353 research outputs found
Design and analysis of stream scheduling algorithms in distributed reservation-based multimedia systems
Ph.DDOCTOR OF PHILOSOPH
Ad-hoc Stream Adaptive Protocol
With the growing market of smart-phones, sophisticated applications that do extensive computation are common on mobile platform; and with consumers’ high expectation of technologies to stay connected on the go, academic researchers and industries have been making efforts to find ways to stream multimedia contents to mobile devices. However, the restricted wireless channel bandwidth, unstable nature of wireless channels, and unpredictable nature of mobility, has been the major road block for wireless streaming advance forward. In this paper, various recent studies on mobility and P2P system proposal are explained and analyzed, and propose a new design based on existing P2P systems, aimed to solve the wireless and mobility issues
Scalable Video Streaming with Prioritised Network Coding on End-System Overlays
PhDDistribution over the internet is destined to become a standard approach for live broadcasting
of TV or events of nation-wide interest. The demand for high-quality live video
with personal requirements is destined to grow exponentially over the next few years. Endsystem
multicast is a desirable option for relieving the content server from bandwidth bottlenecks
and computational load by allowing decentralised allocation of resources to the users
and distributed service management. Network coding provides innovative solutions for a
multitude of issues related to multi-user content distribution, such as the coupon-collection
problem, allocation and scheduling procedure. This thesis tackles the problem of streaming
scalable video on end-system multicast overlays with prioritised push-based streaming.
We analyse the characteristic arising from a random coding process as a linear channel
operator, and present a novel error detection and correction system for error-resilient decoding,
providing one of the first practical frameworks for Joint Source-Channel-Network
coding. Our system outperforms both network error correction and traditional FEC coding
when performed separately. We then present a content distribution system based on endsystem
multicast. Our data exchange protocol makes use of network coding as a way to
collaboratively deliver data to several peers. Prioritised streaming is performed by means
of hierarchical network coding and a dynamic chunk selection for optimised rate allocation
based on goodput statistics at application layer. We prove, by simulated experiments, the
efficient allocation of resources for adaptive video delivery. Finally we describe the implementation
of our coding system. We highlighting the use rateless coding properties, discuss
the application in collaborative and distributed coding systems, and provide an optimised
implementation of the decoding algorithm with advanced CPU instructions. We analyse
computational load and packet loss protection via lab tests and simulations, complementing
the overall analysis of the video streaming system in all its components
Network and Content Intelligence for 360 Degree Video Streaming Optimization
In recent years, 360° videos, a.k.a. spherical frames, became popular among users
creating an immersive streaming experience. Along with the advances in smart-
phones and Head Mounted Devices (HMD) technology, many content providers
have facilitated to host and stream 360° videos in both on-demand and live stream-
ing modes. Therefore, many different applications have already arisen leveraging
these immersive videos, especially to give viewers an impression of presence in a
digital environment. For example, with 360° videos, now it is possible to connect
people in a remote meeting in an interactive way which essentially increases the
productivity of the meeting. Also, creating interactive learning materials using
360° videos for students will help deliver the learning outcomes effectively.
However, streaming 360° videos is not an easy task due to several reasons. First,
360° video frames are 4–6 times larger than normal video frames to achieve the
same quality as a normal video. Therefore, delivering these videos demands higher
bandwidth in the network. Second, processing relatively larger frames requires
more computational resources at the end devices, particularly for end user devices
with limited resources. This will impact not only the delivery of 360° videos but
also many other applications running on shared resources. Third, these videos need
to be streamed with very low latency requirements due their interactive nature.
Inability to satisfy these requirements can result in poor Quality of Experience
(QoE) for the user. For example, insufficient bandwidth incurs frequent rebuffer-
ing and poor video quality. Also, inadequate computational capacity can cause
faster battery draining and unnecessary heating of the device, causing discomfort
to the user. Motion or cyber–sickness to the user will be prevalent if there is an
unnecessary delay in streaming. These circumstances will hinder providing im-
mersive streaming experiences to the much-needed communities, especially those
who do not have enough network resources.
To address the above challenges, we believe that enhancements to the three main
components in video streaming pipeline, server, network and client, are essential.
Starting from network, it is beneficial for network providers to identify 360° video
flows as early as possible and understand their behaviour in the network to effec-
tively allocate sufficient resources for this video delivery without compromising the
quality of other services. Content servers, at one end of this streaming pipeline, re-
quire efficient 360° video frame processing mechanisms to support adaptive video streaming mechanisms such as ABR (Adaptive Bit Rate) based streaming, VP
aware streaming, a streaming paradigm unique to 360° videos that select only
part of the larger video frame that fall within the user-visible region, etc. On the
other end, the client can be combined with edge-assisted streaming to deliver 360°
video content with reduced latency and higher quality.
Following the above optimization strategies, in this thesis, first, we propose a mech-
anism named 360NorVic to extract 360° video flows from encrypted video traffic
and analyze their traffic characteristics. We propose Machine Learning (ML) mod-
els to classify 360° and normal videos under different scenarios such as offline, near
real-time, VP-aware streaming and Mobile Network Operator (MNO) level stream-
ing. Having extracted 360° video traffic traces both in packet and flow level data
at higher accuracy, we analyze and understand the differences between 360° and
normal video patterns in the encrypted traffic domain that is beneficial for effec-
tive resource optimization for enhancing 360° video delivery. Second, we present
a WGAN (Wesserstien Generative Adversarial Network) based data generation
mechanism (namely VideoTrain++) to synthesize encrypted network video traffic,
taking minimal data. Leveraging synthetic data, we show improved performance
in 360° video traffic analysis, especially in ML-based classification in 360NorVic.
Thirdly, we propose an effective 360° video frame partitioning mechanism (namely
VASTile) at the server side to support VP-aware 360° video streaming with dy-
namic tiles (or variable tiles) of different sizes and locations on the frame. VASTile
takes a visual attention map on the video frames as the input and applies a com-
putational geometric approach to generate a non-overlapping tile configuration to
cover the video frames adaptive to the visual attention. We present VASTile as a
scalable approach for video frame processing at the servers and a method to re-
duce bandwidth consumption in network data transmission. Finally, by applying
VASTile to the individual user VP at the client side and utilizing cache storage
of Multi Access Edge Computing (MEC) servers, we propose OpCASH, a mech-
anism to personalize the 360° video streaming with dynamic tiles with the edge
assistance. While proposing an ILP based solution to effectively select cached
variable tiles from MEC servers that might not be identical to the requested VP
tiles by user, but still effectively cover the same VP region, OpCASH maximize
the cache utilization and reduce the number of requests to the content servers in
congested core network. With this approach, we demonstrate the gain in latency
and bandwidth saving and video quality improvement in personalized 360° video
streaming
Building Internet caching systems for streaming media delivery
The proxy has been widely and successfully used to cache the static Web objects fetched by a client so that the subsequent clients requesting the same Web objects can be served directly from the proxy instead of other sources faraway, thus reducing the server\u27s load, the network traffic and the client response time. However, with the dramatic increase of streaming media objects emerging on the Internet, the existing proxy cannot efficiently deliver them due to their large sizes and client real time requirements.;In this dissertation, we design, implement, and evaluate cost-effective and high performance proxy-based Internet caching systems for streaming media delivery. Addressing the conflicting performance objectives for streaming media delivery, we first propose an efficient segment-based streaming media proxy system model. This model has guided us to design a practical streaming proxy, called Hyper-Proxy, aiming at delivering the streaming media data to clients with minimum playback jitter and a small startup latency, while achieving high caching performance. Second, we have implemented Hyper-Proxy by leveraging the existing Internet infrastructure. Hyper-Proxy enables the streaming service on the common Web servers. The evaluation of Hyper-Proxy on the global Internet environment and the local network environment shows it can provide satisfying streaming performance to clients while maintaining a good cache performance. Finally, to further improve the streaming delivery efficiency, we propose a group of the Shared Running Buffers (SRB) based proxy caching techniques to effectively utilize proxy\u27s memory. SRB algorithms can significantly reduce the media server/proxy\u27s load and network traffic and relieve the bottlenecks of the disk bandwidth and the network bandwidth.;The contributions of this dissertation are threefold: (1) we have studied several critical performance trade-offs and provided insights into Internet media content caching and delivery. Our understanding further leads us to establish an effective streaming system optimization model; (2) we have designed and evaluated several efficient algorithms to support Internet streaming content delivery, including segment caching, segment prefetching, and memory locality exploitation for streaming; (3) having addressed several system challenges, we have successfully implemented a real streaming proxy system and deployed it in a large industrial enterprise
Towards video streaming in IoT environments: vehicular communication perspective
Multimedia oriented Internet of Things (IoT) enables pervasive and real-time communication of video, audio and image data among devices in an immediate surroundings. Today's vehicles have the capability of supporting real time multimedia acquisition. Vehicles with high illuminating infrared cameras and customized sensors can communicate with other on-road devices using dedicated short-range communication (DSRC) and 5G enabled communication technologies. Real time incidence of both urban and highway vehicular traffic environment can be captured and transmitted using vehicle-to-vehicle and vehicle-to-infrastructure communication modes. Video streaming in vehicular IoT (VSV-IoT) environments is in growing stage with several challenges that need to be addressed ranging from limited resources in IoT devices, intermittent connection in vehicular networks, heterogeneous devices, dynamism and scalability in video encoding, bandwidth underutilization in video delivery, and attaining application-precise quality of service in video streaming. In this context, this paper presents a comprehensive review on video streaming in IoT environments focusing on vehicular communication perspective. Specifically, significance of video streaming in vehicular IoT environments is highlighted focusing on integration of vehicular communication with 5G enabled IoT technologies, and smart city oriented application areas for VSV-IoT. A taxonomy is presented for the classification of related literature on video streaming in vehicular network environments. Following the taxonomy, critical review of literature is performed focusing on major functional model, strengths and weaknesses. Metrics for video streaming in vehicular IoT environments are derived and comparatively analyzed in terms of their usage and evaluation capabilities. Open research challenges in VSV-IoT are identified as future directions of research in the area. The survey would benefit both IoT and vehicle industry practitioners and researchers, in terms of augmenting understanding of vehicular video streaming and its IoT related trends and issues
User-activity aware strategies for mobile information access
Information access suffers tremendously in wireless networks because of the low correlation between content transferred across low-bandwidth wireless links and actual data used to serve user requests. As a result, conventional content access mechanisms face such problems as unnecessary bandwidth consumption and large response times, and users experience significant performance degradation. In this dissertation, we analyze the cause of those problems and find that the major reason for inefficient information access in wireless networks is the absence of any user-activity awareness in current mechanisms. To solve these problems, we propose three user-activity aware strategies for mobile information access. Through simulations and implementations, we show that our strategies can outperform conventional information access schemes in terms of bandwidth consumption and user-perceived response times.Ph.D.Committee Chair: Raghupathy Sivakumar; Committee Member: Chuanyi Ji; Committee Member: George Riley; Committee Member: Magnus Egerstedt; Committee Member: Umakishore Ramachandra
SPRITE TREE: AN EFFICIENT IMAGE-BASED REPRESENTATION FOR NETWORKED VIRTUAL ENVIRONMENTS
Ph.DDOCTOR OF PHILOSOPH
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