The developed system provides possibility of multichannel video and sound recording and the slowed down repetition during sports and other entertainment actions translation on the air.

      Video signal recording on each channel (camera) is carried by system continuously from the moment of its initialization.

      System operator during continuous recording process on all channels marks the beginning of an interesting moments, from its point of view. Then with one button press he chooses the channel from which the slowed down repetition will be shown, - and the scene is ready to be displayed. Thus there is a possibility of the scene editing: it is possible to "move" forward or back on any quantity of shots precisely choosing the moment from which repetition will be shown. Thus process of recording on all channels does not interrupt. All marked scenes are displayed in the list of events and are ready to be repeated at any moment.

      The stored information is remembered in storehouses and after the translation termination is accessible to any actions: display, editing and record to various storage devices.

      A delay between event and its repetition is minimum. It gives a chance to the operator to notice event and to begin its repetition less, than in two seconds after its beginning. The initial delay is exposed taking into account the operator reaction time.

      Instant switching between different channels provides image reception ten times faster real time. While rewind the image from all channels changes simultaneously, and to choose a channel it is enough to press on image with this channel.

      A possibility of repetition acceleration of the chosen material is provided besides the slowed down reproduction.

      Following repetition preparation is conducted simultaneously with reproduction of current repetition. At once after the beginning of reproduction the operator can begin preparation of repetition from other channel or other event. Consecutive reproduction of several repetitions without a pause between them is also possible.

      Management of system can be carried out by keyboard or mouse. The system makes all these operations, not interrupting recording process of all translation.

      Directly while working it is possible to edit marked events, changing their type, name, channel number, starting time and duration. It is possible to see operatively all edited events after recording have been stopped, to add new events and to make playlist for reproduction entirely all game or the most interesting moments. Thus it is possible to insert various rollers into playlist, for example, sponsor's advertising.

      System allows showing on several images at once from all channels which have been written down during the game. Looking through all channels, it is possible to choose quickly the best foreshortening, to specify an interval of time and a name for the subsequent reproduction in playlist. Here the events marked by the operator are displayed, and events of different type are displayed with different color. It is possible to make playlist of marked fragments.

      The system functions on the basis of PC, under OS Windows XP/Vista.



Theme urgency

      Possibility of the slowed down reproduction during television translations has appeared rather recently. However the slowed down repetitions accompanying television programs, already became so habitual, that it is impossible to imagine translations of sports matches, feature films and a talk shows without them.

      The slowed down reproduction allows raising essentially emotional influence on the spectator and gives audiences a lot of additional information hidden in reproduction with normal speed. That was inaccessible to a human eye earlier, became accessible with slowed down reproduction. In reply to market requirements the various companies - manufacturers of TV-equipment have developed the systems which provides slowed down reproduction during translations.



The purposes and problems

      The purpose of the given work is to develop a full-function server of video repetitions.

      To achieve the given purpose next problems are solved:

scheduling and technical requirements on development of the server’s software;

      The system initial will allow working with various videos devices. Switching from video channel working through interface FireWire (IEEE 1394) however is supposed. Thus, at the given stage of development, format DV (Digital Video) is completely supported. For connection with computer a socket of type IEEE 1394 is used.

      The primary application testing has been held using three channels (cameras) connected to the computer through three sockets IEEE 1394. Adding support for working with high-quality uncompressed video (HD) is in the long term. Thanks to it application can be used during direct transmissions in HDTV format(High definition TV).

      The server software is realized in language C++ using Visual Studio 2005 IDE.



Realization

      The given system is realized for functioning under control of OS Windows XP/Vista. OS Windows gives all necessary means for work both with multimedia devices and for processing of arriving data, namely library DirectX and DirectShow technology. It's very simple to realise the similar application using DirectShow, however with very limited functionality. It is really simple. However, if to complicate a task new problems and complexities are appears. For example: DirectShow gives some base - "bricks" and if to combine them together - the functioning system turns out. However these most "bricks" are only presents base functionality. Many necessary "bricks" are not present. You are to develop them by your own. It would not bring so big complexity in developing if this process has been well described and documented. The basic source of the information - is the documentation on DirectShow from Microsoft (DirectShow SDK). Books and articles on the given subjects are rather limited, And the considerable part of the information turns out from studying of source codes in DirectShow SDK.

      Developed kernel's structure is represented by a set of graphs(in DirectShow terms) for realisations of diferent functionality. The graph in DirectShow is a set of the filters connected among themselves, each of which is responsible for certain sort of information processing. I.e. to organise capture, record, video output - it is necessary to construct the corresponding graph. For example, to construct a graph to output some video file to the device, it is necessary to create and consistently connect among ourselves such filters:

File source (reading)-> File parser(recognition)-> -> Coder (DV a format) -> Some DV output device Filter.

The decoder, in this case, can be absent if data in a file are written down in DV format, differently it is necessary to decode data to uncompressed format for the subsequent coding. In figure 1 such already constructed graph is shown.

Fig. 1 Graph. Outputing video from a file to a device. (20 frames х 0.2 sec., repeat 1 times, 10 seconds animation.)

Prospective scientific novelty

      Existing systems of repetitions servers are enough difficult with a big set of functionality. Their development has begun several years ago and now similar systems are an integral part in a television announcement, especially while sports actions translation. In foreign countries are seriously engaged in such system development. There are similar developments in Russia.

      At present in Ukraine there are no representatives of repetitions servers development. That is one of the key moments of necessity/demand of the given work.

      Besides, the given software, in the long term, can unite a big complex of works connected with video-announcement. Besides the repetitions and redistribution of streams it is possible to realize a combination of several streams in one, mixing, imposing, titration, for example.

      The prices of existing repetitions servers reaches $20 000 and above. The used software and accompanying equipment are very expensive. Certainly, on the big sports actions or during other serious “scaled” translations expenses completely justifies their self. However to rather small studios, similar sort of «heaped up» is not necessary to use. There is no that scale or variety of possible situations. Such studios will be interested in development of a new, more affordable tool for recording and announcement process.



Results description

      At the given stage of development the system allows to grasp and redistribute video streams from three DV channels. Video capture is carried out in two variants. The first - record in format AVI. It is used when there is no necessity to organise repetitions. The second - record in own format. The second variant allows to use flexibly the same file with record both for viewing and a conclusion, and for дозаписи the new information. It is used for the organisation of repetitions.

      During data recording from channels probably arrangement of control points (references), for fast transition to the last noted moment.

       Used playlist allows to contain in itself as sources of data (the reference to video-channels) accepted with the chamber, and file streams. And actions on addition and redistribution of video-channels in playlist occur is transparent for the user. I.e. it is possible to choose a source with a pseudonym of the chamber or to specify a way to video to a file.

      The flexible window system where to each entrance channel own window and elements of management is taken away by it is realised. The Control over target channels and playlistalso are organised in separate windows. The internal designer of the interface allows the operator to adjust appearance and an arrangement of elements of management to the taste and desire. The Dinnamichesky structure of the interface allows both to create new windows, and to delete already existing. I.e. for example it is possible to create two target channels and two windows playlist, and then in the course of work to connect each of channels with corresponding playlist.

Fig. 1 System of monitoring and redistributions of video of streams. A repetitions' server.

Conclusions

      An interesting developing work on creation convenient and simple system of repetitions has been done. The main advantage of this application developing (a repetitions' server) is its simplicity and availability. It does not mean, that in comparison with similar systems it is limited in something. The purpose was to creation a repetitions' serever and a redistributions of video-streams system with base necessary functionality.

      The Greatest complexity in developing consisted in realisation of a kernel, namely all necessary low level means for working with video-streams. Quality of realisation of this important part of the system directly influences quality of work as a whole. Besides this critical part of system represents certain internal framework, having realised which it is possible to add new possibilities rather easily and quickly.



Sources

1. ProSystem - Системы замедленных повторов.
2. DNK - Сервер замедленных повторов Оrad Forum.
3. Архив журнала «625» №5/2004 - Системы замедленного воспроизведения и повтора EVS.
4. BSS - Микшерские пульты, видеокамеры, станция нелинейного монтажа.
5. Standards & Organizations - IEEE 1394.
6. IEEE 1394 - IEEE 1394.
7. VideoDive - Основные характеристики IEEE-1394.
8. Wikipedia - DirectShow.
9. Windows Media Developer Center - Introduction to DirectShow.
10. DirectShow по-русски - Руководство по созданию мультимедийных приложений на русском языке.