The Quality Of Rescue For Variable

Published Date: 02 Nov 2017

Live media services in mobile environments are fetching more essential with the explosion of technologies. Live Media streaming, in particular, is a promising technology for providing services such as live news clips, live sports. To avoid service interruption when the users keep moving, proper data management strategies must be engaged. And Distributed media streaming employs multiple senders to cooperatively and simultaneously transmit a media stream to a receiver over the Internet. Having multiple senders have lead to both sender and path diversity and improved robustness in the system. But at the same time, distributed media streaming has raised many challenging and interesting research problems. In this dissertation, we investigate several of these problems that are related to media quality and fairness to other applications.

First, we study how streaming quality can be improved through distributed retransmission – retransmission from alternate senders rather than the origin of the lost packet. We explore the question of whether distributed retransmission recovers more packet loss than non-distributed retransmission by comparing two naïve distributed retransmission schemes with the traditional non-distributed scheme.

Through analysis, simulations, and experiments over the Internet, we found that distributed retransmission leads to fewer lost packets and shorter loss burst length. To address the practical issue of who to retransmit from, we propose a distributed retransmission scheme that selects a sender with the lowest packet loss rate to retransmit from. Results show that our proposed scheme effectively recovers packet losses and improves playback quality.

Second, we investigate the issue of WSN-friendliness in live media streaming. The traditional notion of WSN-friendliness is not suitable for cooperative applications, such as distributed media streaming, as it is unfair to other single-flow applications. We therefore introduce the notion of task-level WSN-friendliness for distributed media streaming, where we require the total throughput for a set of flows belonging to the same task to be friendly to a WSN. To this end, we design a congestion control protocol to regulate the throughput of the flows in an aggregated manner. The regulation is done in two steps.

In light of the above, we propose the QoS-based dynamic adaptation techniques for the flexible employment and smooth integration of headlight pre-fetching and dynamic chaining to continuously provide quality streaming services to mobile users. And also it provides Variable bit rate delivery. Second, we propose a new mechanism video compression and Multi-hop wireless networking brings benefit for both end users and service providers. For end users, it shortens the duration while user must stay online for uploading their generated content. Also for service providers, it reduces peak traffic volume between edge networks and data centers by slightly shifting the upload timing without incurring much extra latency overhead added.

Third, we proposed controller, nodes adapt the rate of change of their transmitted video quality based on an estimate of the impact that a change in the transmission rate will have on the received video quality. While the proposed method is general, it works particularly well for security videos. In addition, all of these techniques require that the encoder has access to the entire video frame before encoding the video.

INTRODUCTION

Video streaming over wireless networks is compelling for many applications, ranging from news and multimedia messaging services for cell phones, extended broadband Internet access in corporate or community networks, to wireless home entertainment or surveillance camera networks, to audiovisual communication in search-and-rescue operations.

In spite of the growing networking capabilities of modern wireless devices and the sophisticated techniques used by today’s video coding and streaming systems, video streaming over wireless networks remains a challenging task. The wireless radio channel is subject to interference from other nearby transmitters, multipath fading, and shadowing, causing fluctuations in link capacities and sometimes an error prone communication environment. The traffic patterns of compressed video streams typically change over time due to content variations and dynamic user behavior, and the received video quality may degrade drastically in the presence of packet losses, due to error propagation in the compressed bit stream.

Moreover, video streaming applications typically have high data rates and stringent latency requirements, at odds with the limited bandwidth resources in a wireless network. Simultaneous streaming of multiple video sessions can easily lead to network congestion without careful rate allocation. The lack of centralized control in a wireless network, on the other hand, requires that the task of multi-user resource allocation be performed in a distributed manner.

THESIS STRUCTURE

This dissertation focuses on the problem of distributed rate allocation among multiple simultaneous video streaming sessions, so that they can efficiently share a wireless network without incurring excessive congestion. Since neighboring links compete for the same wireless radio channel, the rate of a video stream will not only affect the links along its own route, but also contend with traffic over other nearby links. The rate allocation problem is further complicated by heterogeneity in both the video rate utilities and the wireless link qualities. In this thesis, we take into consideration all the above factors to design a practical, distributed rate allocation protocol for video over wireless. The contributions are summarized as follows:

• Formulation and analysis of a framework for multi-stream rate allocation over wireless networks. In this framework, a wireless network model explicitly captures the effect of traffic contention among neighboring links and heterogeneous link transmission speeds. A parametric video distortion model is used to represent the utility of allocated rate for each stream. The multi-stream rate allocation problem is formulated within the convex optimization framework, with the goal of minimizing total video distortion while avoiding excessive network utilization. We further analyze dynamics of the proposed distributed solution, and establish system stability under proper parameter choices.

• In the present model, the ideas and benefits of two-level cooperative media streaming with headlight pre fetching and dynamic chaining were demonstrated and they using static bit rate delivery. The QoS-based dynamic adaptation techniques for the flexible employment and smooth integration of headlight pre-fetching and dynamic chaining to continuously provide quality streaming services to mobile users. And also it provides Variable bit rate delivery.

• Extension of the new mechanism video compression and Multi-hop wireless networking brings benefit for both end users and service providers. For end users, it shortens the duration while user must stay online for uploading their generated content. Also for service providers, it reduces peak traffic volume between edge networks and data centers by slightly shifting the upload timing without incurring much extra latency overhead added.

Most simulation results presented in this dissertation are collected from scenarios of high-definition (HD) and standard-definition (SD) video streaming, a concrete example being a live media network. Nevertheless, we believe that the general principles of the proposed distributed charge provision etiquette carry over to other types of networks, and expect similar performance gains.

The rest of this dissertation is organized as follows. The next chapter reviews research in the related areas of wireless networking, congestion control, and video coding and streaming systems.

Chapter 3 presents our optimization framework, together with stability analysis and numerical illustrations of the distributed rate allocation algorithm.

In Chapter 4, we explain the design of a practical live media-aware rate allocation protocol, based information exchange between video rate controllers at the end hosts and link state monitors at the relay nodes. Performance of the protocol is compared against a conventional media-unaware scheme based on TFRC, in network simulations involving various network topologies and different types of video content.

Chapter 5 extends the media-aware rate allocation protocol for wireless video multicast. With the proposed controller, nodes adapt the rate of change of their transmitted video quality based on an estimate of the impact that a change in the transmission rate will have on the received video quality. While the proposed method is general, it works particularly well for security videos. In addition, all of these techniques require that the encoder has access to the entire video frame (or even multiple frames) before encoding the video. I) Encode video at low complexity for the encoder; ii) take advantage of the temporal correlation between frames.

Finally, in Chapter 6, we summarize lessons learned from this dissertation and discuss future research directions.

Conclusion

We studied The Quality of Delivery (QoD) of variable bit rate videos over a live video transmission systems that use a scalable source coder with headlight prefetching and P2P chaining. In the face of fast changing moving patterns, the techniques achieve their effectiveness by continuous monitoring of QoS and processing cost, and then adjust the streaming service strategies accordingly. Furthermore, smooth integration of the two levels of cooperation provides even higher quality of services to mobile users at lower cost. We proposed a real-time algorithm for selecting the channel packet length together with an appropriate source-channel rate allocation.

Even with effective adaptation techniques, detrimental playback interruption can still occur. All strategies can only be applied after receiving the media requests from the users. No matter how well we manage our prefetching and P2P streaming, the instability of wireless communication and the unpredictability of user movement can still lead to disconnection and, therefore, playback interruption or long download time. We are currently investigating a bidirectional push and pull technique to actively disseminate information toward their most likely consumers as well as forward requests toward close by neighbors that are most likely to possess the needed answers. Working together with client caching, it is possible to significantly improve service quality. Another possible remedy of the problem is to develop personalized data service solution on the user activities. Using behavior-mining techniques, it is possible to identify user activities and predict the next location and/ or service invocation. In such case, we can provide proactive services which are expected to significantly reduce the likelihood of playback interruption. This solution was robust against changes in the sequence content. The systems have good end-to-end performance in packet erasure and wireless channels. Their low complexity makes them suitable to live video streaming applications.

Future work includes the research on the sources of noise in the QoS measurements. It was observed that not only extreme network behavior shows to be harming QoD but also other effects. Candidates to be analyzed are the congestion and traffic control of the streaming server. Traffic and congestion control is designed to enhance the QoD but there are indications in our data set that at some points the control mechanisms took wrong actions. Therefore the congestion and traffic control algorithms should be studied more closely. Accordingly, the congestion control can be amended to reduce the probability of jitter buffer starvations, hence increasing the QoD. The relation between the control mechanism and the video content also needs to be studied. Another noise source in the measurements was emanating from content dependent events. It was observed that QoD impairments often manifested at the same time in the video files. The indications are that the streaming server is degradation when specific content patterns occur. The causes of this effect are open to research.

And also in future research about the combination of 3D live media streaming and handheld Augmented Reality (AR) technology. It can be the bring this technology from research lab to the real world. We can conclude that users feel the media presentation with 3D graphic and AR technology is more interesting than general 2D game, the immersion of virtual object in real world.

As we move forward, researcher hope this research can be milestone and will inspire further research of respected field. Researcher also hopes can educate the user of handheld device who mostly grew up in the previous era of live media streaming so that they can easily get familiar with this streaming technology applications. Since live media streaming is pretty new technology in our daily life, we need to educate the people as end user so that they can get used and familiar with this technology. In the long run, we hope to explore the live media streaming technology deeper and observe the application of live media streaming technology in various fields, any other purposes and brings more benefit to people in the real world.