Apple Final Cut Pro 7 - Manual (Page 1632)

</clip>
Whitespace
Whitespace in a document includes multiple spaces, tab characters, carriage returns,
newline characters, and so on. An XML parser reads and processes XML tags in a document,
but ignores extra whitespace. To an XML parser, there is no difference between
<clip><name>Coffee house wide shot</name><reel>17</reel></clip>
and
<clip>
<name>Coffee house wide shot</name>
<reel>17</reel>
</clip>
Whitespace is permitted so you can make your XML file more readable without affecting
the fundamental structure or meaning.
Document Type Definitions
Before you can create an XML document, you need to define the rules of your document:
which elements (tags) can exist, which elements contain other elements, which elements
are optional or required, what attributes each element has, and so on. You define the
rules of an XML document in a Document Type Definition, or DTD. Every markup language
has a DTD so that parsers know how to verify the structure of documents. Without a DTD,
it is impossible for the parser to validate an XML document. Every XML document requires
a DTD.
If you are working with a predefined language, such as HTML or the Final Cut Pro XML
Interchange Format, the DTD has already been created for you. All you need to do is
follow the rules of the DTD to create valid Final Cut Pro XML.
Working with XML Created in Different Applications
XML documents can be used to represent almost any kind of information. Unlike languages
such as HTML, XML has no predefined elements. XML is not one format; rather, XML is
used to create specific XML-based markup languages. Just because an application supports
XML does not mean that it can recognize any kind of XML document. For example, a
database application may use an XML format with elements like <row>, <column>, and
<subtotal>, while a graphics application might store information in elements such as
<layer>, <shape>, and <color>. Even though both documents are XML, they are
incompatible because their Document Type Definitions are completely different.
1632 Chapter 97 Using Final Cut Pro XML and QuickTime Metadata