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217
Metascheduling for continuous media
- ACM Transactions on Computer Systems
, 1993
"... Next-generation distributed systems will support corLtLzLzLous medLa (digztal audio and video) in the same framework as other data. Many applications that use continuous media need guaran-teed end-to-end performance (bounds on throughput and delay). To reliably support these requirements, system com ..."
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Cited by 160 (3 self)
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Next-generation distributed systems will support corLtLzLzLous medLa (digztal audio and video) in the same framework as other data. Many applications that use continuous media need guaran-teed end-to-end performance (bounds on throughput and delay). To reliably support these requirements, system components such as CPU schedulers, networks, and file systems must offer performance guarantees. A rnetasclzedtder coordinates these components, negotiating end-to-end guarantees on behalf of clients. The CM-resource model, described in this paper, provides a basis for such a metascheduler. It defines a workload parameterizatlon, an abstract interface to resources, and an algorithm for reserving multiple resources. The model uses an economic approach to dividing end-to-end delay, and it allows system components to “work ahead,” improving the performance of nonreal-time workload.
Designing an On-Demand Multimedia Service
- IEEE Communications Magazine
, 1992
"... Future advances in networking coupled with rapid advances in storage technologies will make it feasible to build a multimedia on-demand server capable of providing services similar to those of a neighborhood videotape rental store on a metropolitan-area network. In this paper, we study various admis ..."
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Cited by 143 (0 self)
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Future advances in networking coupled with rapid advances in storage technologies will make it feasible to build a multimedia on-demand server capable of providing services similar to those of a neighborhood videotape rental store on a metropolitan-area network. In this paper, we study various admission control policies that permit such a multimedia server to satisfy multiple subscribers simultaneously without violating any of their continuous media playback requirements. We propose a quality proportional policy that retrieves media blocks at a rate proportional on an average to the playback rates of media streams, but uses a staggered toggling technique by which successive numbers of media blocks retrieved are fine-tuned individually to admit and service an optimal number of subscribers simultaneously. This policy permits dynamic additions and deletions of requests in a transparent manner (i.e., without causing discontinuity in the retrieval of any of the existing requests). Performan...
A Ghafoor.: Interval-based Conceptual Models for Time-dependent Multimedia Data
- IEEE Transactions on Knowledge and data Engineering
, 1993
"... Abstract–Multimedia data often have time dependencies that must be satisfied at presentation time. To support a general-purpose multimedia information system, these timing relationships must be managed to provide utility to both the data presentation system and the multimedia author. In this paper w ..."
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Cited by 119 (12 self)
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Abstract–Multimedia data often have time dependencies that must be satisfied at presentation time. To support a general-purpose multimedia information system, these timing relationships must be managed to provide utility to both the data presentation system and the multimedia author. In this paper we propose new conceptual models for capturing these timing relationships and managing them as part of a database. Specifically, we introduce and define n-ary and reverse temporal relations along with their temporal constraints. These new relations are a generalization of our earlier temporal models and establish the basis for conceptual database structures and temporal access control algorithms to facilitate forward, reverse, and partial-interval evaluation during multimedia object playout. The proposed relations are defined to ensure a property of monotonically increasing playout deadlines to facilitate both real-time deadline-driven playout scheduling or optimistic interval-based process playout. Furthermore, we show a translation of the conceptual models to a structure suitable for a relational database.
A Continuous Media Player
, 1992
"... . The design and implementation of a continuous media player for Unix workstations is described. The player can play synchronized digital video and audio read from a file server. The system architecture and results of preliminary performance experiments are presented. 1. Introduction Our goal is t ..."
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Cited by 114 (7 self)
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. The design and implementation of a continuous media player for Unix workstations is described. The player can play synchronized digital video and audio read from a file server. The system architecture and results of preliminary performance experiments are presented. 1. Introduction Our goal is to develop a portable user interface and continuous media support library that can be used to implement a variety of multimedia applications (e.g., hypermedia systems, video conferencing, multimedia presentation systems, etc.). A key component of these applications is a continuous media (CM) player that can play scripts composed of one or more synchronized data streams. Example data streams are: digitized video or audio, animation sequences, image sequences, and text. The initial application we are implementing to test our abstractions is a video browser that allows a user to play high quality videos stored in a large database on a shared file server. Figure 1 shows a screen dump of the brows...
Multimedia Documents with Elastic Time
- In: ACM Multimedia 95
, 1995
"... Time is an essential component in interac-tive multimedia documents (or systems). We present the elastic time model for multimedia documents. Using the metaphor of a spring sys-tem, it allows authors to associate with each multimedia object a minimum and a maximum length and a length at rest. Author ..."
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Cited by 53 (5 self)
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Time is an essential component in interac-tive multimedia documents (or systems). We present the elastic time model for multimedia documents. Using the metaphor of a spring sys-tem, it allows authors to associate with each multimedia object a minimum and a maximum length and a length at rest. Authors can con-nect the (elastic) objects by dening temporal relationships among them. If the given speci-cation is consistent, a document is produced which is also elastic, with a minimum, a maxi-mum, and an optimal length. As such, our elas-tic model associates with a document a range of feasible solutions in addition to an optimal one. The author can then select from the acceptable range an alternative length for the document, and the system will compute a revised solution that takes the additional global constraint into eect. The system can answer questions, such as: \Can I show this multimedia presentation in 10 minutes? If so, how should all the ob-jects be scheduled? " Furthermore, the system also takes fairness into consideration and dis-tributes any necessary stretching or shrinking across multimedia objects contained in a docu-ment. As such, the elastic time model provides expressive power and
exibility in document au-The author's current address is: University of
MCP: A Protocol For Coordination and Temporal Synchronization in Multimedia Collaborative Applications
, 1991
"... With the advent of high-speed networks, it is possible to build multimedia distributed applications that involve a geographically dispersed group of users. Development of such applications requires support for coordination and temporal synchronization of traffic over related streams. For instance ..."
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Cited by 44 (3 self)
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With the advent of high-speed networks, it is possible to build multimedia distributed applications that involve a geographically dispersed group of users. Development of such applications requires support for coordination and temporal synchronization of traffic over related streams. For instance, one must consider the problem of coordination in a multipoint communication where more than one sender may transmit data at the same time. Also, a multimedia application may need to synchronize traffic over multiple connections, each carrying traffic from a different medium. When a participant scrolls through an image browser (or a shared editor window) and says, "look at the middle of the display", the statement should be heard at the same time (or just after) the scrolling is completed. Such temporal relationships must be captured in the delivery of traffic over related flows. Existing transport and/or session layer protocols do not explicitly include communication abstractions t...
A Digital On-Demand Video Service Supporting Content-Based Queries
- ACM 1st Multimedia Conference
, 1993
"... Video-on-demand represents a key demonstrative application for enabling multimedia technology in communication, database, and interface research. This application requires solving a number of diverse technical problems including the data synchronization problem for time-dependent data delivery. In ..."
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Cited by 40 (1 self)
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Video-on-demand represents a key demonstrative application for enabling multimedia technology in communication, database, and interface research. This application requires solving a number of diverse technical problems including the data synchronization problem for time-dependent data delivery. In this paper we describe the general requirements of video-on-demand and introduce a system supporting content-based retrieval and playback for the structure and content of digital motion pictures. In our model we capture domain-specific information for motion pictures and provide access to individual scenes of movies through queries on a temporal database. We describe our implementation of this service using existing workstation and storage technology. Keywords: Multimedia databases, video-on-demand, applications, temporal data management, content-based retrieval. 1 Introduction Future multimedia information systems will have a dramatic effect on the dissemination of information to individu...
A Spatio-Temporal Semantic Model For Multimedia Presentations And Multimedia Database Systems
- IEEE Transactions on Knowledge and Data Engineering
, 1999
"... An abstract semantic model based on augmented transition network (ATN) to model multimedia presentations and temporal/spatial multimedia database searching is presented in this paper. The inputs for ATNs are modeled by regular expressions. Regular expressions provide an efficient means for iconic in ..."
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Cited by 40 (22 self)
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An abstract semantic model based on augmented transition network (ATN) to model multimedia presentations and temporal/spatial multimedia database searching is presented in this paper. The inputs for ATNs are modeled by regular expressions. Regular expressions provide an efficient means for iconic indexing of the temporal/spatial relations of media streams and semantic objects. An ATN and its subnetworks are used to represent the appearing sequence of media streams and semantic objects. The arc label is a substring of a regular expression. In this design, a presentation is driven by a regular expression. Each subnetwork has its own regular expression. Database queries relative to text, image, and video can be answered via substring matching at subnetworks. Users have the flexibility to select any part of the presentation to watch by issuing approximate database queries. This means that ATN and its subnetwork can be included in the multimedia database systems which is controlled by a dat...
Dynamic Rate Shaping of Compressed Digital Video
- In Proc. of 2 nd IEEE Intl. Conf. on Image Processing
, 1995
"... We discuss new theoretical and experimental results on the Dynamic Rate Shaping (DRS) approach for transcoding compressed video bitstreams (MPEG-1, MPEG-2, MPEG-4, H.261 as well as JPEG). A set of low complexity algorithms for both constrained and unconstrained DRS are presented. We present the firs ..."
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Cited by 38 (4 self)
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We discuss new theoretical and experimental results on the Dynamic Rate Shaping (DRS) approach for transcoding compressed video bitstreams (MPEG-1, MPEG-2, MPEG-4, H.261 as well as JPEG). A set of low complexity algorithms for both constrained and unconstrained DRS are presented. We present the first extensive experimental study on the various DRS algorithms (causally optimal, memoryless, and rate-based) both in their constrained and generalized forms. The study proves the computational viability of the DRS approach to transcoding and identifies a range of rate shaping ratios for which it is better than requantization, both complexity-wise as well as in performance. We then substantiate the almost-optimal experimental performance of the memoryless algorithm by analyzing the behavior of the DRS problem assuming a first order Autoregressive source. By deriving the statistical and rate-distortion characteristics of different components of the inter-frame rate shaping problem, we offer an explanation as to why the set of optimal breakpoint values for any frame is somewhat invariant to the accumulated motion compensated shaping error from past frames. This result is significant as it opens up the way to construct much simpler memoryless algorithms that give minimal penalty in achieved quality, not just for this, but possibly other types of algorithms. Of equal, if not more, importance is the very first use of matrix perturbation theory for tracking the spectral behavior of the auto-correlation matrix of the source signal and the motion residual it yields. 1 1
Implementation Techniques for Continuous Media Systems and Applications
, 1994
"... In this thesis, I investigate issues in the development of continuous media (CM) applications. CM applications process, transport, or store CM data such as digital audio and video. Introduction of video into applications will require support for sophisticated video effects such as image processing ..."
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Cited by 36 (4 self)
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In this thesis, I investigate issues in the development of continuous media (CM) applications. CM applications process, transport, or store CM data such as digital audio and video. Introduction of video into applications will require support for sophisticated video effects such as image processing, composition and digital filtering. Traditional image processing and composition algorithms operate on uncompressed images, while video is typically stored and delivered in a compressed form. High computational cost, along with the complexity of video decompression, makes traditional algorithms too slow for interactive use on video data. This thesis describes and evaluates a new family of algorithms for computing video effects that run one to two orders of magnitude faster than their ...
