==== VBI_data_descriptor

Defined by DVB in <<ETSI-300-468>>.

[source,xml]
----
<VBI_data_descriptor>
  <!-- One per VBI data service -->
  <service data_service_id="uint8, required">
    <!-- One per field in the service -->
    <field field_parity="bool, default=false" line_offset="uint5, default=0"/>
    <!-- Valid only when data_service_id is not any of 1, 2, 4, 5, 6, 7 -->
    <reserved>
      Hexadecimal content
    </reserved>
  </service>
</VBI_data_descriptor>
----
