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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.
31

H.264 CODEC Blocks Implementation on FPGA

ASLAM, UMAIR January 2014 (has links)
H.264/AVC (Advance Video Coding) standard developed by ITU-T Video Coding Experts Group(VCEG) and ISO/IEC JTC1 Moving Picture Experts Group (MPEG), is one of the most powerful andcommonly used format for video compression. It is mostly used in internet streaming sources i.e.from media servers to end users. This Master thesis aims at designing a CODEC targeting the Baseline profile on FPGA.Uncompressed raw data is fed into the encoder in units of macroblocks of 16×16 pixels. At thedecoder side the compressed bit stream is taken and the original frame is restored. Emphasis isput on the implementation of CODEC at RTL level and investigate the effect of certain parameterssuch as Quantisation Parameter (QP) on overall compression of the frame rather than investigatingmultiple solutions of a specified block of CODEC.
32

Resurgence of religion in public life : expressing Christianity through public service provision

Reynolds, Nicola January 2015 (has links)
Research on faith based organisations involvement in public service provision neglects to consider the personal faith convictions of those working in this field. Using a social constructionist epistemology I investigate if and how faith convictions of employees and volunteers working for Christian based service providers impact on the work they do. Data were collected in two stages using semi structured interviews. Stage one obtained a broad overview of the role of Christian service providers from the perspective of elite Christians representing Christian organisations that have a direct connection to welfare provision in the UK. Stage two took an in-depth look at the issues raised in stage one, seeking to understand them from the perspective of ordinary Christians who work for Christian based service providers. Findings from this thesis further sociological understanding of Christian involvement in religiously plural public spheres, and argues that faith is an intrinsic part of the delivery of public services by people working for faith-based organisations. Drawing on the theoretical concept of Individualised Religiosities as proposed by Luckmann, Bellah, Davie, Beck and others, and the concept of Lived Religion as developed by McGuire and Ammerman, this thesis examines participants constructed understanding of the Christian God and its connection with public service provision. It develops a complex, three fold sociological conceptualisation of Christian perceptions of the God figure as: 1) the Supreme Being, 2) as a parental figure, and 3) an embodied God. This broad conceptualisation illustrates how participants combine institutional activities, such as attending church sermons, with more autonomous religious activities, such as personal conversations with God, to construct a multidimensional understanding of the figure. The embodied God position takes on further significance when understanding that participants use public service work as a form of church . Public service can be viewed as a form of private worship, but by embodying God, they also take God to people that may not practice Christianity. These findings challenge assumptions that the practice of religion in public projects has declined in recent years and that faith organisations are reticent to push their faith when providing services. Religious pluralism results in political expectations that faith groups are religiously neutral when delivering public services. Using Framing Theory this thesis demonstrates that participants are framing faith discourses so that they resonate with discourses deemed acceptable in the public realm. It conceptualises these discourses in two action frames, the Love, and Inclusivity Frames. There are indications of a shift towards using profane terms instead of sacred terms to explain and indirectly promote aspects of the Christian faith. Moreover, Christian teachings of love, compassion and belonging are amplified to counter criticisms that Christianity is a threat to liberal rights and beliefs. These frames, which demonstrate the accommodation of Christian discourse to a religiously plural and/or neutral discourse, have implications for how we understand Christian involvement in the public sphere.
33

Optimization on H.264 De-blocking Filter

Waheed, Abdul-Mohammed January 2008 (has links)
H.264/AVC is the state-of-the-art video coding standard which promises to achieve same video quality at about half the bit rate of previous standards (H.263, MPEG-2). This tremendous achievement in compression and perceptual quality is due to the inclusion of various innovative tools. These tools are highly complex and data intensive as a result poses very heavy computational burden on the processors. De-blocking filter is one among them, it is the most time consuming part of the H.264/AVC reference decoder. In this thesis, a performance analysis of the de-blocking filter is made on Intel Pentium 4 processor and accordingly various optimization techniques have been studied and implemented. For some techniques statistical analysis of video data is done and according to the results obtained optimization is performed and for other techniques SIMD instructions has been used to achieve the optimization. Comparison of optimized techniques using SIMD with the reference software has shown significant speedup thus contributing to the real time implementation of the de-blocking filter on general purpose platform. / De-blocking Filter is the most time consuming part of the H.264 High Profile decoder. The process of De-block filtering specified in the H.264/AVC standard is sequential thus not computationally optimal. In this thesis various optimization algorithms have been studied and implemented. When compared to JM13.2 boundary strength algorithm, Static and ICME algorithms are quite primitive as a result no performance gain is achieved, in fact there is a decrease in performance. This dismal performance is due to various reasons, prominent among them are increased memory access, unrolling of loop to 4x4 boundary and early detection of intra blocks. When it comes to the optimization algorithms of Edge filtering module both the algorithms (SIMD and fast algorithm) showed significant improvement in performance when compared to JM13.2 edge filtering algorithm. This improvement is mainly due to the parallel filtering operation done in edge filtering module. Therefore, by using SSE2 instructions large speed up could be achieved on general purpose processors like Intel, while keeping the conformance with the standard.
34

3D multiple description coding for error resilience over wireless networks

Umar, Abubakar Sadiq January 2011 (has links)
Mobile communications has gained a growing interest from both customers and service providers alike in the last 1-2 decades. Visual information is used in many application domains such as remote health care, video –on demand, broadcasting, video surveillance etc. In order to enhance the visual effects of digital video content, the depth perception needs to be provided with the actual visual content. 3D video has earned a significant interest from the research community in recent years, due to the tremendous impact it leaves on viewers and its enhancement of the user’s quality of experience (QoE). In the near future, 3D video is likely to be used in most video applications, as it offers a greater sense of immersion and perceptual experience. When 3D video is compressed and transmitted over error prone channels, the associated packet loss leads to visual quality degradation. When a picture is lost or corrupted so severely that the concealment result is not acceptable, the receiver typically pauses video playback and waits for the next INTRA picture to resume decoding. Error propagation caused by employing predictive coding may degrade the video quality severely. There are several ways used to mitigate the effects of such transmission errors. One widely used technique in International Video Coding Standards is error resilience. The motivation behind this research work is that, existing schemes for 2D colour video compression such as MPEG, JPEG and H.263 cannot be applied to 3D video content. 3D video signals contain depth as well as colour information and are bandwidth demanding, as they require the transmission of multiple high-bandwidth 3D video streams. On the other hand, the capacity of wireless channels is limited and wireless links are prone to various types of errors caused by noise, interference, fading, handoff, error burst and network congestion. Given the maximum bit rate budget to represent the 3D scene, optimal bit-rate allocation between texture and depth information rendering distortion/losses should be minimised. To mitigate the effect of these errors on the perceptual 3D video quality, error resilience video coding needs to be investigated further to offer better quality of experience (QoE) to end users. This research work aims at enhancing the error resilience capability of compressed 3D video, when transmitted over mobile channels, using Multiple Description Coding (MDC) in order to improve better user’s quality of experience (QoE). Furthermore, this thesis examines the sensitivity of the human visual system (HVS) when employed to view 3D video scenes. The approach used in this study is to use subjective testing in order to rate people’s perception of 3D video under error free and error prone conditions through the use of a carefully designed bespoke questionnaire.
35

Performance Modeling of QoE-Aware Multipath Video Transmission in the Future Internet / Leistungsmodellierung einer Mehrpfad Video Übertragung im zukünftigen Internet unter Berücksichtigung der QoE

Zinner, Thomas January 2012 (has links) (PDF)
Internet applications are becoming more and more flexible to support diverge user demands and network conditions. This is reflected by technical concepts, which provide new adaptation mechanisms to allow fine grained adjustment of the application quality and the corresponding bandwidth requirements. For the case of video streaming, the scalable video codec H.264/SVC allows the flexible adaptation of frame rate, video resolution and image quality with respect to the available network resources. In order to guarantee a good user-perceived quality (Quality of Experience, QoE) it is necessary to adjust and optimize the video quality accurately. But not only have the applications of the current Internet changed. Within network and transport, new technologies evolved during the last years providing a more flexible and efficient usage of data transport and network resources. One of the most promising technologies is Network Virtualization (NV) which is seen as an enabler to overcome the ossification of the Internet stack. It provides means to simultaneously operate multiple logical networks which allow for example application-specific addressing, naming and routing, or their individual resource management. New transport mechanisms like multipath transmission on the network and transport layer aim at an efficient usage of available transport resources. However, the simultaneous transmission of data via heterogeneous transport paths and communication technologies inevitably introduces packet reordering. Additional mechanisms and buffers are required to restore the correct packet order and thus to prevent a disturbance of the data transport. A proper buffer dimensioning as well as the classification of the impact of varying path characteristics like bandwidth and delay require appropriate evaluation methods. Additionally, for a path selection mechanism real time evaluation mechanisms are needed. A better application-network interaction and the corresponding exchange of information enable an efficient adaptation of the application to the network conditions and vice versa. This PhD thesis analyzes a video streaming architecture utilizing multipath transmission and scalable video coding and develops the following optimization possibilities and results: Analysis and dimensioning methods for multipath transmission, quantification of the adaptation possibilities to the current network conditions with respect to the QoE for H.264/SVC, and evaluation and optimization of a future video streaming architecture, which allows a better interaction of application and network. / Die Applikationen im Internet passen sich immer besser an unterschiedliche Anforderungen der Nutzer und variierende Netzwerkbedingungen an. Neue Mechanismen ermöglichen die zielgerichtete Anpassung der Anwendungsqualität und damit der benötigten Bandbreite. Im Falle von Videostreaming ermöglicht der skalierbare Videocodec H.264/SVC, die flexible Veränderung der Bildwiederholungsrate, der Auflösung des Videos und der Bildqualität an die vorhandenen Ressourcen im Netzwerk. Um eine gute vom Nutzer erfahrene Dienstgüte (Quality of Experience, QoE) zu garantieren, muss die Videoqualität richtig angepasst und optimiert werden. Aber nicht nur die Anwendungen des heutigen Internets haben sich verändert. Gerade in den letzten Jahren entstanden neue Netzwerk- und Transporttechnologien, welche eine flexiblere und effizientere Nutzung der Kommunikationsnetze erlauben. Eine dieser Techniken ist die Virtualisierung von Netzwerken. Sie erlaubt es auf einem gemeinsamen physikalischen Netz verschiedene logische Netze zu betreiben, die zum Beispiel Anwendungs-abhängige Adressierung unterstützen, eigene Namensgebung erlauben oder ein individuelles Ressourcen Management ermöglichen. Neuartige Transportmechanismen wie Mehrpfadübertragung auf Netzwerk- und Transportebene des ISO/OSI Stacks streben eine effiziente Ausnutzung der zur Verfügung stehenden Übertragungsmöglichkeiten an. Doch die simultane Übertragung von Daten über heterogene Kommunikationspfade und –technologien führt unausweichlich zu einer Veränderung der Reihenfolge, in der die Pakete ankommen. Es werden zusätzliche Mechanismen und Puffer benötigt, um die ursprüngliche Paketreihenfolge wieder herzustellen und so einen störenden Einfluss auf den Datentransport zu verhindern. Die richtige Dimensionierung dieser Puffer sowie die Klassifizierung des Einflusses von variierenden Pfadparametern wie Bandbreite und Verzögerungen setzen passende Evaluierungsmethoden voraus. Darüber hinaus werden für die Auswahl von geeigneten Pfaden aus einer Menge vorhandener Pfade echtzeitfähige Bewertungsmechanismen benötigt. Eine bessere Interaktion zwischen Applikationen und Netzwerk und der damit verbundene Informationsaustausch ermöglicht die effiziente Anpassung der Applikationsqualität an das Netzwerk und umgekehrt. Diese Doktorarbeit analysiert eine auf Mehrpfadübertragung und skalierbarer Videokodierung basierende Videostreaming Architektur und erarbeitet die folgenden Optimierungsmöglichkeiten und Auswertungen: Analyse- und Dimensionierungsmethoden für Mehrpfadübertragung, Quantifizierung der Anpassungsmöglichkeiten von SVC an das Netzwerk unter Berücksichtigung der QoE und Evaluierung und Optimierung einer zukünftigen Videostreaming Architektur, welche eine stärkere Interaktion zwischen Applikation und Netzwerk ermöglicht.
36

Information flow in task-oriented groups

January 1953 (has links)
R. Duncan Luce ... [et al.]. / "August 31, 1953." / Bibliography: p. 95. / Army Signal Corps Contract DA36-039 sc-100 Project 8-102B-0 Dept. of the Army Project 3-99-10-022
37

An Efficient Motion Estimation Method for H.264-Based Video Transcoding with Arbitrary Spatial Resolution Conversion

Wang, Jiao January 2007 (has links)
As wireless and wired network connectivity is rapidly expanding and the number of network users is steadily increasing, it has become more and more important to support universal access of multimedia content over the whole network. A big challenge, however, is the great diversity of network devices from full screen computers to small smart phones. This leads to research on transcoding, which involves in efficiently reformatting compressed data from its original high resolution to a desired spatial resolution supported by the displaying device. Particularly, there is a great momentum in the multimedia industry for H.264-based transcoding as H.264 has been widely employed as a mandatory player feature in applications ranging from television broadcast to video for mobile devices. While H.264 contains many new features for effective video coding with excellent rate distortion (RD) performance, a major issue for transcoding H.264 compressed video from one spatial resolution to another is the computational complexity. Specifically, it is the motion compensated prediction (MCP) part. MCP is the main contributor to the excellent RD performance of H.264 video compression, yet it is very time consuming. In general, a brute-force search is used to find the best motion vectors for MCP. In the scenario of transcoding, however, an immediate idea for improving the MCP efficiency for the re-encoding procedure is to utilize the motion vectors in the original compressed stream. Intuitively, motion in the high resolution scene is highly related to that in the down-scaled scene. In this thesis, we study homogeneous video transcoding from H.264 to H.264. Specifically, for the video transcoding with arbitrary spatial resolution conversion, we propose a motion vector estimation algorithm based on a multiple linear regression model, which systematically utilizes the motion information in the original scenes. We also propose a practical solution for efficiently determining a reference frame to take the advantage of the new feature of multiple references in H.264. The performance of the algorithm was assessed in an H.264 transcoder. Experimental results show that, as compared with a benchmark solution, the proposed method significantly reduces the transcoding complexity without degrading much the video quality.
38

An Efficient Motion Estimation Method for H.264-Based Video Transcoding with Arbitrary Spatial Resolution Conversion

Wang, Jiao January 2007 (has links)
As wireless and wired network connectivity is rapidly expanding and the number of network users is steadily increasing, it has become more and more important to support universal access of multimedia content over the whole network. A big challenge, however, is the great diversity of network devices from full screen computers to small smart phones. This leads to research on transcoding, which involves in efficiently reformatting compressed data from its original high resolution to a desired spatial resolution supported by the displaying device. Particularly, there is a great momentum in the multimedia industry for H.264-based transcoding as H.264 has been widely employed as a mandatory player feature in applications ranging from television broadcast to video for mobile devices. While H.264 contains many new features for effective video coding with excellent rate distortion (RD) performance, a major issue for transcoding H.264 compressed video from one spatial resolution to another is the computational complexity. Specifically, it is the motion compensated prediction (MCP) part. MCP is the main contributor to the excellent RD performance of H.264 video compression, yet it is very time consuming. In general, a brute-force search is used to find the best motion vectors for MCP. In the scenario of transcoding, however, an immediate idea for improving the MCP efficiency for the re-encoding procedure is to utilize the motion vectors in the original compressed stream. Intuitively, motion in the high resolution scene is highly related to that in the down-scaled scene. In this thesis, we study homogeneous video transcoding from H.264 to H.264. Specifically, for the video transcoding with arbitrary spatial resolution conversion, we propose a motion vector estimation algorithm based on a multiple linear regression model, which systematically utilizes the motion information in the original scenes. We also propose a practical solution for efficiently determining a reference frame to take the advantage of the new feature of multiple references in H.264. The performance of the algorithm was assessed in an H.264 transcoder. Experimental results show that, as compared with a benchmark solution, the proposed method significantly reduces the transcoding complexity without degrading much the video quality.
39

The implementation of H.264 algorithm with parallel extended MMX instruction set

Shen, Cheng-Ying 20 August 2008 (has links)
The H.264 Protocol is an important method for the multimedia transmission and calculation, but it is difficult to work smoothly on the embedded systems because of the low clock in the working environment of the embedded system .Although many new multimedia instruction sets have been developed, the immediate multimedia calculation is still difficult to implement on the embedded system. So this paper uses the ¡§Multimedia Operation Register¡¨, a SIMD architecture, to implement H.264 algorithm on the embedded system to improve the performance of handling multimedia calculation. Multimedia Operation Register, which performs the parallel execution of the multi-data-streaming, uses the bit slice concept to design operation pair combining bit storage cell and bit computation. According to the characteristic , which is the address having constant distance between more than two data being used saved in the Memory, this paper using the striping addressing mode , which can cooperate with the parallel execution of multi-data-streaming , to load the data having strode addresses from the Memory in one instructions. On the other hand, this paper designs a new instruction set based on the Intel MMX instruction set and the operation feature of multimedia calculation. When a designer uses single-data-steaming to implement the H.264 Protocol by the multimedia instruction sets, he will use more interactions to do the same thing in every block. Now this paper can use fewer interactions to do the same thing because the Multimedia Operation Register can use the parallel execution of the multi-data-stream to calculate the data in many different blocks to implement H.264 Protocol at the same time. On the other hand, this paper can reallocate the number of the registers to the arithmetic unit which will be used smartly by changing the working mode. This paper also saves much execution time of some actions such as the transpose of the matrix, the data resorting and the SAD (Sum of Absolute Differences) calculation by using new instructions. In order to reduce the times of memory access, this paper uses the method which rotates the data between two registers to let the data been used as possible as it can. So the coding efficiency can be improved explosively by using all the methods which have been introduced. The conclusion in this paper shows that the parallel execution of the multi-data-streaming will be a very important method to handle multimedia calculation. And this paper advances an innovative architecture to implement the parallel execution of the multi-data- streaming. According to the simulation in 5th chapter, the speedup of handling H.264 Protocol by Multimedia Operation Register is more than four times with MMX instruction set. In the SAD calculation, it even can have ten times advanced then MMX instruction set. At last the efficacy is even better than the latest multimedia instruction set -¡§SSE4¡¨.
40

Adaptive Frame Structure Determination for Hierarchical B Frame Coding

Lai, Chung-Ping 09 September 2009 (has links)
The hierarchical B picture coding is introduced into the extension of H.264/AVC in order to improve coding performance and provide temporal scalability as well. In general, coding performance is affected by the content variation in each GOP (Group of Picture). Therefore, the ways to determine the size of sun-GOP is a critical problem for video coding. In this thesis, the adaptive GOP structure determination scheme is proposed to select the appropriate sub-GOP size with content complexity consideration. We compute the frame difference by hierarchical B picture structure and use the information to be a basis of sub-GOP decision. Hence, we can get proper combination of sub-GOP. Experimental results show the RD curves that our proposed method compares with the fixed GOP setting in the existing hierarchical B picture coding of SVC.

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