On the merits of SVC-based HTTP adaptive streaming

NOMS 2016 - 2016 IEEE/IFIP Network Operations and Management Symposium, 2016

HTTP Adaptive Streaming (HAS) is the de facto standard for over-the-top video streaming. In HAS, video content is encoded at multiple quality levels and temporally divided into multiple segments. The client can select the quality level for every video segment, allowing smoother playback and a better Quality of Experience (QoE). Although results are promising, current solutions often suffer from high round-trip time (RTT) cycles in mobile networks. This is especially true for scalable video coding (SVC), where multiple requests are required to retrieve a single video segment. Meanwhile, the IETF has standardized the HTTP/2 protocol since February 2015, providing new features that allow a reduction of the page load time in web browsing. In this paper, we propose a novel approach based on HTTP/2's server push feature to actively push the base layer of live, SVCencoded content from server to client. This allows to eliminate one RTT cycle for every video segment, which has a significant impact on the user's QoE. Evaluating the proposed approach, we show that compared with HTTP/1.1, an improvement of 65.42% can be achieved for the average video quality in high-RTT networks. Compared to an AVC-based solution, the freeze frequency and duration are reduced by 54.55% and 53.06% respectively, while the loss in video quality is limited to 4.51%. Since playout freezes should be avoided at the cost of a lower video quality, we conclude that the proposed approach beneficially impacts the user's QoE.

IEEE Access, 2018

News-based websites and portals provide significant amounts of multimedia content to accompany news stories and articles. In this context, the HTTP adaptive streaming is generally used to deliver video over the best-effort Internet, allowing smooth video playback and an acceptable Quality Of Experience (QoE). To stimulate the user engagement with the provided content, such as browsing between videos, reducing the videos' startup time has become more and more important: while the current median load time is in the order of seconds, research has shown that the user waiting times must remain below two seconds to achieve an acceptable QoE. In this paper, four complementary components are optimized and integrated into a comprehensive framework for low-latency delivery of news-related video content: 1) server-side encoding with short video segments; 2) HTTP/2 server push at the application layer; 3) serverside user profiling to identify relevant content for a given user; and 4) client-side storage to hold proactively delivered content. Using a large data set of a major Belgian news provider, containing millions of textand video-based article requests, we show that the proposed framework reduces the videos' startup time in different mobile network scenarios by over 50%, thereby improving the user interaction and skimming available content.

2015

Internet video is experiencing a dramatic growth in both fixed and mobile environments. All available data points indicate that Internet video is likely to be the long-awaited killer application for mobile data networks. It will also create significant new business opportunities for the fixed Internet access providers. Internet video is currently dominated by a handful proprietary technologies that exploit and reuse existing Web infrastructure to deliver live and On-Demand video services. To address these market demands, MPEG in coordination with 3GPP has taken the lead to define an enabler standard for streaming video and multimedia delivery over the Internet. MPEG Dynamic Adaptive Streaming over HTTP (DASH) specifies a delivery format that enables interoperability between different servers and client from various vendors. DASH clients can select and dynamically switch Representations in order to provide a seamless user experience. The standard evolves the proprietary HTTP streamin...

2016

Although HTTP-based video streaming can easily penetrate firewalls and profit from Web caches, the underlying TCP may introduce large delays in case of a sudden capacity loss. To avoid an interruption of the video stream in such cases we propose the Backward-Shifted Coding (BSC). Based on Scalable Video Coding (SVC), BSC adds a time-shifted layer of redundancy to the video stream such that future frames are downloaded at any instant. This pre-fetched content maintains a fluent video stream even under highly variant network conditions and leads to high Quality of Experience (QoE). We characterize this QoE gain by analyzing initial buffering time, re-buffering time and content resolution using the Ballot theorem. The probability generating functions of the playback interruption and of the initial buffering latency are provided in closed form. We further compute the quasi-stationary distribution of the video quality, in order to compute the average quality, as well as temporal variabil...

International Journal of Multimedia Data Engineering and Management, 2016

In this work, the authors present a novel bandwidth management solution for optimizing overall quality of experience (QoE) of multiple video streaming sessions. Instead of allocating bandwidth equally among competing flows, they propose to tailor the bandwidth allocation to both content complexity of requested video and playout buffer status of individual clients. The authors formulate the multi-client bandwidth allocation problem within the convex optimization framework, which is flexible enough to accommodate a wide variety of video quality metrics. Further, the authors present a practical architecture based on software defined networking (SDN) with two components: video quality monitoring and video quality optimization. Testbed-based experiments confirm that with quality-optimized allocation the network can support up to 75% more users at the same level of quality-of-experience (QoE) than conventional equal-rate allocations.

2017

Users quite often experience volatile channel conditions which negatively influence multi-media transmission. HTTP adaptive streaming has emerged as a new promising technology where the video quality can be adjusted to variable network conditions. Nevertheless, the new technology does not remain without drawbacks. As it has been observed, multiple video players sharing the same network link have often problems with achieving good efficiency and stability of play-out due to a mutual interference and competition among video players. Our investigation indicates that there may be another cause for under-performance of the streamed video. In an emulated environment, we implemented three algorithms of adaptive video play-out based on bandwidth or buffer assessment. As we show, traffic generated by players employing the same or similar play-out strategies is positively correlated and syn-chronised (clustered), whereas traffic originated from different play-out strategies shows negative or no correlations. However, when some of the parameters of the play-out strategies are randomised, the correlation and synchronisation diminish what has a positive impact on the smoothness of the traffic and on the video quality perceived by end users. Our research shows that non-correlated traffic flows generated by play-out strategies improve efficiency and stability of streamed adaptive video.

HCI in Work and Learning, Life and Leisure, 2010

Akamai oers the largest Content Delivery Network (CDN) service in the world. Building upon its CDN, it recently started to offer High Denition (HD) video distribution using HTTP-based adaptive video streaming. In this paper we experimentally investigate the performance of this new Akamai service aiming at measuring how fast the video quality tracks the Internet available bandwidth and to what extent the service is able to ensure continuous video distribution in the presence of abrupt changes of available bandwidth. Moreover, we provide details on the client-server protocol employed by Akamai to implement the quality adaptation algorithm. Main results are: 1) any video is encoded at ve dierent bit rates and each level is stored at the server; 2) the video client computes the available bandwidth and sends a feedback signal to the server that selects the video at the bitrate that matches the available bandwidth; 3) the video bitrate matches the available bandwidth in roughly 150 seconds; 4) a feedback control law is employed to ensure that the player buer length tracks a desired buer length; 5) when an abrupt variation of the available bandwidth occurs, the suitable video level is selected after roughly 14 seconds and the video reproduction is aected by short interruptions.

2014 21st International Conference on Telecommunications (ICT), 2014

Dynamic adaptive streaming over HTTP (DASH) has gained a significant momentum for multimedia streaming due to its ability in crossing firewalls and availability of infrastructure. In the mean time scalable video coding (SVC) is building a similar momentum as it enables efficient media storage and caching. In this work, we identify the main components of adaptive SVC-DASH client and propose an streaming heuristic over dynamic multiple connections. The proposed algorithm is experimentally tested under different connection and link configurations. Our results show that the algorithm successfully achieves interruption free streaming under all the tested bandwidth and link configurations. Additionally, the usage of multiple connections results in noticeable improvements in the achieved streaming quality for large link delays.

2012 IEEE Consumer Communications and Networking Conference (CCNC), 2012

Video services are being adopted widely in both mobile and fixed networks. For their successful deployment, the content providers are increasingly becoming interested in evaluating the performance of such traffic from the final users' perspective, that is, their Quality of Experience (QoE). For this purpose, subjective quality assessment methods are costly and can not be used in real time. Therefore, automatic estimation of QoE is highly desired. In this paper, we propose a noreference QoE monitoring module for adaptive HTTP streaming using TCP and the H.264 video codec. HTTP streaming using TCP is the popular choice of many web based and IPTV applications due to the intrinsic advantages of the protocol. Moreover, these applications do not suffer from video data loss due to the reliable nature of the transport layer. However, there can be playout interruptions and if adaptive bitrate video streaming is used then the quality of video can vary due to lossy compression. Our QoE estimation module, based on Random Neural Networks, models the impact of both factors. The results presented in this paper show that our model accurately captures the relation between them and QoE.

EURASIP Journal on Wireless Communications and Networking, 2014

Dynamic adaptive streaming over HTTP (DASH) has become a promising solution for video delivery services over the Internet in the last few years. Currently, several video content providers use the DASH solution to improve the users' quality of experience (QoE) by automatically switching video quality levels (VQLs) according to the network status. However, the frequency of switching events between different VQLs during a video streaming session may disturb the user's visual attention and therefore affect the user's QoE. As one of the first attempts to characterize the impact of VQL switching on the user's QoE, we carried out a series of subjective tests, which show that there is a correlation between the user QoE and the frequency, type, and temporal location of the switching events. We propose a novel parameter named switching degradation factor (SDF) to capture such correlation. A DASH algorithm with SDF parameter is compared with the same algorithm without SDF. The results demonstrate that the SDF parameter significantly improves the user's QoE, especially when network conditions vary frequently.