- Email: [email protected]
I-Media: An integrated Media server and Media database as a basic component of a cross Media publishing system
Comput. & Graphics, Vol. 21, No. 6, pp. 693-702, 1997 c: 1997 ElsevierScienceLtd. All rights reserved Printed in Great Britain 0097-8493/97 $17.00+0.00
Pergamon PII: Soo97-8493(97)
Graphics in Electronics Printing
and Publishing
I-MEDIA: AN INTEGRATED MEDIA SERVER AND MEDIA DATABASE AS A BASIC COMPONENT OF A CROSS MEDIA PUBLISHING SYSTEM J6RG ZEDLER+ and MARWAN RAMADAN Fraunhofer-Institut
fiir Graphische Datenverarbeitung (Fraunhofer Institute for Computer Graphics), RundetrumstraDe 6. 64 283 Darmstadt, Germany e-mail: [email protected]
Abstract-The publication of the same information on different media, the so-called Cross Media Publishing (CMP), is becoming one of the central aspects in today’s publishing industry. CMP centers on a media independent document definition and an efficient integrated publishing on different media: e.g. as a paper document, as an online document in the World Wide Web, and as an offline (CD-ROM based) multimedia presentation. The aim of CMP is to get these different media at the same stage, while-and that is important-spending an acceptable amount of additional effort (in time and money) for production. In this paper we present a solution for a key problem of Cross Media Publishing, the handling of media data (images, audio, video, etc.) by using a combined approach of server and database systems functionality. The integrated multimedia server and database i-Media and its role in a complete CMP solution will be presented. 0 1997 Elsevier Science Ltd. All rights reserved
1. INTRODUCTION
AND BASIC REFLECTIONS
In thesedays the publishing industry is affected by enormouschangesregardingstructuresand contents. Sincethe completelyelectronicproduction of printed documentsis becomingmore and more commonand new technologiesand mediasuchasthe World Wide Web (WWW) and CD-ROM based multimedia presentationsshow an overwhelming success,the traditional workflow in the publishing world is no longer timely. Moreover, the publishing world has becomecomplex, since several different platforms, applications, and media must be supported in an open architecture. Now that a reader has the possibility to choose from different types of media he also expectsto get the sameinformation irrespectiveof what he chose. He can then decidedependingon his situation which mediaplatform fits best. In this paper we will presenta solution for a key problem of CrossMedia Publishing,the handling of media data. A media managementsystem will be presented, which offers an added value by a combined approach of an object-oriented database managementsystem(OODBMS) configured to the purposesof an CMP system and expanded with additional serverfunctionality, e.g. regardingformat conversionin an automated,configurableway. Conceptually all media types-text, image (both raster and vector images),audio, video, and animation-are supportedand the specialtechnical pub-
+ Author for correspondence. 693
lishing requirements,e.g. OPI serverfunctionality or DTP/multimedia authoring tool support are taken into account. In this sectionwe will shortly explain the requirements of Cross Media Publishing(seeSection 1.2). We will tak:e a look at the variety of formats and standards (Section 1.3) and the media dependent advantages,disadvantagesand technical restrictions (Section 1.4). 1.1. Naming The term media is usedfor a variety of things. To avoid confusion, we will use in this paper the following naming: l
l
Images,audio, video, and animations are called Media Data or Document Resources or shortly Resources. Media data is often saved in special mediaand platform dependentformats. Documentsare publishedon paper (Print Media) or as electronic documents (New Media or Electronic Media). Electronic documentscould be made available either online or offline. Offline documentsare usuallypublishedon storagemedia such as CD-ROM. Documentsare publishedon so-calledTarget Media or Media Platforms.
1.2. Cross Media Publishing In Fig. 1, an example of a cross-mediaproduced and publishedarticle is shown.It wasprinted on an offset press as a color brochure. Then it was converted to an HTML document with embedded GIF and JPEG images,to a PDF document with
694
J. ZedlerandM. Ramadan
paper version (offset print)
CD-ROM based multimedia presentation (Macromedia Director)
HTML based WWW presentation (Netscape Navigator)
PDF documant (Netscape Navigator with Adobe Acrobat Plug-In)
Fig. 1.CMP example.
integrated “weblinks”, as well as to a CD-ROM basedmultimedia presentation with PICT images and additional sound and video clips. A stripped version of the multimedia document is also accessableasa Shockwavedocumentvia Internet. See http://www.igd.fhg.de/www/igd-al/crossmedia/index-e.html for the electronicdocuments. The basis of CMP is a media independent document description. Media independent means that you can convert a document(automatically) to any mediaplatform. To achieve a high quality, the technical requirements of a media independentformat are given by the media platform with the highest demands. Therefore a media independentdocument contains among other things: l
l
l
high resolution raster images(necessaryfor print, although not necessaryfor screenpresentation), audio, video, and animations (although not supportedby print media),and hypertext functionality (although again not supported by print media).
Becauseof the continuing high acceptance of paper documents, Cross Media Publishing is seen especiallyfrom the print publishing’spoint of view. Advanced and commonly used publishing systems like Adobe FrameMaker, Adobe PageMaker, or Quark XPress have to fit into an integrated CMP systemarchitecture, as well as sophisticatedauthoring tools. 1.3. Formats of the publishing industry In the publishing industry a variety of standardized as well as proprietary data formats have been established.Formats like PostScript,EPS, and TIFF for print media or HTML, JPEG, and GIF for the Web have to be taken into accountwhen settingup a CrossMedia Publishingsolution. In the following we will shortly mention someof the most important formats used. A more detailed discussioncan be found in [l].
1.3.1.Formats of the prepress world. The prepress world is coined by the de-facto industry standard Adobe PostScript[2] usedfor documentencoding,as well as the derived formats EPS (Encapsulated PostScript [3]) and AI (Adobe Illustrator), which are widely usedfor interchangeof illustrations. Raster images are usually encoded in TIFF (Tagged Image File Format [4]), which can handle bitmaps,gray level images,aswell as RGB, CMYK or even device independently (CIE Lab) encoded imagesin arbitrary resolutions. Becauseof the high resolution of raster images there are tremendousrequirementsdue to storage capacity in the prepressworld. A typical letter format four color image requiresabout 30 MByte, when encodedas an uncompressedCMYK TIFF. To reduce the load on the network and the DTP computersAldus has specifiedOPI (Open Prepress Interface [5]), which has become a widely used standard.A so-calledOPI server managesthe high resolution imagesand calculates a low resolution sample,which is used for positioning on the DTP computer.When sendinga documentwith embedded OPI imagesto a printer, the OPI server substitutes transparently for the user the samplesby the high resolution originals. Using an OPI servercan boost up productivity during printing easilyby a factor of loo! More and more Adobe’s Portable Document Format (PDF) [6, 71 is becoming used as a page descriptionlanguagesuitablefor both displayingon screenaswell asfor printing on b/w or color printing devices. Currently PDF is mostly generated by “distilling” PostScript (usingAdobe’s Acrobat technology). Automatic generationof hypertext elements (especially links) and integration of document information in PDF format is possibleby using “pdfinark” commandsencodedin PostScript. 1.3.2. Formats of the World Wide Web ( WWW). The standard document format for the Web is HTML [8], which is not a pagedescriptionlanguage suchasPostScript or PDF, but a documentmarkup language.The layout is not fixed in the document.
i-Media: an integrated media server and database
695
Based upon markups enclosed in the document the l electroniconlinedocumentbasedon HTML: often appearance of the document is defined by the WWW bad presentation quality (publisher has little client, depending on the current windows size, as well control lover layout); bad printability; computer as the adjusted fonts. with network connectionnecessary;usually small network bandwidth; often one logical documentis Raster images are encoded in GIF (Graphic Interchange File format) for bitmap or color lookup divided into several HTML files, which makes table (LUT) images, and JPEG is used for contone archiving or printing disadvantageous; l electronicdocumentbasedon PDF: not well suited RGB color images. Animations are supported, e.g. as animated GIF for readingon computer display; computernecesor Java-Applets. Extensions via WWW client plugsary; usually more memory intensive than, e.g. ins are widely used. Adobe is for example pushing its HTML-based documents; l electronic CD-ROM based offline presentations: PDF format by offering plug-ins for several WWW clients for free. Because of its good printability (see information often not up-to-date; computernecesSection 1.4) PDF is becoming common on the Web sary; often bad printability. also. 1.3.3. Formats of multimedia authoring software. Based on the different purposesmany different Multimedia authoring systemssuch as Macromedia formats are used for the encodingof text, images, Director and Asymetrix Toolbook typically uses audio, video, and animation.Moreover, the technical platform specificformats, such as PICT for images surroundingconditions are of importance: on Apple Macintosh computersand BMP for images on Microsoft Windows computers,to give just an l different color spaces:RGB for displaying on example. screenand CMYK for printing deviceindependent Moreover, there are several additional image color (CIE Lab) not yet widely used; formats as well as audio and video formats l different color depth: color tables are famousfor supportedby the authoring systems.A completelist displaying on screenbecauseof its compactness would be too extensiveto be discussed here. and becauseof technicallimitations of typical PCs graphic hardware; l different required resolutions:usually low resolu1.4. Media platforms: advantages, disadvantages, and tion (approximate 72 dpi) for displaying on technical restrictions computer screens, but resolutions of about Media platforms differ in severalaspects:they are 300 dpi (gray and color images)and of up to either electronically availableor not, either online or 3000or 4000dpi (bitmaps)for printing purposes; offline accessable, and so on. A typical advantageof one media platform is often a disadvantageon the l different documentconceptsusedin the publishing world (page description languages(PDL) like other platform. The aspectsare listedbelowin detail. PostScript or PDF as well as document markup Advantages. languages,suchas HTML). l print document:excellentpresentationquality and readability; no computer required for reading; no Following these technical restrictions, e.g. for bandwidth problems;easy markup; social aspects every single image used in a document one easily (i.e. people are used to read paper documents); getseight or more different variations in format and layout under control of the publisher, size!This is one reasonwhy CrossMedia Publishing l electronic online documentbasedon HTML: upnowadays is expensive,becauseconverting images to-date information; hypertext functionality; (or any other document resource)from one format search functionality; compact format; (informa- to another is done as a manual step, which is time tion when you needit), consumingand labour respectivelycost intensiveas l electronic (online or offline) document basedon well as error prone. Data consistencyis in danger PDF: hypertext functionality; searchfunctionality; when no automatic mechanismsare available (imaup-to-date information when online accessable; gine what happens,if an imagehas to be changed good printability; well suited for archiving pur- when you have eight different variations of this poses;layout under control of publisher, image!). l electronic offline document basedon multimedia Here you needa sophisticatedmediamanagement authoring systems,usually on CD-ROM: excellent system,which doesboth the administrationof media presentationquality on screen;support of audio, (storage,accesscontrol, versioning,data consistency) video, and animation (no problemswith network and automated conversionsregarding format, size. bandwidth); hypertext and search functionality; color spaceor color depth. layout under control of publisher. Although multimediadatabasesare availableeven as products, they are lacking support of the Disadvantages. requirements of Cross Media Publishing. In the l print document:information often not up-to-date; following we will propose a concept and an no hypertext functionality; audio, video, and implementationfor an “intelligent” mediamanageanimation not supported; ment systern,suitablefor CMP purposes.
J. Zedier and M. Ramadan
696 2. I-MEDIA:
INTEGRATED
MEDIA
SERVER
AND
DATABASE
In this sectionwe will explain the basicconcepts and functionsof the i-Media serverand database(see Section 2.1) as well as its role in the context of a CrossMedia Publishingsystem(seeSection2.2). 2.1. i-Media
server and database
To handlethe different formats mentionedabove, a multimediadatabasesystemis well suited. For the special purposesof Cross Media Publishing additional support for the user (publisher)is necessary. For example conversion of an image from one format to another is a task, which could be done on an automated way, configured by the special needsof the publisher. The generalidea of i-Media is the integration of multimedia database functionality and additional functionality like automatic format conversion and OPI serverfunctionality. It consistsof two parts: the database itself and the server, which allows a prescribedaccessto the database. The databasesystempart of i-Media handlesthe resources(mediadata of any kind), especially: native format files (such as Aldus/Macromedia FreeHand, Quark XPress or Adobe Photoshop files), links to resourcesused in the generic files (e.g. embeddedTIFF or EPSimages), interchangetiles, variations of the abovementionedregarding -versions, -formats, and -languages usedin text. The servercontains:
There are many different application specific formats usedfor theseinput channels.In the context of this paper, application specificfiles are namedas Native Format Files. Theie files are not particularly suitable for interchange, therefore standard interchangefile formats are neededfor further processing, usually generatedby an export module of the above mentionedtools and systems.The interchangefiles are calledGeneric Representation or Source Files. The formar must be suitabie to generatefurther variations needed for the different media platforms automatically, e.g. for an image resource EPS illustrations or high resolutionTIFF imagescan be used. 2.1.:!. Integrated “intelligence” of media data. An important added value in our approach is the integrated “intelligence” of media data. which gives also the nameof the system(i-Media = “intelligent media”). A media object keepsa log of every conversion from one format or sizeto another (which filter was used,which parameterswereexpected).Therefore, it is possiblethat the userchecksin a correctedversion of an image and the object itself starts to do the necessaryconversionto ail usedformats, sizes,color spaces.color depthsand so on. In the exampleshownin Fig. 2, an imageresource (iImageObject)is illustrated partly. It consistsof an English and a German (language)variation of an imagewhich is created by using Macromedia FreeHand 5 (FH5). Every version of this image is availableas an EPSfile (generatedby the illustration software) and as format variations, which were automatically calculatedusinginternal and external filters. After calculation the following imagefiles are accessibleby the CMP systemfor every version of the iImageObject:
a user and group managementwhich is used to grant and restrict accessrights to mediadata (see 4 an EPSimageusedfor print publishing:this serves below); as a genericrepresentation,too (i.e. it is usedas a l a version management which allows to createnew basisfor the calculationof ail further variationsin version and to remove old versions; format and size); l check-in/check-out functionality which allows a l a TIFF imageusedfor internal reasonsonly (it is user to change media data and to lock access easier to convert the raster image format TIFF during changes; than EPS, which consistsof text, raster and vector l a configurable and extensibleset of filters, which images); allow for automatic format conversion as well as l two BMP images (a thumbnail version for OPI serverfunctionality. previewing and a full screen version for best quality displaying) used for Microsoft Windows Media data (resources)are stored in an objectbasedmultimediapresentations; oriented manner, usingan object oriented database l a small GIF image (again a thumbnail version) managementsystem(seeSection 3). and a JPEG imagefor usein a HTML document. 2.1.1. Native format files and generic representations. The mediadata which is storedin the database
comefrom a variety of input channels.Rasterimages for example are often scannedon drum or flatbed scanningdevices.Illustrations are usually generated by some high level illustration software such as Aldus/Macromedia FreeHand or Adobe Illustrator, video clips are edited by Adobe Premiereor other video editing systems.
In the exampleof Fig. 2 the userhascheckedout the English version l.Oe to correct a mistake.After correction he checksin a new version (l.le). He puts the application specificfile (native format file) aswell as a genericrepresentationof the image(sourcefile, in this case the EPS encoded image) into the database.
i-Media: an integrated media server and database
691
ilmageObject
n
version
1.Os A
version
Y
1.19
version
1 .Og
?I GIF
Fig. 2. An image resource (iImageObject) check.ed in after rework.
After check-in of the new version the variations (illustrated with dashed lines) are calculated automatically, without further interaction with the user, just by traversing the filter tree of version l.Oe and executing exactly the same filters for version l.le. What happens to the documents that reference this image resource? The next time the publisher touches the document he can update the references (which were indicated by the CMP system to be old, because a newer version of the image resource is available). Data consistency on all media platforms can be guaranteed by the CMP system.
2.2. Integration into a CA4P solution The above-described i-Media server and database system plays a vital role in a Cross Media Publishing system. Subsequently we will explain how the iMedia server communicates with its clients, the Cross Media Publishing system and an OPI server (see Fig. 3). The i-Media server consists of an object-oriented database management system, a user management module and a set of internal filters. It has access to the i-Media database via an OODBMS. Additional external filters (stand-alone running applications, e.g. a RIP such as Aladdin Ghostscript or Harlequin Scriptworks) can be called by the i-Media server.
A Cross Media Publishing system (client A) uses the i-Media server for the management of its media data. An editor running within the CMP system allows the media independent definition of documents. Third-party applications such as DTP systems allow the creation and modification of media data. A set of export modules allow the conversion to different media platforms. These “modules” could be converters which allow a fully automated generation of media platform specific document (e.g. suitable for HTML documents). A module could also be thirdparty stand.-alone system such as Quark XPress for print publishing or Macromedia Director for multimedia presentations. To allow the user of the CMP system to share the benefits of the OPI specification, another client of the i-Media server, the OPI server (client B) could run, e.g. on a powerful workstation and translates OPI PostScript (PostScript encoded documents, were OPI comments were placed instead of the high resolution images) to PostScript, which could be send sent to an image or plate setter or even to a digital printing press. 2.3. Advantages The advantages of this approach l
are as follows:
the database ensures the consistency of the data, even if last minute changes have to be made and
J. Zedler and M. Ramadan
698
User(s) L+&&+, CMP syslml (Client A)
zqF~mFl Export
..’
-HTMLIGIFIJPEQ/...
-
r3i-Media mabsaa
External
Filters I
I
Fig. 3. Architecture of i-Media server and database and its clients (CMP system and OPI server).
l
l
several variations in format, color space, color depth and size of an image are in use the i-Media server relieves the user of manual and recurrent tasks like format conversion and as a result of the above: the publisher can publish his document on several media while spending an acceptable amount of additional effort.
3. IMPLEMENTATION
In this section we will explain some implementation details of the i-Media system. It has to be stated that the system is currently under development and still much has to be done. Because of the complexity of the i-Media system it is neither efficient nor affordable to implement it from scratch. Moreover, several of the problems we have to solve, especially regarding database functionality, are already implemented in a variety of systems which can be used as implementation basis.
3.1. Media class hierarchy We have identified five different classes of document resources: text, images (both raster and vector images), audio, video, and animation. Although several aspects are specific for the different classes (e.g. which formats were used for encoding and which filters are available for conversion), there is media object information, which has to be supported independent of the class. As a result the document resources are organized as a hierarchy of classes, with a virtual class (iMed.iaClass) as the root class; see Fig. 4. The derived classes are:
l l l l l
iTextClass for text, iImageClass for raster and vector images, iALdioClass for sound and other audio data, iVi.deoClass for videos, iAnimat ionclass for animations (e.g. animated GIF or Java applets).
iAnimatiinClass
Fig. 4. iMediaClass hierarchy.
i-Media: an integrated media server and database In the iMediaClass functionality necessaryfor all mediadata is embedded.This is a container for the native format file(s), a list of links to depending files, the variants in language,version, and format, userinformation, aswell as statusinformation. An overview of attributes of the iMediaClass is given in the following table:
699
Which filters are used for transformation is a matter of configuration. To achievethat the i-Media systemcan usefilters in an open and extensibleway, every filter is describedby an external filter configuration file. It is up to the administrator of the iMedia systemto maintain theseconfiguration files and to add ‘33:remove filters.
Attribute.
Description:
Name: Version:
This name is a unique object identifier and the database’s primary index. Moreover, this is the resource handle, used in the media independent document description. The version number of this object used by the version control module.
Format:
This attribute describes the native format and the source file format.
Language:
This is the language variation for the object. This can be. for example, English, French, German, rabic, Japanese and so on.
Backtracking:
With this information, the i-Media system can find all dependent objects.
Owner:
Each object is owned by exactly one user. This user can grant and restrict access to the object.
Checked:
A user can check out media data. If an object is checked out, the system allows only READ access to this object (lock is set) until it is checked in again.
All subclassesinherit all attributes from the iMediaClass.
The subclasses themselves
define all
The following exampleshowsa filter description for a program
which
converts
TIFF
images with
mediadependentattributes. Theseattributes consists 24 bit RGB colors to BMP imageswith 256 RGB especiallyof a list of all possiblefilters suitable for colors (8 bit):
filter
( name description command class ( 1 group source
I destination
1
"TIFFZBMP" “Convert TIFF 24 Bit RGB to BMP 8 Bit “tiff2bmp SSOURCE !IDESTINATION”
RGB"
i Image "converter"
(
{
colorspace colordepth format
RGB 24 TIFF
colorspace colordepth format
RGB 8 BMP
Another example shows a filter definition for a the resourceclass.As an example:of courseit does not make sensethat an imageobject usesa filter for noisereduction filter. Here variablesare usedwhen audio compression. calling the :hlter. The user will be asked for two parameters,onefor the low frequencyvalue and one 3.2. Usage ofJilters for the high frequency value (seethe graphic on the 3.2.1. Concept. All media transformations will following page). This “language” like style description of a filter done by a group of programs, called filters. For example there are filters to convert one distinct has many advantages.First, it is easily read by humans. Second, future filter extensions can be media format into another, filters to convert text with country specific encoding (e.g. German umrealized by creation of new key words. No old descriptionfiles have to be changed.This systemof lauts), filters to scale images, to do color transformation or quantisation (e.g. from full color RGB filter descriptions is extensible to meet future (24 bit) to 4 bit (Windows systemcolor LUT)), to requirementsof filters. 3.2.2. Internal and external Jilters. We distinguish name just a few.
J. Zedler and M. Ramadan
700
filter
I name description command class { group
parameter
parameter
“NOISEREDUCTION’ “Reduce the noise for audio data” “noisereduct -l$FREQLOW -h$FREQHIGH
$SOuRCE $DESTINATION”
iAudio “manipulator” 1 variable tyDe range default unit I variable tbw range default unit
FREQLOW real I 25 to SFREQHIGH 1 8000 ‘Hz n FREQHIGH real t SFREQLOW to 25000
1
20000
"HZ"
source
c foxmat
WAV
destination
I format
WAV
between two different types of filter, so-called internal and external filters. An internal filter is an integrated part of the iMedia system, an external filter is a third-party solution, a stand-alone running program, which is invoked by the i-Media Server. External filters are for example software RIPS (Raster Image Processors) such as Aladdin Ghostscript or Harlequin Scriptworks. Advanced image processing applications such as Adobe Photoshop could serve as external filters also. The following internal image filters are already implemented and ready to use: format converters (TIFF2BMP, TIFF2GIF, TIFFZJPEG, JPEG2GIF, JPEG2BMP, and several other format converters); scaling filters (usually used for proportional downsampling); color space filters (RGB-CMYK, CMYK-RGB, etc.); quantization filters (reduction of color depth, usage of color LUT based upon different algorithms: static LUT (usually given by a system or platform), “Popularity” algorithm, “Median Cut” algorithm, “Octree” algorithm.
3.2.3. Example The following example illustrates the use of filters. Figure 5 is a detailed description of which filters are to be called by the i-Media system for the example already used in Section 2.1.2. An EPS file is RIP-ped by ScriptWorks, which is an external filter (illustrated by a dashed circle); the result of this process is saved as a TIFF image. The TIFF image is then downsampled (scaled) and quantized (reduction of color depth) and converted
to several formats (BMP, GIF, and JPEG). All these transformations are done using internal filters. 3.3. Security and user/group mechanisms In most publishing environments there is more than one user accessing the i-Media server. Therefore security and user/group mechanisms are needed. Figure 6 shows the basic concept of the user administration in the i-Media server. Everyone who wants to get access to the media data has to have a unique user identification and has to belong to at least one group. As default, a user inherits the rights of his group. But because it may happen that special access to some media data (both, more or less rights) is needed, the class hierarchy is the one presented in Fig. 6. As mentioned above, every media object (every instance an iMediaClass subclass) has an owner that can grant and restrict access rights to the media object. 3.4. OODBMS An object-oriented database management system will solve certain implementation problems. Additionally, the i-Media system is designed to be objectoriented and can be directly mapped to a OODBMS. We are currently evaluating which OODBMS fits our needs. One of the alternatives currently under investigation is the “SHORE” system from the University of Wisconsin-Madison 191. “SHORE” offers a C++ interface and is freely available. 3.5. Implementation status The design phase of i-Media is finished and the whole system is currently under development. The media classes iAudioClass, iVideoClass and iAnimat ionclass are integrated conceptually,
i-Media: an integrated media server ant. database
701
EPS
ii
0 JPEG
I
BMP
Fig. 5. Usage of filters for automatic calculation of variations of an image resource.
but are currently not a matter of implementation. Because of the importance of text and images we are spending most of our efforts on the implementation of iTextClass and iImageClass and of course on the basic class iMediaClass.
4. CONCLUSION
We have illustrated the basic idea of Cross Media Publishing and we have stated that the receiver (reader) of documents can profit from CMP because he can choose the media platforms which best fit his needs. We have made clear that an integrated CMP can both allow a faster and cheaper cross-media production and prevent data consistency problems.
We have presented a new concept of an integrated multimedia server and database which is focused on the special :needs for Cross Media Publishing. The embedded “intelligence” of media objects and its configurabil:ty is an added value to normal multimedia databases and can solve the handling problem of media data in a CMP system. We have outlined the ongoing implementation work, which will realize basic concepts of the i-Media system.
4.1. Future work A lot of rmplementation work is still to be done. First of all, an OODBMS has to be integrated into the i-Media system. Additional image filters have to be implemented, too.
J. Zedler and M. Ramadan
702 r
SecurityClass
UserClass
Fig. 6. SecurityClass hierarchy Currently an CMP editor is implemented as a JAVA application at the Fraunhofer-IGD [lo]. This editor has to be connected to the i-Media system. Later, further implementation has to be done to integrate filters for audio, video, and animation data. REFERENCES
1. Schiinhut, J., Electronic Document Printing and Publishing--Which format for what? Eurographics ‘93
State of the Art Report, Eurographics Technical Report Series, 1993. 2. Adobe Systems Incorporated, PostScript Language Reference Manual, 2nd edn. Addison-Wesley, Reading, MA, 1990. 3. Adobe Systems Incorporated, Encapsulated PostScript File Format SpeciJication. Adobe Developer Support Version 3.0, Adobe Systems Incorporated, 1992. 4. Aldus Corporation, TIFF-Tagged Image File Format-Revision 6.0 Final. Aldus Corporation, 1992. 5. Aldus Corporation, OPI-Open Prepress Interface Specification 1.3. Aldus Corporation, 1993. 6. Adobe Systems Incorporated, Updates to the Portable Document Format Reference Manual. Adobe Developer Support, Technical Note #5156. Adobe Systems Incorporated, 1994. I. Brenz, T.. Cohn, R. and Meehan, J. R., Portable Document Format Reference Manual. 2nd edn. Adobe Systems Incorporated, 1996. 8. Sandia National Laboratories, HTML Reference Manutrl. http://www.sandia.govisci~compute/html~ref.html, 1996. 9, Carey, M. J. et al., Shoring up Persistent Applications. In ACM-SIGMOD Dutu, Conference 10.
Conference Proceedings.
on the Management 1994.
of
Frohlich, A., Implementierung eines Editors zur Eingabe und Bearbeitung wissenschaftlicher Veriiffentlichungen unter besonderer Berticksichtigung der Anforderungen von Cross Media Publishing (in German). Studienarbeit, Technische Hochschule Darmstddt, 1997.
Pergamon PII: Soo97-8493(97)
Graphics in Electronics Printing
and Publishing
I-MEDIA: AN INTEGRATED MEDIA SERVER AND MEDIA DATABASE AS A BASIC COMPONENT OF A CROSS MEDIA PUBLISHING SYSTEM J6RG ZEDLER+ and MARWAN RAMADAN Fraunhofer-Institut
fiir Graphische Datenverarbeitung (Fraunhofer Institute for Computer Graphics), RundetrumstraDe 6. 64 283 Darmstadt, Germany e-mail: [email protected]
Abstract-The publication of the same information on different media, the so-called Cross Media Publishing (CMP), is becoming one of the central aspects in today’s publishing industry. CMP centers on a media independent document definition and an efficient integrated publishing on different media: e.g. as a paper document, as an online document in the World Wide Web, and as an offline (CD-ROM based) multimedia presentation. The aim of CMP is to get these different media at the same stage, while-and that is important-spending an acceptable amount of additional effort (in time and money) for production. In this paper we present a solution for a key problem of Cross Media Publishing, the handling of media data (images, audio, video, etc.) by using a combined approach of server and database systems functionality. The integrated multimedia server and database i-Media and its role in a complete CMP solution will be presented. 0 1997 Elsevier Science Ltd. All rights reserved
1. INTRODUCTION
AND BASIC REFLECTIONS
In thesedays the publishing industry is affected by enormouschangesregardingstructuresand contents. Sincethe completelyelectronicproduction of printed documentsis becomingmore and more commonand new technologiesand mediasuchasthe World Wide Web (WWW) and CD-ROM based multimedia presentationsshow an overwhelming success,the traditional workflow in the publishing world is no longer timely. Moreover, the publishing world has becomecomplex, since several different platforms, applications, and media must be supported in an open architecture. Now that a reader has the possibility to choose from different types of media he also expectsto get the sameinformation irrespectiveof what he chose. He can then decidedependingon his situation which mediaplatform fits best. In this paper we will presenta solution for a key problem of CrossMedia Publishing,the handling of media data. A media managementsystem will be presented, which offers an added value by a combined approach of an object-oriented database managementsystem(OODBMS) configured to the purposesof an CMP system and expanded with additional serverfunctionality, e.g. regardingformat conversionin an automated,configurableway. Conceptually all media types-text, image (both raster and vector images),audio, video, and animation-are supportedand the specialtechnical pub-
+ Author for correspondence. 693
lishing requirements,e.g. OPI serverfunctionality or DTP/multimedia authoring tool support are taken into account. In this sectionwe will shortly explain the requirements of Cross Media Publishing(seeSection 1.2). We will tak:e a look at the variety of formats and standards (Section 1.3) and the media dependent advantages,disadvantagesand technical restrictions (Section 1.4). 1.1. Naming The term media is usedfor a variety of things. To avoid confusion, we will use in this paper the following naming: l
l
Images,audio, video, and animations are called Media Data or Document Resources or shortly Resources. Media data is often saved in special mediaand platform dependentformats. Documentsare publishedon paper (Print Media) or as electronic documents (New Media or Electronic Media). Electronic documentscould be made available either online or offline. Offline documentsare usuallypublishedon storagemedia such as CD-ROM. Documentsare publishedon so-calledTarget Media or Media Platforms.
1.2. Cross Media Publishing In Fig. 1, an example of a cross-mediaproduced and publishedarticle is shown.It wasprinted on an offset press as a color brochure. Then it was converted to an HTML document with embedded GIF and JPEG images,to a PDF document with
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paper version (offset print)
CD-ROM based multimedia presentation (Macromedia Director)
HTML based WWW presentation (Netscape Navigator)
PDF documant (Netscape Navigator with Adobe Acrobat Plug-In)
Fig. 1.CMP example.
integrated “weblinks”, as well as to a CD-ROM basedmultimedia presentation with PICT images and additional sound and video clips. A stripped version of the multimedia document is also accessableasa Shockwavedocumentvia Internet. See http://www.igd.fhg.de/www/igd-al/crossmedia/index-e.html for the electronicdocuments. The basis of CMP is a media independent document description. Media independent means that you can convert a document(automatically) to any mediaplatform. To achieve a high quality, the technical requirements of a media independentformat are given by the media platform with the highest demands. Therefore a media independentdocument contains among other things: l
l
l
high resolution raster images(necessaryfor print, although not necessaryfor screenpresentation), audio, video, and animations (although not supportedby print media),and hypertext functionality (although again not supported by print media).
Becauseof the continuing high acceptance of paper documents, Cross Media Publishing is seen especiallyfrom the print publishing’spoint of view. Advanced and commonly used publishing systems like Adobe FrameMaker, Adobe PageMaker, or Quark XPress have to fit into an integrated CMP systemarchitecture, as well as sophisticatedauthoring tools. 1.3. Formats of the publishing industry In the publishing industry a variety of standardized as well as proprietary data formats have been established.Formats like PostScript,EPS, and TIFF for print media or HTML, JPEG, and GIF for the Web have to be taken into accountwhen settingup a CrossMedia Publishingsolution. In the following we will shortly mention someof the most important formats used. A more detailed discussioncan be found in [l].
1.3.1.Formats of the prepress world. The prepress world is coined by the de-facto industry standard Adobe PostScript[2] usedfor documentencoding,as well as the derived formats EPS (Encapsulated PostScript [3]) and AI (Adobe Illustrator), which are widely usedfor interchangeof illustrations. Raster images are usually encoded in TIFF (Tagged Image File Format [4]), which can handle bitmaps,gray level images,aswell as RGB, CMYK or even device independently (CIE Lab) encoded imagesin arbitrary resolutions. Becauseof the high resolution of raster images there are tremendousrequirementsdue to storage capacity in the prepressworld. A typical letter format four color image requiresabout 30 MByte, when encodedas an uncompressedCMYK TIFF. To reduce the load on the network and the DTP computersAldus has specifiedOPI (Open Prepress Interface [5]), which has become a widely used standard.A so-calledOPI server managesthe high resolution imagesand calculates a low resolution sample,which is used for positioning on the DTP computer.When sendinga documentwith embedded OPI imagesto a printer, the OPI server substitutes transparently for the user the samplesby the high resolution originals. Using an OPI servercan boost up productivity during printing easilyby a factor of loo! More and more Adobe’s Portable Document Format (PDF) [6, 71 is becoming used as a page descriptionlanguagesuitablefor both displayingon screenaswell asfor printing on b/w or color printing devices. Currently PDF is mostly generated by “distilling” PostScript (usingAdobe’s Acrobat technology). Automatic generationof hypertext elements (especially links) and integration of document information in PDF format is possibleby using “pdfinark” commandsencodedin PostScript. 1.3.2. Formats of the World Wide Web ( WWW). The standard document format for the Web is HTML [8], which is not a pagedescriptionlanguage suchasPostScript or PDF, but a documentmarkup language.The layout is not fixed in the document.
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Based upon markups enclosed in the document the l electroniconlinedocumentbasedon HTML: often appearance of the document is defined by the WWW bad presentation quality (publisher has little client, depending on the current windows size, as well control lover layout); bad printability; computer as the adjusted fonts. with network connectionnecessary;usually small network bandwidth; often one logical documentis Raster images are encoded in GIF (Graphic Interchange File format) for bitmap or color lookup divided into several HTML files, which makes table (LUT) images, and JPEG is used for contone archiving or printing disadvantageous; l electronicdocumentbasedon PDF: not well suited RGB color images. Animations are supported, e.g. as animated GIF for readingon computer display; computernecesor Java-Applets. Extensions via WWW client plugsary; usually more memory intensive than, e.g. ins are widely used. Adobe is for example pushing its HTML-based documents; l electronic CD-ROM based offline presentations: PDF format by offering plug-ins for several WWW clients for free. Because of its good printability (see information often not up-to-date; computernecesSection 1.4) PDF is becoming common on the Web sary; often bad printability. also. 1.3.3. Formats of multimedia authoring software. Based on the different purposesmany different Multimedia authoring systemssuch as Macromedia formats are used for the encodingof text, images, Director and Asymetrix Toolbook typically uses audio, video, and animation.Moreover, the technical platform specificformats, such as PICT for images surroundingconditions are of importance: on Apple Macintosh computersand BMP for images on Microsoft Windows computers,to give just an l different color spaces:RGB for displaying on example. screenand CMYK for printing deviceindependent Moreover, there are several additional image color (CIE Lab) not yet widely used; formats as well as audio and video formats l different color depth: color tables are famousfor supportedby the authoring systems.A completelist displaying on screenbecauseof its compactness would be too extensiveto be discussed here. and becauseof technicallimitations of typical PCs graphic hardware; l different required resolutions:usually low resolu1.4. Media platforms: advantages, disadvantages, and tion (approximate 72 dpi) for displaying on technical restrictions computer screens, but resolutions of about Media platforms differ in severalaspects:they are 300 dpi (gray and color images)and of up to either electronically availableor not, either online or 3000or 4000dpi (bitmaps)for printing purposes; offline accessable, and so on. A typical advantageof one media platform is often a disadvantageon the l different documentconceptsusedin the publishing world (page description languages(PDL) like other platform. The aspectsare listedbelowin detail. PostScript or PDF as well as document markup Advantages. languages,suchas HTML). l print document:excellentpresentationquality and readability; no computer required for reading; no Following these technical restrictions, e.g. for bandwidth problems;easy markup; social aspects every single image used in a document one easily (i.e. people are used to read paper documents); getseight or more different variations in format and layout under control of the publisher, size!This is one reasonwhy CrossMedia Publishing l electronic online documentbasedon HTML: upnowadays is expensive,becauseconverting images to-date information; hypertext functionality; (or any other document resource)from one format search functionality; compact format; (informa- to another is done as a manual step, which is time tion when you needit), consumingand labour respectivelycost intensiveas l electronic (online or offline) document basedon well as error prone. Data consistencyis in danger PDF: hypertext functionality; searchfunctionality; when no automatic mechanismsare available (imaup-to-date information when online accessable; gine what happens,if an imagehas to be changed good printability; well suited for archiving pur- when you have eight different variations of this poses;layout under control of publisher, image!). l electronic offline document basedon multimedia Here you needa sophisticatedmediamanagement authoring systems,usually on CD-ROM: excellent system,which doesboth the administrationof media presentationquality on screen;support of audio, (storage,accesscontrol, versioning,data consistency) video, and animation (no problemswith network and automated conversionsregarding format, size. bandwidth); hypertext and search functionality; color spaceor color depth. layout under control of publisher. Although multimediadatabasesare availableeven as products, they are lacking support of the Disadvantages. requirements of Cross Media Publishing. In the l print document:information often not up-to-date; following we will propose a concept and an no hypertext functionality; audio, video, and implementationfor an “intelligent” mediamanageanimation not supported; ment systern,suitablefor CMP purposes.
J. Zedier and M. Ramadan
696 2. I-MEDIA:
INTEGRATED
MEDIA
SERVER
AND
DATABASE
In this sectionwe will explain the basicconcepts and functionsof the i-Media serverand database(see Section 2.1) as well as its role in the context of a CrossMedia Publishingsystem(seeSection2.2). 2.1. i-Media
server and database
To handlethe different formats mentionedabove, a multimediadatabasesystemis well suited. For the special purposesof Cross Media Publishing additional support for the user (publisher)is necessary. For example conversion of an image from one format to another is a task, which could be done on an automated way, configured by the special needsof the publisher. The generalidea of i-Media is the integration of multimedia database functionality and additional functionality like automatic format conversion and OPI serverfunctionality. It consistsof two parts: the database itself and the server, which allows a prescribedaccessto the database. The databasesystempart of i-Media handlesthe resources(mediadata of any kind), especially: native format files (such as Aldus/Macromedia FreeHand, Quark XPress or Adobe Photoshop files), links to resourcesused in the generic files (e.g. embeddedTIFF or EPSimages), interchangetiles, variations of the abovementionedregarding -versions, -formats, and -languages usedin text. The servercontains:
There are many different application specific formats usedfor theseinput channels.In the context of this paper, application specificfiles are namedas Native Format Files. Theie files are not particularly suitable for interchange, therefore standard interchangefile formats are neededfor further processing, usually generatedby an export module of the above mentionedtools and systems.The interchangefiles are calledGeneric Representation or Source Files. The formar must be suitabie to generatefurther variations needed for the different media platforms automatically, e.g. for an image resource EPS illustrations or high resolutionTIFF imagescan be used. 2.1.:!. Integrated “intelligence” of media data. An important added value in our approach is the integrated “intelligence” of media data. which gives also the nameof the system(i-Media = “intelligent media”). A media object keepsa log of every conversion from one format or sizeto another (which filter was used,which parameterswereexpected).Therefore, it is possiblethat the userchecksin a correctedversion of an image and the object itself starts to do the necessaryconversionto ail usedformats, sizes,color spaces.color depthsand so on. In the exampleshownin Fig. 2, an imageresource (iImageObject)is illustrated partly. It consistsof an English and a German (language)variation of an imagewhich is created by using Macromedia FreeHand 5 (FH5). Every version of this image is availableas an EPSfile (generatedby the illustration software) and as format variations, which were automatically calculatedusinginternal and external filters. After calculation the following imagefiles are accessibleby the CMP systemfor every version of the iImageObject:
a user and group managementwhich is used to grant and restrict accessrights to mediadata (see 4 an EPSimageusedfor print publishing:this serves below); as a genericrepresentation,too (i.e. it is usedas a l a version management which allows to createnew basisfor the calculationof ail further variationsin version and to remove old versions; format and size); l check-in/check-out functionality which allows a l a TIFF imageusedfor internal reasonsonly (it is user to change media data and to lock access easier to convert the raster image format TIFF during changes; than EPS, which consistsof text, raster and vector l a configurable and extensibleset of filters, which images); allow for automatic format conversion as well as l two BMP images (a thumbnail version for OPI serverfunctionality. previewing and a full screen version for best quality displaying) used for Microsoft Windows Media data (resources)are stored in an objectbasedmultimediapresentations; oriented manner, usingan object oriented database l a small GIF image (again a thumbnail version) managementsystem(seeSection 3). and a JPEG imagefor usein a HTML document. 2.1.1. Native format files and generic representations. The mediadata which is storedin the database
comefrom a variety of input channels.Rasterimages for example are often scannedon drum or flatbed scanningdevices.Illustrations are usually generated by some high level illustration software such as Aldus/Macromedia FreeHand or Adobe Illustrator, video clips are edited by Adobe Premiereor other video editing systems.
In the exampleof Fig. 2 the userhascheckedout the English version l.Oe to correct a mistake.After correction he checksin a new version (l.le). He puts the application specificfile (native format file) aswell as a genericrepresentationof the image(sourcefile, in this case the EPS encoded image) into the database.
i-Media: an integrated media server and database
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ilmageObject
n
version
1.Os A
version
Y
1.19
version
1 .Og
?I GIF
Fig. 2. An image resource (iImageObject) check.ed in after rework.
After check-in of the new version the variations (illustrated with dashed lines) are calculated automatically, without further interaction with the user, just by traversing the filter tree of version l.Oe and executing exactly the same filters for version l.le. What happens to the documents that reference this image resource? The next time the publisher touches the document he can update the references (which were indicated by the CMP system to be old, because a newer version of the image resource is available). Data consistency on all media platforms can be guaranteed by the CMP system.
2.2. Integration into a CA4P solution The above-described i-Media server and database system plays a vital role in a Cross Media Publishing system. Subsequently we will explain how the iMedia server communicates with its clients, the Cross Media Publishing system and an OPI server (see Fig. 3). The i-Media server consists of an object-oriented database management system, a user management module and a set of internal filters. It has access to the i-Media database via an OODBMS. Additional external filters (stand-alone running applications, e.g. a RIP such as Aladdin Ghostscript or Harlequin Scriptworks) can be called by the i-Media server.
A Cross Media Publishing system (client A) uses the i-Media server for the management of its media data. An editor running within the CMP system allows the media independent definition of documents. Third-party applications such as DTP systems allow the creation and modification of media data. A set of export modules allow the conversion to different media platforms. These “modules” could be converters which allow a fully automated generation of media platform specific document (e.g. suitable for HTML documents). A module could also be thirdparty stand.-alone system such as Quark XPress for print publishing or Macromedia Director for multimedia presentations. To allow the user of the CMP system to share the benefits of the OPI specification, another client of the i-Media server, the OPI server (client B) could run, e.g. on a powerful workstation and translates OPI PostScript (PostScript encoded documents, were OPI comments were placed instead of the high resolution images) to PostScript, which could be send sent to an image or plate setter or even to a digital printing press. 2.3. Advantages The advantages of this approach l
are as follows:
the database ensures the consistency of the data, even if last minute changes have to be made and
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User(s) L+&&+, CMP syslml (Client A)
zqF~mFl Export
..’
-HTMLIGIFIJPEQ/...
-
r3i-Media mabsaa
External
Filters I
I
Fig. 3. Architecture of i-Media server and database and its clients (CMP system and OPI server).
l
l
several variations in format, color space, color depth and size of an image are in use the i-Media server relieves the user of manual and recurrent tasks like format conversion and as a result of the above: the publisher can publish his document on several media while spending an acceptable amount of additional effort.
3. IMPLEMENTATION
In this section we will explain some implementation details of the i-Media system. It has to be stated that the system is currently under development and still much has to be done. Because of the complexity of the i-Media system it is neither efficient nor affordable to implement it from scratch. Moreover, several of the problems we have to solve, especially regarding database functionality, are already implemented in a variety of systems which can be used as implementation basis.
3.1. Media class hierarchy We have identified five different classes of document resources: text, images (both raster and vector images), audio, video, and animation. Although several aspects are specific for the different classes (e.g. which formats were used for encoding and which filters are available for conversion), there is media object information, which has to be supported independent of the class. As a result the document resources are organized as a hierarchy of classes, with a virtual class (iMed.iaClass) as the root class; see Fig. 4. The derived classes are:
l l l l l
iTextClass for text, iImageClass for raster and vector images, iALdioClass for sound and other audio data, iVi.deoClass for videos, iAnimat ionclass for animations (e.g. animated GIF or Java applets).
iAnimatiinClass
Fig. 4. iMediaClass hierarchy.
i-Media: an integrated media server and database In the iMediaClass functionality necessaryfor all mediadata is embedded.This is a container for the native format file(s), a list of links to depending files, the variants in language,version, and format, userinformation, aswell as statusinformation. An overview of attributes of the iMediaClass is given in the following table:
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Which filters are used for transformation is a matter of configuration. To achievethat the i-Media systemcan usefilters in an open and extensibleway, every filter is describedby an external filter configuration file. It is up to the administrator of the iMedia systemto maintain theseconfiguration files and to add ‘33:remove filters.
Attribute.
Description:
Name: Version:
This name is a unique object identifier and the database’s primary index. Moreover, this is the resource handle, used in the media independent document description. The version number of this object used by the version control module.
Format:
This attribute describes the native format and the source file format.
Language:
This is the language variation for the object. This can be. for example, English, French, German, rabic, Japanese and so on.
Backtracking:
With this information, the i-Media system can find all dependent objects.
Owner:
Each object is owned by exactly one user. This user can grant and restrict access to the object.
Checked:
A user can check out media data. If an object is checked out, the system allows only READ access to this object (lock is set) until it is checked in again.
All subclassesinherit all attributes from the iMediaClass.
The subclasses themselves
define all
The following exampleshowsa filter description for a program
which
converts
TIFF
images with
mediadependentattributes. Theseattributes consists 24 bit RGB colors to BMP imageswith 256 RGB especiallyof a list of all possiblefilters suitable for colors (8 bit):
filter
( name description command class ( 1 group source
I destination
1
"TIFFZBMP" “Convert TIFF 24 Bit RGB to BMP 8 Bit “tiff2bmp SSOURCE !IDESTINATION”
RGB"
i Image "converter"
(
{
colorspace colordepth format
RGB 24 TIFF
colorspace colordepth format
RGB 8 BMP
Another example shows a filter definition for a the resourceclass.As an example:of courseit does not make sensethat an imageobject usesa filter for noisereduction filter. Here variablesare usedwhen audio compression. calling the :hlter. The user will be asked for two parameters,onefor the low frequencyvalue and one 3.2. Usage ofJilters for the high frequency value (seethe graphic on the 3.2.1. Concept. All media transformations will following page). This “language” like style description of a filter done by a group of programs, called filters. For example there are filters to convert one distinct has many advantages.First, it is easily read by humans. Second, future filter extensions can be media format into another, filters to convert text with country specific encoding (e.g. German umrealized by creation of new key words. No old descriptionfiles have to be changed.This systemof lauts), filters to scale images, to do color transformation or quantisation (e.g. from full color RGB filter descriptions is extensible to meet future (24 bit) to 4 bit (Windows systemcolor LUT)), to requirementsof filters. 3.2.2. Internal and external Jilters. We distinguish name just a few.
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filter
I name description command class { group
parameter
parameter
“NOISEREDUCTION’ “Reduce the noise for audio data” “noisereduct -l$FREQLOW -h$FREQHIGH
$SOuRCE $DESTINATION”
iAudio “manipulator” 1 variable tyDe range default unit I variable tbw range default unit
FREQLOW real I 25 to SFREQHIGH 1 8000 ‘Hz n FREQHIGH real t SFREQLOW to 25000
1
20000
"HZ"
source
c foxmat
WAV
destination
I format
WAV
between two different types of filter, so-called internal and external filters. An internal filter is an integrated part of the iMedia system, an external filter is a third-party solution, a stand-alone running program, which is invoked by the i-Media Server. External filters are for example software RIPS (Raster Image Processors) such as Aladdin Ghostscript or Harlequin Scriptworks. Advanced image processing applications such as Adobe Photoshop could serve as external filters also. The following internal image filters are already implemented and ready to use: format converters (TIFF2BMP, TIFF2GIF, TIFFZJPEG, JPEG2GIF, JPEG2BMP, and several other format converters); scaling filters (usually used for proportional downsampling); color space filters (RGB-CMYK, CMYK-RGB, etc.); quantization filters (reduction of color depth, usage of color LUT based upon different algorithms: static LUT (usually given by a system or platform), “Popularity” algorithm, “Median Cut” algorithm, “Octree” algorithm.
3.2.3. Example The following example illustrates the use of filters. Figure 5 is a detailed description of which filters are to be called by the i-Media system for the example already used in Section 2.1.2. An EPS file is RIP-ped by ScriptWorks, which is an external filter (illustrated by a dashed circle); the result of this process is saved as a TIFF image. The TIFF image is then downsampled (scaled) and quantized (reduction of color depth) and converted
to several formats (BMP, GIF, and JPEG). All these transformations are done using internal filters. 3.3. Security and user/group mechanisms In most publishing environments there is more than one user accessing the i-Media server. Therefore security and user/group mechanisms are needed. Figure 6 shows the basic concept of the user administration in the i-Media server. Everyone who wants to get access to the media data has to have a unique user identification and has to belong to at least one group. As default, a user inherits the rights of his group. But because it may happen that special access to some media data (both, more or less rights) is needed, the class hierarchy is the one presented in Fig. 6. As mentioned above, every media object (every instance an iMediaClass subclass) has an owner that can grant and restrict access rights to the media object. 3.4. OODBMS An object-oriented database management system will solve certain implementation problems. Additionally, the i-Media system is designed to be objectoriented and can be directly mapped to a OODBMS. We are currently evaluating which OODBMS fits our needs. One of the alternatives currently under investigation is the “SHORE” system from the University of Wisconsin-Madison 191. “SHORE” offers a C++ interface and is freely available. 3.5. Implementation status The design phase of i-Media is finished and the whole system is currently under development. The media classes iAudioClass, iVideoClass and iAnimat ionclass are integrated conceptually,
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EPS
ii
0 JPEG
I
BMP
Fig. 5. Usage of filters for automatic calculation of variations of an image resource.
but are currently not a matter of implementation. Because of the importance of text and images we are spending most of our efforts on the implementation of iTextClass and iImageClass and of course on the basic class iMediaClass.
4. CONCLUSION
We have illustrated the basic idea of Cross Media Publishing and we have stated that the receiver (reader) of documents can profit from CMP because he can choose the media platforms which best fit his needs. We have made clear that an integrated CMP can both allow a faster and cheaper cross-media production and prevent data consistency problems.
We have presented a new concept of an integrated multimedia server and database which is focused on the special :needs for Cross Media Publishing. The embedded “intelligence” of media objects and its configurabil:ty is an added value to normal multimedia databases and can solve the handling problem of media data in a CMP system. We have outlined the ongoing implementation work, which will realize basic concepts of the i-Media system.
4.1. Future work A lot of rmplementation work is still to be done. First of all, an OODBMS has to be integrated into the i-Media system. Additional image filters have to be implemented, too.
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SecurityClass
UserClass
Fig. 6. SecurityClass hierarchy Currently an CMP editor is implemented as a JAVA application at the Fraunhofer-IGD [lo]. This editor has to be connected to the i-Media system. Later, further implementation has to be done to integrate filters for audio, video, and animation data. REFERENCES
1. Schiinhut, J., Electronic Document Printing and Publishing--Which format for what? Eurographics ‘93
State of the Art Report, Eurographics Technical Report Series, 1993. 2. Adobe Systems Incorporated, PostScript Language Reference Manual, 2nd edn. Addison-Wesley, Reading, MA, 1990. 3. Adobe Systems Incorporated, Encapsulated PostScript File Format SpeciJication. Adobe Developer Support Version 3.0, Adobe Systems Incorporated, 1992. 4. Aldus Corporation, TIFF-Tagged Image File Format-Revision 6.0 Final. Aldus Corporation, 1992. 5. Aldus Corporation, OPI-Open Prepress Interface Specification 1.3. Aldus Corporation, 1993. 6. Adobe Systems Incorporated, Updates to the Portable Document Format Reference Manual. Adobe Developer Support, Technical Note #5156. Adobe Systems Incorporated, 1994. I. Brenz, T.. Cohn, R. and Meehan, J. R., Portable Document Format Reference Manual. 2nd edn. Adobe Systems Incorporated, 1996. 8. Sandia National Laboratories, HTML Reference Manutrl. http://www.sandia.govisci~compute/html~ref.html, 1996. 9, Carey, M. J. et al., Shoring up Persistent Applications. In ACM-SIGMOD Dutu, Conference 10.
Conference Proceedings.
on the Management 1994.
of
Frohlich, A., Implementierung eines Editors zur Eingabe und Bearbeitung wissenschaftlicher Veriiffentlichungen unter besonderer Berticksichtigung der Anforderungen von Cross Media Publishing (in German). Studienarbeit, Technische Hochschule Darmstddt, 1997.