Error Correction and Concealment of Bock Based, Motion-Compensated Temporal Predition, Transform Coded Video

Error Correction and Concealment of Block Based, Motion-Compensated Temporal Prediction, Transform Coded Video David L. Robie 133 Pages Directed by Dr. Russell M. Mersereau The use of the Internet and wireless networks to bring multimedia to the consumer continues to expand. The transmission of these products is always subject to corruption due to errors such as bit errors or lost and ill-timed packets; however, in many cases, such as real time video transmission, retransmission request (ARQ) is not practical. Therefore receivers must be capable of recovering from corrupted data. Errors can be mitigated using forward error correction in the encoder or error concealment techniques in the decoder. This thesis investigates the use of forward error correction (FEC) techniques in the encoder and error concealment in the decoder in block-based, motion-compensated, temporal prediction, transform codecs. It will show improvement over standard FEC applications and improvements in error concealment relative to the Motion Picture Experts Group (MPEG) standard. To this end, this dissertation will describe the following contributions and proofs-of-concept in the area of error concealment and correction in block-based video transmission. A temporal error concealment algorithm which uses motion-compensated macroblocks from previous frames. A spatial error concealment algorithm which uses the Hough transform to detect edges in both foreground and background colors and using directional interpolation or directional filtering to provide improved edge reproduction. A codec which uses data hiding to transmit error correction information. An enhanced codec which builds upon the last by improving the performance of the codec in the error-free environment while maintaining excellent error recovery capabilities. A method to allocate Reed-Solomon (R-S) packet-based forward error correction that will decrease distortion (using a PSNR metric) at the receiver compared to standard FEC techniques. Finally, under the constraints of a constant bit rate, the tradeoff between traditional R-S FEC and alternate forward concealment information (FCI) is evaluated. Each of these developments is compared and contrasted to state of the art techniques and are able to show improvements using widely accepted metrics. The dissertation concludes with a discussion of future work.Ph.D.Committee Chair: Mersereau, Russell; Committee Member: Altunbasak, Yucel; Committee Member: Fekri, Faramarz; Committee Member: Lanterman, Aaron; Committee Member: Zhou, Haomi

Efficient compression of motion compensated residuals

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Novel source coding methods for optimising real time video codecs.

The quality of the decoded video is affected by errors occurring in the various layers of the protocol stack. In this thesis, disjoint errors occurring in different layers of the protocol stack are investigated with the primary objective of demonstrating the flexibility of the source coding layer. In the first part of the thesis, the errors occurring in the editing layer, due to the coexistence of different video standards in the broadcast market, are addressed. The problems investigated are ‘Field Reversal’ and ‘Mixed Pulldown’. Field Reversal is caused when the interlaced video fields are not shown in the same order as they were captured. This results in a shaky video display, as the fields are not displayed in chronological order. Additionally, Mixed Pulldown occurs when the video frame-rate is up-sampled and down-sampled, when digitised film material is being standardised to suit standard televisions. Novel image processing algorithms are proposed to solve these problems from the source coding layer. In the second part of the thesis, the errors occurring in the transmission layer due to data corruption are addressed. The usage of block level source error-resilient methods over bit level channel coding methods are investigated and improvements are suggested. The secondary objective of the thesis is to optimise the proposed algorithm’s architecture for real-time implementation, since the problems are of a commercial nature. The Field Reversal and Mixed Pulldown algorithms were tested in real time at MTV (Music Television) and are made available commercially through ‘Cerify’, a Linux-based media testing box manufactured by Tektronix Plc. The channel error-resilient algorithms were tested in a laboratory environment using Matlab and performance improvements are obtained

Integrated and Heterogenous Mobile Edge Caching (MEC) Networks

The recent phenomenal growth of the global mobile data traffic, mainly caused by intelligent Internet of Things (IoTs), is the most significant challenge of wireless networks within the foreseeable future. In this context, Mobile Edge Caching (MEC) has been recognized as a promising solution to maintain low latency communication. This, in turn, improves the Quality of Service (QoS) by storing the most popular multimedia content close to the end-users. Despite extensive progress in MEC networks, however, there are still limitations that should be addressed. Through this Ph.D. thesis, first, we perform a literature review on recent works on MEC networks to identify challenges and potential opportunities for improvement. Then, by highlighting potential drawbacks of the reviewed works, we aim to not only enhance the cache-hit-ratio, which is the metric to quantify the users’ QoS, but also to improve the quality of experience of caching nodes. In this regard, we design and implement a Deep Reinforcement Learning (DRL)-based connection scheduling framework [1] to minimize users’ access delay by maintaining a trade-off between the energy consumption of Unmanned Aerial Vehicles (UAVs) and the occurrence of handovers. We also use D2D communication [2] to increase the network’s capacity without adding any infrastructure. Another approach to effectively use the limited storage capacity of caching nodes is to increase the content diversity by employing the coded caching strategies in cluster-centric networks. Despite all the researches on the cluster-centric cellular networks, there is no framework to determine how different segments can be cached to increase the data availability in a UAV-aided cluster-centric cellular network. Moreover, to date, limited research has been performed on UAV-aided cellular networks to provide high QoS for users in both indoor and outdoor environments. Through this thesis research, we aim to address these gaps [3,4]. In addition, another goal of this thesis is to design real-time caching strategies [5–9] to predict the upcoming most popular content to improve the users’ access delay. Last but not least, capitalizing on recent advancements of indoor localization frameworks [10–14], we aim to develop a proactive caching strategy for an integrated indoor/outdoor MEC network

MediaSync: Handbook on Multimedia Synchronization

This book provides an approachable overview of the most recent advances in the fascinating field of media synchronization (mediasync), gathering contributions from the most representative and influential experts. Understanding the challenges of this field in the current multi-sensory, multi-device, and multi-protocol world is not an easy task. The book revisits the foundations of mediasync, including theoretical frameworks and models, highlights ongoing research efforts, like hybrid broadband broadcast (HBB) delivery and users' perception modeling (i.e., Quality of Experience or QoE), and paves the way for the future (e.g., towards the deployment of multi-sensory and ultra-realistic experiences). Although many advances around mediasync have been devised and deployed, this area of research is getting renewed attention to overcome remaining challenges in the next-generation (heterogeneous and ubiquitous) media ecosystem. Given the significant advances in this research area, its current relevance and the multiple disciplines it involves, the availability of a reference book on mediasync becomes necessary. This book fills the gap in this context. In particular, it addresses key aspects and reviews the most relevant contributions within the mediasync research space, from different perspectives. Mediasync: Handbook on Multimedia Synchronization is the perfect companion for scholars and practitioners that want to acquire strong knowledge about this research area, and also approach the challenges behind ensuring the best mediated experiences, by providing the adequate synchronization between the media elements that constitute these experiences