Real-time multiple video player systems

Multimedia distance education is the teaching mode based on computer and network, so that we can accomplish the tasks of teaching in different places or at different times. The distributed multimedia distance education system is low cost, and it can effectively overcome the limitations of time and space, and is being morewidely used. Multimedia distance education system needs to solve the key problem of how to transfer the audio and video to the destination by internet technology effectively. The multimedia distance education system needs to transmit audio and video in real time, so the transmission delay must be reduced in order to ensure the teaching and interaction between teachers and students. In this paper, we design a more advanced and efficient remote teaching system based on the node management of a distributed system. Firstly, we take the distributed multimedia technology as the key technology and an important means to facilitate the transmission of streaming media data. Then, we put forward the method of configuration management and state management in the media server cluster. Secondly, on the basis of the previous method, we put forward a method of load balancing management based on RTCP control message. Based on the design in this paper, we realize the orderly and efficient management of the media server cluster in a distributed system. Finally, we simulate the performance test of the node management in the media server cluster to validate the advantages of the node management. This design can effectively reduce the transmission delay of streaming media data.

Multimedia synchronization is the essential technology for the integration of multimedia in distributed multimedia systems. The multimedia synchronization model has been recognized by many researchers as a premise of the implementation of multimedia synchronization. In distributed multimedia systems, the characteristic of multimedia synchronization is dynamic, and the key medium has the priority in multimedia synchronization. The previously proposed multimedia synchronization models cannot meet these requirements. So a new multimedia dynamic synchronization model—DSPN, based on the timed Petri-net has been designed in this paper. This model can not only let the distributed multimedia system keep multimedia synchronization in a more precise and effective manner according to the runtime situation of the system, but also allow the user to interact with the presentation of multimedia.

Windows NT has become a widespread, general purpose operating system and is seeing increased use in real-time applications. However Windows NT was nor designed for real-time operation and, in such environments, the all too common Windows NT system stop event (crash or Blue Screen of Death) can prove catastrophic. Consequently three commercial real-time extensions are available for Windows NT: Hyperkernel from Imagination Systems, INtime from RadiSys, and RTX from VenturCom. These extensions add determinism for real-time applications along with the capability for real-time applications to survive a Windows NT stop event. Each solution has a different architecture and our rests revealed that each solution has a different response to Windows NT crashes. These extensions differ in the types of stop events which can be survived the code required to survive a stop event, I/O capabilities after a stop event, and real-time performance during a stop event. However, all of these solutions allow some level of protection until the user can initiate an orderly shutdown at an appropriate time.

Highly dynamic programming environments for embedded real-time systems require a strict isolation of real-time threads from each other to achieve dependable systems. We propose a new real-time scheduling technique, called guaranteed percentage (GP) scheme that assigns each thread a specific percentage of the processor power. A hardware scheduler in conjunction with a multithreaded processor guarantees the execution of instructions of each thread according to their assigned percentages within a time interval of 100 processor cycles. We compare performance and implementation overhead of GP scheduling against fixed priority, preemptive (FPP), earliest deadline first (EDF), and least laxity first (LLF) scheduling using several benchmarks on our Komodo microcontroller that features a multithreaded Java processor kernel. Our evaluations show that GP scheduling reaches a speed-up similar to EDF and FPP but worse than LLF. However its hardware implementation costs are still reasonable, whereas the LLF overhead is prohibitive. Only GP reaches the isolation goal among the examined scheduling schemes.

Cloud computing and big data: Technologies and applications

Adaptive reservation is a real-time scheduling technique in which each application is associated a fraction of the computational resource (a reservation) that can be dynamically adapted to the varying requirements of the application by using appropriate feedback control algorithms. An adaptive reservation is typically implemented by using an aperiodic server (e.g. sporadic server) algorithm with fixed period and variable budget. When the feedback law demands an increase of the reservation budget, the system must run a schedulability test to check if there is enough spare bandwidth to accommodate such increase. The schedulability test must be very fast, as it may be performed at each budget update, i.e. potentially at each instance of a task; yet, it must be as efficient as possible, to maximize resource usage. In this paper, we tackle the problem of performing an efficient on-line schedulability test for adaptive resource reservations in fixed priority schedulers. In the literature, a number of algorithms have been proposed for on-line admission control in fixed priority systems. We describe four of these tests, with increasing complexity and performance. In addition, we propose a novel on-line test, called Spare-Pot algorithm, which has been specifically designed for the problem at hand, and which shows a good cost/performance ratio compared to the other tests.

There have been research works on supporting QoS (Quality of Service) in a distributed multimedia systems. These researches can be categorized as following; system platform, real-time operating system, transport protocol, communication architecture. In distributed multimedia environment, QoS must be guaranteed in end systems, but much less progress has been made in addressing this problem. As the processing power of end systems increases, most of the bottleneck occurs in communication protocol, especially transport protocol. To meet an end-to-end QoS, overall QoS architectures must be integrated. In this paper, we propose a new QoS architecture and control mechanisms (group control, and flow control) to guarantee an end-to-end QoS for distributed multimedia services. We also verify proposed architecture by applying them to a multimedia conferencing system in LAN.

ABSTRACTAn Augmented virtual environment (AVE) is concerned with the fusion of real-time video with 3D models or scenes so as to augment the virtual environment. In this paper, a new approach to establish an AVE with a wide field of view is proposed, including real-time video projection, multiple video texture fusion and 3D visualization of moving objects. A new diagonally weighted algorithm is proposed to smooth the apparent gaps within the overlapping area between the two adjacent videos. A visualization method for the location and trajectory of a moving virtual object is proposed to display the moving object and its trajectory in the 3D virtual environment. The experimental results showed that the proposed set of algorithms are able to fuse multiple real-time videos with 3D models efficiently, and the experiment runs a 3D scene containing two million triangles and six real-time videos at around 55 frames per second on a laptop with 1GB of graphics card memory. In addition, a realistic AVE with a wide field of view was created based on the Digital Earth Science Platform by fusing three videos with a complex indoor virtual scene, visualizing a moving object and drawing its trajectory in the real time.

Cloud gaming systems host the game in the cloud, and stream players' gaming videos to the terminals in the form of encode video frames. To address the high bandwidth issue of real-time gaming video transmission, a cloudlet-assisted multiplayer cloud gaming system was proposed to encourage cooperative video sharing via a secondary ad-hoc network, on the purpose of exploiting the similarities of video frames among multiple players in a same game. However, the video cooperative sharing among players also introduces fairness problems. In this paper, we complete the ad hoc cloudlet-assisted cloud gaming system by further considering the mobility of terminal devices and the diversity of network quality for distinct players. With mathematical formulation, we study the players' behavior in cooperative sharing patterns and propose a reputation-based multiplayer fairness scheme in terms of frame encoding. Experimental results illustrate the impact of mobility on the system performance and evaluate that the proposed solution provides better fairness gaming ecosystem compared to the existing platform.

The significant resource requirements of distributed real-time multimedia applications often push today's system platforms to their limits. As a consequence, efficient, economic and adaptive management of resources is a major issue in distributed multimedia systems. This paper outlines a model-based time service encompassing three different aspects of time that are fundamental for sophisticated strategies within cross layer failure semantics, flow control, and synchronization.

Image and video processing algorithms present a necessary tool for various domains related to computer vision such as medical applications, pattern recognition and real time video processing methods. The performance of these algorithms have been severely hampered by their high intensive computation since the new video standards, especially those in high definitions require more resources and memory to achieve their computations. In this paper, we propose a new framework for multimedia (single image, multiple images, multiple videos, video in real time) processing that exploits the full computing power of heterogeneous machines. This framework enables to select firstly the computing units (CPU or/and GPU) for processing, and secondly the methods to be applied depending on the type of media to process and the algorithm complexity. The framework exploits efficient scheduling strategies, and allows to reduce significantly data transfer times thanks to an efficient management of GPU memories and to the overlapping of data copies by kernels executions. Otherwise, the framework includes several GPU-based image and video primitive functions, such as silhouette extraction, corners detection, contours extraction, sparse and dense optical flow estimation. These primitives are exploited in different applications such as vertebra segmentation in X-ray and MR images, videos indexation, event detection and localization in multi-user scenarios. Experimental results have been obtained by applying the framework on different computer vision methods showing a global speedup ranging from 5 to 100, by comparison with sequential CPU implementations.

Background/Objectives: To analyze the caching strategies used in distributed system and techniques involved in scheduling. Methods/Statistical Analysis: System with two or more processor when working simultaneously has the demand over the processing speed in distributed system for sharing the hard disk, memory and other memory devices. A CACHE memory or computer memory with very short access time used for storage of frequently used instruction or data. An extreme fast memory is built into CPU or located next to the chip. Findings: The major possible vulnerabilities over dirty data and cache coherence are also discussed. Many implementations are done for estimating the usage of hardware cache over Distributed real time and embedded system. Various real time applications are integrated with DRE system to reduce the execution time based on optimization techniques. Applications/Improvements: In this paper various techniques over cache with shared multi-processor system covers to reduce the average data access time with various inputs as workload application to check the performance of the system over different cache levels.

Performance of personal computers has been increasing steadily since their introduction in the early eighties. Personal computers available today employ technologies that were not long ago exclusively used on super computers and main-frames. One of the most recent developments in the personal computer technology is the usage of multiprocessors in order to increase the computing power. However, since it is known that computing power increase is not directly proportional to the number of processors, the performance increase gained from additional processors is difficult to predict. Many researchers claim that personal computer technology, based on Intel x86 design, has scaling problems when multiple processors are used. Computer manufacturers so far have failed to provide reliable information related to scaling problems. In order to analyze the performance gain from an additional processor in a personal computer and to study the performance dependence of the computer architecture on the operating system, a dual processor computer system was designed and built from the functional blocks available on the market. The fast Fourier transform algorithm was adopted and modified, to be used as the computation intensive performance indicator. The FFT algorithm was run on the designed two-processor system under Windows NT Workstation version 4.0, and Linux version 2.0 with and without the use of the threading techniques and the performance gain due to the second processor was determined. It was observed that the addition of the second processor resulted in the maximum speedup of 1.91 under Windows NT and 1.67 under Linux, when the threading techniques were used. Furthermore it was observed that without the use of the threading, the addition of the second processor, under specific conditions, impaired the system's performance. The paper presents the details of the performance study.

In this paper, we develop a novel real-time instruction-level loop scheduling technique to reduce leakage energy consumption for applications with loops on VLIW architecture. We first prove that the scheduling problem with the minimum leakage energy consumption within a timing constraint is NP-complete. Then, LEMLS (leakage energy minimization loop scheduling) algorithm is designed to repeatedly regroup a loop based on rotation scheduling (Chao et al., 1997), and decrease leakage energy integrating with leakage power reduction mechanism. We conduct experiments on a set of DSP benchmarks based on the power model of the VLIW processors in (Liao et al., 2002). The results show that our algorithm achieves significant leakage energy saving compared with list scheduling and the algorithm in (You et al., 2006).

We introduce an open meta-model that will be easily enriched to cover new real-time scheduling models and techniques. On the one hand, it will be possible to connect several independent schedulability analysis tools, following closely the advances in real-time scheduling theory, dealing with a temporal model that will be covered by our metamodel. On the other hand, we will use model transformation techniques in order to extract information from different design methodologies. This extraction can be done at different stages of the design (early for sensitivity analysis, at a later stage for temporal validation) to create a temporal model of the designed system, without the designer to be an expert in scheduling theory. We are working currently on the meta-model phase. The objective is to cover enough concepts to be able to represent a big part of the real-time scheduling models and problems, without introducing too much complexity. This paper uses the UML profile mechanism to describe such a meta-model.