EDM profile for technical metadata
- Adina Ciocoiu
To provide additional useful facets and filtering of Europeana resources the addition of technical metadata at the level of the WebResource, which was currently absent from EDM, is needed. This specification applies to five media types which Europeana currently supports, namely: Sound, Video, Text, Image and 3D objects. This profile lists the properties that will apply to the WebResource class and an additional class that were defined to support such functionality.
- 1 Approach
- 2 Properties
- 2.1 edm:codecName
- 2.2 ebucore:hasMimeType
- 2.3 ebucore:fileByteSize
- 2.4 ebucore:duration
- 2.5 ebucore:width
- 2.6 ebucore:height
- 2.7 edm:spatialResolution
- 2.8 ebucore:sampleSize
- 2.9 ebucore:sampleRate
- 2.10 ebucore:bitRate
- 2.11 ebucore:frameRate
- 2.12 edm:hasColorSpace
- 2.13 edm:componentColor
- 2.14 ebucore:orientation
- 2.15 ebucore:audioChannelNumber
- 2.16 rdf:type
- 3 Classes
The working document that contains background information and that forms the basis of this listing is available here:https://docs.google.com/spreadsheets/d/17LjVpdUHsqpLhvQ0kvvDd7ja6eAPhSB9dN3NQ0kEbko/edit?pli=1&gid=0#gid=0 . Most of the added properties come from the EBUCore set of properties, available at: http://www.ebu.ch/metadata/ontologies/ebucore/index.html
Approach
A minimal approach has been adopted to the addition of properties to EDM. Not all functions require the addition of a specific property. Consider for example the filtering of Europeana objects based on the presence of a usable thumbnail. This can be detected by checking for the presence of a URL in the “edm:preview” property (and the resource flagged accordingly in a search system) without the need for a specific EDM property to hold that flag in Europeana’s reference data.
Some values can be used to generate further values and, depending on the stage in the processing of data where this happens, a property may be needed to record the output. For example, the orientation of an image will be generated by processing numeric values given in the height and width properties, giving the result as “Portrait” or “Landscape”. A few properties have been created in the EDM namespace even though similar properties already exist elsewhere (e.g. Exif and EBUCore). This is because the allowable values did not match our requirements at this time (e.g. EDM needs literal values in some cases).
These properties are: “edm:hasColorSpace”, “edm:componentColor”, “edm:spatialResolution” and “edm:codecName”.
Properties
All the properties defined below should be applied to edm:WebResource.
edm:codecName | |
|---|---|
URI |
|
Label | Codec |
Definition | The name of a device or computer program capable of encoding or decoding a digital data stream or signal (i.e. coder-decoder) |
Domain | edm:WebResource |
Obligation & Occurrence | Optional (Minimum: 0, Maximum: 1) |
Example | mp4v |
Comment | Used for video |
ebucore:hasMimeType | |
|---|---|
URI |
|
Label | MIME Type |
Definition | The main MIME types as defined by IANA: e.g. audio, video, text, application, or a container MIME type. |
Subproperty of | ebucore:hasFormat |
Domain | edm:WebResource |
Obligation & Occurrence | Optional (Minimum: 0, Maximum: 1) |
Example | video/mp4 |
Comment | The controlled values are defined by IANA list of internet media types. Used for Video, Image, Sound, Text, 3D. |
ebucore:fileByteSize | |
|---|---|
URI |
|
Label | File size |
Definition | The size of a Media Resource expressed in bytes. |
Domain | edm:WebResource |
Range | xsd:long (as defined in EBUCore) |
Obligation & Occurrence | Optional (Minimum: 0, Maximum: 1) |
Example | 39508 |
Comment | To indicate the storage requirements or file size of a digital resource. The file size is expressed in bytes. Used for Video, Image, Sound, Text, 3D. |
ebucore:duration | |
|---|---|
URI |
|
Label | Duration |
Definition | The duration of a track or a signal expressed in ms. |
Subproperty of | ebucore:duration |
Domain | edm:WebResource |
Obligation & Occurrence | Optional (Minimum: 0, Maximum: 1) |
Example | 270000 |
Comment | An implementation decision was made to use this property instead of a more normative property such as “ebucore:durationNormalPlayTime” so that a duration could be expressed as a number. Used for Video and Sound. |
ebucore:width | |
|---|---|
URI |
|
Label | Width |
Definition | The width of e.g. a video frame typically expressed as a number of pixels. |
Domain | edm:WebResource |
Range | xsd:integer |
Obligation & Occurrence | Optional (Minimum: 0, Maximum: 1) |
Example | 1024 |
Comment | To define different widths of a video image e.g. display, active etc. Used for Video and Image. |
ebucore:height | |
|---|---|
URI |
|
Label | Height |
Definition | The height of e.g. a video frame typically expressed as a number of pixels. |
Domain | edm:WebResource |
Range | xsd:integer (as defined in EBUCore) |
Obligation & Occurrence | Optional (Minimum: 0, Maximum: 1) |
Example | 768 |
Comment | To define different heights of a video image e.g. display, active etc. Used for Video and Image. |
edm:spatialResolution | |
|---|---|
URI |
|
Label | Spatial resolution |
Definition | The spatial resolution of a media resource expressed in DPIs. |
Domain | edm:WebResource |
Range | xsd:nonNegativeInteger (as defined in EBUCore) |
Obligation & Occurrence | Optional (Minimum: 0, Maximum: 1) |
Example | 300 |
Comment | Used for Text (e.g. PDFs). |
ebucore:sampleSize | |
|---|---|
URI |
|
Label | Sample size |
Definition | The size of an audio sample in bits. Also called bit depth. |
Domain | edm:WebResource |
Range | xsd:integer (as defined in EBUCore) |
Obligation & Occurrence | Optional (Minimum: 0, Maximum: 1) |
Example | 16 |
Comment | Used for Sound. |
ebucore:sampleRate | |
|---|---|
URI |
|
Label | Sample rate |
Definition | The frequency at which an audio is sampled per second. Also called sampling rate. |
Domain | edm:WebResource |
Range | xsd:integer (as defined in EBUCore) |
Obligation & Occurrence | Optional (Minimum: 0, Maximum: 1) |
Example | 44100 |
Comment | Used for Sound. |
ebucore:bitRate | |
|---|---|
URI |
|
Label | Bitrate |
Definition | To provide the bitrate at which the Media Resource can be played in bits |
Domain | edm:WebResource |
Range | xsd:nonNegativeInteger (as defined in EBUCore) |
Obligation & Occurrence | Optional (Minimum: 0, Maximum: 1) |
Example | 128000 |
Comment | Used for Video and Sound. |
ebucore:frameRate | |
|---|---|
URI |
|
Label | Frame rate |
Definition | The frame rate of the video signal in frames per second. |
Domain | edm:WebResource |
Range | xsd:double (as defined in EBUCore) |
Obligation & Occurrence | Optional (Minimum: 0, Maximum: 1) |
Example | 300 |
Comment | Used for Video. |
edm:hasColorSpace | |
|---|---|
URI |
|
Label | Color Space |
Definition | The color space of an image resource i.e. “grayscale” or “sRGB” |
Domain | edm:WebResource |
Obligation & Occurrence | Optional (Minimum: 0, Maximum: 1). |
Example | grayscale |
Comment | Used for Image. |
edm:componentColor | |
|---|---|
URI |
|
Label | Component Color |
Definition | A significant color present in an image. The colors must be taken from the CSS3 standard color palette and are expressed as a hexadecimal binary value. |
Domain | edm:WebResource |
Range | xsd:hexBinary |
Obligation & Occurrence | Optional (Minimum: 0, Maximum: 6) |
Example | FF0000 |
Comment | Used for Image. |
ebucore:orientation | |
|---|---|
URI |
|
Label | Orientation |
Definition | The orientation of a document or an image i.e. “landscape” or “portrait”. |
Domain | edm:WebResource |
Range | xsd:string (as defined in EBUCore) |
Obligation & Occurrence | Optional (Minimum: 0, Maximum: 1) |
Example | portrait |
Comment | The value is generated by comparing the values in “ebucore:height” and “ebucore:width”. Used for Image. |
ebucore:audioChannelNumber | |
|---|---|
URI |
|
Label | Audio channels |
Definition | The total number of audio channels contained in the Media Resource. |
Domain | edm:WebResource |
Range | xsd:nonNegativeInteger (as defined in EBUCore) |
Obligation & Occurrence | Optional (Minimum: 0, Maximum: 1) |
Example | 2 |
Comment | Used for Sound. |
rdf:type | |
|---|---|
URI |
|
Label | Type |
Definition | To indicate the type of a resource. |
Range | rdfs:Resource |
Obligation & Occurrence | Optional (Minimum: 0, Maximum: 1) |
Example |
|
Comment | This is used to indicate that a web resource contains searchable, machine readable text. In the context of this EDM extension, “rdf:type” has been introduced to be used in relation with classes relevant for this extension, especially “edm:FullTextResource”. |
Classes
edm:FullTextResource | |
|---|---|
URI | |
Label | Full-text Resource |
Definition | A resource that has machine readable full text content. |
Subclass of | edm:InformationResource |
Example | Typically this could be the result of a newspaper that has been digitised as an image or PDF file and then OCRed to produce a separate file with the full text. |
Comment | When full-text is available for a digital object it must be represented in a specific class. This is because in some cases the WebResource that provides the view of the object to end-users does not contain the full-text in machine readable form. This is taken from the Europeana Libraries report on full-text. |
Document history:
Jan 20, 2015 Robina Clayphan, Hugo Manguinhas - Final version after review
Feb 17, 2015 Hugo Manguinhas, Antoine Isaac - Additional comments incorporated