27,535 research outputs found
Streaming H.264 scalable video over data distribution service in a wireless environment
The Data Distribution Service (DDS) middleware is enjoying a rapid adoption in high-performance, mission-critical networks. At the same time, the H.264 Scalable Video Coding (SVC) has been recently standardized and it is deemed to be an effective solution for video streaming over a channel with time-varying bandwidth, like the wireless one. In these conditions, it is critical to adapt the video bit-rate to the actual wireless capacity, and bit-rate adaptation is extremely simple for a H.264 SVC video. In this paper we devise, evaluate and demonstrate a technique for streaming H.264 SVC video over a DDS middleware. The contribution is threefold: i) we design a structure of the DDS data-unit able to carry H.264 SVC video-units; ii) we devise a receiver-driven rate-control mechanism based on our DDS data-unit and exploiting specific DDS functionality; iii) we implement and show the effectiveness of our mechanism in an 802.11 wireless scenario, comparing our proposal with other solution
Effects of Lline Rate on vVideo QoS over Wireless Networks: an Experimental Approach
Video streaming over Wireless Local Area Networks (WLANS) is becoming an increasingly popular service. However, end user OoS is highly influenced by many factors. These include the video codec used, the packetization scheme, error concealment and correction techniques, the complexity of the video, propagation losses, and the line rate. In this paper the effect of the line rate on the capacity of the network when streaming multimedia content is analyzed experimentally. It is shown that as the line rate decreases the bandwidth load of the video stream dramatically increases leading to poor QoS at the client side. As automatic line rate adaptation schemes are typically employed in the majority of WLAN adapters, clients have no control over the line rate of their connection and consequently can suffer from a poor QoS for their video streaming services
High Quality of Service on Video Streaming in P2P Networks using FST-MDC
Video streaming applications have newly attracted a large number of
participants in a distribution network. Traditional client-server based video
streaming solutions sustain precious bandwidth provision rate on the server.
Recently, several P2P streaming systems have been organized to provide
on-demand and live video streaming services on the wireless network at reduced
server cost. Peer-to-Peer (P2P) computing is a new pattern to construct
disseminated network applications. Typical error control techniques are not
very well matched and on the other hand error prone channels has increased
greatly for video transmission e.g., over wireless networks and IP. These two
facts united together provided the essential motivation for the development of
a new set of techniques (error concealment) capable of dealing with
transmission errors in video systems. In this paper, we propose an flexible
multiple description coding method named as Flexible Spatial-Temporal (FST)
which improves error resilience in the sense of frame loss possibilities over
independent paths. It introduces combination of both spatial and temporal
concealment technique at the receiver and to conceal the lost frames more
effectively. Experimental results show that, proposed approach attains
reasonable quality of video performance over P2P wireless network.Comment: 11 pages, 8 figures, journa
Cross-Layer Design of Source Rate Control and Congestion Control for Wireless Video Streaming
Cross-layer design has been used in streaming video over the wireless channels to optimize the overall system
performance. In this paper, we extend our previous work on joint design of source rate control and congestion control for
video streaming over the wired channel, and propose a cross-layer design approach for wireless video streaming. First, we extend the
QoS-aware congestion control mechanism (TFRCC) proposed in our previous work to the wireless scenario, and provide a detailed
discussion about how to enhance the overall performance in terms of rate smoothness and responsiveness of the transport protocol.
Then, we extend our previous joint design work to the wireless scenario, and a thorough performance evaluation is conducted
to investigate its performance. Simulation results show that by cross-layer design of source rate control at application layer and
congestion control at transport layer, and by taking advantage of the MAC layer information, our approach can avoid the throughput
degradation caused by wireless link error, and better support the QoS requirements of the application. Thus, the playback quality is
significantly improved, while good performance of the transport protocol is still preserved
Scalable Video Streaming for Single-Hop Wireless Networks Using a Contention-Based Access MAC Protocol
Limited bandwidth and high packet loss rate pose a serious challenge for video streaming applications over
wireless networks. Even when packet loss is not present, the bandwidth fluctuation, as a result of an arbitrary number of active flows in an IEEE 802.11 network, can significantly degrade the video quality. This paper aims to enhance the quality of video streaming applications in wireless home networks via a joint optimization of video layer-allocation technique, admission control algorithm, and medium access control (MAC) protocol. Using an Aloha-like MAC protocol, we propose a novel admission control framework, which can be viewed as an optimization problem that maximizes the average quality of admitted videos, given a specified minimum video quality for each flow. We present some hardness results for the optimization problem under various conditions and propose some heuristic algorithms for finding a good solution. In particular, we show that a simple greedy layer-allocation algorithm can perform reasonably well, although it is typically not optimal. Consequently, we present a more expensive heuristic algorithm that guarantees to approximate the optimal solution within a constant factor. Simulation results demonstrate that our
proposed framework can improve the video quality up to 26% as compared to those of the existing approaches
Scalable video streaming in wireless mesh networks.
Wireless mesh network provides efficient and reliable services for large scale communications. Video streaming in wireless networks enhances the services by delivering multimedia information to end users. However, because of the dynamic conditions of networks and variety of users, how to smoothly deliver the multimedia data to users without wasting precious network resources is still a challenge. This thesis addressed this challenge by investigating several key issues in video streaming in wireless mesh networks. Firstly, a video streaming system, Swan Video Streaming system (SVS), over wireless mesh networks was designed and developed. Secondly, a scalable video coding scheme was adopted in SVS. Video bit streams were split into two layers, base layer and enhancement layer. These two layers of video streams were packed into two multicast groups to allow users to get access them separately based on their processing ability and network conditions. This prevents the waste of network bandwidth by eliminating the delivery of videos to all the users regardless of their conditions. Thirdly, to improve the video robustness and reduce the overhead of the network for real-time video streaming, the important parameter messages of scale coded videos are transmitted in a reliable manner. SDP (Session Description Protocol) and RTCP (Real-time Transport Control Protocol) were improved to transmit the control messages at the beginning of video transmission and during video transmission stages, respectively. A new rearrangement method in RTCP of received packets was also proposed to improve the efficiency of algorithm and reduce network overhead. In addition, based on the feedback from video server and receivers, server and receivers can adjust their output bit rate and receiving rate according to different conditions of network to reduce the congestion. The above approaches have been evaluated in the developed SVS testbed. Tests results show the approaches are effective and feasible in real application scenarios
Effective Multi-Connection Video Streaming Over WiMAX
The idea of multi-connection congestion control was originally applied to aggregate flows passing from computer cluster to cluster communicating over the public Internet. This paper considers the extension of multi-connection streaming to wired/wireless networks and in doing so reviews theoretical results for multi-connection streaming, including virtual multi-connections within a single physical connection. Streaming a single video over multiple TCP-Friendly Rate Control connections is a promising way of separately coping with both wireless channel losses and traffic congestion, without the need for cross-layer intervention or retransmission delay at the data-link layer. At the same time, the wireless channel is properly utilized, as throughput improves with an increasing number of connections. Nevertheless, over IEEE 802.16e (mobile WiMAX) tuning is needed to select the number of connections and the Time Division Duplex (TDD) frame size. The paper assesses the impact on video quality of packet drops due both to channel loss over a WiMAX access link and router buffer overflow across an all-IP network, consisting of broadband wireless access and core network. The paper also considers end-to-end delay and start-up delay when employing several connections. Results show that provided the TDD frame size is selected appropriately then using multiple connections preserves video quality and improves wireless channel utilization, with a minimal impact on end-to-end delay. As a trade-off, there is an increase in start-up delay arising from the need to avoid possible buffer underflow
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