Copyright © @@@@ W3C® (MIT, ERCIM, Keio), All Rights Reserved. W3C liability, trademark and document use rules apply.
This specification defines an ontology and a client-side API for cross-community data integration of information related to media objects on the Web. The purpose of the ontology and the API is to help circumventing the profileration of video metadata formats by providing partial mappings between the existing formats.
The ontology and API differ in their area of application: The API provides methods for client side processing. The ontology is a description of relations between existing formats, which is used in the API for data integration.
1 Introduction
1.1 Purpose of this specification
1.2 Formats in scope
1.3 Formats out of scope
2 Terminology and Identifiers
2.1 Terminology
2.2 Identifiers of formats
3 Property value types definitions
3.1 Basic property value types
3.1.1 URI
3.1.2 Date
4 Property definition
4.1 Description of approach for the property definitions
4.2 Basic properties
4.2.1 subject
4.2.2 description
4.2.3 createDate
4.2.4 orientation
4.2.5 rights
4.2.6 creator
4.2.7 location created
4.2.8 location shown
5 API definition
5.1 The Metadata object
5.2 Definition of methods for retrieving metadata
5.2.1 getCreateDate
A References
B Acknowledgements (Non-Normative)
This section is informative.
This specification defines an ontology and a client-side API for cross-community data integration of information related to media objects on the Web. The purpose of the ontology and the API is to help circumventing the profileration of video metadata formats by providing partial mappings between the existing formats.
The ontology and API differ in their area of application: The API provides methods for client side processing. The ontology is a description of relations between existing formats, which is used in the API for data integration.
| Editorial note | |
| The Working Group is seeking feedback on the question whether the API and the ontology should be seperate specifications, or whether both should be created within one document, since they are closely related. | |
The properties defined in the ontology focus on usage scenarios related to video on the web. Nevertheless they also take formats into account which are not specific to video, but which are of importance for video. An example of this is information from Dublin Core [Dublin Core].
This specification does not aim on defining new properties for media objects. As a result, there is no detailed description of properties, but mainly references to definitions in existing formats.
In this specification the following formats related to media objects on the Web have been taken into account .
Note:
This specification is based on a review of existing formats and the properties they provide. This review does not aim to be complete, and this specification does not aim to cover all properties defined in these formats. The choice of properties is motivated by their wide usage.
[ID3]
[IPTC]
[EXIF2.2]
[MWG Guidelines Image]. This specification does not define properties on its own, but provides guidance for relating information from existing formats, mainly [EXIF2.2], [IPTC] and [XMP].
[MPEG 7]
[XMP]
[YouTube Data API Protocol]. This document contains information about [Media RSS]. For the creation of mappings, the Media RSS specification has been consulted seperately.
tbd: Cable Labs Video-On-Demand Content specification 2.0, TV-Anytime Metadata, CDDB, EBU, VRA, DIG35.
The following formats have been decided to be out of scope for this specification.
[MPEG 21]
This section is normative.
A property is a name or a label for sets of information from existing formats for media objects on the web. An example property is createDate. In existing formats such a property can have different names like yt:recorded in [YouTube Data API Protocol]. Properties are defined in sec. 4 Property definition.
A property will not be included in this specification if there is no existing format which deploys information related to the property.
A resource is a media object which contains information related to a property.
Mapping is the description of relations between (a) sets of information from existing formats for media objects on the web, and (b) properties. Mappings are defined in sec. 4 Property definition.
Property value types are the types of values used in a property. Property value types are defined in sec. 3 Property value types definitions. The are relying mostly on XML Schema data types [XML Schema 2].
Methods are part of the API defined in this specification. They are used to get or set properties in a resource. Methods are defined in sec. 5 API definition.
The following table lists identifiers which are used to identify formats in this specification.
| Identifier | Format | Example | Reference |
| dc | Dublin Core | tbd | [Dublin Core] |
| exif | EXIF 2.2 | tbd | [EXIF2.2] |
| id3 | ID3 | tbd | [ID3] |
| iptc | IPTC | tbd | [IPTC] |
| mr | Media RSS | tbd | [Media RSS] |
| mpeg7 | MPEG 7 | tbd | [MPEG 7] |
| xmp | XMP | tbd | [XMP] |
| yt | YouTube Data API Protocol | tbd | [YouTube Data API Protocol] |
URI "Uniform Resource Identifier" are defined in [RFC 3986]. In this specification the term URI is used since it is well known. However the term is used as meaning IRIs "Internationalized Resource Identifiers (IRIs)" [RFC 3987], that is URIs which may contain non-escaped characters other than ASCII. The data type is anyURI .
A Date value is represented using the XML Schema dateTime data type.
This section is normative.
The following information is available for each property:
rough description of purpose
mappings to existing formats
method(s) in the API in sec. 5 API definition
Name of the property: createDate.
Purpose of the property: The date and time the resource was created.
Property value type(s): date
Related methods: see sec. 5.2.1 getCreateDate
Mappings:
id3:TDAT
exif:DateTimeDigitized (based on [MWG Guidelines Image]). This is taken only into account if both xmp:createDate and exif:DateTimeOriginal are missing.
exif:DateTimeOriginal (based on [MWG Guidelines Image])
iptc:DateCreated (based on [MWG Guidelines Image]). This is taken only into account if both xmp:createDate and exif:DateTimeOriginal are missing.
xmp:CreateDate (based on [MWG Guidelines Image])
Metadata objectThe Metadata object is used to retrieve metadata across existing formats. It can be invoked in the following manner, assuming an <video> element [HTML 5] with an id attribute with the value MyVid:
Element vid = doc.getElementById("MyVid");
Metadata o2 = vid.getMetadata();
o2.getCreateDate();The Metadata object provides various methods to retrieve metadata from existing formats. See sec. 5.2 Definition of methods for retrieving metadata for these methods.
getCreateDateDate getCreateDate()Gets the createDate of the resource.
Return value type: Date
Related property: createDate
This document is the work of the W3C Media Annotations Working Group.
Members of the Working Group are (at the time of writing, and by alphabetical order): Werner Bailer (K-Space), Tobias Bürger (University of Innsbruck), Jaime Delgado (Universitat Politècnica de Catalunya), Jean-Pierre EVAIN ((public) Invited expert), Ralf Klamma ((public) Invited expert), WonSuk Lee (Electronics and Telecommunications Research Institute (ETRI)), Véronique Malaisé (Vrije Universiteit), Erik Mannens (IBBT), Hui Miao (Samsung Electronics Co., Ltd.), Thierry Michel (W3C/ERCIM), Frank Nack (University of Amsterdam), Soohong Daniel Park (Samsung Electronics Co., Ltd.), Silvia Pfeiffer (W3C Invited Experts), Felix Sasaki (W3C/Keio), Joakim Söderberg (ERICSSON), Ruben Tous (Universitat Politècnica de Catalunya), Raphaël Troncy (CWI), Vassilis Tzouvaras (K-Space), Davy Van Deursen (IBBT).
The people who have contributed to discussions on public-media-annotation@w3.org are also gratefully acknowledged.