Scalable VoD Research Articles

An integrated scheme for streaming scalable encoded video-on-demand over CR networks

In this paper, we propose an adaptive scheme to deliver scalable VoD streams over a cognitive radio network (CRN) that consists of a base station (BS) and multiple secondary users (SUs). The proposed scheme aims at improving the perceptual quality of the received videos at the SUs end while maintaining a continuous playback. To do so, the scheme opportunistically exploits the idle primary channel(s) as sensed by the BS. Moreover, to reduce the impact of the intermittent availability nature of the CR channels, we propose a channel allocation algorithm that fairly allocates the idle channel(s) among the active SUs while jointly taking into consideration the status of the playback buffers at the SUs as well as the quality of the available channels. Additionally, the proposed scheme schedules the video frames on the allocated slots by exploiting the flexibility of the scalable video encoder as well as the adaption of the used modulation level based on the channel conditions to meet a predetermined target bit error rate (BER). Simulation results demonstrate the efficiency of the proposed scheme in exploiting the scalability feature of the transmitted video sequences to efficiently use the dynamic CR resources while achieving improved peak signal-to-noise ratio of the reconstructed video streams with uninterrupted playback.

SeekStream: adapting to dynamic user behavior in P2P video‐on‐demand

SummaryIn recent years, the users' perceived quality of experience (QoE) in streaming services has gained a lot of attention. Particularly, a number of research efforts have focused on providing live streaming and video‐on‐demand (VoD) services using peer‐to‐peer (P2P) architectures. However, in these proposed architectures, the heterogeneity of users and their dynamic behavior has not been sufficiently studied. In a real life scenario, where users have highly heterogeneous bandwidth resources (cable, DSL, 3G networks, etc) and can arbitrarily decide to perform a VCR function (stop, fast forward and seeking), ignoring this behavior can significantly deteriorate the system's efficiency and the perceived QoE. In this paper, we present SeekStream, a scalable P2P VoD architecture that ensures the stable delivery of the video stream to every participating user even in cases of high heterogeneity and frequent seeking operations. Specifically, SeekStream is a set of algorithms that optimize the P2P overlay dynamically and in a distributed fashion, making it adaptive to users dynamic behavior and bandwidth changes. The available bandwidth resources of the participating users are optimally exploited, keeping the contribution from the media server(s) to a minimal level. To illustrate the performance of the proposed algorithms, we are using a centralized overlay network manager that discovers the optimal network graph as a reference. We have developed an extensive P2P VoD simulator that shows the efficiency, scalability, and stability of our system under variant and dynamic conditions. The algorithms of our proposed system introduce less than 4% bandwidth overhead while we achieve high offloading of the media server(s). SeekStream guarantees a high block reception rate for the users, even under extreme seeking patterns. Copyright © 2016 John Wiley & Sons, Ltd.

A dependable multisource streaming system for peer-to-peer -based video on demand services provisioning

In this article, we present the design, implementation, and analysis of a scalable VOD (Video On Demand) distribution architecture for IP networks. The focus of our work is on the underlying multisource streaming architecture upon which the P2P (Peer-to-Peer) -based VOD services provisioning system relies. While multipoint-to-point multisource streaming is the core building block for a distributed VOD services provisioning system, it also introduces new reliability challenges as the streaming failure probability increases with the number of sources in a session. A major contribution of our work is the design of a suite of distinct yet complementary reliability/failover mechanisms that can be leveraged to improve the dependability of multisource streaming, and the viability of P2P-based VOD systems in general. Our work shows that the reliability/failover mechanisms can be arranged, combined, and alternated in advanced adaptation policies in order to deal with different conditions exhibited by the network. Another contribution of our work consists of implementing and assessing the performance of the different reliability mechanisms and adaptation policies in a real prototype system. We evaluate both the accuracy of streaming problems diagnosis, and the efficiency of the reliability mechanisms, in two adaptation strategies: one responsive to loss variation, and the other responsive to delay variation.

Analysis of a large-scale VOD architecture for broadband operators: a P2P-based solution

VOD services distribution is gaining unprecedented interest from the consumer communication industry due to its growing success in both the Internet and residential broadband market. In this article we present a scalable VOD distribution architecture for broadband operators. The solution is based on a P2P streaming concept in which a VOD streaming session requested by a given STB is actually provisioned via a multisource streaming session. This solution has the advantage of scaling naturally with the number of STBs in the network. In this article we focus on efficiently translating the popularity distribution into content availability in the network. Different aspects related to this issue are analyzed and challenges highlighted.

Building Scalable Wireless VoD Systems Through Efficient Management of Collocated Access Points

The growing need for ubiquitous access to video on demand (VoD) applications by large audiences has driven researches to build new scalable VoD systems that can guarantee Quality of Service (QoS) over wireless networks. In this paper, we propose and evaluate a novel system-level design that guarantees QoS by eliminating the service latency for short videos over IEEE 802.11 networks. Furthermore, our VoD system attains scalable performance by employing collocated access points (APs) coupled with an efficient association management of clients to the APs using a generic least-loaded-first heuristic on non-overlapping channels. Simulated results of our VoD system demonstrated that it achieved scalable performance due to its effective use of available bandwidth of the APs while supporting a low blockage rate for short videos up to 360 s. These results suggest that our VoD system can be an attractive solution for several classes of scalable VoD applications that require QoS guarantee such as movie trailers, news, video clips, and commercials.

P-chaining: a practical VoD service scheme autonomically handling interactive operations

Providing scalable VoD streaming services has recently become a hot issue, and many approaches have been proposed. Because video streaming services through the Internet are widely used, the need to support VCR operations also increases. However, there are few approaches to supporting VCR operations on the Internet. We propose a service scheme based on chaining, in which clients as well as the server provide streaming services. In the proposed scheme, services are provided by unicast and managed locally using node lists. In addition, our scheme can support frequent VCR operations without incurring significant overhead in the server workload. We have evaluated our scheme through simulation with real traces from a content distribution network (CDN) company and with various parameters. The results show that the proposed scheme reduces server workload significantly. The results also verify that frequent VCR operations can be served smoothly without causing too much overhead.

Assessing the efficiency of stream reuse techniques in P2P video-on-demand systems

Many works have reported simulated performance benefits of stream reuse techniques such as batching, chaining, and patching to the scalability of VoD systems. However, the relative contribution of such techniques has been rarely evaluated in practical implementations of scalable VoD servers. In this work, we investigated the efficiency of representative stream reuse techniques on the GloVE system, a low-cost scalable VoD platform whose resulting performance depends on the combination of the stream techniques it uses. More specifically, we evaluated performance of the GloVE system on delivering multiple MPEG-1 videos to clients connected to the server through a 100 Mbps Ethernet switch, and arrival rates varying from 6 to 120 clients/min. We present experimental results including startup latency, occupancy of server's channels, and aggregate bandwidth that GloVE demanded for several combinations of stream reuse techniques. Overall, our results reveal that stream reuse techniques in isolation offer limited performance scalability to VoD systems and only balanced combination of batching, chaining, and patching explains the scalable performance of GloVE on delivering highly popular videos with low startup latency while using the smallest number of server's channels.

A scalable video-on-demand system using multi-batch buffering techniques

A video-on-demand (VoD) system delivers videos on demand over an installed network. Due to the large size of digitized videos, expensive video servers with high I/O capability are needed in order to provide VoD services in metropolitan areas. In addition, there is a great need for efficient networking distribution/interaction schemes so that the video servers can serve as many clients as possible. In particular, because of scalability problems, the classical unicast VoD system is not suitable for large-scale deployments. In this paper, a highly scalable VoD system with a low per-user cost is described and evaluated. We first analyze the performance degradation problems using recently proposed VoD systems, namely batched and centralized-buffer VoD systems that occur during the handling of interactions. Then a new system called the multi-batch buffer (MBB) system, which attempts to solve these problems, is proposed. The proposed system handles a majority of interaction requests by scalable buffering techniques employed in the buffer of the local servers and the set-top boxes (STB). We have performed extensive simulation for the analysis and performance evaluation of our proposed VoD system. The simulation results demonstrate that our VoD system is very scalable and outperforms related state-of-the-art VoD systems.

A scalable video-on-demand system using future reservation of resources and multicast communications

In a video-on-demand (VoD) system the user can select and play movies according to his/her own quality of service (QoS) requirements. Upon receipt of the user request, a typical VoD system checks whether there are enough available resources to deliver the requested movie to the user's host. If the response is yes, the movie presentation can start; otherwise, a rejection is sent back to the user. This means that the response is based only on the system's load at the time the request is made and assumes that the service duration (movie length) is infinite. In this paper we propose a scalable VoD (SVoD) system which decouples the starting time of the service from the time the service request is made and requires that the duration of the requested service must be specified. In response to a user request, SVoD determines the QoS with which the movie can be presented at the time the service request is made, and at certain later times carefully chosen. As an example if the requested QoS cannot be supported at the time the service request is made, SVoD allows to compute the earliest time, when the user can play the movie with the desired QoS. This time can also be determined in a way to use multicast communication to deliver the same movie to several users. The scalability achieved by SVoD is quantified and compared with that of typical VoD. The performance quantification, performed through the use of simulations, shows that SVoD achieves (in average) high resource utilization and decreases (in average) the blocking probability of user requests. In the worst case (very unlikely to happen) SVoD performs similarly to VoD. However, at any case SVoD provides a more useful feedback to the user helping him/her to make appropriate decisions.