P2P Video Research Articles

Enabling resilient P2P video streaming: survey and analysis

Peer-to-Peer (P2P) techniques for multimedia streaming have been shown to be a good enhancement to the traditional client/server methods when trying to reduce costs and increase robustness. Due to the fact that P2P systems are highly dynamic, the main challenge that has to be addressed remains supporting the general resilience of the system. Various challenges arise when building a resilient P2P streaming system, such as network failures and system dynamics. In this paper, we first classify the different challenges that face P2P streaming and then present and analyze the possible countermeasures. We classify resilience mechanisms as either core mechanisms, which are part of the system, or as cross-layer mechanisms that use information from different communication layers, which might inflict additional costs. We analyze and present resilience mechanisms from an engineering point of view, such that a system engineer can use our analysis as a guide to build a resilient P2P streaming system with different mechanisms and for various application scenarios.

Low-complexity unbalanced multiple description coding based on balanced clusters for adaptive peer-to-peer video streaming

Multiple description scalable coding based on T+2D wavelet decomposition structure is highly flexible for peer-to-peer (P2P) video streaming. Finding the optimal truncation point of each wavelet-decomposed code block (CB) within each description is an NP-hard problem (Akyol et al., 2007 [1]). For P2P video streaming, it is necessary to implement an efficient multiple description encoder with three attributes; “adaptive” (due to the time-varying capacity of the P2P network links and nodes), “low-complexity” (because of the low processing power of the receiving peer) with arbitrarily “unbalanced descriptions” (because of the unequal capacities of the different sending peers). To design a multiple description encoder with the above mentioned features, we propose a simple clustering algorithm for partitioning the CBs into a limited number of clusters. This simple and efficient clustering algorithm significantly reduces the size of redundancy-rate assignment matrix, such that one can find the optimal channel-aware cluster-level redundancy-rate assignment matrix using a low-complexity full search approach. This approach improves the decoding quality compared to the co-echelon adaptive frameworks (Akyol et al., 2007 [1]; Tillo et al., 2007 [8]) in which a non-optimal heuristic rate assignment pattern is used. Especially for the unbalanced P2P scenario (which is the usual case), the performance gain of the proposed approach over the one presented in Tillo et al. (2007) [8] (generating only balanced descriptions) is significant (0.95–3.0 dB). In addition, the proposed clustering approach may be analytically represented by closed-form relations for low-complexity computation of the optimal encoding parameters. Our complexity analysis shows that the proposed approach requires 52–96% less computations compared to the framework in Akyol et al. (2007) [1]. Therefore, an efficient real-time post-encoding adaptation mechanism may be realized. The simulation results demonstrate that the adaptive proposed framework outperforms the approach presented in Akyol et al. (2007) [1] by (0.26–0.95 dB) and the non-adaptive multiple description coding by (1.1–2.3 dB).

High-Quality P2P Video Streaming System Considering the Cooperation of Constitution Information and Delivery Status

Recently, video streaming services using P2P (Peer-to-Peer) have attracted attention to solve the problem of load concentration on servers and to reduce large latency. Many P2P streaming systems, like Coolstreaming, however, take a complicated approach to control playback timing severely. This leads to less churn resiliency and less adaptability to fluctuation of network traffic. Therefore, we focus on a simple and robust approach to realize “pseudo” streaming with high quality, which is based on BitTorrent. In the existing methods with the simple approach, peers download pieces just closer to playback timing to decrease the playback discontinuity. However, these methods do not consider the constitution of video structure in sophisticated manner. P2P streaming system must consider several important metrics for high-quality and fair distribution. Therefore, in this paper, we propose a new P2P video streaming system considering the cooperation of three important metrics; video structure, playback timing, and piece dispersion on network. In this system, users vary three piece selections to suit the delivery status. Specifically, users preferentially download pieces which affect the video quality, which are closer to playback timing, and which improve the delivery efficiency. Moreover, we show the effectiveness of the proposed method by computer simulation.

Unequal Protection of Video Data According to Slice Relevance

In this paper, we devise a procedure that mimics the behavior of a progressive video stream starting from a non progressive one such as H.264/AVC encoded video. This allows one to unequally protect the video data in an efficient way, according to their importance and the network state. The reported results demonstrate the superior performance of the proposed approach in comparison to state-of-the-art methods for resilient transmission of H.264/AVC data. Moreover, the flexibility in terms of redundancy insertion and achieved quality levels, allows one to span different applications, possibly including P2P video streaming.

TURINstream: A Totally pUsh, Robust, and effIcieNt P2P Video Streaming Architecture

This paper presents TURINstream, a novel P2P video streaming architecture designed to jointly achieve low delay, robustness to peer churning, limited protocol overhead, and quality-of-service differentiation based on peers cooperation. Separate control and video overlays are maintained by peers organized in clusters that represent sets of collaborating peers. Clusters are created by means of a distributed algorithm and permit the exploitation of the participant nodes upload capacity. The video is conveyed with a push mechanism by exploiting the advantages of multiple description coding. TURINstream design has been optimized through an event driven overlay simulator able to scale up to tens of thousands of peers. A complete prototype of TURINstream has been developed, deployed, and tested on PlanetLab. We tested our prototype under varying degree of peer churn, flash crowd arrivals, sudden massive departures, and limited upload bandwidth resources. TURINstream fulfills our initial design goals, showing low average connection, startup, and playback delays, high continuity index, low control overhead, and effective quality-of-service differentiation in all tested scenarios.

Skype Video congestion control: An experimental investigation

The Internet is facing a significant evolution from being a delivery network for static content to an efficient platform for multimedia content delivery. Well-known examples of applications driving this evolution are YouTube Video on Demand, Skype Audio/Video conference, IPTV and P2P video distribution. While YouTube streams videos using the Transmission Control Protocol (TCP), time-sensitive applications, such as Skype Audio/Video conference, employ the UDP because they can tolerate small loss percentages but not delays due to TCP recovery of lost packets via retransmissions. Since, differently from the TCP, the UDP does not implement congestion control, these applications must implement congestion control at the application layer in order to avoid congestion and preserve network stability. In this paper we investigate Skype Video congestion control in order to assess to what extent this application is able to throttle its sending rate to match the unpredictable Internet bandwidth while preserving resource for co-existing best-effort TCP traffic. We have found that: (1) Skype Video adapts its sending rate by varying frame rate, frame quality and video resolution; (2) in many scenarios a Skype Video call refrains from fully utilizing all available bandwidth thus not sending videos at the highest possible quality; (3) Skype Video employs an adaptive FEC action that is proportional to the experienced loss rate; (4) the sending rate matches a changing available bandwidth with a transient time as large as a hundred of seconds; (5) the minimum bandwidth required for a video call is 40kbps at 5 frames per second.

Redesigning multi-channel P2P live video systems with View-Upload Decoupling

In current multi-channel P2P live video systems, there are several fundamental performance problems including exceedingly-large channel switching delays, long playback lags, and poor performance for less popular channels. These performance problems primarily stem from two intrinsic characteristics of multi-channel P2P video systems: channel churn and channel-resource imbalance. In this paper, we propose a radically different cross-channel P2P streaming framework, called View-Upload Decoupling (VUD). VUD strictly decouples peer downloading from uploading, bringing stability to multi-channel systems and enabling cross-channel resource sharing. We propose a set of peer assignment and bandwidth allocation algorithms to properly provision bandwidth among channels, and introduce substream-swarming to reduce the bandwidth overhead. We evaluate the performance of VUD via extensive simulations as well with a PlanetLab implementation. Our simulation and PlanetLab results show that VUD is resilient to channel churn, and achieves lower switching delay and better streaming quality. In particular, the streaming quality of small channels is greatly improved.

A new fast P2P video transmission method applied in asymmetrical speed channel environment

In an asymmetrical speed channel environment like asymmetric digital subscriber line, the up-link bandwidth is normally smaller than the down-link bandwidth, which will lead to extremely low utilization of down-link bandwidth when current P2P video transmission is applied. To overcome this, a new fast P2P video transmission method applied in an asymmetrical speed channel environment is proposed in this paper. On the basis of the many-to-one concept, the proposed method uses a new multi-peer aggregation technique to enhance the utilization of down-link bandwidth. In addition, an adaptive peer assignment algorithm is also introduced in order to minimize the overall transmission time. Experimental results show that by using our proposed method, the utilization of down-link bandwidth is significantly improved, and the overall transmission time is greatly reduced.

Bandwidth Reduction via Localized Peer-to-Peer (P2P) Video

This paper presents recent research into P2P distribution of video that can be highly localized, preferably sharing content among users on the same access network and Central Office (CO). Models of video demand and localized P2P serving areas are presented. Detailed simulations of passive optical networks (PON) are run, and these generate statistics of P2P video localization. Next-Generation PON (NG-PON) is shown to fully enable P2P video localization, but the lower rates of Gigabit-PON (GPON) restrict performance. Results here show that nearlyallof the traffic volume of unicast video could be delivered via localized P2P. Strong growth in video delivery via localized P2P could lower overall future aggregation and core network bandwidth of IP video traffic by 58.2%, and total consumer Internet traffic by 43.5%. This assumes aggressive adoption of technologies and business practices that enable highly localized P2P video.

Resource-awareness and trade-off optimisation in P2P video streaming

Recently, various P2P platforms have become widely popular tools for delivering both real-time and on-demand video services over the internet. However, these P2P TV approaches do experience some limitations, which adversely affect their performance. For instance, most P2P applications are designed to balance CPU load and memory but not network resources or vice versa. Through an experimental-based study and simulation, this paper unveils strengths and shortcomings of these tools and suggests methods for improving the P2P IPTV performance. The findings are based on the analysis of traffic traces from P2P streaming applications such as Zattoo, Joost, Sopcast and Babelgum and the simulation of the proposed approach.

Tree-aware selective frame discard for P2P IPTV system on set-top boxes

Peer-to-peer (P2P) streaming provides an effective means to enlarge the service scale for set-top box (STB) based internet protocol television (IPTV). A major challenge of designing such a P2P IPTV system is how to provide high-quality P2P video streaming over resource constrained devices. In this paper, we present a P2P IPTV system, which tailors to support live video streaming on resource constrained STB devices. Specifically, we propose a tree-aware selective frame discard algorithm for the P2P IPTV system, which performs a differentiated frame discard strategy by taking into account the location of a STB node in P2P multicast tree. Simulation results demonstrate that our proposed scheme enhances the media quality of STB based P2P streaming on congested links.

On-demand waypoints for live P2P video broadcasting

A peer-to-peer architecture has emerged as a promising approach to enabling the ubiquitous deployment of live video broadcasting on the Internet. However the performance in these architectures is unpredictable and fundamentally constrained by the characteristics of the members participating in the broadcast. By characteristics, we refer to user dynamics, out-going bandwidth connectivity, whether the member is behind NAT/firewall, and the network conditions among participating members. While several researchers have looked at hybrid P2P/CDN approaches to address these issues, such approaches require provisioning of centralized server resources prior to a broadcast, which complicates the goal of ubiquitous video broadcasting. In this paper, we explore an alternative architecture where users are willing to donate their bandwidth resources to a broadcast event, even though they are not a participant in the event. Such users constitute what we term a waypoint community. Any given broadcast event involves constructing overlays only based on participants to the extent possible, however waypoints may be dynamically invoked in an on-demand, performance-driven fashion to improve the performance of a broadcast. We present the design of a system built on this idea. Detailed results from trace-driven experiments over the PlanetLab distributed infrastructure and Emulab demonstrate the potential of the waypoint architecture to improve the performance of purely P2P-based overlays.

Adaptive topology formation for peer-to-peer video streaming

In this paper we propose an adaptive P2P video streaming framework to address the challenges due to bandwidth heterogeneity and peer churn on the Internet. This adaptive streaming framework consists of two major components, source rate adaptation and adaptive overlay topology formation, to maximize the video quality and fully utilize the overall peer upload capacity. In the source rate adaptation, the video server adapts the video source rate automatically based on the local measurement of peers’ download rates, so that the P2P network is not overloaded beyond its bandwidth capacity and peers are able to achieve smooth video playback. To combat bandwidth heterogeneity, we propose to construct a desirable link-level homogeneous overlay topology using a Markov chain Monte Carlo method, so that peers achieve an equal per-connection upload/download bandwidth. In this link-level homogeneous network, video flows do not encounter any bottlenecks along the delivery paths, and peers achieve high download rates to ensure smooth video playback. We also design a fully distributed algorithm to implement the dual mechanisms of the adaptive topology formation and the source rate maximization. To evaluate the performance of our streaming framework, we conduct both mathematical analysis and extensive simulations. The simulation results confirm our analysis and show that the proposed distributed algorithm is able to maximize the video playback quality with fast convergence.

Inferring playback rate and rate resets of P2P video streaming transmissions by piecewise line envelope approximation

Conventionally, P2P video is regarded as CBR traffic. However, our measurements have shown that the rate reset cannot be neglected in a practical IPTV system because each rate reset often leads to performance degradation. Thus, addressing the problem of inferring playback rate and rate reset in a P2P video system is significant. In this article, an algorithm termed piecewise linear envelope approximation (PLEA) is proposed, in which a follow-up time is introduced to smooth rate fluctuations in a small time scale and to adapt rate jumps in a large time scale automatically. With the PLEA algorithm, discontinuity introduced by blind segmentations adopted by current methods is avoided. Furthermore, unlike existing algorithms in which both segmentation and combinations are performed in multiple runs, only a single computation path is involved in the PLEA algorithm. This makes PLEA algorithm amenable to implementation of low complexity by either software or hardware. Both theoretical analysis and experiment based on measured data show that the PLEA outperforms existing algorithms based on segmentation.

Peer Assisted Video Streaming With Supply-Demand-Based Cache Optimization

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> In this paper, we consider a hybrid P2P video on-demand architecture that utilizes both the server and the peer resources for efficient transmission of popular videos. In our system architecture, each peer dedicates some cache space to store a particular segment of a video file as well as some of its upload bandwidth to serve the cached segment to other peers. Peers join the system and issue a streaming request to a control server. Control server directs the peers to streaming servers or to other peers who have the desired video segments. Control server also decides which peer should cache which video segment. Our main contribution in this paper is to determine the proper caching strategies at peers such that we minimize the average load on the streaming servers. </para>

Investigating the Scheduling Sensitivity of P2P Video Streaming: An Experimental Study

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> Peer-to-peer (P2P) technology has recently been employed to deliver large scale video multicast services on the Internet. Considerable efforts have been made by both academia and industry on P2P streaming design. While academia mostly focus on exploring design space to approach the theoretical performance bounds, our recent measurement study on several commercial P2P streaming systems indicates that they are able to deliver good user quality of experience with seemingly simple designs. One intriguing question remains: <emphasis emphasistype="boldital">how elaborate should a good P2P video streaming design be?</emphasis> Towards answering this question, we developed and implemented several representative P2P streaming designs, ranging from theoretically proved optimal designs to straightforward “naive” designs. Through an extensive comparison study on PlanetLab, we unveil several key factors contributing to the successes of simple P2P streaming designs, including system resource index, server capacity and chunk scheduling rule, peer download buffering and peering degree. We also identify regions where naive designs are inadequate and more elaborate designs can improve things considerably. Our study not only brings us better understandings and more insights into the operation of existing systems, it also sheds lights on the design of future systems that can achieve a good balance between the performance and the complexity. </para>

Pathpair: a fast available bandwidth estimation tool with the asymptotic one way delay comparison model

Significant research has been dedicated to active probing methods used to estimate the end-to-end available bandwidth (avail-bw) of a network path. The measurement speed of an avail-bw estimation tool is vital to real-time network services such as transport control protocol (TCP) slow start, path selection for P2P applications and video streaming services and so on. In addition, a fast avail-bw estimation tool sends less probing traffic to a measured network. Pathload, a one way delay (OWD) based tool, has been widely regarded as one of the most accurate tools, but its estimation speed is often 10 or more seconds per measurement. A fast OWD-based avail-bw estimation scheme has been explored. This scheme is based on the proposed asymptotic OWD comparison model, and an estimation tool called Pathpair has been developed. Validated in a real Internet environment, experimental results show that with Pathpair the measurement speed has been significantly improved (1–3 s per measurement), while preserving accuracy compared with other major tools like Pathload and Spruce.

On the impact of user mobility on peer-to-peer video streaming

Wireless mesh networks are emerging as a promising solution for ubiquitous Internet access with mobility support. In such networks, user mobility may lead to Internet gateway changes and consequently, impact the performance of continuous media applications. In this article, we investigate the impact of user mobility on the performance of peer-to-peer video applications over wireless mesh networks. Peer-to-peer video streaming applications rely on the collaborative behavior of peers to assist the source in delivering multimedia content, reduce costs, and increase the scalability of video distribution. We identify practical issues related to mobility for P2P video streaming implementation in WMNs, such as addressing and forwarding strategies. Furthermore, we evaluate the performance of different P2P streaming applications as the user walks in our WMN testbed. Results indicate mobile users benefit from the frequent shortlived connections established in modern P2P video sessions.

Hybrid Fault Tolerant Peer to Peer Video Streaming Architecture

In this paper, we propose a fault tolerant hybrid p2p-CDN video streaming arhitecture to overcome the problems caused by peer behavior in peer-to-peer (P2P) video streaming systems. Although there are several studies modeling and analytically investigating peer behaviors in P2P video streaming systems, they do not come up with a solution to guarantee the required Quality of the Services (QoS). Therefore, in this study a hybrid geographical location-time and interest based clustering algorithm is proposed to improve the success ratio and reduce the delivery time of required content. A Hybrid Fault Tolerant Video Streaming System (HFTS) over P2P networks conforming the required QoS and Fault Tolerance is also offered. The simulations indicate that the required QoS can be achieved in streaming video applications using the proposed hybrid approach.

Bandwidth Impacts of Localizing Peer-to-Peer IP Video Traffic in Access and Aggregation Networks

This paper examines the burgeoning impact of peer-to-peer (P2P) traffic IP video traffic. High-quality IPTV or Internet TV has high-bandwidth requirements, and P2P IP video could severely strain broadband networks. A model for the popularity of video titles is given, showing that some titles are very popular and will often be available locally; making localized P2P attractive for video titles. The bandwidth impacts of localizing P2P video to try and keep traffic within a broadband access network area or within a broadband access aggregation network area are examined. Results indicate that such highly localized P2P video can greatly lower core bandwidth usage.