Music Representation of Score, Sound, MIDI, Structure and Metadata All Integrated in a Single Multilayer Environment Based on XML - Intelligent Music Information Systems: Tools and Methodologies - page 318

Box 6. Notational layer: Spine event mapping

<notational>
<graphic _ instance _ groupdescription="Manuscript">
<graphic _ instanceile _ name="images\page _ 1.tif"
ile _ format="image _ tiff"encoding _ format="image _ tiff"
position _ in _ group="1"measurement _ unit="pixels">
<graphic _ eventevent _ ref="p1v1 _ 1"
upper _ left _ x="977"upper _ left _ y="451"
lower _ right _ x="999"lower _ right _ y="483"/>
<graphic _ eventevent _ ref="p1v1 _ 2"
upper _ left _ x="999"upper _ left _ y="458"
lower _ right _ x="1011"lower _ right _ y="483"/>
<graphic _ eventevent _ ref="p1v1 _ 3"
upper _ left _ x="1026"upper _ left _ y="462"
lower _ right _ x="1042"lower _ right _ y="493"/>
…
</graphic _ instance>
<graphic _ instanceile _ name="images\page _ 2.tif"
ile _ format="image _ tiff"encoding _ format="image _ tiff"
position _ in _ group="2"measurement _ unit="pixels">
<graphic _ eventevent _ ref="p1v1 _ 100"
upper _ left _ x="710"upper _ left _ y="123"
lower _ right _ x="732"lower _ right _ y="170"/>
<graphic _ eventevent _ ref="p1v1 _ 101"
upper _ left _ x="738"upper _ left _ y="90"
lower _ right _ x="775"lower _ right _ y="149"/>
<graphic _ eventevent _ ref="p1v1 _ 102"
upper _ left _ x="813"upper _ left _ y="105"
lower _ right _ x="836"lower _ right _ y="154"/>
…
</graphic _ instance>
</graphic _ instance _ group>
…
</notational>

of events is expressed in term of space measure-
ment units (e.g., pixels, inches, centimetres) and
is directly related to virtual space coordinates in
the Spine structure. The way to map spine events
in digital images is creating a sort of bounding
box for each event, using corner coordinates in
pixels or other absolute measurement units. Box
6 illustrates this technique.
Performance layer lies between Notational
and Audio layers. File formats supported by this
level encode parameters of notes to be played and
parameters of sounds to be created by computer per-
formances. This layer supports symbolic formats
such as Csound, MIDI and SASL/SAOL files.
Finally, Audio layer describes the properties
of the audio material related to the piece. Once

given piece, MX can link and map not only n
files belonging to a particular version, but also
the files coming from m different versions. The
m x n graphic instances are grouped and num-
bered, to keep trace of their original position in
the collection.
Representations mainly belong to two classes:
notational and graphical. A notational instance is
often in a binary format, such as NIFF 5 ; neverthe-
less, there exist also text-based and XML-based
formats. In this case, the occurrence of music
events is identified by the offset between the
event-related binary encoding and the beginning
of file. On the contrary, a graphical instance con-
tains images representing the score, usually in a
binary format like JPEG or TIFF. The occurrence