Title: Controlled Vocabulary for Dublin Core format: List of Terms
Namespace URI: http://rs.tdwg.org/format/values/
Preferred namespace abbreviation: acformat:
Date version issued: 2020-10-13
Date created: 2020-10-13
Part of TDWG Standard: http://www.tdwg.org/standards/638
This version: http://rs.tdwg.org/ac/doc/format/2020-10-13
Latest version: http://rs.tdwg.org/ac/doc/format/
Replaced by: http://rs.tdwg.org/ac/doc/format/2023-02-24
Abstract: Audubon Core borrows the Dublin Core terms dc:format and dcterms:format to provide information about the physical or electronic format of a media item. This controlled vocabulary provides values for those two terms.
Contributors: Steven J Baskauf (Vanderbilt University Heard Libraries), Matthew Blissett (GBIF), Douglas Boyer (Duke University)
Creator: TDWG Audubon Core Maintenance Group
Bibliographic citation: Audubon Core Maintenance Group. 2020. Controlled Vocabulary for Dublin Core format: List of Terms. Biodiversity Information Standards (TDWG). http://rs.tdwg.org/ac/doc/format/2020-10-13
This document includes terms intended to be used as a controlled value for Dublin Core terms dc:format and dcterms:format, which are borrowed by Audubon Core.
1.1 Status of the content of this document
Section 1 is informative (non-normative).
Section 2 is normative except as noted.
Section 3 is informative.
In Section 4, the values of the Term IRI, Definition, and Controlled value are normative. The value of Usage (if it exists for a given term) is normative. The values of Has broader concept and Has exact match are normative. The values of Term Name are non-normative, although one can expect that the namespace abbreviation prefix is one commonly used for the term namespace. Label and the values of all other properties are non-normative.
1.2 RFC 2119 key words
The key words “MUST”, “MUST NOT”, “REQUIRED”, “SHALL”, “SHALL NOT”, “SHOULD”, “SHOULD NOT”, “RECOMMENDED”, “MAY”, and “OPTIONAL” in this document are to be interpreted as described in RFC 2119.
2 Use of Terms
2.1 Relationship of value types to property terms
In accordance with the Audubon Core Term List document, unabbreviated term IRIs MUST be used as values of the property dcterms:format. Controlled value strings SHOULD be used as values of the property dc:format.
2.2 Relationship between concepts and concept schemes
The entry for the property dc:format in the Audubon Core term list document specifies that three kinds of string values are RECOMMENDED: Internet Media Types (MIME types), special string values for physical media, or commonly used file extensions. This controlled vocabulary defines two SKOS concept schemes, a concept scheme for media types and physical media (the first two kinds of values specified for dc:type) and a concept scheme for file extensions (the last recommended kind of value). Because the Internet Assigned Numbers Authority (IANA) maintains a registry of media types and Audubon Core maintains a controlled list of physical media types, using values from the media types and physical media concept scheme is RECOMMENDED over the file extensions concept scheme.
The concept scheme for media types and physical media defines a skos:broader relation between each specific media type or physical medium and one of the six Top-level Media Types defined by RFC 2046 that are related to multimedia: application, audio, image, model, text, and video. This relation MAY be used by clients to infer the general category of the media item format.
The concept scheme for file extensions defines concepts for many common file extensions used for digital media files. These concepts are usually related to one of the media types and physical media by a skos:exactMatch relation. Metadata creators MAY use a controlled value from the file extensions concept scheme, but because of the asserted skos:exactMatch relation aggregators MAY substitute the equivalent value from the media types and physical media concept scheme.
2.3 Example workflows (non-normative)
Workflow 1: A data provider uses spreadsheets containing a column for literal values for dc:format. The spreadsheets are populated with file extensions that are controlled string values from the concept scheme for file extensions. The spreadsheets are provided to an aggregator whose software “looks up” the controlled string values in the concept scheme for file extensions and determines the equivalent concepts from the concept scheme for media types and physical media. The IRIs from the concept scheme for media types and physical media are used as standardized values for dcterms:format in the aggregator’s database.
Workflow 2: A data aggregator acquires data about multimedia items that includes file names or URLs, but no format information. The aggregator extracts the file extensions from the files or URLs and uses the concept schemes to assign a dcterms:format IRI value from the concept scheme for media types and physical media to each item. In cases where an item has a file extension that does not correspond to one of the controlled value strings in the concept scheme for file extensions, the aggregator uses a community-maintained table of alternate file extension values to determine the appropriate format concept for the media item.
Workflow 3: A data aggregator harvests media items from an open data repository. The remote server provides the media type via a Content-Type header and the file extension is determined from the file name. The aggregator cross-checks the media type value against the file extension value and uses the skos:exactMatch relations in the SKOS concept schemes to determine whether the values are consistent. Inconsistent pairs of values are flagged for manual checking. Previously unknown file extensions are flagged for additional research and possible inclusion in the community-maintained table of alternate file extension values.
3 Term index
Concept schemes
file extensions concept scheme |
media types and physical media concept scheme
Media types and physical media concept scheme
3GPP |
AIFF |
AMR |
application |
ARW raw image |
ASF |
audio |
audio cassette |
audio CD |
audio DVD |
AVI |
Blu-ray video disc |
BMP |
CIFF raw image |
CR2 |
CR3 raw image |
data CD |
data DVD |
DICOM |
digital audio tape |
Digital Negative |
extended MPEG-2 Transport Stream |
FLAC |
GIF |
gLTF |
gLTF binary |
image |
JPEG |
JPEG 2000 |
Kodak Photo CD image |
M4V |
MiniDisc |
mixed CD (data and audio) |
model |
MP3 |
MP4 audio |
MP4 video |
MPEG |
MTL |
Nikon NEF Raw |
NTSC video DVD |
OBJ |
OGG audio |
OGG multiplex |
OGG video |
PAL video DVD |
PDF |
photographic print |
photographic slide |
Photoshop |
physical artwork |
plain text |
PNG |
QuickTime |
reel-to-reel audio tape |
RW2 raw image |
STL |
SVG |
text |
TIFF |
video |
video CD |
vinyl record |
VRML |
WAVE |
WMA |
WMV |
Word (post-2007) document |
Word (pre-2003) document |
X3D VRML |
X3D XML |
ZVI
File extensions concept scheme
3GPP |
AIFF |
AMR |
ARW raw image |
ASF |
AVI |
BMP |
Canon Raw |
CIFF raw image |
CR3 raw image |
DICOM |
Digital Negative |
FLAC |
GIF |
gLTF |
gLTF binary |
JPEG |
JPEG 2000 |
Kodak Photo CD image |
M4V |
MP3 |
MP4 audio |
MP4 video |
MTL |
MWA |
Nikon NEF Raw |
OBJ |
OGG audio |
OGG multiplex |
OGG video |
PDF |
Photoshop |
plain text |
PLY |
PNG |
QuickTime |
RW2 raw image |
STL |
SVG |
TIFF |
VRML |
WAVE |
WMV |
Word (post-2007) document |
Word (pre-2003) document |
X3D VRML |
X3D XML |
ZVI
4 Vocabulary
4.1 Concept schemes
4.3 File extensions concept scheme