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Accrding to the PMPEG-1/2 standard, full motion video can be compressed and stored in an information warehouse. Multiplexing with normal voice calls, it is retrieved and delivered to the customer's local BISDN central office via 1...
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Accrding to the PMPEG-1/2 standard, full motion video can be compressed and stored in an information warehouse. Multiplexing with normal voice calls, it is retrieved and delivered to the customer's local BISDN central office via 155 Mb/s trunks. These vice calls have higher priority than video-on-demand (VOD) so that normal vice services will not be influenced by VOD transmission. The number of vice calls always fluctuates in real-time. Thus, an efficient traffic control scheme is highly desired to guarantee a given level of performance and achieve as great as possible use of available bandwidth.
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Broadcasting is an efficient transmission scheme to provide on-demand service for very popular movies in a multicast environment. In this paper, a comparative study is first performed to evaluate various broadcasting protocols in ...
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Broadcasting is an efficient transmission scheme to provide on-demand service for very popular movies in a multicast environment. In this paper, a comparative study is first performed to evaluate various broadcasting protocols in terms of maximum waiting time, client buffer requirement and receiver bandwidth. It is found that some existing broadcasting schemes are not practical to provide a small delay video-on-demand (VoD) service if the client buffer size is not large enough. It is shown that the staggered and skyscraper protocols are the only feasible solutions to support an insensitive delay VoD system with limited client buffer and receiver bandwidth. Two first segment partition schemes are then proposed to further reduce the maximum waiting time of these two broadcasting schemes. The results show that if 15 min of video data can be stored in the buffer, Skyscraper with our proposed schemes can serve the customers within 10 s using 16 video channels. For Staggered broadcasting with our schemes, the maximum waiting time can also be reduced from 7.5 min to less than 1 min.
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A big portion of Internet traffic nowadays is video. A good understanding of user behavior in online Video-on-Demand (VoD) systems can help us design, configure and manage video content distribution. With the help of a major VoD s...
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A big portion of Internet traffic nowadays is video. A good understanding of user behavior in online Video-on-Demand (VoD) systems can help us design, configure and manage video content distribution. With the help of a major VoD service provider, we conducted a detailed study of user behavior watching streamed videos over the Internet. We engineered the video player at the client side to collect user behavior reports for over 540 million sessions. In order to isolate the possible effect of session quality of experience (QoE) on user behavior, we use only the sessions with perfect QoE, and leave out those sessions with QoE impairments (such as freezes). Our main finding is that users spend a lot of time browsing: viewing part of one video after another, and only occasionally (around 20% of the time) watching a video to its completion. We consider seek (jump to a new position of the video) as a special form of browsing -repeating partial viewing of the same video. Our analysis leads to a user behavior model in which a user transitions through a random number of short views before a longer view, and repeats the process a random number of times. This model can be considered an extension, and a more detailed alternative to the closed queueing network formulation introduced by Wu et al. (2009) . As an application of our user behavior model, we use it to measure video popularity. We study the similarity of our approach to subjective evaluation and simple view count based metric, and conclude our approach gives results closer to subjective evaluation.
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This paper proposes idea of videotoms usage in quality tests of video signals. This concept simplifies parametric model creation for television services such as IPTV (Internet Protocol Television), VoD (Video on Demand) and others...
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This paper proposes idea of videotoms usage in quality tests of video signals. This concept simplifies parametric model creation for television services such as IPTV (Internet Protocol Television), VoD (Video on Demand) and others. Videotom is simple, well-defined video sequence in the context of video quality tests. Presented idea was used in both objective and subjective tests of influence selected network parameters: jitter of delay, packet loss and packet corrupt on the video quality measured using Mean Square Error (MSE) and Mean Opinion Score (MOS) metrics. Results showed that proposed method is useful especially for subjective tests and it can reduce costs and time for them.
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In Video-on-Demand (VoD) services, the playback continuity is one of the most crucial factors for end-user to judge service quality. It is even more significant than the actual video image quality since new generation VoD users co...
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In Video-on-Demand (VoD) services, the playback continuity is one of the most crucial factors for end-user to judge service quality. It is even more significant than the actual video image quality since new generation VoD users commonly have heterogeneous requirements on service according to their context. Moreover, managing dynamic situations in VoD service is always a challenge, especially in the unpredictable user preferences and network conditions. In this paper, i) Autonomous Decentralized VoD System (ADVODS) has been proposed to satisfy different service quality demands of users and, ii) the Autonomous Node Allocation Technology (ANAT) is proposed for assuring service continuity. With the help of autonomous nodes and mobile agents, ANAT can applies different backup policies to users with different Service Level Agreements (SLA), and dynamically update the backup schema to adapt the changing situations such as various service time or congestion events. Drawing on the evaluation results this paper shows that proposed system architecture has a better performance on streaming service provision and continuity.
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In this paper, we develop a batching algorithm to provide Video on Demand (VoD) streaming service over wireless networks considering heterogeneous characteristics of VoD service. The proposed batching service considers both renegi...
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In this paper, we develop a batching algorithm to provide Video on Demand (VoD) streaming service over wireless networks considering heterogeneous characteristics of VoD service. The proposed batching service considers both reneging behavior and adaptive modulation and coding (AMC). Two reneging behavior models are considered: the exponential and the convex models. A nonlinear programming problem is suggested for each reneging model to minimize the service latency with the reneging probability and the network capacity constraints. The performance of the reneging and AMC based network capacity of the proposed batching algorithm is experimented and compared to the unicast procedures. Simulations are performed to illustrate the excellence of the proposed batching algorithm. The AMC based network capacity and exponential reneging improve the latency by 66-77 and 35-46% respectively for high service arrival rates.
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Providing real-time Internet video streaming anytime, anywhere and using any devices from different access networks preserves more challenges to equilibrate the quality of service (QoS) and security protection (QoP). Because encry...
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Providing real-time Internet video streaming anytime, anywhere and using any devices from different access networks preserves more challenges to equilibrate the quality of service (QoS) and security protection (QoP). Because encryption/decryption for video packets are time-consuming processes to protect real-time video streaming services from eavesdropping, our observation is that the playback buffer occupancy (PBO) can simply indicate time availability to adjust security level to affect the packet sending rate. In this paper, we present an end-to-end buffer-aware feedback control from client PBO for effectively securing media streaming for heterogeneous clients over ubiquitous Internet. That is, security-level adjustments can be applied further to keep PBO running away from overflow and underflow to pursue an effective leverage between QoS and QoP. To further boost the protection, we also apply the Diffie-Hellman key negotiation method to provide the dynamic key changes. Moreover, since the running PBO will vary on the dynamics of Internet from access time, client devices and access networks, the different applied security levels and key changes during the video streaming session will make eavesdropper more difficult to recover all the encrypted videos delivered in public networks. We demonstrate the leverage performance in preserving both QoS and QoP for ubiquitous video streaming in our proposed schemes by comprehensive experiments on a true VoD system. The experimental results show our secure VoD scheme can achieve cost-effective leverage of QoS and QoP from different inserted network dynamics, even if client buffer size is limited to 256 KB only.
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The choice between a P2P and a conventional centralized realization of VoD service on cable television network can be made after a comparison of the traffic in different sections of the network. Until recently, the centralized arc...
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The choice between a P2P and a conventional centralized realization of VoD service on cable television network can be made after a comparison of the traffic in different sections of the network. Until recently, the centralized architecture has been the most popular architecture for providing VoD service to subscribers of cable television network. With the growth of the network, however, this type of architecture has become inapplicable because of the need for a large number of outgoing video streams from the central VoD server, i.e. high bit rate through the central transmission network. The objective of this paper is to compare the necessary bit rates on different network sections of P2P and centralized VoD architecture and to study the influence of the more important parameters on these bit rates.
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A novel and simple approach for defining end-to-end quality of service (QoS) in video-on-demand (VoD) services is presented. Using this approach, we derive a schedulable region for a video server which guarantees end-to-end QoS, w...
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A novel and simple approach for defining end-to-end quality of service (QoS) in video-on-demand (VoD) services is presented. Using this approach, we derive a schedulable region for a video server which guarantees end-to-end QoS, where a specific QoS required in the video client translates into a QoS specification for the video server. Our methodology is based on a generic model for VoD services, which is extendible to any VoD system. In this kind of system, both the network and the video server are potential sources of QoS degradation. Specifically, we examine the effect that impairments in the video server and video client have on the video quality perceived by the end user. The Columbia VoD testbed is presented as an example to validate the model through experimental results. Our model can be connected to network QoS admission control models to create a unified approach for admission control of incoming video requests in the video server and network
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This paper concerns quality evaluation of the telecommunication services: VoIP (representing the RT interactive class) and VoD (representing the MM streaming class). Subjective and objective methods and tools for perceived quality...
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This paper concerns quality evaluation of the telecommunication services: VoIP (representing the RT interactive class) and VoD (representing the MM streaming class). Subjective and objective methods and tools for perceived quality measurement are analyzed and compared. Subjective tests are performed for selected video sequences using the Double-Stimulus Impairment Scale (DSIS) method. Thus the objective algorithms (VQM and VQmon) are calibrated. Speech quality is measured using the objective methods: PESQ and POLQA. Threshold values for network parameters (packet loss rate, delay jitter) are set, that guarantee the acceptable service quality.
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