mei:when 

Indicates a point in time either absolutely (using the absolute attribute),
or relative to another when element (using the since, interval and inttype
attributes).

Element Information

Model

Attributes

QName Type Fixed Default Use Inheritable Annotation
absolute optional 
Provides an absolute value for the time point.
abstype mei:mei_data.BETYPE optional 
Specifies the kind of values used in the absolute
attribute.
data restriction of list of mei:mei_data.URI optional 
Used to link metadata elements to one or more data-containing
elements.
interval union of(xs:time, restriction of xs:decimal) optional 
Specifies the time interval between this time point and the one
designated by the since attribute. This attribute can only be interpreted meaningfully
in conjunction with the inttype attribute.
inttype mei:mei_data.BETYPE optional 
Specifies the kind of values used in the interval
attribute.
label xs:string optional 
Provides a name or label for an element. The value may be any
string.
n optional 
Provides a number-like designation for an element.
since mei:mei_data.URI optional 
Identifies the reference point for determining the time of the current
when element, which is obtained by adding the interval to the time of the reference
point. The value should be the ID of another when element within the same parent
element. If the since attribute is omitted and the absolute attribute is not specified,
then the reference point is understood to be the immediately preceding when
element.
xml:base mei:mei_data.URI optional 
Provides a base URI reference with which applications can resolve relative
URI references into absolute URI references.
xml:id xs:ID optional 
Regularizes the naming of an element and thus facilitates building links
between it and other resources. Each id attribute within a document must have a unique
value.

Used By

Elements mei:clip, mei:recording

Source 

<xs:element name="when">
  <xs:annotation>
    <xs:documentation>Indicates a point in time either absolutely (using the absolute attribute), or relative to another when element (using the since, interval and inttype attributes).</xs:documentation>
  </xs:annotation>
  <xs:complexType>
    <xs:attributeGroup ref="mei:mei_att.common.attributes"/>
    <xs:attributeGroup ref="mei:mei_att.datapointing.attributes"/>
    <xs:attribute name="absolute">
      <xs:annotation>
        <xs:documentation>Provides an absolute value for the time point.</xs:documentation>
      </xs:annotation>
    </xs:attribute>
    <xs:attribute name="interval">
      <xs:annotation>
        <xs:documentation>Specifies the time interval between this time point and the one designated by the since attribute. This attribute can only be interpreted meaningfully in conjunction with the inttype attribute.</xs:documentation>
      </xs:annotation>
      <xs:simpleType>
        <xs:union memberTypes="xs:time">
          <xs:simpleType>
            <xs:restriction base="xs:decimal">
              <xs:minInclusive value="1"/>
            </xs:restriction>
          </xs:simpleType>
        </xs:union>
      </xs:simpleType>
    </xs:attribute>
    <xs:attribute name="abstype" type="mei:mei_data.BETYPE">
      <xs:annotation>
        <xs:documentation>Specifies the kind of values used in the absolute attribute.</xs:documentation>
      </xs:annotation>
    </xs:attribute>
    <xs:attribute name="inttype" type="mei:mei_data.BETYPE">
      <xs:annotation>
        <xs:documentation>Specifies the kind of values used in the interval attribute.</xs:documentation>
      </xs:annotation>
    </xs:attribute>
    <xs:attribute name="since" type="mei:mei_data.URI">
      <xs:annotation>
        <xs:documentation>Identifies the reference point for determining the time of the current when element, which is obtained by adding the interval to the time of the reference point. The value should be the ID of another when element within the same parent element. If the since attribute is omitted and the absolute attribute is not specified, then the reference point is understood to be the immediately preceding when element.</xs:documentation>
      </xs:annotation>
    </xs:attribute>
  </xs:complexType>
</xs:element>

Sample