Office Open XML

Office Open XML (OOXML) is an XML based file format that has been published as ISO 29500 and ECMA-376. It is used as default file format by Microsoft Office since 2007.

A new import filter is currently (as of May 2014) in development. Its design and implementation is described on this page. The legacy importer and exporter is described here.

File Format

The file format is described by several documents:

• Specifications:
  • ISO 29500:2012 (http://www.iso.org/iso/home/store/catalogue_tc/catalogue_detail.htm?csnumber=61750)
  • ISO 29500:2008
  • ECMA-376 (http://www.ecma-international.org/publications/standards/Ecma-376.htm)
  • (ECMA) TC-45 (http://www.ecma-international.org/news/TC45_current_work/TC45_available_docs.htm)
• Microsoft Extensions ([Overview http://msdn.microsoft.com/en-us/library/gg548604%28v=office.12%29.aspx]):
  • for PowerPoint (http://msdn.microsoft.com/en-us/library/dd926741%28v=office.12%29.aspx)

There are three main markup languages (MLs) for the three main applications:

• WordprocessingML
• SpreadsheetML
• PresentationML

Markup languages that are shared by all applications are

• DrawingML
• VML (for legacy files)

OOXML files are, similar to ODF files, ZIP containers with one entry per XML stream. OOXML calls these entries parts.