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Marzo). Streaming video over the Internet: approaches and directions.
- IEEE Transactions on Circuits and Systems for Video Technology,
, 2001
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Disk Scheduling in a Multimedia I/O system
- in Proceedings of ACM Multimedia'93
, 1993
"... This article provides a retrospective of our original paper by the same title in the Proceedings of the First ACM Conference on Multimedia, published in 1993. This article examines the problem of disk scheduling in a multimedia I/O system. In a multimedia server, the disk requests may have constant ..."
Abstract
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Cited by 139 (0 self)
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This article provides a retrospective of our original paper by the same title in the Proceedings of the First ACM Conference on Multimedia, published in 1993. This article examines the problem of disk scheduling in a multimedia I/O system. In a multimedia server, the disk requests may have constant data rate requirements and need guaranteed service. We propose a new scheduling algorithm, SCAN-EDF, that combines the features of SCAN type of seek optimizing algorithm with an Earliest Deadline First (EDF) type of real-time scheduling algorithm. We compare SCAN-EDF with other scheduling strategies and show that SCAN-EDF combines the best features of both SCAN and EDF. We also investigate the impact of buffer space on the maximum number of video streams that can be supported. We show that by making the deadlines larger than the request periods, a larger number of streams can be supported. We also describe how we extended the SCAN-EDF algorithm in the PRISM multimedia architecture. PRISM is an integrated multimedia server, designed to satisfy the QOS requirements of multiple classes of requests. Our experience in implementing the extended SCAN-EDF algorithm in a generic operating system is discussed and performance metrics and results are presented to illustrate how the SCAN-EDF extensions and implementation strategies have succeeded in meeting the QOS requirements of different classes of requests.
A Cross Media Adaptation Strategy for Multimedia Presentations
- IN ACM MULTIMEDIA '99 PROCEEDINGS
, 1999
"... Adaptation techniques for multimedia presentations are mainly concerned with switching between different qualities of single media elements to reduce the data volume and by this to adapt to limited presentation resources. This kind of adaptation, however, is limited to an inherent lower bound, i.e., ..."
Abstract
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Cited by 44 (2 self)
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Adaptation techniques for multimedia presentations are mainly concerned with switching between different qualities of single media elements to reduce the data volume and by this to adapt to limited presentation resources. This kind of adaptation, however, is limited to an inherent lower bound, i.e., the lowest acceptable technical quality of the respective media type. To overcome this limitation, we propose cross-media adaptation in which the presentation alternatives can be media elements of different media type, even different fragments. Thereby, the alternatives can extremely vary in media type and data volume and this enormously widens the possibilities to efficiently adapt to the current presentation resources. However, the adapted presentation must still convey the same content as the original one, hence, the substitution of media elements and fragments must preserve the presentation semantics. Therefore, our cross-media adaptation strategy provides models for the automatic augme...
Multimedia Storage Servers: A Tutorial and Survey
- IEEE COMPUTER
, 1995
"... Multimedia storage servers provide access to multimedia objects including text, images, audio, and video. The design of such servers fundamentally differs from conventional servers due to: (1) the real-time storage and retrieval, as well as (2) the large storage space and data transfer rate requirem ..."
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Cited by 32 (1 self)
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Multimedia storage servers provide access to multimedia objects including text, images, audio, and video. The design of such servers fundamentally differs from conventional servers due to: (1) the real-time storage and retrieval, as well as (2) the large storage space and data transfer rate requirements of digital multimedia. In this paper, we present an overview of the architectures and algorithms required for designing digital multimedia storage servers.
A Scalable Video-on-Demand Service for the Provision of VCR-like Functions
- In: 2nd International Conference on Multimedia Computing and Systems
, 1995
"... Abstract – One approach to supporting continuous media traffic is via resource reservation at connection establishment time. The shortcomings of this approach are the lack of flexibility in re-negotiating bandwidth parameters after connection establishment and the inability to react to changing serv ..."
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Cited by 32 (6 self)
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Abstract – One approach to supporting continuous media traffic is via resource reservation at connection establishment time. The shortcomings of this approach are the lack of flexibility in re-negotiating bandwidth parameters after connection establishment and the inability to react to changing server load conditions. In this paper we propose a “selected access scheme” for re-negotiating continuous media delivery from a video-on-demand server. We consider the overall system perspective on resource availability rather than a per-connection resource management scheme. The selected access scheme is combined with data placement strategies for the server to dynamically access desired video frames from a shared storage device. This approach is especially suitable for video data compressed and stored using an inter-frame encoding scheme such as specified by the MPEG standard. Simulation results show that the proposed model can utilize server bandwidth, improve the reliability of playback, reduce the buffering needed, and support VCR-like functions without blocking user access to the storage device. Keywords: Selected access scheme, data placement strategies, scalable service, MPEG, quality of service and VCR-like functions.
Providing vcr functionality in a constant quality video-on-demand transportation service
- In Proc. of the IEEE Int'l Conf. on Multimedia Systems'96
, 1996
"... The use of bandwidth smoothing techniques for the delivery of prerecorded compressed video has been shown to be an effective technique in reducing the network bandwidth requirements needed to play back video. Any fixed allocation ..."
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Cited by 31 (4 self)
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The use of bandwidth smoothing techniques for the delivery of prerecorded compressed video has been shown to be an effective technique in reducing the network bandwidth requirements needed to play back video. Any fixed allocation
Efficient Support for Scan Operations in Video Servers
- Proceedings of the 3rd ACM International Conference on Multimedia
, 1996
"... In this paper, we present an algorithm that integrates scalable compression techniques with placement algorithms for disk-arrays to provide efficient support for interactive scan operations (i.e., fast-forward and rewind) in video servers. We demonstrate that by suitably exploiting the characteristi ..."
Abstract
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Cited by 28 (1 self)
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In this paper, we present an algorithm that integrates scalable compression techniques with placement algorithms for disk-arrays to provide efficient support for interactive scan operations (i.e., fast-forward and rewind) in video servers. We demonstrate that by suitably exploiting the characteristics of video streams and human perceptual tolerances, the overhead of such interactive operations can be substantially reduced. We present an analytical model for evaluating the impact of the fast-forward operation on the performance of the disk-array-based server. We validate the model through extensive simulations and analyze our results. KEYWORDS Video servers, scan operations, disk arrays INTRODUCTION Recent advances in computing and communication technologies promise to create an infrastructure in which computer systems will support a wide range of interactive multimedia services in a variety of commercial and entertainment domains (e.g., advertising, product announcements, customer su...
Stream Conversion to Support Interactive Playout of Videos in a Client Station
- In Proceedings of the International Conference On Multimedia Computing and Systems (ICMCS), Washington D.C
, 1996
"... In this paper we address the problem of supporting interactive playout of an MPEG encoded video stream at a player device. We propose a method for transforming the standard MPEG stream to a local form at the player device, which then enables the device to support efficient interactive playout, speci ..."
Abstract
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Cited by 28 (3 self)
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In this paper we address the problem of supporting interactive playout of an MPEG encoded video stream at a player device. We propose a method for transforming the standard MPEG stream to a local form at the player device, which then enables the device to support efficient interactive playout, specifically for backward playout, even when the buffer space available is constrained. Explicitly, we devise a stream conversion scheme that encodes P frames as I frames after the decompression and playout of each P frame. Such a scenario of transforming a P frame to an I frame is termed P-I conversion. Note that using the technique of P-I conversion, backward playout will not require any additional memory buffer than normal forward playout, thus avoiding the large buffer requirement that would be needed for backward playout in the original MPEG stream because of interframe dependencies. It will be seen that since this P-I conversion is performed after a P frame is decompressed and played out, t...
Using Rotational Mirrored Declustering for Replica Placement in a Disk-Array-Based Video Server
- ACM Multimedia Systems
, 1995
"... In a video-on-demand (VOD) environment, disk-arrays are often used to support the disk bandwidth requirement. This can pose serious problems on available disk bandwidth upon disk failure. In this paper, we explore the approach of replicating frequently accessed movies to provide high data bandwidth ..."
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Cited by 24 (1 self)
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In a video-on-demand (VOD) environment, disk-arrays are often used to support the disk bandwidth requirement. This can pose serious problems on available disk bandwidth upon disk failure. In this paper, we explore the approach of replicating frequently accessed movies to provide high data bandwidth and fault-tolerance required in a disk-array-based video server. An isochronous continuous video stream imposes different requirements from a random access pattern on databases or files. Explicitly, we propose a new replica placement method, called rotational mirrored declustering (RMD), to support high data availability for disk arrays in a VOD environment. In essence, RMD is similar to the conventional mirrored declustering in that replicas are stored in different disk arrays, however different from the latter in that the replica placements in different disk arrays under RMD are properly rotated. Combining the merits of prior chained and mirrored declustering methods, RMD is particularly ...
An Evaluation of VBR Disk Admission Algorithms for Continuous Media File Servers
- PROCEEDINGS OF THE 5TH ACM MULTIMEDIA CONFERENCE
, 1997
"... In this paper, we address the problem of choosing a disk admission algorithm for continuous media streams where each stream may have a different bit rate, and more importantly, where the bit rate within a single stream may vary considerably. We evaluate several different Variable Bit Rate (VBR) disk ..."
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Cited by 22 (4 self)
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In this paper, we address the problem of choosing a disk admission algorithm for continuous media streams where each stream may have a different bit rate, and more importantly, where the bit rate within a single stream may vary considerably. We evaluate several different Variable Bit Rate (VBR) disk admission control algorithms for continuous media. An algorithm which accepts too few streams under-utilizes the server resources, while an algorithm which accepts too many streams over-utilizes the resources resulting in inadequate service (i.e. missing or delayed data) to the clients. The evaluation process is based on a representative set of video streams encoded in MJPEG. We conclude that one particular algorithm, the VBR simulation algorithm, performs the best among realizable algorithms in terms of system utilization and delivery guarantees and performs close to an optimal algorithm.
