Sustainability of Digital Formats: Planning for Library of Congress Collections

The OpenDocument Presentation Document Format (ODP), Version 1.2 (given the short name ODF_presentation_1_2 here) is a format for editable documents that are presentations based on sequences of "slides." Designed to be a native format for applications for assembling slide-show presentations, the format is sometimes called ODP after its usual file extension. The term ODP will be used here to refer to ODF_presentation_1_2 and other chronological versions of the OpenDocument Presentation format. It is one of several subtypes in the ODF family for particular content categories. This description relates to part 1 of the ODF 1.2 specification as published by OASIS and the equivalent ISO/IEC 26300-1:2015 specification. The standard specifies markup for presentations using the ODF presentation:, draw:, and text: namespaces in particular. Other namespaces used in many presentations are table:, anim:, smil:.

The primary ODF markup used for presentations is actually in the draw: namespace, with the <draw:page> element as the usual container for a single slide. The content.xml file’s <office:presentation> element typically holds a series of <draw:page> elements, each of which has a unique draw:name attribute, often in the form pagen. The presentation: namespace is used for presentation-specific elements, such as <presentation:notes>, <presentation:animations> and specifications for headers and footers on slides.

The ODF specification covers two physical forms for ODF documents, a flat form as a single XML file and a package form based on the ZIP_6_2_0 format. This description focuses on the more commonly used ZIP-based package format for ODF presentation files, given the .odp file extension. Files using the same markup specification and package but with an extension of .otp are for use as presentation document templates.

An ODF package can be recognized as a presentation document in several ways. Externally, there are file extensions for two ways in which ODF presentation documents may be used in graphics applications, as noted above. The primary internal indication is that the mandatory file named mimetype will contain one of the corresponding strings listed as File type signifiers below. An additional way to recognize an ODF presentation document is that the <office:body> element, a child of the root <office:document-content> element in content.xml has the child element <office:presentation>.

The ZIP-based package for any ODF file contains, at a minimum, five files: a one-line mimetype file containing a single text string; content.xml; styles.xml; meta.xml; and settings.xml. The typical content.xml file for a minimal presentation document has the basic form:

• <office:document-content>
• <office:automatic-styles>
• ... styles created automatically based on direct user choices, e.g., for margins or default fill color for shapes, with references to fuller and named style specifications in styles.xml ...
• </office:automatic-styles>
• <office:body>
• <office:presentation>
• <draw:page draw:name="page1"> ... content for a slide. The name shown here is conventional rather than required by the standard, which only requires uniqueness.
• <draw:page draw:name="page2"> ...
• ...
• </office:presentation>
• </office:body>
• </office:document-content>
• Note that several of these elements will usually have attributes omitted here. Additional elements in the office: namespace may be included within the office:presentation element to reflect application-specific defaults.

For details of the ZIP-based package for ODF_presentation_1_2, see ODF_package_1_2. The package specification defines the form for the package manifest, and options for digital signatures, encryption, etc.

See Notes in ODF Family for more information about the flat XML-only variant of ODF files. For a flat ODF presentation file, the root <office:document> element has an office:mimetype attribute with one of the values listed below as File signifiers.

Apart from changes to the underlying package format, changes made to the markup for ODF presentations between ODF versions 1.1 and 1.2 were limited to a few enhancements.

Specifications from OASIS: Open Document Format for Office Applications (OpenDocument) Version 1.2. Markup specification for ODF 1.2 presentation documents are found primarily in chapters 9 and 10 of Part 1 of the specification. The technical specification is through a normative RNG schema for primary component files for ODF documents..

The identical specification is published as ISO/IEC 26300-1:2015, Information technology -- Open Document Format for Office Applications (OpenDocument) v1.2 Part 1: OpenDocument Schema.

The ODF 1.2 specification is divided into three parts, with the bulk of the markup specification in Part 1: OpenDocument Schema. The package specification has is in Part 3: Packages.

See ODF_Family for a listing of namespaces that can be incorporated into any ODF 1.1 or ODF 1.2 document and links to associated specifications.

The major office suites using ODF as primary native format family include special applications for developing presentations and can read and write presentation documents as defined in ODF 1.2:

• LibreOffice uses ODF 1.2 as its native format, according to July 17, 2015 blog post from The Document Foundation. See LibreOffice Impress and LibreOffice 4.2 Impress Guide.
• OpenOffice introduced support for ODF 1.2 in the beta version of 3.0 in 2008, according to Release Notes for OpenOffice 3.0 beta. Apache OpenOffice Impress uses ODP as its native format.
• Calligra's presentation application is Stage. Calligra Stage uses ODP as the underlying file format.

Microsoft Office has supported direct editing of ODF 1.2 presentation documents since Office 2013. PowerPoint features not supported or only partially supported in the .odp format are listed in Use PowerPoint to open or save a presentation in the OpenDocument Presentation (.odp) format in a dropdown section on Supported features in .ODP format. This list suggests that some types of animation and transition supported in PowerPoint and by PPTX can not be represented in ODP. There are also a number of vector graphic capabilities and design settings available in PowerPoint, that cannot be used in an ODP file. A feature comparison from LibreOffice focuses on the application functionality rather than the format. See Notes in the description of PPTX Transitional (Office Open XML) for a discussion of issues relating to conversion between PPTX and ODP, both issues that have been found in practice, and potential issues based on functionality added more recently.

See Adoption among the Sustainability Factors for PPTX Transitional (Office Open XML) for discussion of the market for presentation software. Additional useful references below highlight the crowded market for presentation software, with a recent emphasis on creative ways to leave behind the traditional slide-by-slide flow. Lists of alternatives to PowerPoint often have no mention of any application using ODP as native format. Where LibreOffice is recommended, it is often as a largely compatible free alternative to PowerPoint. Comments welcome.

See ODF-Family for more detail on adoption of ODF in general, and particularly for mandates or recommendations for ODF when exchanging editable documents among government agencies and the individiduals or organizations they serve.

The structure and text of an ODP file are all represented in XML and hence viewable without special tools, although XML-aware tools that can show the element hierarchy make viewing and interpretation more convenient. The most commonly used parts, elements, and attributes have recognizable names. Simple documents can be interpreted with very basic tools. However, interpreting the semantics of some elements and the correspondence of some elements and attributes to charting terminology or functionality will require not only understanding of the schema and the specification text, but familiarity with the associated terminology and functionality.

As for other members of the ODF 1.2 family, ODF_presentation_1_2 added support for metadata based on RDF (W3C's Resource Description Framework). As well as using RDF for metadata for the document package as a whole, RDF can be attached to elements within the document's content. The use of "custom" metadata as specified in ODF 1.1 is deprecated in ODF 1.2.

Pre-defined metadata elements for the document as a whole, stored in an <office:meta> element include:

• From the Dublin core namespace, using the dc: prefix: Title, Creator (of most recent modification), Description, Subject, Date (last modified), Language
• From the ODF specification, using the meta: prefix: Generator (creating software application), Keywords, Initial Creator, Creation Date and Time, Modification Date and Time, Print Date and Time, Document Template, Document Statistics (word count, page count, etc.),

The pre-defined elements are all optional and repeatable. However, applications are not required to update multiple occurrences in a specific way to reflect modifications to a document.

Also supported in both ODF 1.1 and ODF 1.2 is an XML structure for user-defined metadata, based on triplets of name, data type, and value.

Depends on features used. Presentation documents in ODF_presentation_1_2 format are often self-contained, but may include links to externally stored data.

No specific set of factors for assessing quality and functionality of a presentation format has been developed. This format description uses selected factors for assessing formats for images and text.

Graphics and text on a slide are structured to scale with monitor size. Raster images can be incorporated in a slide and "may have an arbitrary format" but the ODF standard recommends use of PNG.

Support for animations, slide transitions, and user interactions during presentations. Selected elements borrowed from the Synchronized Multimedia Integration Language (SMIL) 2.0 specification can be used to animate text on a slide.

Selected elements borrowed from the Synchronized Multimedia Integration Language (SMIL) 2.0 specification can be used to animate text on a slide.

See OASIS OpenDocument Essentials: Chapter 7. Presentations for examples of markup for transitions, animations, and interactions. Elements borrowed from the Synchronized Multimedia Integration Language (SMIL) 2.0 specification can be used to animate text on a slide.

See Notes section in description for PPTX Transitional (Office Open XML) for discussion of issues relating to conversion between PPTX and ODP.

See ODF_package_1_2 for discussion of changes to ODF in general between versions 1.1 and 1.2. Changes to the markup for presentations between versions 1.1 and 1.2 were primarily enhancements requested by implementers. Appendix G of the ODF 1.2 schema specification suggests that a functional extension was support for tables in presentations. No elements or attributes were added to the presentation: namespace.

ODF 1.3 was approved as an OASIS Committee Specification in December 2020, according to a December 4, 2020 announcement. This followed several periods of public review in 2019 and 2020. The next stage in the multi-step OASIS process is to gather three "statements of use", written statements that a party has successfully used or implemented the specification. See Approval of an OASIS Standard.

The specification for ODF 1.3 has been re-organized into four Parts. Part 1 is a brief introduction; Part 2 is the Packages specification; Part 3 defines the OpenDocument Schema, which includes specifications for the ODF content subtypes, including presentations; and Part 4 defines the Recalculated Formula (OpenFormula) Format. The presentation specification is in subclause 3.6 and clause 10 (Graphic Content) of ODF 1.3, Part 3. Since slides can incorporate text, tables, charts, etc., many other clauses are relevant. Judging from the change log in Appendix G of ODF 1.3, Part 3, changes related to graphics appear to be mainly clarifications and corrections. Comments welcome.

See ODF_family for more on the history ODF in general.