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XML basics

What is an XML file? Structure, examples and uses

Understand XML tags, attributes and common uses, from documents and data feeds to video timelines. Learn why the XML format matters before converting a file.

Published by EDL Toolbox ·

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XML describes structured information

XML stands for Extensible Markup Language. It represents information using named elements, attributes and text. The names describe the data: a document might contain products, an invoice, a website sitemap or an editing timeline. XML is a way of organizing that information, rather than one universal kind of document.

The .xml extension tells you about the syntax. It does not tell you which application understands the contents. A shopping feed and a film edit can both be XML while requiring entirely different software.

A small XML example

<?xml version="1.0" encoding="UTF-8"?>
<shot-list project="Example">
  <shot id="1">
    <name>Opening &amp; skyline</name>
    <reel>A001</reel>
  </shot>
</shot-list>

This invented shot list has one root element, shot-list. It contains a shot with an id attribute and two child elements. The ampersand in the name is escaped as &amp;. Indentation makes the hierarchy easier to read; the opening and closing tags define the structure. This is an explanatory example, not an editing interchange file that EDL Toolbox can import.

Well-formed XML is not the same as a supported format

XML names are case-sensitive, elements must nest correctly, and attribute values need quotes. A missing closing tag can make the document unreadable by an XML parser. Correct syntax only establishes that a parser can read the structure: a receiving application still needs to understand what the elements mean.

A schema or document type can define additional rules for a particular vocabulary. For example, an application may require a duration or a reference to a source file. Passing a general syntax check does not prove that a video timeline can be imported, that its media exists or that its timing is correct.

Where XML appears

  • Data exchange: structured records passed between business applications.
  • Web publishing: sitemaps and feeds describing pages or updates.
  • Documents and settings: structured text, application configuration and metadata.
  • Postproduction: editing interchange formats describing clips, tracks and timing.

XML and HTML serve different purposes. HTML provides the standard elements for web pages; XML permits application-specific vocabularies. JSON is another common way to exchange structured data, while CSV describes rows and columns. Moving between these formats requires a decision about how their structures correspond, not just a different filename.

XML in video editing

FCP7 XML uses an xmeml root; FCPXML uses fcpxml. These are different editing formats. They can describe where media is used in a sequence, but a timeline XML is not the movie itself. Turning that edit into an MP4 requires the source media and rendering in an editing application.

EDL Toolbox supports the documented subset of these editing XML formats for conversion to EDL or AAF. It does not convert invoices, sitemaps or arbitrary XML to a timeline. Identifying the file first saves a failed import and tells you whether you need a data tool, a text editor or a video application.

References and further reading