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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
41

Adaptive techniques for scalable video compression

Mehrseresht, Nagita, Electrical Engineering & communication, UNSW January 2005 (has links)
In this work we investigate adaptive techniques which can be used to improve the performance of highly scalable video compression schemes under resolution scaling. We propose novel content adaptive methods for motion compensated 3D discrete wavelet transformation (MC 3D-DWT) of video. The proposed methods overcome problems of ghosting and non-aligned aliasing artifacts, which can arise in regions of motion model failure, when the video is reconstructed at reduced temporal or spatial resolutions. We also study schemes which facilitate simultaneous scaling of compressed video bitstreams based on both constant bit-rate and constant distortion criteria, using simple and generic scaling operations. In regions where the motion model fails, the motion compensated temporal discrete wavelet transform (MC TDWT) causes ghosting artifacts under frame-rate scaling, due to temporal lowpass filtering along invalid motion trajectories. To avoid ghosting artifacts, we adaptively select between different lowpass filters, based on a local estimate of the motion modelling accuracy. Experimental results indicate that the proposed adaptive transform substantially removes ghosting artifacts while also preserving the high compression efficiency of the original MC TDWT. We also study the impact of various MC 3D-DWT structures on spatial scalability. Investigating the interaction between spatial aliasing, scalability and energy compaction shows that the t+2D structure essentially has higher compression efficiency. However, where the motion model fails, structures of this form cause non-aligned aliasing artifacts under spatial scaling. We propose novel adaptive schemes to continuously adapt the structure of MC 3D-DWT based on information available within the compressed bitstream. Experimental results indicate that the proposed adaptive structure preserves the high compression efficiency of the t+2D structure while also avoiding the appearance of non-aligned aliasing artifacts under spatial scaling. To provide simultaneous rate and distortion scaling, we study ???layered substream structure. Scaling based on distortion generates variable bit-rate traffic which satisfies the desired average bit-rate and is consistent with the requirements of leaky-bucket traffic models. We propose a novel method which also satisfies constraints on instantaneous bit-rate. This method overcomes the weakness of previous methods with small leaky-bucket buffer sizes. Simulation results indicate promising performance with both MC 3D-DWT interframe and JPEG2000 intraframe compression.
42

Rate control based on human visual perception characteristics and its application in encoding time-lapse video /

Nguyen, Anthony Giang. January 2002 (has links)
Thesis (Ph. D.)--University of Washington, 2002. / Vita. Includes bibliographical references (leaves 111-116).
43

Adaptive techniques for scalable video compression

Mehrseresht, Nagita, Electrical Engineering & communication, UNSW January 2005 (has links)
In this work we investigate adaptive techniques which can be used to improve the performance of highly scalable video compression schemes under resolution scaling. We propose novel content adaptive methods for motion compensated 3D discrete wavelet transformation (MC 3D-DWT) of video. The proposed methods overcome problems of ghosting and non-aligned aliasing artifacts, which can arise in regions of motion model failure, when the video is reconstructed at reduced temporal or spatial resolutions. We also study schemes which facilitate simultaneous scaling of compressed video bitstreams based on both constant bit-rate and constant distortion criteria, using simple and generic scaling operations. In regions where the motion model fails, the motion compensated temporal discrete wavelet transform (MC TDWT) causes ghosting artifacts under frame-rate scaling, due to temporal lowpass filtering along invalid motion trajectories. To avoid ghosting artifacts, we adaptively select between different lowpass filters, based on a local estimate of the motion modelling accuracy. Experimental results indicate that the proposed adaptive transform substantially removes ghosting artifacts while also preserving the high compression efficiency of the original MC TDWT. We also study the impact of various MC 3D-DWT structures on spatial scalability. Investigating the interaction between spatial aliasing, scalability and energy compaction shows that the t+2D structure essentially has higher compression efficiency. However, where the motion model fails, structures of this form cause non-aligned aliasing artifacts under spatial scaling. We propose novel adaptive schemes to continuously adapt the structure of MC 3D-DWT based on information available within the compressed bitstream. Experimental results indicate that the proposed adaptive structure preserves the high compression efficiency of the t+2D structure while also avoiding the appearance of non-aligned aliasing artifacts under spatial scaling. To provide simultaneous rate and distortion scaling, we study ???layered substream structure. Scaling based on distortion generates variable bit-rate traffic which satisfies the desired average bit-rate and is consistent with the requirements of leaky-bucket traffic models. We propose a novel method which also satisfies constraints on instantaneous bit-rate. This method overcomes the weakness of previous methods with small leaky-bucket buffer sizes. Simulation results indicate promising performance with both MC 3D-DWT interframe and JPEG2000 intraframe compression.
44

Low complexity multiview video coding

Khattak, Shadan January 2014 (has links)
3D video is a technology that has seen a tremendous attention in the recent years. Multiview Video Coding (MVC) is an extension of the popular H.264 video coding standard and is commonly used to compress 3D videos. It offers an improvement of 20% to 50% in compression efficiency over simulcast encoding of multiview videos using the conventional H.264 video coding standard. However, there are two important problems associated with it: (i) its superior compression performance comes at the cost of significantly higher computational complexity which hampers the real-world realization of MVC encoder in applications such as 3D live broadcasting and interactive Free Viewpoint Television (FTV), and (ii) compressed 3D videos can suffer from packet loss during transmission, which can degrade the viewing quality of the 3D video at the decoder. This thesis aims to solve these problems by presenting techniques to reduce the computational complexity of the MVC encoder and by proposing a consistent error concealment technique for frame losses in 3D video transmission. The thesis first analyses the complexity of the MVC encoder. It then proposes two novel techniques to reduce the complexity of motion and disparity estimation. The first method achieves complexity reduction in the disparity estimation process by exploiting the relationship between temporal levels, type of macroblocks and search ranges while the second method achieves it by exploiting the geometrical relation- ship between motion and disparity vectors in stereo frames. These two methods are then combined with other state-of-the-art methods in a unique framework where gains add up. Experimental results show that the proposed low-complexity framework can reduce the encoding time of the standard MVC encoder by over 93% while maintaining similar compression efficiency performance. The addition of new View Synthesis Prediction (VSP) modes to the MVC encoding framework improves the compression efficiency of MVC. However, testing additional modes comes at the cost of increased encoding complexity. In order to reduce the encoding complexity, the thesis, next, proposes a bayesian early mode decision technique for a VSP enhanced MVC coder. It exploits the statistical similarities between the RD costs of the VSP SKIP mode in neighbouring views to terminate the mode decision process early. Results indicate that the proposed technique can reduce the encoding time of the enhanced MVC coder by over 33% at similar compression efficiency levels. Finally, compressed 3D videos are usually required to be broadcast to a large number of users where transmission errors can lead to frame losses which can degrade the video quality at the decoder. A simple reconstruction of the lost frames can lead to inconsistent reconstruction of the 3D scene which may negatively affect the viewing experience of a user. In order to solve this problem, the thesis proposes, at the end, a consistency model for recovering frames lost during transmission. The proposed consistency model is used to evaluate inter-view and temporal consistencies while selecting candidate blocks for concealment. Experimental results show that the proposed technique is able to recover the lost frames with high consistency and better quality than two standard error concealment methods and a baseline technique based on the boundary matching algorithm.
45

On design of a scalable video data placement strategy for supporting a load balancing video-on-demand storage server.

January 1997 (has links)
by Kelvin Kwok-wai Law. / Thesis (M.Phil.)--Chinese University of Hong Kong, 1997. / Includes bibliographical references (leaves 66-68). / Abstract --- p.i / Acknowledgments --- p.iii / Chapter 1 --- Introduction --- p.1 / Chapter 1.1 --- Background --- p.1 / Chapter 1.2 --- Motivation --- p.2 / Chapter 1.3 --- Scope --- p.3 / Chapter 1.4 --- Dissertation Outline --- p.4 / Chapter 2 --- Background and Related Researches --- p.6 / Chapter 2.1 --- Interactive Services --- p.6 / Chapter 2.2 --- VOD Architecture --- p.7 / Chapter 2.3 --- Video Compression --- p.10 / Chapter 2.3.1 --- DCT Based Compression --- p.11 / Chapter 2.3.2 --- Subband Video Compression --- p.12 / Chapter 2.4 --- Related Research --- p.14 / Chapter 3 --- Multiple Resolutions Video File System --- p.16 / Chapter 3.1 --- Physical Disk Storage System --- p.16 / Chapter 3.2 --- Multi-resolution Video Data Placement Scheme --- p.17 / Chapter 3.3 --- Example of our Video Block Assignment Algorithm --- p.23 / Chapter 3.4 --- An Assignment Algorithm for Homogeneous Video Files --- p.26 / Chapter 4 --- Disk Scheduling and Admission Control --- p.33 / Chapter 4.1 --- Disk Scheduling Algorithm --- p.33 / Chapter 4.2 --- Admission Control --- p.40 / Chapter 5 --- Load Balancing of the Disk System --- p.43 / Chapter 6 --- Buffer Management --- p.49 / Chapter 6.1 --- Buffer Organization --- p.49 / Chapter 6.2 --- Buffer Requirement For Different Video Playback Mode --- p.51 / Chapter 7 --- Conclusions --- p.63 / Bibliography --- p.66
46

Classification of Near-Duplicate Video Segments Based on their Appearance Patterns

Murase, Hiroshi, Takahashi, Tomokazu, Deguchi, Daisuke, Shamoto, Yuji, Ide, Ichiro January 2010 (has links)
No description available.
47

An examination of how undergraduate students can be prepared for careers in non-linear video editing

Horvath, Stephen M. January 2000 (has links)
Thesis (M.S.)--Kutztown University of Pennsylvania, 2000. / Source: Masters Abstracts International, Volume: 45-06, page: 2807. Typescript. Abstract precedes thesis as preliminary leaf 2. Includes bibliographical references (leaves 44-47).
48

Fast multi-frame and multi-block selection for H.264 video coding standard /

Chang, Andy. January 2003 (has links)
Thesis (M. Phil.)--Hong Kong University of Science and Technology, 2003. / Includes bibliographical references (leaves 57-58). Also available in electronic version. Access restricted to campus users.
49

Masculinity at the video game arcade : 1972-1983

Kocurek, Carly Ann 12 November 2013 (has links)
As the United States shifted toward a service-based economy and an increasingly digital media environment, American youth -- particularly young men and boys -- found an opportunity to play with these values in the then-novel video game arcade. The video game industry first came of age between the successful commercialization of Pong in 1972 and the U.S. gaming industry crash of 1983. In the interim, economic and play practices in the arcade itself and media representations of the arcade and its habitués shaped and responded to the economic and cultural upheavals of the period. Arcade machines were the first computers many Americans confronted. Through public discourse about gaming and gamers, Americans engaged in a critical debate about computerization, the move to digital media culture, the restructuring of the U.S. labor economy, and the competitiveness of American youth -- particularly boys -- in a Cold War culture conceived as both hostile and technologically oriented. This study demonstrates that video gaming was an arena in which Americans grappled with larger tensions about masculinity, globalization, labor, and digitalization. By analyzing gaming as a practice of everyday life, this work not only offers a cultural history of this period of gaming, but critical insights into the crystallization of masculine identity in a postindustrial, postmodern economy. / text
50

RESEARCH ON VIDEO OBJECT PLANE WITH APPLICATION IN TELEOPERATIONS

Khan, Mohsin 23 April 2013 (has links)
Teleoperations is a significant field in robotics research; its applications range from emergency rooms in hospitals to space station orbiting the Earth to Mars rovers scavenging the red planet for microscopic life. We have developed a new user defined selective video object plane scheme. This selective filter works with standard H.264 encoder which is developed using Intel IPP and uses the latest multicore capabilities of new processors and can encode and transmit high definition videos over internet in real time. The area of interest is extracted and encoded at a different frame rate and noise level than rest of the frame. Our modified algorithm uses user input as well as motion detection of individual pixels to define video object plane. Video object plane filter is designed to be used for video with slow moving objects for cases like surgical procedures. The results of our compression algorithm have been verified using SSIM, PSNR and human perception survey. All these results of our VOP showed better performance than comparable encoders at the same bandwidth.

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