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1.
A survey on peer-to-peer video streaming systems 总被引:2,自引:1,他引:2
Video-over-IP applications have recently attracted a large number of users on the Internet. Traditional client-server based
video streaming solutions incur expensive bandwidth provision cost on the server. Peer-to-Peer (P2P) networking is a new paradigm
to build distributed network applications. Recently, several P2P streaming systems have been deployed to provide live and
on-demand video streaming services on the Internet at low server cost. In this paper, we provide a survey on the existing
P2P solutions for live and on-demand video streaming. Representative P2P streaming systems, including tree, multi-tree and
mesh based systems are introduced. We describe the challenges and solutions of providing live and on-demand video streaming
in P2P environment. Open research issues on P2P video streaming are also discussed.
相似文献
Chao LiangEmail: |
2.
In this paper, we study the bandwidth allocation problem for serving video requests in a mobile real-time video player system.
One of the main issues to maintain the quality of services (QoS) in mobile video playback is to ensure sufficient number of
video frames available at the client side while a video is being played. However, due to the limited bandwidth of a mobile
network and variable workload streaming video, this is not easy to achieve in practice. In addition, the communication link
between mobile clients and a video server is subject to frequent errors and temporary disconnection. In this paper, we propose
to use the notion of buffered bandwidth in addition to the network bandwidth to support real-time playback of videos at mobile clients. Based on this, we designed
a bandwidth allocation scheme called Cooperative Pre-Fetching (CP) in which the amount of bandwidth to be allocated to serve a video request depends on the current buffer level of the
video at the client relative to the target buffer level of the client. In determining the target buffer level, we consider
the errors in communication to the client as well as the other clients who are concurrently served by the system. The buffered
video frames at the clients are then used to minimize the impact of error in communications on the overall QoS of video playbacks
in the whole system.
相似文献
Kam-Yiu Lam (Corresponding author)Email: |
3.
A video streaming proxy server needs to handle hundreds of simultaneous connections between media servers and clients. Inside,
every video arrived at the server and delivered from it follows a specific arrival and delivery schedule. While arrival schedules
compete for incoming network bandwidth, delivery schedules compete for outgoing network bandwidth. As a result, a proxy server
has to provide sufficient buffer and disk cache for storage, together with memory space, disk space and disk bandwidth. In
order to optimize the throughput, a proxy server has to govern the usage of these resources. In this paper, we first analyze
the property of a traditional smoothing algorithm and a video staging algorithm. Then we develop, based on the smoothing algorithm,
a video staging algorithm for video streaming proxy servers. This algorithm allows us to devise an arrival schedule based
on the delivery schedule. Under this arrival and delivery schedule pair, we can achieve a better resource utilization rate
gracefully between different parameter sets. It is also interesting to note that the usage of the resources such as network
bandwidth, disk bandwidth and memory space becomes interchangeable. It provides the basis for inter-resource scheduling to
further improve the throughput of a video streaming proxy server system.
相似文献
Daniel P. K. LunEmail: |
4.
Pradeep K. Atrey Wei-Qi Yan Mohan S. Kankanhalli 《Multimedia Tools and Applications》2007,34(1):107-135
This paper addresses the problem of ensuring the integrity of a digital video and presents a scalable signature scheme for
video authentication based on cryptographic secret sharing. The proposed method detects spatial cropping and temporal jittering
in a video, yet is robust against frame dropping in the streaming video scenario. In our scheme, the authentication signature
is compact and independent of the size of the video. Given a video, we identify the key frames based on differential energy
between the frames. Considering video frames as shares, we compute the corresponding secret at three hierarchical levels.
The master secret is used as digital signature to authenticate the video. The proposed signature scheme is scalable to three
hierarchical levels of signature computation based on the needs of different scenarios. We provide extensive experimental
results to show the utility of our technique in three different scenarios—streaming video, video identification and face tampering.
相似文献
Mohan S. KankanhalliEmail: |
5.
An important research issue in video streaming is how to efficiently utilize the network resources to provide clients instant
access to multiple video objects. Caching strategy and transmission scheme are the two essential points inside the video streaming
framework. Recent research efforts on them are not sufficient due to their inflexible support for scalable encoded video streams
and heterogeneous requests from clients. In this paper, we propose an optimized caching strategy (OCS) and a scalable transmission
scheme (STS) for scalable coded video streaming. By exploring the characteristics of video streaming workload and system design
objectives, OCS and STS work efficiently to minimize both network bandwidth cost and user access latency. Firstly, we analyze
the caching problem for the proxy-assisted video streaming system and derive a maneuverable caching scenario. Secondly, we
develop an efficient transmission scheme for scalable coded videos. Thirdly, we formulate a multi-objective optimization model
with closed-form expressions to obtain the optimized caching strategy. Finally, with designed algorithms, an excellent compromise
between two competing objectives (minimizing the bandwidth cost and the access latency) is achieved. We start our evaluation
by studying the optimized caching strategy for a single video object. Then we apply the strategy to multiple video objects
and illustrate the tradeoff between the optimization objectives. Our evaluation results show that compared with other caching
strategies, the proposed optimized scalable caching strategy can achieve a significant reduction in bandwidth cost with even
a small proxy cache size. Meanwhile, the best performance (in terms of bandwidth cost) is obtained together with the proposed
scalable batch-patching transmission scheme.
相似文献
Kenneth OngEmail: |
6.
This work investigates the modeling of aggregate available bandwidth in multi-sender network applications. Unlike the well-established
client–server model, where there is only one server sending the requested data, the available bandwidth of multiple senders
when combined together does exhibit consistent properties and thus can be modeled and estimated. Through extensive experiments
conducted in the Internet this work proposed to model the aggregate available bandwidth using a normal distribution and then
illustrates its application through a hybrid download-streaming algorithm and a playback-adaptive streaming algorithm for
video delivery under different bandwidth availability scenarios. This new multi-source bandwidth model opens a new way to
provide probabilistic performance guarantee in best-effort networks such as the Internet, and is particularly suitable for
the emerging peer-to-peer applications, where having multiple sources is the norm rather than the exception.
相似文献
Jack Y. B. LeeEmail: |
7.
R. Venkatesh Babu Andrew Perkis Odd Inge Hillestad 《Multimedia Tools and Applications》2008,37(2):211-231
This paper deals with monitoring user perception of multimedia presentations in a Universal Multimedia Access (UMA) enabled
system using objective no-reference (NR) metrics. These NR metrics are designed for an UMA-enabled system, in a novel architecture,
for a multimedia viewer. The first metric measures block-edge impairments in a video frame at the receiver end, based on the
observation that they occur in regions with low spatial activity. The second metric evaluates the quality of the reconstructed
video frame in the event of packet loss. Here, the structure of the artifact is itself exploited for the evaluation. Both
the metrics involve low computational complexity and are feasible for real-time monitoring of streaming video in a multimedia
communication scenario. Further, in rate-adaptive streaming of video, these metrics could serve as feedback parameters to
dynamically adapt the bit rates based on network congestion.
相似文献
Odd Inge HillestadEmail: |
8.
Streaming of scalable h.264 videos over the Internet 总被引:1,自引:0,他引:1
Aylin Kantarcı 《Multimedia Tools and Applications》2008,36(3):303-324
To investigate the benefits of scalable codecs in the case of rate adaptation problem, a streaming system for scalable H.264
videos has been implemented. The system considers congestion level in the network and buffer status at the client during adaptation
process. The rate adaptation algorithm is content adaptive. It selects an appropriate substream from the video file by taking
into account the motion dynamics of video. The performance of the system has been tested under congestion-free and congestion
scenarios. The performance results indicate that the system reacts to congestion properly and can be used for Internet video
streaming where losses occur unpredictably.
相似文献
Aylin KantarcıEmail: |
9.
Large scale video streaming over the Internet requires a large amount of resources such as server I/O bandwidth and network
bandwidth. A number of video delivery techniques can be used to lower these requirements. Periodic broadcast by a central
server combined with proxy caching offers a significant reduction of the aggregate network and server I/O bandwidth usage.
However, the resources available to a single server are still limited. In this paper we propose a system with multiple geographically distributed servers. The problem of multiple servers for periodic broadcast is quite different from the problem of object location for multiple
web servers. Multiple servers offer increased amount of resources and service availability and may potentially allow a further
reduction of network bandwidth usage. On the other hand, the benefit of periodic broadcast mostly comes from high demand videos.
With multiple servers holding a video, the demand of the video at each server is reduced. Therefore, it is a challenge to
use multiple servers efficiently. We first analyze the dependence of the resource requirements on the number and locations
of the servers. Based on the character of the function describing such a dependence, we formulate and solve the problem of
video location and delivery, in a way that minimizes resource usage. We explore a trade-off between network and I/O bandwidth
requirements. We evaluate our proposed solutions through a number of tests.
相似文献
David H. C. DuEmail: |
10.
P-chaining: a practical VoD service scheme autonomically handling interactive operations 总被引:1,自引:1,他引:0
Providing scalable VoD streaming services has recently become a hot issue, and many approaches have been proposed. Because
video streaming services through the Internet are widely used, the need to support VCR operations also increases. However,
there are few approaches to supporting VCR operations on the Internet. We propose a service scheme based on chaining, in which
clients as well as the server provide streaming services. In the proposed scheme, services are provided by unicast and managed
locally using node lists. In addition, our scheme can support frequent VCR operations without incurring significant overhead
in the server workload. We have evaluated our scheme through simulation with real traces from a content distribution network
(CDN) company and with various parameters. The results show that the proposed scheme reduces server workload significantly.
The results also verify that frequent VCR operations can be served smoothly without causing too much overhead.
相似文献
Heon Y. YeomEmail: |
11.
Service replication is an effective way to address resource requirements and resource availability problem. Dynamic service
selection enables clients to choose a server offering the best performance. Proper server selection is especially important
for video streaming over the Internet due to its high bandwidth requirements. However, given the length of a typical video
transmission, the server priorly selected may no longer be an optimal one for the duration of the entire transmission. More
importantly, a server may fail during the transmission of a video. In this paper we examine the possibility of switching to
another server during an on-going transmission for Periodic Broadcast schemes. Due to the timing requirements typical for
Periodic Broadcast the server switch may cause playback disruptions. We analyze the magnitude of the problem and propose an
easy to implement solution. We define the criteria, additional to the bandwidth availability for example, according to which
a new server should be selected. The client is also required to delay its playback by the amount of time bounded by the server
transmission offset. In addition, we propose an alternative method to ensure uninterrupted playback that relies on proxy caching.
Simulation results show that our approach can significantly reduce the likelihood of playback disruptions.
相似文献
David H. C. DuEmail: |
12.
Meng-Yen Hsieh Yueh-Min Huang Tzu-Chinag Chiang 《Multimedia Tools and Applications》2007,34(2):155-177
Mobile ad hoc networks without centralized infrastructure change their topology rapidly because of node mobility, making multimedia
applications difficult to run across wireless networks. Moreover, video transmission over ad hoc networks causes frequent
transmission loss of video packets owing to end-to-end transmission with a number of wireless links, and requires essential
bandwidth and restricted delay to provide quality-guaranteed display. This paper presents an architecture supporting transmission
of multiple video streams in ad hoc networks by establishing multiple routing paths to provide extra video coding and transport
schemes. This study also proposes an on-demand multicast routing protocol to transport layered video streams. The multicast
routing protocol transmits layered video streaming based on a weight criterion, which is derived according to the number of
receivers, delay and expiration time of a route. A simulation is performed herein to indicate the viability and performance
of the proposed approach. The simulation results demonstrate that the proposed transport scheme is more effective than other
video transport schemes with single or multiple paths.
相似文献
Tzu-Chinag ChiangEmail: |
13.
This paper presents a framework for allocating radio resources to the Access Points (APs) introducing an Access Point Controller
(APC). Radio resources can be either time slots or subchannels. The APC assigns subchannels to the APs using a dynamic subchannel
allocation scheme. The developed framework evaluates the dynamic subchannel allocation scheme for a downlink multicellular
Orthogonal Frequency Division Multiple Access (OFDMA) system. In the considered system, each AP and the associated Mobile
Terminals (MTs) are not operating on a frequency channel with fixed bandwidth, rather the channel bandwidth for each AP is
dynamically adapted according to the traffic load. The subchannels assignment procedure is based on quality estimations due
to the interference measurements and the current traffic load. The traffic load estimation is realized with the measurement
of the utilization of the assigned radio resources. The reuse partitioning for the radio resources is done by estimating mutual
Signal to Interference Ratio (SIR) of the APs. The developed dynamic subchannel allocation ensures Quality of Service (QoS),
better traffic adaptability, and higher spectrum efficiency with less computational complexity.
相似文献
Chanchal Kumar Roy (Corresponding author)Email: |
14.
MPEG-4 video coding stream with Fine Granularity Scalability (FGS) can be flexibly dropped by very fine granularity so as
to adapt to the available network bandwidth. The MPEG-4 FGS model is similar to the imprecise computation model originally
proposed in the real-time scheduling field. In both models, it is required that all the mandatory tasks be completely scheduled
before their deadlines even in the worst case, which is called the feasible mandatory constraint. The problem is how to maximize
the number of the scheduled tasks based on the importance of tasks and to satisfy the feasible mandatory constraint. We adapt
the existing unit-time tasks scheduling algorithm to address the problem by using a weighted assignment scheme that adds constant
weights to mandatory tasks. Under the feasible mandatory constraint, we prove that the proposed algorithm maximizes the total
weights of the scheduled tasks, and all mandatory tasks are guaranteed to be completely scheduled before their deadlines.
The experimental results show the performance of the video quality for our scheduling algorithm by the measurements of Peak
Signal to Noise Ratio (PSNR).
相似文献
LihChyun Shu (Corresponding author)Email: |
15.
Real-time 2D to 3D video conversion 总被引:1,自引:0,他引:1
Ianir Ideses Leonid P. Yaroslavsky Barak Fishbain 《Journal of Real-Time Image Processing》2007,2(1):3-9
We present a real-time implementation of 2D to 3D video conversion using compressed video. In our method, compressed 2D video
is analyzed by extracting motion vectors. Using the motion vector maps, depth maps are built for each frame and the frames
are segmented to provide object-wise depth ordering. These data are then used to synthesize stereo pairs. 3D video synthesized
in this fashion can be viewed using any stereoscopic display. In our implementation, anaglyph projection was selected as the
3D visualization method, because it is mostly suited to standard displays.
相似文献
Ianir IdesesEmail: |
16.
We propose a cross-layer approach with tightly-coupled time synchronization for real-time support and predictable lifetime
in battery-operated sensor networks. Our design spans a sensor hardware platform with hardware-based global time synchronization,
a TDMA link layer protocol with collision-free multi-hop support and node scheduling algorithms for maximum concurrency and
streaming. Our dual-radio sensor platform, FireFly, features an IEEE 802.15.4 transceiver and supports global time synchronization
indoors by using an AM radio carrier-current method and an atomic clock receiver for outdoors. A TDMA-based link protocol,
RT-Link, leverages the hardware for fixed and mobile nodes with a near-optimal and predictable node lifetime of over 2 years.
It outperforms comparable sensor network link protocols such as B-MAC and S-MAC in terms of end-to-end latency and throughput
and node lifetime across all duty cycle ratios. Operating over RT-Link is MAX, a scheduling framework which offers optimal
transmission concurrency and bandwidth management for networks with regular structure. Through analysis and experiments we
show that global time sync is a robust, economical and scalable alternative to in-band software-based techniques. To illustrate
the capabilities and flexibility of our platform, we describe our experiences with two-way voice streaming over multiple hops.
We have deployed a 42-node network with sub-100 μs synchronization accuracy in the NIOSH experimental coal mine for people-tracking
and voice communication.
相似文献
Raj RajkumarEmail: |
17.
3GPP packet-switched streaming service (PSS) is a standardized packet-based mobile streaming service, which is based on IETF
RTSP/SDP standards. PSS can be implemented over GPRS networks; however these cannot usually guarantee any data rates or delay
bounds, but allow sufficient bandwidth for mobile streaming. GPRS cell reselections pose additional challenges for streaming,
since several seconds of data transmission breaks may occur, and data may even be lost. The level of error protection of GPRS
is good enough for mobile streaming, if the correct quality of service (QoS) profile is configured. In this paper, we study
the effect of different QoS parameters configurations to find optimal values for PSS over GPRS. The paper shows also a method
for optimizing cell reselection management at the application layer, in order to provide seamless mobility. Results show that
despite all the limitations of a GPRS environment, PSS is feasible with a decent quality of service.
相似文献
Igor D. D. Curcio (Corresponding author)Email: |
18.
Dynamic video summarization using two-level redundancy detection 总被引:1,自引:0,他引:1
The mushroom growth of video information, consequently, necessitates the progress of content-based video analysis techniques.
Video summarization, aiming to provide a short video summary of the original video document, has drawn much attention these
years. In this paper, we propose an algorithm for video summarization with a two-level redundancy detection procedure. By
video segmentation and cast indexing, the algorithm first constructs story boards to let users know main scenes and cast (when
this is a video with cast) in the video. Then it removes redundant video content using hierarchical agglomerative clustering
in the key frame level. The impact factors of scenes and key frames are defined, and parts of key frames are selected to generate
the initial video summary. Finally, a repetitive frame segment detection procedure is designed to remove redundant information
in the initial video summary. Results of experimental applications on TV series, movies and cartoons are given to illustrate
the proposed algorithm.
相似文献
Wei-Bo Wang |
19.
Simultaneous transmission of multiple high quality video streams from a server to the clients is becoming an increasingly
important class of traffic in a network of workstations or cluster environment. With a powerful symmetric multiprocessor (SMP)
as the server and a high-speed network, such transmission is practicable from a hardware point of view. However, the actual
construction of such a video data server system entails tackling a number of difficult problems related to the provision of
strict quality of service (QoS) guarantees. Among others, the smoothing and scheduling of multiple video packet streams are
two crucial issues. Smoothing is concerned with reducing the rate variability of video streams in view of the fact that video
data are usually compressed in a variable bit rate fashion. Scheduling is important to guarantee the requested QoS levels
while maximizing the utilization of the resources. Although much work on smoothing has been done, it is not clear which scheduling
scheme is suitable for multiplexing smoothed video data to the network. In this paper we present an extensive performance
study of the EDF and RM scheduling algorithms which are modified to provide QoS guarantees for smoothed video data. With a
probabilistic definition of QoS, admission control conditions are incorporated into the two algorithms. Furthermore, a counter-based
scheduling module is included as the core scheduling mechanism which adaptively adjusts the actual QoS levels assigned to
requests. Our theoretical analysis of the two modified algorithms, called QEDF and QRM, shows that the QRM algorithm is more
robust than the QEDF algorithm for different workload and utilization conditions. We also propose to use a new metric called
meta-QoS to quantify the overall performance of a packet scheduler given a set of simultaneous requests. In our experiments
based on an SMP-based Linux platform, we find that the QRM algorithm can sustain a rather stable level of meta-QoS even when
the workload and utilization levels are increased. On the other hand, the QEDF algorithm, due to its conservative admission
control policy, is found to be not suitable for a high level of utilization and a large number of requests. In view of the
lower complexity of the QRM algorithm, it seems that the QRM approach is a more suitable candidate for packet scheduling in
the client-server environment considered in our study.
相似文献
Yu-Kwong Kwok (Corresponding author)Email: |
20.
The effect of Internet use as a mediating variable on self-efficacy as it relates to the cognition of network-changing possibility
(i.e., connecting people or groups with different social backgrounds) was examined. The results showed that Internet use (i.e.,
the frequency of sending e-mail, friends made on the Internet) had a positive effect on the cognition of network-changing
possibility. The cognition that it is possible to connect people with different social backgrounds by using the Internet also
had a positive effect on self-efficacy. On the other hand, the cognition that it is possible to find people or groups who
share beliefs and interests by using the Internet negatively affected self-efficacy. Hence, it was found that the effect of
Internet use on self-efficacy was different as a function of cognition of network-changing possibility.
Research for this study was supported by grants from the Japan Society for the Promotion of Science, KAKANHI15330137.
相似文献
Kaichiro Furutani (Corresponding author)Email: |
Tetsuro KobayashiEmail: |
Mitsuhiro UraEmail: |