• Journal of KIISE:Computer Systems and Theory
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• v.31 no.9
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• pp.527-535
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• 2004

Handling mixed workload in digital set-top box or streaming server becomes an important issue as integrated file system gets momentum as the choice for the next generation file system. The next generation file system is required to handle real-time audio/video playback while being able to handle text requests such as web page, image file, etc. Legacy file system provides only best effort I/O service and thus cannot properly support the QoS of soft real-time I/O. In this paper, we would like to present our experience in developing the file system which fan guarantee the QoS of multimedia stream. We classify all application I/O requests into two category: periodic I/O and sporadic I/O. The QoS requirement of multimedia stream could be guaranteed by giving a higher priority to periodic requests than sporadic requests. The proto-type file system(Qosfs) is developed on Linux Operating System.

• The KIPS Transactions:PartA
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• v.9A no.2
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• pp.163-170
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• 2002

Previous buffer cache schemes for continuous media file system only exploited the sequentiality of continuous media accesses and didn't consider looping references. However, in some video applications like foreign language learning, users mark the scene as loop area and then application automatically playbacks the scene several times. In this paper, we propose a novel buffer cache scheme for continuous media file system that sequential and looping references exist together. Proposed scheme increases the cache hit ratio by detecting reference pattern of files and appling an appropriate replacement policy to each file.

• Journal of KIISE:Computer Systems and Theory
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• v.31 no.5_6
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• pp.268-278
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• 2004

In this paper, we describe our experience in the design and implementation of the SMART file system to handle multimedia workload. Our work has three design objectives: (ⅰ) efficient support for sequential workload, (ⅱ) avoiding disk fragmentation, (ⅲ) logical unit based file access. To achieve these three objectives, we develop a file system where a file consists of linked list of Data Unit Group. Instead of tree like structure of the legacy Unix file system, we use single level file structure. Our file system can also access the file based upon the logical unit which can be video frame or audio samples. Data Unit Group is a group of logical data units which is allocated continuous disk blocks. At the beginning of each Data Unit Group, there exists an index array. Each index points to the beginning of logical data units, e.g. frames in the Data Unit Group. This index array enables the random access and sequencial access of semantic data units. SMART file system is elaborately tailored to effectively support multimedia workload. We perform physical experiments and compare the performance of SMART file system with EXT2 file system and SGI XFS file system. In this experiment, SMART file system exhibits superior performance under streaming workload.

• Journal of Internet Computing and Services
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• v.17 no.1
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• pp.55-64
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• 2016

Existing Android applications for streaming video in real time are dependent on the codec, which composes the encoding function, and the version of Android operating system. Also, for streaming video in real time, most applications should be connected with a separate desktop PC. To overcome these disadvantages, we propose a new application, which records and streams video in real time. Specifically, the proposed application uses the flash video file format, which is the common media file format supported by various versions of Android operating system. Through experiments, we show that it is possible for the proposed application to record the video screens more than 20 frames per second and to stream it in real time while using the existing video encoding methods.

• The Journal of Information Technology
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• v.12 no.3
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• pp.49-57
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• 2009

This Paper provides perceptual metrics for video quality based on properties of human visual system, and audio quality based on human audition. All metrics work without reference signals, allowing non-intrusive, in-service measurements. A simple and easy-to-learn user interface displays the metrics and saves them in popular file formats like CSV. In this paper, proposed method was able to various and corrective measurement for the multimedia service video quality. As that it was able to application to set up service guide line and the methode of measurement and system for the set up standardization of the high quality video service.

• Journal of Biomedical Engineering Research
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• v.26 no.5
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• pp.301-307
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• 2005

We introduce a new multimedia telemedicine system which is called Telemedicine for Real-time Emergency Multi-consultation(TREM), based on multiple connection between medical specialists. Due to the subdivision of medical specialties, the existing one-to-one telemedicine system needs be modified to a simultaneous multi-consulting system. To facilitate the consultation the designed system includes following modules: high-quality video, video conferenceing, bio-signal transmission, and file transmission. In order to enhance the operability of the system in different network environment, we made it possible for the user to choose appropriate data acquisition sources of multimedia data and video resolutions. We have tested this system set up in three different places: emergency room, radiologist's office, and surgeon's office. All three communicating systems were successful in making connections with the multi-consultation center to exchange data simultaneously in real-time.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.7
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• pp.879-884
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• 2020

In the conventional video file system, videos are stored in a high performance server which has mass storage hard disks or disk arrays. For 3D internet broadcasting, real time operations are required to transmit video files to many clients. This paper describes the design of the 3D internet broadcasting system which can provide realtime streaming service to many users in the 5G environment. In reality, unicast is used to transmit multimedia contents over the internet rather than IP multicast since IP multicast has its own drawbacks in deployment, security, maintenance and so on. In addition, multimedia broadcasting service system like VoD has difficulties in applying to 3D internet broadcasting system since it requires a large amount of system and network resources. In this work, we develop a 3D internet broadcasting system which can construct effective data delivery by minimizing performance-degrading factors.

• The Journal of Society for e-Business Studies
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• v.9 no.4
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• pp.137-155
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• 2004

A video-conference system is being utilized in web based application services in various fields due to the widespread use of Internet and the progress of computer technologies. This system should use the public IP address for sharing file and white board and it is difficult to manage the internal network users of the firewall and non-public IP address users. In this paper, we propose an Application Level Gateway which transforms non-public IP address into public IP address. This mechanism is for the internal network users of the firewall or non-public IP address users over the Internet. We also propose a Control Daemon which manages video and audio media dynamically according to network bandwidth. This mechanism can start and terminate a video conference and manage the process of the video conference.

• Journal of KIISE:Computer Systems and Theory
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• v.33 no.9
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• pp.574-584
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• 2006

Recently, ISO/IEC 23000 (also known as 'MPEG-A') has proposed a new file format called 'MAF(Multimedia Application File Format)[1]' which provides a capability of integrating/storing the widely-used compression standards for audio and video and the metadata in MPEG-7 form into a single file format. However, it is still very hard to verify the usefulness of MPEG-A in the real applications because there is still no real system that fully implements this standard. In this thesis, a design and implementation of a multimedia retrieval system based on MPEG-A standard on PC and mobile device is presented. Furthermore, an extension of MPEG-A for describing the metadata for video is also proposed. It is selected and defined as a subset of MPEG-7 MDS[4] and TV-anytime[5] for video that is useful and manageable in the mobile environments. In order to design the multimedia retrieval system based on MPEG-A, we define the system requirements in terms of portability, extensibility, compatibility, adaptability, efficiency. Based on these requirements, we design the system which composed of 3 layers: Application Layer, Middleware Layer, Platform Layer. The proposed system consists of two sub-parts, client-part and server-part. The client-part consists of MAF authoring tool, MAP player tool and MAF searching tool which allow users to create, play and search the MAF files, respectively. The server-part is composed of modules to store and manage the MAF files and metadata extracted from MAF files. We show the usefulness of the proposed system by implementing the client system both on MS-Windows platform on desk-top computer and WIPI platform on mobile phone, and validate whether it to satisfy all the system requirements. The proposed system can be used to verify the specification in the MPEG-A, and to proves the usefulness of MPEG-A in the real application.

• International journal of advanced smart convergence
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• v.5 no.3
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• pp.61-65
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• 2016

In the TV broadcasting, movie production and business the transportation of video between creators (programmers, studios) and distributors (broadcast and cable networks, cable and satellites companies) is still a mix of File Transfer Protocol (FTP), physical delivery, and expensive multicast satellite. Cloud-based file sync-and-share providers like Dropbox and box are playing an increasing role, but the industry's unique demands for speed and multicasting have fueled the growth of IP Video transport. This paper gives a solid grasp of the major elements of IP video technology, including content preparation, system architecture alternatives and network performance management.