Sustainability of Digital Formats: Planning for Library of Congress Collections

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PPTX Strict (Office Open XML), ISO 29500-1: 2008-2016

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Format Description Properties Explanation of format description terms

Identification and description Explanation of format description terms

Full name PPTX Strict, (Office Open XML, PresentationML) ISO 29500-1:2008-2016, also ECMA-376, Editions 2-5.
Description

The Strict variant of PPTX described here disallows a variety of elements and attributes that are permitted in the more common Transitional variant (PPTX/OOXML_2012). The markup for the Strict variant is essentially a subset of markup for the Transitional variant, but the schemas use different namespaces and are distributed separately in complete form.

The primary distinction between Strict and Transitional PPTX is that all use of the deprecated VML (Vector Markup Language) is disallowed in the Strict variant. DrawingML is used for all graphics features in PPTX Strict. Also disallowed are attributes or elements related to a deprecated practice for expressing percentages as integers used when techniques to save space and calculation time were deemed necessary.

The Strict variant of PPTX was introduced during the standardization in ISO/IEC 29500 in 2008 with the intention of excluding features included in ECMA-376, Edition 1 that were present simply to handle bugs and features of earlier applications or to permit continued use of deprecated markup (e.g. VML markup for drawings). The intent of the split of the markup specification into Strict (Part 1) and Transitional (Part 4) was that applications would create new documents in the Strict variant; however, in practice, pressure for backwards compatibility has meant that most new files are marked up by applications using the Transitional namespace even if they use no features that are incompatible with the Strict specification.

For discussion of other aspects of the Strict PPTX format, see the description of the more common Transitional variant of PPTX, PPTX/OOXML_2012.

Production phase Can be used in any production phase. Likely used primarily for creating documents (initial state); for editing and review (middle-state); and for final use or distribution.
Relationship to other formats
    Subtype of OOXML_Family, OOXML Format Family -- ISO/IEC 29500 and ECMA 376
    Subtype of OPC/OOXML_2012, Open Packaging Conventions (Office Open XML), ISO 29500-2:2008-2012
    Modification of PPTX/OOXML_2012, PPTX Transitional (Office Open XML), ISO 29500:2008-2016, ECMA-376, Editions 1-5. The Transitional form of PPTX allows additional legacy markup to address backward compatibility with bugs and features of older presentation software. The legacy markup is specified in Part 4 of ISO/IEC 29500. The Transitional variant has more support for backwards compatibility when converting documents from older formats.
    May contain MCE/OOXML_2012, Markup Compatibility and Extensibility (Office Open XML), ISO 29500-3:2008-2015, ECMA-376, Editions 1-4
    Defined via XML, Extensible Markup Language (XML)

Local use Explanation of format description terms

LC experience or existing holdings In 2017, the Library of Congress is not aware of any documents in the Strict form of PPTX in its collections.
LC preference As of February 2017, no format preference has been explicitly expressed by the Library of Congress in relation to acquisition of digital presentations for its collections.

Sustainability factors Explanation of format description terms

Disclosure International open standard. Maintained by ISO/IEC JTC1 SC34/WG4 as Part 1 of ISO/IEC 29500, first published in 2008.
    Documentation

ISO/IEC 29500-1, Information technology -- Document description and processing languages -- Office Open XML File Formats -- Part 1: Fundamentals and Markup Language Reference. Latest version (dated 2016 as of February 2017) is available from ISO/IEC Publicly Available Standards.

All editions of the OOXML standards as published by ECMA are available from ECMA-376: Office Open XML File Formats. The split between Strict and Transitional variants of PPTX was introduced in Edition 2 of ECMA-376 which is identical to ISO/IEC 29500:2008.

Adoption

Versions of LibreOffice since 4.2.3 can read Strict XLSX files. The Feature Comparison provided by LibreOffice for version 5.3 (released in early 2017) indicates that Strict XLSX files can be read but not written. However, the existence of Support OOXML strict export as a project on a to-do list for LibreOffice suggests that this capability may be introduced before long. A test using LibreOffice 5.2 confirmed that XLSX files written by that application are always in the more common Transitional form, regardless of which of two .xlsx options is chosen from the dropdown menu in the Save As feature. Two options are presented in LibreOffice because of a few small differences found in some files produced by Microsoft Office, particularly by Office 2007. See Useful References below.

The Strict variant of PPTX was not widely used or supported as of 2014; support is more common as of early 2017. The ability to read Strict PPTX files was implemented in Microsoft's PowerPoint 2010; PowerPoint 2013 added the ability to write Strict files as an option. Office 365 (a cloud-based product) can also read and write Strict files. Office for Mac 2011 could neither write nor read Strict files. Office for Mac 2016 can read but not write Strict files.

Whether the Strict version of PPTX is more widely used in the future will likely depend on whether pressure on software vendors from governments for its adoption outweighs market pressure, which currently seems to favor backwards compatibility.

    Licensing and patents See the more common Transitional form of PPTX, PPTX/OOXML_2012 and OOXML_Family.
Transparency See the more common Transitional form of PPTX, PPTX/OOXML_2012.
Self-documentation See the more common Transitional form of PPTX, PPTX/OOXML_2012.
External dependencies See the more common Transitional form of PPTX, PPTX/OOXML_2012.
Technical protection considerations See the more common Transitional form of PPTX, PPTX/OOXML_2012.

Quality and functionality factors Explanation of format description terms

Still Image
Normal rendering See the more common Transitional form of PPTX, PPTX/OOXML_2012 for functionality supported.

File type signifiers and format identifiers Explanation of format description terms

Tag Value Note
Filename extension pptx
Used for Strict and the more common Transitional form of PPTX. A file with the .ppsx extension, intended to run as a slideshow rather than open for editing is based on the same specification and may have essentially identical markup.
Internet Media Type application/vnd.openxmlformats-officedocument.presentationml.presentation
From IANA registration.
XML namespace declaration http://purl.oclc.org/ooxml/presentationml/main
This namespace declaration is for the Strict variant of PPTX. It occurs in the mandatory Main Document part of a PPTX file (package), usually with the name /ppt/presentation.xml and mapped to the prefix p. The same namespace declaration will be found in a Strict .ppsx file.
Other Target="ppt/presentation.xml"
Will usually occur in the top-level Relationships part (/_rels/.rels part in an OPC package in the <Relationships> element of a PPTX or PPSX file. In the Strict variant, it will be the target of a relationship of type http://purl.oclc.org/ooxml/relationships/officeDocument. See root namespace and source relationship for Presentation Part in ISO/IEC 29500-1:2012, ยง13.3.6.
Pronom PUID See note.  PRONOM has no separate entry for the Strict variant of PPTX. See the more common Transitional form of PPTX, PPTX/OOXML_2012.
Wikidata Title ID Q26207824
Office Open XML Presentation Document, Strict, ISO/IEC 29500:2012. See https://www.wikidata.org/wiki/Q26207824
Wikidata Title ID Q26207794
Office Open XML Presentation Document, Strict, ISO/IEC 29500:2011. See https://www.wikidata.org/wiki/Q26207794
Wikidata Title ID Q26207727
Office Open XML Presentation Document, Strict, ISO/IEC 29500:2008. See https://www.wikidata.org/wiki/Q26207727
Wikidata Title ID Q26211539
Office Open XML Presentation Document, Strict, ISO/IEC 29500:2012, with Microsoft extensions. See https://www.wikidata.org/wiki/Q26211539
Wikidata Title ID Q26211516
Office Open XML Presentation Document, Strict, ISO/IEC 29500:2011, with Microsoft extensions. See https://www.wikidata.org/wiki/Q26211516
Wikidata Title ID Q26208271
Office Open XML Presentation Document, Strict, ISO/IEC 29500:2008, with Microsoft extensions. See https://www.wikidata.org/wiki/Q26208271

Notes Explanation of format description terms

General See the more common Transitional form of PPTX, PPTX/OOXML_2012
History For chronologies of the OOXML standard and for versions of Microsoft Office, see OOXML_Family. See also the more common Transitional form of PPTX, PPTX/OOXML_2012

Format specifications Explanation of format description terms


Useful references

URLs


Last Updated: Tuesday, 21-Feb-2017 17:31:52 EST