-off for a target transmission rate over packet erasure channel.

Effective Video Coding for Multimedia Applications
Effective Video Coding for Multimedia Applications

Author: Sudhakar Radhakrishnan

Publisher: BoD – Books on Demand

Published: 2011-04-26

Total Pages: 270

ISBN-13: 953307177X

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Information has become one of the most valuable assets in the modern era. Within the last 5-10 years, the demand for multimedia applications has increased enormously. Like many other recent developments, the materialization of image and video encoding is due to the contribution from major areas like good network access, good amount of fast processors e.t.c. Many standardization procedures were carrried out for the development of image and video coding. The advancement of computer storage technology continues at a rapid pace as a means of reducing storage requirements of an image and video as most situation warrants. Thus, the science of digital video compression/coding has emerged. This storage capacity seems to be more impressive when it is realized that the intent is to deliver very high quality video to the end user with as few visible artifacts as possible. Current methods of video compression such as Moving Pictures Experts Group (MPEG) standard provide good performance in terms of retaining video quality while reducing the storage requirements. Many books are available for video coding fundamentals.This book is the research outcome of various Researchers and Professors who have contributed a might in this field. This book suits researchers doing their research in the area of video coding.The understanding of fundamentals of video coding is essential for the reader before reading this book. The book revolves around three different challenges namely (i) Coding strategies (coding efficiency and computational complexity), (ii) Video compression and (iii) Error resilience. The complete efficient video system depends upon source coding, proper inter and intra frame coding, emerging newer transform, quantization techniques and proper error concealment.The book gives the solution of all the challenges and is available in different sections.

Distributed Multiple Description Coding
Distributed Multiple Description Coding

Author: Huihui Bai

Publisher: Springer Science & Business Media

Published: 2011-11-19

Total Pages: 183

ISBN-13: 1447122488

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This book examines distributed video coding (DVC) and multiple description coding (MDC), two novel techniques designed to address the problems of conventional image and video compression coding. Covering all fundamental concepts and core technologies, the chapters can also be read as independent and self-sufficient, describing each methodology in sufficient detail to enable readers to repeat the corresponding experiments easily. Topics and features: provides a broad overview of DVC and MDC, from the basic principles to the latest research; covers sub-sampling based MDC, quantization based MDC, transform based MDC, and FEC based MDC; discusses Sleplian-Wolf coding based on Turbo and LDPC respectively, and comparing relative performance; includes original algorithms of MDC and DVC; presents the basic frameworks and experimental results, to help readers improve the efficiency of MDC and DVC; introduces the classical DVC system for mobile communications, providing the developmental environment in detail.

Performance of Wyner-Ziv Video Codec Under Rayleigh Fading Channel
Performance of Wyner-Ziv Video Codec Under Rayleigh Fading Channel

Author:

Publisher:

Published: 2005

Total Pages: 62

ISBN-13:

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In this thesis, we analyze the performance of a Wyner-Ziv codec over a flat-fading Rayleigh channel. In current interframe video compression systems, the encoder performs predictive coding to exploit the similarities of successive frames. The Wyner-Ziv Theorem on source coding with side information available only at the decoder suggests that an asymmetric video codec, where individual frames are encoded separately, but decoded conditionally (given temporally adjacent frames) could achieve similar efficiency. A transformdomain Wyner-Ziv coding scheme for motion video that uses intraframe encoding, but interframe decoding is implemented. In this system, the transform coefficients of a Wyner-Ziv frame are encoded independently using a scalar quantizer and turbo coder. The decoder uses previously reconstructed frames to generate side information to conditionally decode the Wyner-Ziv frames. In this work, the video is encoded using the Wyner-Ziv video codec that is implemented. The key(even) frames are compressed using a standard H.263 intra-frame encoder and the Wyner-Ziv(odd) frames are coded using Wyner-Ziv coding. Since Wyner-Ziv ceodec acts as a combined source channel coder there is no further channel coding performed on this bitstream. But, the H.263 compressed key frames are protected using RCPC codes. The compressed video is simulated over a flat-fading Rayleigh channel with Additive White Gaussian Noise(AWGN). The experimental results show that Wynwr-Ziv codec performs better than pure intra coding under channel noise and also they offer impressive bitrate savings.

Advanced Video Communications over Wireless Networks
Advanced Video Communications over Wireless Networks

Author: Ce Zhu

Publisher: CRC Press

Published: 2017-12-19

Total Pages: 523

ISBN-13: 1351832743

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Wireless video communications encompass a broad range of issues and opportunities that serve as the catalyst for technical innovations. To disseminate the most recent advances in this challenging yet exciting field, Advanced Video Communications over Wireless Networks provides an in-depth look at the fundamentals, recent technical achievements, challenges, and emerging trends in mobile and wireless video communications. The editors have carefully selected a panel of researchers with expertise in diverse aspects of wireless video communication to cover a wide spectrum of topics, including the underlying theoretical fundamentals associated with wireless video communications, the transmission schemes tailored to mobile and wireless networks, quality metrics, the architectures of practical systems, as well as some novel directions. They address future directions, including Quality-of-Experience in wireless video communications, video communications over future networks, and 3D video communications. The book presents a collection of tutorials, surveys, and original contributions, providing an up-to-date, accessible reference for further development of research and applications in mobile and wireless video communication systems. The range of coverage and depth of expertise make this book the go-to resource for facing current and future challenges in this field.