Digital preservation format literature review
The following is the first step in the development of recommendations on digital preservation formats, a deliverable of the National Heritage Digitization Strategy. The tables summarize findings across a number of publicly available documents. They list formats for various types of media and indicate which are accepted or recommended by larger institutions for long-term digital preservation. While these tables do not yet constitute recommendations, they serve as a summary of existing practices by large memory institutions.
Table of contents
- Legend of abbreviations found in column “Published documents"
- Explanation of table headings
- Text formats
- Still image formats
- Moving image formats
- Audio formats
- Bibliography
- Acknowledgements
Legend of abbreviations found in column "Published documents”
Accep: accepted format. The institution will accept files in this format for long-term preservation. An accepted format may or may not be the preferred format.
Pref: preferred format. The institution prefers that files be provided in this format for long-term preservation.
Pref(+): preferred format that may also be used as an access or preservation format as well.
Pres: preservation format.
Pres(+): a preservation format, which can also be used as an access or transfer format.
PUID: PRONOM unique identifier (a unique number assigned by the PRONOM registry to a specific file format).
RAW video: video preserved in the format produced by the hardware that originally recorded the information. Because hardware varies, this term does not refer to a specific format but rather to the format that is proprietary to that hardware manufacturer.
Rec: recommended format. The institution recommends that files be saved in this format for long-term preservation.
Trans: transfer format. Files may be transferred to the institution in this format for long-term preservation. The institution may or may not convert this information to an alternate preservation format.
Explanation of table headings
Extension: if the format is for a file, this refers to the standard file name suffix (typically three or four letters in length) following the “.” This extension indicates to an operating system in what format a file is stored and thus how the file is to be handled.
Format specification: reference to any published specifications for the format in question.
Formats: includes file formats or other digital formats for information contained within a file. The format names under this heading are often given as abbreviations; an external link is provided for further information regarding the abbreviation and its underlying format.
PRONOM: an online information system about data file formats and their supporting software products. Originally developed to support the accession of electronic records held by the National Archives (UK) and the long-term preservation of such records, PRONOM is now available online to anyone.
Published documents: headers in this section include the document name, the name of the publishing institution, the date published (if available) and an online link to the source document. Information in each column of this section identifies which file formats were preferred, recommended or accepted as a transfer format by that institution.
PUID: the PRONOM unique identifier is a label assigned in the PRONOM registry that uniquely identifies file formats and their various versions; a specific version of a specific file format has a unique PUID.
Recommendation category: applies to audio where recommendations may apply to an encoding format or a file (container or wrapper) format.
Text formats
Formats | Format details | Published document | ||||||||
---|---|---|---|---|---|---|---|---|---|---|
Extension | Format specifications | PRONOM PUID Example file formats include: |
Library and Archives Canada: Guidelines on File Formats for Transferring Information Resources of Enduring Value (2014) | Library of Congress: Sustainability of Digital Formats: Planning for Library of Congress Collections (2004-2015) |
Library of Congress: Recommended Formats Statement (2016–2017) | Harvard Library: File Format & Content Creation Guidance | The National Archives (UK): Preserving Digital Records: Guidance | Archives d'État (Switzerland): Formats de fichiers adaptés à l'archivage électronique à moyen et long terme (2011) | National Archives of Australia: Long-term File Formats | |
Common text formats | ||||||||||
Plain text (encoding) | not applicable | UTF-8, UTF-16, ISO-8859-1, ISO-8859-15 or US-ASCII | x-fmt/111 x-fmt/22 x-fmt/283 |
trans | - | rec | - | trans | pres | pres |
ODF | .odt, .ott | ISO/IEC 26300:2006, Information Technology – Open Document Format for Office Applications (OpenDocument) v1.0 | fmt/136 fmt/290 fmt/291 |
trans | - | - | - | trans | - | accep/pres |
XML | .xml | - | XML: fmt/120 fmt/121 fmt/101 fmt/896 |
- | pref | rec | - | trans | - | - |
SGML | .sgml | - | x-fmt/195 | - | pref | - | - | - | - | - |
EPUB | .epub | - | fmt/483 | trans | - | - | - | - | - | - |
PDF/A | - | PDF/A: fmt/95 fmt/354 fmt/476 fmt/477 fmt/478 fmt/479 fmt/480 fmt/481 |
trans | pref | rec | pres | trans | pres | - | |
- | fmt/559 fmt/560 fmt/561 fmt/562 fmt/563 fmt/564 fmt/565 fmt/558 fmt/14 fmt/15 fmt/16 fmt/17 fmt/18 fmt/19 fmt/20 fmt/276 fmt/95 fmt/354 fmt/476 fmt/477 fmt/478 fmt/479 fmt/480 fmt/481 fmt/493 fmt/144 fmt/145 fmt/157 fmt/146 fmt/147 fmt/158 fmt/148 fmt/488 fmt/489 fmt/490 fmt/492 fmt/491 |
- | pref | rec | pres | trans | - | - | ||
Word (binary) | .doc | - | x-fmt/329 fmt/473 fmt/609 fmt/39 x-fmt/273 x-fmt/274 x-fmt/275 x-fmt/276 fmt/37 fmt/38 x-fmt/131 x-fmt/42 x-fmt/43 fmt/40 x-fmt/44 fmt/523 fmt/412 fmt/754 fmt/892 fmt/494 x-fmt/129 |
- | - | - | pres | trans | - | - |
Word (xml) | .docx | - | fmt/412 | - | - | - | pres | - | - | - |
Rich text | .rtf | fmt/969 fmt/45 fmt/50 fmt/52 fmt/53 fmt/355 |
- | - | - | pres | trans | - | - | |
HTML | .html | - | fmt/103 fmt/96 fmt/97 fmt/98 fmt/99 fmt/100 fmt/471 fmt/102 fmt/583 |
- | pref | - | - | - | - | - |
Open Office Writer | .sxw | - | fmt/128 | - | - | - | - | trans | - | - |
WordPerfect (different versions) | .wpd | - | WPD: x-fmt/44 x-fmt/203 x-fmt/393 fmt/949 x-fmt/394 fmt/892 |
- | - | - | pres | trans | - | - |
Other text formats | ||||||||||
OEBPS.1.2, (Open eBook Publication Structure, version 1.2, for novels, textbooks, scholarly monographs, etc.) | not applicable | Open eBook Forum Publication Structure 1.2 | none | - | pref | - | - | - | - | - |
DTB (Digital Talking Book, ANSI/NISO Z39.86 with full transcript of text for novels, textbooks, scholarly monographs, etc.) | not applicable | ANSI/NISO Z39.86 | none | - | pref | - | - | - | - | - |
Journal Archiving and Interchange Document Type Definition (DTD). For articles and e-journals | not applicable | NLM Journal Archiving and Interchange Tag Suite | x-fmt/315 | - | pref | - | - | - | - | - |
Microsoft Word Template .dot | .dot | - | x-fmt/45 fmt/755 |
- | - | - | - | trans | - | - |
XML Schema Definition | .xsd | - | XML: fmt/120 fmt/121 fmt/101 fmt/896 |
- | - | - | - | trans | - | - |
Still image formats
FORMATS | FORMAT DETAILS | PUBLISHED DOCUMENTS | |||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Extension | Format specifications | PRONOM PUID | Library and Archives Canada: Guidelines on File Formats for Transferring Information Resources of Enduring Value (2014) | Library of Congress: Sustainability of Digital Formats: Planning for Library of Congress Collections (2004-2015) |
Library of Congress: Recommended Formats Statement 2016–2017 | Harvard Library: File Format & Content Creation Guidance | The National Archives (UK): Preserving Digital Records: Guidance | Archives d'Etat (Switzerland): Formats de fichiers adaptés à l'archivage électronique à moyen et long terme (2011) | National Archives of Australia: Long-term File Formats | McMaster University, Digital Archive: Preservation Policy (2013) | |
Common still image formats | |||||||||||
TIFF (raster) | .tiff, .tif | TIFF Revision 6.0 Final – June 3, 1992, Adobe Systems Incorporated (PDF format) | fmt/353 (many other versions) | trans | pref | rec | pres | trans | trans | - | pres |
JPEG2000 (raster) | .jp2 | ISO/IEC 15444-1:2004, Information technology – JPEG 2000 image coding system: Core coding system Overview of JPEG 2000 |
x-fmt/392 | trans | pref | rec | pres | trans | - | - | - |
JPEG (raster) | .jpeg, .jpg | fmt/42 fmt/43 fmt/44 |
- | pref(+) | rec | pres(+) | trans | - | accep/pres | - | |
PNG (raster) | .png | ISO/IEC 15948:2004, Information technology – Computer graphics and image processing – Portable Network Graphics (PNG): Functional specification |
fmt/11 fmt/12 fmt/13 |
trans | pref | rec | - | trans | - | pres | - |
GIF (raster) | .gif | - | fmt/3 fmt4 |
- | pref | rec | pres | trans | - | - | - |
PDF (various versions, PDF/A preferred) | trans | pref | - | - | - | pres | accep/pres | - | |||
DNG (raster) | .dng | - | fmt/436 fmt/152 fmt/437 fmt/438 fmt/730 |
- | - | rec | - | trans | - | - | - |
BMP (raster) | .bmp | fmt/114 fmt/115 fmt/116 fmt/117 fmt/118 fmt/119 |
- | pref | rec | - | trans | - | - | - | |
Open Document Graphics (raster) | .odg .otg | - | fmt/139 fmt/296 fmt/297 |
- | - | - | - | trans | - | accep/pres | - |
Scalable Vector Graphics (vector) | .svg | fmt/92 fmt/413 |
- | pref | rec | - | - | - | accep/pres | - | |
OpenOffice Draw (vector) | .sxd | - | fmt/127 | - | - | - | - | - | - | trans | - |
Corel Draw CDR (vector) | .cdr | - | fmt/467 x-fmt/375 x-fmt/378 fmt/427 fmt/466 x-fmt/379 fmt/465 fmt/464 x-fmt/29 x-fmt/291 x-fmt/292 x-fmt/374 fmt/428 fmt/429 |
- | - | - | - | - | - | trans | - |
Microsoft Visio Drawing (vector) | .vsd | - | x-fmt/258 x-fmt/259 fmt/433 x-fmt/113 |
- | - | - | - | - | - | trans | - |
Other still image formats | |||||||||||
AutoCad Drawing Interchange Format | .dxf | DXF Reference | many versions | - | pref | - | - | - | - | - | - |
Encapsulated Postscript | .eps | - | - | - | - | rec | - | - | - | - | - |
Shape files | .shp, .shx, .dbf | - | - | - | - | rec | - | - | - | - | - |
Moving image formats
FORMATS | FORMAT DETAILS | PUBLISHED DOCUMENTS | |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Extension | Format specifications | PRONOM PUID | Library and Archives Canada: Guidelines on File Formats for Transferring Information Resources of Enduring Value (2014) | Library of Congress: Sustainability of Digital Formats: Planning for Library of Congress Collections (2004-2015) |
Library of Congress: Recommended Formats Statement 2016–2017 | Harvard Library: File Format & Content Creation Guidance | The National Archives (UK): Preserving Digital Records: Guidance | Archives d'Etat (Switzerland): Formats de fichiers adaptés à l'archivage électronique à moyen et long terme (2011) | National Archives of Australia: Long-term File Formats | Digital Preservation Office at the University of Michigan: A Quick Guide to Digital Video Files (2010) |
Digital Preservation Coalition: Preserving Moving Pictures and Sound (2012) |
McMaster University, Digital Archive: Preservation Policy (2013) | |
Common moving image formats | |||||||||||||
AVI | .avi | - | fmt/5 | trans | - | - | - | - | - | - | - | - | pres |
MPEG-1 | .mpg, .mpeg | - | x-fmt/385 fmt/649 |
- | pref | - | - | trans | - | - | - | - | - |
MPEG-2 | .mpg, .mpeg | - | x-fmt/386 | - | pref | - | - | trans | - | - | pres | - | - |
MPEG-4 | .mp4 .m4v . M4a .f4v .f4a | - | fmt/199 | - | pref | - | - | trans | - | - | pres | - | - |
Quicktime (MOV) | .mov, .qtm | - | x-fmt/384 | trans | - | - | pres | trans | - | - | - | - | - |
MXF | .mxf | - | fmt/200 | trans | - | - | pres | trans | - | - | - | pres | - |
WMV | .wmv, .asf | - | fmt/133 | - | - | - | - | trans | - | - | - | - | - |
FLASH | .swf | - | fmt/104 fmt/105 fmt/106 fmt/107 fmt/108 fmt/109 fmt/110 |
- | - | - | - | trans | - | - | - | - | - |
OGG | .ogg, .ogv | - | fmt/203 fmt/945 |
- | - | - | - | trans | - | accep/pres | - | - | - |
Motion JPG2000 | .mj2 .mjp2 .m2v | - | fmt/337 | - | - | - | - | trans | - | - | - | - | - |
Digital Cinema Initiative Distribution Master (DCDM) | not applicable | Digital Cinema Initiatives, DCI Specification Version 1.2, 2012 SMPTE 428-1-2006: D-Cinema Distribution Master (DCDM) – Image Characteristics |
not applicable | - | - | trans | - | - | - | - | - | - | - |
Digital Moving Picture Exchange (DPX) | .dpx | SMPTE ST 268:2003, File Format for Digital Moving-Picture Exchange (DPX) Version 2.0 | fmt/193 (1.0) fmt/541 (2.0) |
- | - | trans | - | - | - | - | - | - | - |
WebM | .webm | fmt/573 | - | - | - | - | - | - | trans | - | - | - | |
Matroska | .mkv | - | fmt/569 | - | - | - | - | - | - | - | accep/pres | - | |
Other moving image formats | |||||||||||||
RAW video | various | - | mixed | - | - | - | - | - | - | accep/pres | - | - | - |
Audio formats
FORMATS | FORMAT DETAILS | PUBLISHED DOCUMENTS | ||||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Extension | Recommendation category | Format specifications | PRONOM PUID | Library and Archives Canada: Guidelines on File Formats for Transferring Information Resources of Enduring Value (2014) | Library of Congress: Sustainability of Digital Formats: Planning for Library of Congress Collections (2004-2015) |
Library of Congress: Recommended Formats Statement 2016-2017 | Harvard Library: File Format & Content Creation Guidance | The National Archives (UK): Preserving Digital Records: Guidance | Archives d'Etat (Switzerland): Formats de fichiers adaptés à l'archivage électronique à moyen et long terme (2011) | National Archives of Australia: Long-term File Formats | Digital Preservation Office at the University of Michigan: A Quick Guide to Digital Video Files (2010) |
Digital Preservation Coalition: Preserving Moving Pictures and Sound (2012) |
McMaster University, Digital Archive: Preservation Policy (2013) | |
Common audio formats | ||||||||||||||
BWF | .wav | file format | Specification of the Broadcast Wave Format (BWF) (PDF format) | Version 1: fmt/2 Version 2.0: fmt/527 |
trans | pref | rec | - | trans | - | - | - | pres | - |
WAVE | .wav .wave | container-wrapper format | Multimedia Programming Interface and Data Specifications 1.0 (PDF format) | fmt/6 | - | pref | rec | pres | trans | pres | - | - | - | pres |
AIFF | .aif, .aiff | container-wrapper format | - | x-fmt/135 | - | pref | - | - | - | - | - | - | - | - |
MPEG-4 | .mp4 .m4v . m4a .f4v .f4a | encoding format & container-wrapper | - | fmt/199 | - | pref (mono, stereo and surround) |
- | pres | trans | - | - | - | - | - |
MP3 | .mp3 | encoding format & container-wrapper | ISO/IEC-11172-3:1993, Information technology – Coding of moving pictures and associated audio for digital storage media at up to about 1,5 Mbit/s – Part 3: Audio ISO/IEC 13818-3:1998, Information technology – Generic coding of moving pictures and associate audio information – Part 3: Audio |
fmt/134 | - | pref | - | - | trans | - | - | - | - | - |
FLAC | .flac | encoding format (may or may not be wrapped in a file format by the same name) | - | fmt/279 | - | - | - | - | - | - | pres | - | pres | pres |
OGG | .ogg .oga | encoding format & container-wrapper | - | fmt/203 | - | - | - | - | - | trans | - | - | - | |
WMA | .wma .asf | container-wrapper format | - | fmt/132 | - | - | - | - | - | trans | - | - | - | |
MIDI | .mid | file format | - | x-fmt/230 | - | - | - | - | - | trans | - | - | - | |
Other audio formats | ||||||||||||||
AAC_ADIF, Advanced Audio Coding (MPEG-2), Audio Data Exchange Format | .aac | encoding format & container-wrapper | Documentation no longer available, but reproduced by the Library of Congress. | not applicable | - | pref | - | - | - | - | - | - | - | - |
QTA_AAC, QuickTime Audio, AAC Codec | .aac | encoding format & container-wrapper | QuickTime File format from Apple Computer Inc. (note that there are two format specifications). | not applicable | - | pref | - | - | - | - | - | - | - | - |
WMA_WMA9_PRO, Windows Media Audio File with WMA9 Professional Codec | .wma | encoding format & Container-wrapper | File format based in ASF (Advanced Systems Format) that wraps a Windows Media 9 professional audio bitstream. | not applicable | - | pref | - | - | - | - | - | - | - | - |
WMA_WMA9, Windows Media Audio File with WMA9 Codec | .wma | encoding format & container-wrapper | File format based in ASF (Advanced Systems Format) that wraps a Windows Media 9 professional audio bitstream. | not applicable | - | pref | - | - | - | - | - | - | - | - |
AAC_ADIF, Advanced Audio Coding (MPEG-2), Audio Data Exchange Format | .m4p, .m4b | encoding format & container-wrapper | - | not applicable | - | pref | - | - | - | - | - | - | - | - |
QTA_AAC, QuickTime Audio, codec AAC | .m4p, .m4b | encoding format & container-wrapper | - | not applicable | - | pref | - | - | - | - | - | - | - | - |
WMA_WMA9_PRO, Windows Media Audio File with WMA9 Professional Codec | .wma | encoding format & container-wrapper | - | not applicable | - | pref | - | - | - | - | - | - | - | - |
Bibliography
Archives d’État (Switzerland). Formats de fichiers adaptés à l’archivage électronique à moyen et long terme (PDF format) (available in French only), 2011.
Digital Preservation Coalition. Preserving Moving Pictures and Sound, 2012.
Digital Preservation Office at the University of Michigan. A Quick Guide to Digital Video Files, 2010.
Harvard Library. File Formats and Naming: Formats, n.d.
Library and Archives Canada. Guidelines on File Formats for Transferring Information Resources of Enduring Value, 2014.
Library of Congress. Sustainability of Digital Formats: Planning for Library of Congress Collections, 2004–2015.
Library of Congress. Recommended Formats Statement , 2016–2017.
McMaster University, Digital Archive. Preservation Policy, 2013.
National Archives of Australia. Long-term File Formats, n.d.
The National Archives (UK). Preserving Digital Records: Guidance, n.d.
Acknowledgements
Material found in this document was collected by Paul Durand of the Canadian Museum of History, William Vinh-Doyle of the Provincial Archives (New Brunswick) and Ern Bieman of the Canadian Heritage Information Network (CHIN). Tables were compiled by Paul Durand. All content was reviewed by members of the Digitization and Digital Preservation Discussion Group (Canada).
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