In order to satisfy the needs of the new emerging applications, the music notation formats are going to be transformed. Among the emerging applications of music we can see: music distribution, Internet exploitation of music, cooperative editing of music, production and adoption of multimedia digital objects based on music, distance learning/tuition of music, etc. In many of these applications, the music notation model has to provide distinct mechanisms for modeling symbolic and visual aspects. 
In this page, WEDELMUSIC format is presented. It is a XML compliant format that presents multimedia capabilities and includes identification, classification, symbolic, visual, versioning, printing, protection, image score, image, document, performance, video, and lyric aspects. It keeps separate visual/formatting and symbolic aspects. It can be profitably used as a format for new applications, and as a format for interchanging symbolic description of music scores. 
The format is supported by a free music editor. 


INTRODUCTION back to top
The problems of music notation modeling have been addressed in computer systems several times. Among the several possible computer-based applications of music, the notation editing for professional publishing and visualization is one of the more complex for the intrinsic complexity of music notation. Music publishing requires the production of high quality music scores in terms of the number of symbols and their precise placement. In commercial editors used to prepare music scores for publishing, the number of elementary symbols is close to 300 while in MIDI is close to 40. Commercial music editors for publishing are mainly oriented towards placing music symbols on the score page rather than modeling relationships among symbols. 

Recently, new needs for new computer-based applications of music have been identified: (i) cooperative music editing in orchestras and music schools, such as in project MOODS (Music Object-Oriented Distributed System) ESPRIT; (ii) music score distribution via Internet, such as in the many WWW sites distributing music scores or MIDI files; (iii) integration of multimedia aspects of music for educational applications; (iv) distribution of interactive music via Internet, music that can be manipulated by the end users in the respect of the owner rights. 

In all these new applications, the mechanisms of automatic formatting of music are becoming important since the visualization area is typically different with respect to that in which the music score is generated. 

Music distribution and interchange formats

Music can be distributed via Internet by using images, audio and symbolic files. Presently, the distribution of music is limited to images of music scores (PDF or GIF) or simple symbolic files (Finale, Sibelius, MIDI), while the distribution of audio files (such as mp3) is widely diffused. The music received from Internet can be interactive or not. For interactive music we intend symbolic music that can be manipulated in a certain measure: addition/deletion of symbols, transposition, reformatting, etc. Images of music sheets do not allow the music manipulation, while the MIDI model is interactive and too coarse for satisfying needs of professionals, since MIDI provides a reduced set of music notation symbols. MIDI is the most frequently used format for music interchange. 
In the past years, NIFF has been developed with the aim of defining an interchange format for music notation among music notation editing/publishing and scanning programs. NIFF format includes in a unique model integrating both visual and logical aspects. This makes hard the delivering of music independently of the visualization details as needed for Internet distribution. Relationships among symbols are defined via specific links. 
Internet is presently dominated by the distribution of documents by using the so-called mark-up languages derived from SGML, HyTime, XML, etc. A mark-up language consists of a set of constructs to express how text has to be processed with the main aim of text visualization. With generalized mark-up languages it is specified only what you have, rather than how it has to be visualized. The visual aspects are specified by using standard tags for stating the typographic features: spacing, font change, etc. For example, by using XSL a formatting styles can be defined. This means that a clear distinction has to be performed between the content and formatting aspects. Mark-up languages have been created for formatting textual documents and not for defining relationships among document symbols. This is one of the main problems to adopt mark-up languages for modeling music. 
SMDL (Standard Music Description Language) has been the first mark-up language for music and was built on SGML and HyTime standards -- ISO 10743. The aim was the definition of an interchange abstract model. SMDL model includes the following aspects: logical (symbolic), gestural, visual and analytical. The logical aspect includes the music content (pitches, rhythms, dynamics, articulations, etc.). In SMDL, the visual domain describes the musical typographic details of scores (the symbol, placing, fonts etc.). SMDL cannot be used as a standard interchange format for the visual aspect but only for the logical aspects of music. The main problem of SMDL remains the lack of a formal model for the visual aspects and thus of tools for editing and printing music in SMDL. SMDL was also analyzed in CANTATE and MOODS projects obtaining the same results. 
Recently, several other XML compliant mark-up languages for music modeling have been proposed, among them: MNML (Musical Notation Markup Language), MusicML, MML (Music Markup Language), MusiXML, etc. The MNML is a simplified version of SMDL. In MNML, it is possible to fully describe the basic melody and lyrics of a music piece. It is incomplete in describing all the needed details of real music scores (annotations, publishing aspects, etc.). MusicML can only represent notes and rests. Even staccato points and slurs are missing. MusiXML is quite unstructured and several relationships among music notation symbols are not established. None of the reviewed XML formats for music is completely satisfactory in modeling real music notation aspects. The adoption of symbolic model totally separate by the visualization issues makes the distribution of interactive music a very complex task. In MOODS, a cooperative editor of music has been proposed. It was based on a non-XML-based format. The solution was the definition of a specific language called MILLA (Music Intelligent Formatting Language) for defining rules for a formatting engine and leaving the possibility of forcing exceptional conditions. 
This paper presents WEDELMUSIC model and language. It can be considered the XML evolution of MOODS format. With WEDELMUSIC several early problems of MOODS for music modeling have been solved, in addition WEDELMUSIC is a multimedia model. We do not claim to have solved all problems related to music notation modeling, but only to provide an effective framework that includes most music symbols and their relationships, and on the basis of which several new and innovative applications can be built and where some exceptions and several modeling problems highlighted in can be formalized. In this paper, a short overview of the advantages in adopting WEDELMUSIC model and language is given. WEDELMUSIC format presents multimedia capabilities and includes identification, classification, symbolic, visual, versioning, printing, protection, image score, image, document, performance, video, lyric, aspects. It keeps separate visual/formatting and symbolic aspects. WEDELMUSIC format can be profitably used for new applications and as a format for interchanging symbolic description of music scores. 

This section reviews the most important modeling problems in the view of the emerging applications of music notation. As stated by several authors in the past, the modeling of music notation presents several problems: (i) the intrinsic complexity of formalizing music notation and relationships among music symbols; (ii) the needs of providing different visualizations/views of the same music in the main score and parts; (iii) the complexity of automatic organizing music symbols; (iv) the needs of adding new symbols for expanding the music notation model towards modern music and users' needs; (v) the needs of presenting new functionalities for multimedia applications. 

Music Notation Relationships

The modeling of all relationships among notation symbols is a complex task. As the number of symbols grows, the number of relationships among them grows more than proportionally. The syntax and semantics of music are strictly related and cannot simply be modeled by using only non-visual (relationships among symbols) or visual aspects of music (positions with respect to the staff). The modeling of music symbol relationships is not enough to describe the music notation: for example, a diminuendo starting between two notes (and ending on the second) depicts the instant in which it has to be applied. The description of music as a collection of graphical symbols on the page disregarding their relationships is too much dependent on the visualization device (automatic reformatting is really complex). In most of the commercial music editors, the music notation symbols are simply managed as graphical symbols that can be placed on the screen. When the music has to be distributed along the network for its visualization on different devices, structural description of symbol relationships and visualization rules have to follow separate mechanisms and formalizations such as in MOODS. 

Main Score and Parts, Different Visualizations

The automatic generation of the main score from the separate parts and the extraction of parts from a main score are complex tasks for real music, since the conductor's main score is typically formatted in different manner from the musicians' scores. 
Parts are printed by using compressed versions of music notation symbols. Parts usually present also several instrumental, personal symbols, which are typically excluded from the main score. The main score may present some specific textual notes or symbols for the conductor. The main score may show more than one part on a unique staff, in this case, they are treated as distinct voices/layers. In parts, other indications are added to facilitate coordination among musicians; for instance, the so-called grace/cue notes. The main score and parts present typically different justifications, line breaking and page breaking. In some music editors, even the insertion of measure in a part provokes a huge manual work of reformatting for the replication of performed changes on the main score, or vice versa. In order to solve these problems, a unified model for main score and parts has to be defined. A solution was given suggesting the adoption of a unique model and distinct views for showing music on the basis of each specific need and context. A similar solution has been adopted in MOODS and in WEDELMUSIC for maintaining a unified model for the main score and parts. 

Music Notation Visualization/Formatting

The positioning of music elements on the score presents many critical conditions. A music editor should help the users to produce well-formatted music scores. In most of the music editors, this task is addressed by considering only the visual representation of music symbols and not their relationships. Very few music editors (Finale, MusicEase, Score, Lime, Sibelius, etc.) address problems of (i) automatic placement of symbols and/or (ii) music justification. Some of these are capable of correctly arranging a limited number of symbols. 
As above highlighted, some visual aspects of music scores cannot be formalized in terms of symbol relationships. For this reason, the visual arrangement of music notation symbols completes the description of the music scores. Music can be considered a visual language with its own rules . For this reason, the modeling of the visual rules for formatting music is needed for completing the model. 

Definition of New Symbols

Typically, there is the need of adding new symbols for stating specific instrument aspects, and/or expanding the music notation model towards modern music. The addition of new symbols means to add font, relationships among the other symbols, execution rules and formatting rules. For example, the addition of a symbol modeling a special figure (such as a cloud of notes) implies a deep changes in the music notation model; while the addition of a new marker for notes can be performed by adding positioning rules and font since the relationship with the note is already established. 

Multimedia applications

At a first glance, the new applications related to Internet distribution of music scores seem not much different from the music editors that are currently on the market. The applications of the next years will be mainly based on: (i) cooperative work on music, (ii) interactivity of music, (iii) the availability of different integrated information associated to the music piece, (iv) music as support for tuition systems. In all these cases, music has to be independently presented on the visualization support features, formatting and resolution. Then, the following functionalities have to be available. 
  • a clear distinction between the music notation model and the visualization rules: reformatting in automatic manner on the basis of the user's needs, etc. 
  • music notation model has to be abstract enough to allow the interactivity with music at symbolic level: adding and deleting symbols, changing symbols features, etc. 
  • Music model has to integrate the several aspects: audio, symbolic music notation, images of music score, documents, video, etc. 
  • Mechanisms for distributing music by using shops, libraries, conservatories, etc., as Local Distributors. 
  • A refined protection model for Digital Right Management. 
The first two problems may be covered by formal models supported by a separate engine for the automatic formatting of music on the basis of rules. Ideally, this work is infeasible, but good compromises can be obtained. 
The new multimedia applications are bringing music in a new era. Simple audio files or music sheets are losing their nature to be included in more complex multimedia objects. In this view, WEDELMUSIC format allows the modeling of westerns music, plus tablatures and the exploitation of several new functionalities. 
WEDELMUSIC is a XML compliant format that includes constructs for the description of integrated music objects. Digital music objects compliant with the WEDELMUSIC format are called WEDEL objects. These are focussed on a specific music piece or concept. Each WEDEL object presents sections about its: identification, classification, protection, printing, symbolic music (fonts, formatting rules, versions), image score, performance, documents, lyric, audio, video, and color image. In the following, these aspects are discussed with the rational for their inclusion. 
Identification section allows the identification of the music piece. Typical identification codes such as ISMN are included. Each WEDEL object has a unique identification, ID, called WDFID, such as each of its components, WDFCID. 
Classification section allows the classification of the music piece according to multilingual archive mechanisms integrating both Z39.50 and UNIMARK fields, plus other fields. Distinct classification records may be set for the whole object and for its components. Protection section models details about the encryption of the WEDEL object and the watermarking of music (audio files and music sheets). Each operation that can be performed on the WEDEL object can be permitted or inhibited; more than 50 different multimedia functionalities can be distinctly managed. A permission table is available for the definition of Digital Right Management policies. This model allows analyzing the needs of the end-users with statistic tools. 
Printing section includes the description for printing music packages contained in the WEDEL object. For example a package may include the main score plus the orchestra layout and the cover; the CD cover, the biography of the author, the story of the CD making, etc. 
Symbolic Music section describes the scoring information, musical notation symbols, and their relationships. Symbolic music can include main score and parts. The symbolic description includes specific sections for classification and identification of the music score (main score and parts). Formatting rules are formalized in MILLA language such in MOODS: positioning symbols, decision about the stem length, decisions about the placement several symbols up or down the staff, orientation of the beam, ordering to place notation symbols around the notes: slurs, accents, ornaments, etc. The user may decide to apply different rules to automatically reformatting the music piece. For managing the versioning the changes performed on the main scores and parts (for logical aspects) can be collected, classified and reapplied according to the mechanism of the Additional Command List. In any case, in any version, the symbolic music can be printed watermarking the music sheets. 
Image of Music Sheets section allows to integrate images of music scores into the WEDEL object without converting them into symbolic format. Thus, in the same WEDEL object both symbolic notation and original images can be present. The same WEDEL object may contain images of the main score and of related parts even in more versions. Images of Music Sheets can be in GIF, TIFF formats, BMP, GIF, PIC, PCX, TGA, etc. This allows building WEDEL objects to compare original music score with revised and currently used symbolic versions. It is a good support for revitalizing and recovering cultural heritage. 
Audio section may contains none, one or more audio files. Their format can be WAVE, MIDI, MP3, etc. Each audio file may present its identification and classification sections plus other additional fields. Audio files can be watermarked according to the parameters of the WEDEL object. 
Performance section describes the synchronization aspects between each audio file and the music score of the WEDEL object. The synchronization of audio files allows the contemporaneous visualization and listening of music score with the selected audio adjusting of execution rate during the execution. 
Documents section may include none, one or more documents. Each document may present its identification, classification sections plus additional descriptive information. Documents may be author biography, critical description of the piece, description of the music piece, etc., any document related to the music score of the WEDEL object. Their format can be PDF, MS-WORD, Textual (TXT, in ASCII), HTML, etc. Documents on different languages could be included as well. This section could include also a document version of the music score. It can be in PDF or PostScript as well. Documents may have special HTTP links to other elements in the WEDEL object. 
Lyric section may present none, one or more elements containing the text of the lyrics associated with the music score and thus with the WEDEL object. Each lyric text has its identification, classification sections plus additional descriptive information. The lyric can be associated with a symbolic part. 
Video section may contain none, one or more video files. No limitations are imposed on their format: AVI, MPEG, etc., size and image rate. Video files in the WEDEL object are very useful for (i) presenting the hands of a the musician playing music for didactical purpose (this can be visualized while showing the music score on the screen); (ii) including/showing the video of a live performance and the songs text; etc. 
Image section may include none, one or more color images. No limitations are imposed on their format: GIF, TIFF, PCX, etc., and resolution. The first are typically used for showing the portrait of the author/performer, the picture related to the music or opera, or performer, the home/city of the author/performer, a picture of the instrument, a picture of the live performance, the CD cover, etc. 

Integration aspects

Each section of the above described may be missing except for some mandatory parts of the identification and classification sections. Depending on the missing parts the different functionalities of the WEDEL object can be present. In each WEDEL object, several relationships among its components can be established as depicted in Fig.1. 
For example, the following relationships can be established: 
  • Symbolic-lyric: different lyric files can be referred to the same symbolic file. 
  • Symbolic-image score: relationship performed via the number associated with the measures 
  • Image score to symbolic: relationship performed via the number associated with the measures 
  • From Symbolic to video, images, documents, audio files: relationships performed via http links that can be assigned to music notation elements 
  • Images of music score to lyric: 
  • From symbolic or images of music score to the audio via performance section: each audio file can be synchronized with the music score. 
WEDEL object representation
Fig.1 - WEDEL object representation.

Editing and Navigating in the WEDEL object Structure

For the navigation and the building of WEDEL objects a specific tool has been developed. It is called WEDEL Editor (see Fig.2). The WEDEL object structure and thus most of the relationships among the WEDEL object components can be defined by the WEDEL editor. 
WEDEL Editor and other tools
Fig.2 - WEDEL Editor and other tools.