MULTIMEDIA '01最新文献

{"title":"Intra-flow loss recovery and control for VoIP","authors":"H. Sanneck, Nguyen Tuong, L. Le, A. Wolisz, G. Carle","doi":"10.1145/500141.500206","DOIUrl":"https://doi.org/10.1145/500141.500206","url":null,"abstract":"\"Best effort\" packet-switched networks, like the Internet, do not offer a reliable transmission of packets to applications with real-time constraints such as voice. Thus, the loss of packets impairs the application-level utility. For voice this utility impairment is twofold: on one hand, even short bursts of lost packets may decrease significantly the ability of the receiver to conceal the packet loss and the speech signal playout is interrupted. On the other hand, some packets may be particular sensitive to loss as they carry more important information in terms of user perception than other packets.We first develop an end-to-end model based on loss run-lengths with which we can describe the loss distribution within a flow. These packet-level metrics are then linked to user-level objective speech quality metrics. Using this framework, we find that for low-compressing sample-based codecs (PCM) with loss concealment isolated packet losses can be concealed well, whereas burst losses have a higher perceptual impact. For high-compressing frame-based codecs (G.729) on one hand the impact of loss is amplified through error propagation caused by the decoder filter memories, though on the other hand such coding schemes help to perform loss concealment by extrapolation of decoder state. Contrary to sample-based codecs we show that the concealment performance may \"break\" at transitions within the speech signal however.We then propose mechanisms which differentiate between packets within a voice data flow to minimize the impact of packet loss. We designate these methods as \"intra-flow\" loss recovery and control. At the end-to-end level, identification of packets sensitive to loss (sender) as well as loss concealment (receiver) takes place. Hop-by-hop support schemes then allow to (statistically) trade the loss of one packet, which is considered more important, against another one of the same flow which is of lower importance. As both packets require the same cost in terms of network transmission, a gain in user perception is obtainable. We show that significant speech quality improvements can bem achieved and additional data and delay overhead can be avoided while still maintaining a network service which is virtually identical to best effort in the long term.","PeriodicalId":416848,"journal":{"name":"MULTIMEDIA '01","volume":"202 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128733279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On clustering and retrieval of video shots","authors":"C. Ngo, T. Pong, HongJiang Zhang","doi":"10.1145/500141.500151","DOIUrl":"https://doi.org/10.1145/500141.500151","url":null,"abstract":"Clustering of video data is an important issue in video abstraction, browsing and retrieval. In this paper, we propose a two-level hierarchical clustering approach by aggregating shots with similar motion and color features. Motion features are computed directly from 2D tensor histograms, while color features are represented by 3D color histograms. Cluster validity analysis is further applied to automatically determine the number of clusters at each level. Video retrieval can then be done directly based on the result of clustering. The proposed approach is found to be useful particularly for sports games, where motion and color are important visual cues when searching and browsing the desired video shots. Since most games involve two teams, clsssification and retrieval of teams becomes an interesting topic. To achieve these goals, nevertheless, an initial as well as critical step is to isolate team players from background regions. Thus, we also introduce approach to segment foreground objects (players) prior to classification and retrieval.","PeriodicalId":416848,"journal":{"name":"MULTIMEDIA '01","volume":"9 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117207779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Fast client-server video summarization for continuous capture","authors":"John Dixon, C. Owen","doi":"10.1145/500141.500225","DOIUrl":"https://doi.org/10.1145/500141.500225","url":null,"abstract":"This paper describes a keyframe summarization method for client-server applications. This technique is designed for applications where a camera is collecting content on a continuous basis that must be transmitted in a summarized form to a remote database server over wireless network. The system combines three keyframe selection methods including a novel fast motion-based selection method, keyframe pooling and clustering for bandwidth control, and network bandwidth estimation.","PeriodicalId":416848,"journal":{"name":"MULTIMEDIA '01","volume":"18 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116096381","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Server-based smoothing of variable bit-rate streams","authors":"S. Anastasiadis, K. Sevcik, M. Stumm","doi":"10.1145/500141.500165","DOIUrl":"https://doi.org/10.1145/500141.500165","url":null,"abstract":"We introduce an algorithm that uses buffer space available at the server for smoothing disk transfers of variable bit-rate streams. Previous smoothing techniques prefetched stream data into the client buffer space, instead. However, emergence of personal computing devices with widely different hardware configurations means that we should not always assume abundance of resources at the client side. The new algorithm is shown to have optimal smoothing effect under the specified constraints. We incorporate it into a prototype server, and demonstrate significant increase in the number of streams concurrently supported at different system scales. We also extend our algorithm for striping variable bit-rate streams on heterogeneous disks. High bandwidth utilization is achieved across all the different disks, which leads to server throughput improved by several factors at high loads.","PeriodicalId":416848,"journal":{"name":"MULTIMEDIA '01","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116161007","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"SARI: self-authentication-and-recovery image watermarking system","authors":"Ching-Yung Lin, Shih-Fu Chang","doi":"10.1145/500141.500266","DOIUrl":"https://doi.org/10.1145/500141.500266","url":null,"abstract":"In this project, we designed a novel image authentication system based on a our semi-fragile watermarking technique. The system, called SARI, can accept quantization-based lossy compression to a determined degree without any false alarm and can sensitively detect and locate malicious manipulations. It's the first system that has such capability in distinguishing malicious attacks from acceptable operations. Furthermore, the corrupted area can be approximately recovered by the information hidden in the other part of the contentimage. The amount of information embedded in our SARI system has nearly reached the theoretical maximum zero-error information hiding capacity of digital images. The software prototype includes two parts - the watermark embedder that's freely distributed and the authenticator that can be deployed online as a third-party service or used in the recipient side.","PeriodicalId":416848,"journal":{"name":"MULTIMEDIA '01","volume":"29 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126962547","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"System support for providing integrated services from networked multimedia storage servers","authors":"Ravi Wijayaratne, A. L. Narasimha Reddy","doi":"10.1145/500141.500183","DOIUrl":"https://doi.org/10.1145/500141.500183","url":null,"abstract":"In this paper, we describe our experience in building an integrated multimedia storage system, Prism. Our current Linux-based implementation of Prism provides three levels of service: deadline guarantees for periodic applications, best-effort better response times for interactive applications and starvation-free throughput guarantees for aperiodic applications. Prism separates resource allocation from resource scheduling. Resource allocation is controlled across the service classes by a system-wide policy and service class specific admission controllers. Resource scheduling is done at the resources. This separation allows Prism to be deployed even when the storage system is separated on a network from the file system.We report on the important aspects of Prism architecture, innovations required to build Prism on top of Linux and lessons learned during the implementation and testing of Prism. We present experimental results to show that Prism achieves its goals in supporting multiple service classes within a single system. We compare Prism against standard Linux operating system to show the impact of our approach.","PeriodicalId":416848,"journal":{"name":"MULTIMEDIA '01","volume":"45 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"125052426","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"TeleExperience: communicating compelling experience","authors":"R. Jain","doi":"10.1145/500141.500143","DOIUrl":"https://doi.org/10.1145/500141.500143","url":null,"abstract":"We experience our environment using our natural senses: sight, sound, touch, taste, and smell. These senses combined with the knowledge of the world allow us to experience and function in the world. Data are observed facts or measurements. Information is derived from data in a specific context. Experience is direct observation or participation in an event. The development of civilization is the story of the development of understanding of 'experience' and how to share it with fellow human beings of current and future generations. The desire to share experiences and desire to experience various events where one can not be present, will continue to be the motivating factor in the development of exciting technology in the future. A look at history shows how our society evolved to become an 'information society' and is on its way to becoming an 'experience society'.Compelling and engaging experiences require immersion in a rich set of multimedia data and information so that one can directly observe a subset of the data and information. TeleExperience is a natural major step in technology evolution. It will impact every aspect of our society including education, business, sexual behavior, and health care. TeleExperience will give rise to an experience society. In this presentation, we will examine the role of multimedia information systems, multimedia presentations, situated computing, perception systems, and personalization approaches to realize TeleExperience. Then we will discuss aspects of taking a promising and exciting technology from 'laboratory to popular practice' based on practical experience.","PeriodicalId":416848,"journal":{"name":"MULTIMEDIA '01","volume":"375 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122051575","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Interactive media on demand: generic recording and replay of interactive media streams","authors":"V. Hilt, M. Mauve, J. Vogel, W. Effelsberg","doi":"10.1145/500141.500251","DOIUrl":"https://doi.org/10.1145/500141.500251","url":null,"abstract":"In this demonstration we present a generic recording service for distributed interactive media, i.e., media which allow a distributed group of users to interact with the medium itself. Typical examples of this media class are shared whiteboard systems, distributed virtual environments and networked computer games. By defining an abstract model and an application level protocol we were able to develop the first generic recording service for arbitrary distributed interactive media. This service is called Interactive Media on Demand (IMoD), and it is able to record and replay all applications that are based on the RTP/I protocol. In particular it allows random access to the recorded media streams. We demonstrate the IMoD system by recording and replaying a shared whiteboard, a networked computer game and a 3D telecooperation application.","PeriodicalId":416848,"journal":{"name":"MULTIMEDIA '01","volume":"11 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131275020","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"ReMDoR: remote multimedia document retrieval over partial order transport","authors":"P. Conrad, A. Caro, P. Amer","doi":"10.1145/500141.500167","DOIUrl":"https://doi.org/10.1145/500141.500167","url":null,"abstract":"This paper presents results from performance experiments that demonstrate and quantify performance improvements when a PO/R transpor5t service is used instead of an ordered/reliable service (O/R e.g., TCP) or an unordered/unreliable service (e.g. UDP). We first describe the Remote Multimedia Document Retrieval system (ReMDoR), an experimental application developed by the authors to evaluate the performance of remote document retrieval over a variety of transport protocols. We then provide a detailed analysis of experiments comparing O/R service to PO/R service for retrieval of a multimedia document. Our results show that between 5% and 10% loss, user-perceivable improvements in progressive display are obtained when PO/R service is used. These results suggest that when packet losses occur in an underlying packet-switched network, transport services providing reliable delivery over independent streams (such the emerging Internet protocol SCTP) are beneficial for retrieval of streaming multimedia.","PeriodicalId":416848,"journal":{"name":"MULTIMEDIA '01","volume":"30 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116442490","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"IMKA: a multimedia organization system combining perceptual and semantic knowledge","authors":"A. Benitez, Shih-Fu Chang, John R. Smith","doi":"10.1145/500141.500267","DOIUrl":"https://doi.org/10.1145/500141.500267","url":null,"abstract":"In the demo, we present the IMKA system, which implements the innovative approach of integrating perceptual information such as low-level features and images, and symbolic information such as words to represent the knowlege associated with a large multimedia collection for multimedia organization and retrieval. The IMKA system utilizes the unique MediaNet framework, which greatly extends existing knowlege representation tools in the text domain (e.g., semantic networks and WordNet) and the multimedia domain (e.g. Multimedia Thesaurus) by combining perceptual and semantic concepts in the same network and by supporting perceptual and semantic relationships among concepts exemplified by different media. It also brings the level of multimedia retrieval closer to users' needs by translating low-level feature queries to high-level semantic queries and vice versa. We will demonstrate the process of constructing the MediaNet knowledge base and new ways of searching multimedia in the IMKA system by presenting the current implementation of the IMKA system that uses image collections from online sources.","PeriodicalId":416848,"journal":{"name":"MULTIMEDIA '01","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116515055","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}