This specification defines an API to access metadata information related to media resources on the Web. The overall purpose is to provide developers with a convenient access to metadata information stored in different metadata formats. The API provides means to access the set of metadata properties defined in the Ontology for Media Resources 1.0 specification. These properties are used as a pivot vocabulary in this API. The core of this specification is the definition of API interfaces for retrieving metadata information in synchronous and asynchronous way as well as interfaces for structured return types along with the specification of the behavior of an API implementation. The API has been designed for both client and server side implementations.

Introduction

This specification defines an API to access metadata information related to media resources on the Web. The overall purpose is to provide developers with a convenient access to metadata information stored in different metadata formats. The core properties, defined in the Ontology for Media Resources 1.0 specification, will be used as a pivot vocabulary in this API. The description of relations between these core properties and the metadata formats in scope are documented in the Ontology for Media Resources 1.0 specification in order to provide cross-community data integration. This API is described using the interface definition language Web IDL [[WEBIDL]]. The decision to use Web IDL, which offers bindings for ECMAScript and Java, can be based on the Use Cases and Requirements for Ontology and API for Media Resources 1.0 [[!MEDIA-ANNOT-REQS]].

This API defines/exposes interfaces that enables users/applications to consume metadata in an interoperable manner. Here, interoperability between metadata formats is ensured by the use of the Ontology for Media Resources 1.0 as pivot metadata format. This API offers operations to request particular metadata information represented in a certain metadata format related to media resources on the Web. Further it specifies the actual representation of the core properties and the behaviour of this API.

Formats in scope

Refers to the formats in scope of Ontology for Media Resources 1.0.

Formats out of scope

Refers to the Formats out of scope of Ontology for Media Resources 1.0.

Terminology

In this document the terms "Ontology", "Media Resource", "Property", "Mapping" and "Property value types" are to be interpreted as defined in Section 2 of Ontology for Media Resources 1.0.

Design consideration

Before introducing the two example usage scenarios of this API, two modes of operations must be defined: asynchronous and synchronous mode. For this API the asynchronous mode is considered to be used as default where calls return without waiting for the request to finish its execution: a call-back function is provided to be invoked when the request terminates. In contrast to that, the synchronous mode implicates an immediate answer to every request.

We consider two scenarios, where this API could be implemented:

The two scenarios are shown in Figure 1.

Diagram showing 2 scenarios with different usage of the API.

Figure 1: Two scenarios with different usage of this API.

Note: This specification only defines this API for Media Resources. Other components depicted in Figure 1 (e.g., access/extraction/storage of metadata) are not covered.

Scenario 1: User agent
In this scenario, this API is implemented in a user agent (e.g., browser or browser plugin) and exposed as a JavaScript API (using the WebIDL JavaScript binding). Usually, such an implementation is per default an example for an asynchronous processing. Besides the "API for Media Resources 1.0", the user agent includes components for metadata access (and possibly extraction) and mappings for a supported set of formats, e.g., as defined in the property mapping table of the Ontology for Media Resources 1.0 specification. Further, the metadata sources (the media resource and/or metadata document(s)) must be retrievable, while the access (e.g., establish connection, retrieval) to the metadata sources is handled by the user agent.
Scenario 2: Web service
In the second scenario, this API is encapsulated in a Web Service following the principle of synchronous processing. Such an implementation would be typically used by a non-UI client, such as an agent harvesting metadata. However, this API could be also accessed from a user agent, and used the same way as described in scenario 1 with the help of a JavaScript library for accessing the Web Service. In the implementation of the Web Service, this scenario also allows supporting a media repository (e.g. content provider's archive database, movie store). With the help of such a service the user agent could retrieve metadata sources, which might have a custom metadata format not supported by a user agent. In contrast to an integrated component (see scenario 1), an implementation of this API in a web service could do more complex mappings on the fly than a component integrated in a user agent, and can be more flexible (e.g., supporting additional formats).

In both scenarios, this API serves as a mediator between a client application and the actual metadata sources. Interoperability is ensured by defining i) operations for accessing the metadata information, ii) common object structure and iii) API behaviour (e.g., status codes). Following this, an implementation has to implement this stack of components:

Note that, this API provides access to metadata information stored in different metadata formats. As such, different instances of the same property can exist.

API Description

This API defines a number of interfaces using [[WEBIDL]]. These can be grouped in the following categories:

Next, the different interfaces and exposed operations (in case of the MediaResource interfaces and its implementing interfaces) are discussed. Implementations of this API MUST support at least one of the versions and MUST support the other interfaces defined in this document. We have not specified exceptions on the operations or on accessing the attributes. Instead, a status code is returned (in the synchronous API) or can be accessed (in the asynchronous API) in case an error occurs indicating the state of processing (see Section 4.7).

Then, the interfaces for the return types, i.e., MediaAnnotation and its specializations, and MetadataSource are defined.

The IDL fragment in Appendix A of this specification must be interpreted as required for conforming IDL fragments, as described in the “Web IDL” specification. [[WEBIDL]]

MediaResource interface

The MediaResource interface is the core of this API and provides operations to access the metadata properties of a specific media resource. Here, a clear separation between asynchronous and synchronous mode of operation has been achieved by defining two implementing interfaces, the AsyncMediaResource and the SyncMediaResource interface. Objects of these interfaces will be created by calling createMediaResource of the MediaResource interface. The actual connection to a specified metadata source will be created with the execution of the getMediaProperty operation of AsyncMediaResource or SyncMediaResource interface.

short getSupportedModes()
This operation is called to identify the implemented mode. The return codes should be as follows: 1 for asynchronous, 2 for synchronous and 3 for both modes.
MediaResource createMediaResource(in DOMString mediaResource, in optional MetadataSource[] metadataSources, in optional int mode)
This operation instantiates an object of either AsyncMediaResource or SyncMediaResource interface. Further, it allows to set the specific media resource and metadata sources to which this API is applied.
DOMString mediaResource
This attribute must set the specific media resource that should be processed by the API.
optional MetadataSource[] metadataSources
This attribute should specify additional metadata sources.
optional short mode
This attribute should specify the desired mode of operation. 1 for asynchronous and 2 for synchronous mode should be used.

Examples in Javascript

Example for getSupportedModes:


ma = new MediaResource();
var mode = ma.getSupportedModes();

/** Resulting in:
 * { "supportedModes" : 3 }
 */

Example for createMediaResource:


metadataSources = new MetadataSource[2];
metadataSources[0] = new MetadataSource(
                         "http://www.w3.org/2008/WebVideo/Annotations/drafts/metadata_formats/DC_example1.xml","dc");
metadataSources[1] = new MetadataSource(
                         "http://www.w3.org/2008/WebVideo/Annotations/wiki/images/9/93/MAWG-Stockholm-20090626.JPG","exif");

mediaResource = new MediaResource();

if (mediaResource.getSupportedModes() == 1 || mediaResource.getSupportedModes() == 3) {
    aSyncObject = mediaResource.createMediaResource(
                         "http://www.w3.org/2008/WebVideo/Annotations/wiki/images/9/93/MAWG-Stockholm-20090626.JPG",
                         metadataSources, 1);
			     
} else if (mediaResource.getSupportedModes() == 2 || mediaResource.getSupportedModes() == 3)  {
    syncObject = mediaResource.createMediaResource(
                         "http://www.w3.org/2008/WebVideo/Annotations/wiki/images/9/93/MAWG-Stockholm-20090626.JPG",
                         metadataSources, 2);
}

AsyncMediaResource interface

The AsyncMediaResource interface provides a number of operations that allow accessing the metadata of a media resource. By calling the getMediaProperty operation with the argument "title" we can retrieve the title of the corresponding media resource.

Next, we give the Web IDL description of the AsyncMediaResource interface and describe the different operations that are part of it. The mediaResource argument identifies the media resource, for which the implementation of this API should try to find relevant metadata sources. Optionally, references to metadata sources can be passed using an array of objects, each implementing the MetadataSource interface. This interface holds an URI identifying the metadata source (metadataSource) and the name of the actual metadata format (sourceFormat).

In this section the MediaAnnotations interface is used in the interface definitions. It serves as a container to hold general values about properties enabling an iteration over a set of different properties. Its explanation can be found in Section 4.4

void getMediaProperty (DOMString[] propertyNames, PropertyCallback successCallback, ErrorCallback errorCallback, optional DOMString fragment, optional DOMString sourceFormat, optional DOMString subtype, optional DOMString language)
This operation allows retrieval of the value of a specific property, several or all properties in an asynchronous manner. The specific property is passed as an argument and a list of objects is returned that hold the values according to the requested property. These objects implement the MediaAnnotation interface, described in Section 4.4. Depending on the requested property, the returned objects implement a different subtypes (inheriting from the MediaAnnotation interface). Requesting "title" gives back an array of objects implementing the Title interface, requesting "creator" results in objects implementing the Creator interface and so on. These interfaces are described in Section 4.5. An example can be found here.
DOMString[] propertyNames
This argument identifies an array containing the properties for which the values need to be retrieved. For an empty array all properties carrying values will be retrieved. Optional arguments allow refining the request.
PropertyCallback successCallback
This argument holds a callback object for asynchronous requests to the property. The successCallback object implements the PropertyCallback interface and holds a handleEvent operation that needs to be called once all data for the requested property is gathered. This handleEvent operation needs to be called with a new MediaAnnotation array.
ErrorCallback errorCallback
This argument holds a callback object for failure of asynchronous requests to the property. The errorCallback object implements the ErrorCallback interface and holds a handleEvent operation that needs to be called if an attempt fails. This handleEvent operation needs to be called with a new DOMString representing the status code of the error (see Section 4.7 for details).
optional DOMString fragment
This argument contains a URI identifying the specific media fragment for which the metadata is requested. The URI MUST conform to the URI for Media Fragment [[!MEDIA-FRAGMENTS]] specification. This parameter is optional.
optional DOMString sourceFormat
This argument identifies a specific metadata format. It SHOULD use the metadata format identifiers defined in the Ontology for Media Resources 1.0 specification. If a metadata format is defined, only the metadata available in the corresponding metadata format are retrieved. This parameter is optional.
optional DOMString language
This argument allows to identify the language of the metadata. Values for the metadata will only be returned if it is available in the specified language. Recommended best practice is to use BCP 47 [[BCP47]]. This parameter is optional.
void getOriginalMetadata (DOMString sourceFormat, MetadataCallback successCallback, ErrorCallback errorCallback)
This operation allows retrieval of the original metadata according to the specified source format in an asynchronous manner. An example can be found here.
DOMString sourceFormat
This argument identifies a specific metadata format. It SHOULD use the metadata format identifiers defined in the Ontology for Media Resources 1.0 specification. If a metadata format is defined, only the metadata available in the corresponding metadata format are retrieved.
MetadataCallback successCallback
This argument holds a callback object for asynchronous requests for the original metadata. The successCallback object implements the MetadataCallback interface and holds a handleEvent operation that needs to be called once all properties having values are listed. This handleEvent operation needs to be called with a new DOMString array holding the original metadata.
ErrorCallback errorCallback
This argument holds a callback object for failure of asynchronous requests for the original metadata. The errorCallback object implements the ErrorCallback interface and holds a handleEvent operation that needs to be called if an attempt fails. This handleEvent operation needs to be called with a new DOMString representing the status code of the error (see Section 4.7 for details).

Callback interfaces

PropertyCallback interface

The PropertyCallback interface holds a handleEvent operation that needs to be called once all data for the requested property has been gathered.

void handleEvent(MediaAnnotation[] mediaAnnotations)
This operation is called when all data is gathered corresponding to a request for values of one or more properties.
MediaAnnotation[] mediaAnnotations
This argument holds a list of objects with values according to the requested property. These objects implement the MediaAnnotation interface, described in Section 4.4. Depending on the requested property, the returned objects implement a different subtypes (inheriting from the MediaAnnotation interface).

MetadataCallback interface

The MetadataCallback interface holds a handleEvent operation that needs to be called once the requested metadata has been gathered.

void handleEvent(DOMString[] metadata)
This operation is called when all data is gathered corresponding to a request for the original metadata.
DOMString[] metadata
This argument holds a list of DOMStrings representing the original metadata. Note that, multiple metadata instances can exist (e.g., one Dublin core and one MPEG-7 document).

Examples in Javascript

Example for asynchronous getMediaProperty:

aSyncMediaResource = mediaResource.createMediaResource("http://www.imdb.com/title/tt0133152/", new Array(), 1);
aSyncMediaResource.getMediaProperty(["title"], successCallback, errorCallback, "", "", "");
				
function successCallback(MediaAnnotation[] mediaAnnotations) {
    ...
}

/** Resulting in:
 * [ { "Title" : {
 *         "propertyName" : "title",
 *         "value" : "Planet of the apes",
 *         "language" : en-us",
 *         ...
 *         "statusCode" : 200
 *         }
 * },
 * { "Title" : {
 *         "propertyName" : "title",
 *         "value" : "Monkey Planet",
 *         "language" : en-us",
 *         ...,
 *         "statusCode" : 200
 *         }
 * },
 * { ...
 * } ]
 */
		
function errorCallback(DOMString error) {
    ...
}

/** Resulting in:
 * { error: { "statusCode" : 415 } }
 */

Example for asynchronous getOriginalMetadata :

aSyncMediaResource = mediaResource.createMediaResource(
                         "http://www.w3.org/2008/WebVideo/Annotations/wiki/images/9/93/MAWG-Stockholm-20090626.JPG",
                          new Array(), 1);
aSyncMediaResource.getOriginalMetadata("dc", successCallback, errorCallback);

function successCallback(DOMString[] metadata) {
    ...
}

/** Resulting in:
 * [ { "statusCode" : 200
 * },
 * {"originalMetadata" : "<metadata xmlns='http://example.org/myapp/'
 *                                        xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance'
 *                                        xsi:schemaLocation='http://example.org/myapp/ http://example.org/myapp/schema.xsd'
 *                                        xmlns:dc='http://purl.org/dc/elements/1.1/'>
 *                                          <dc:title>DC title</dc:title>
 *                                  </metadata>"
 * } ]
 */

						
function errorCallback(DOMString error) {
   ...
}

/** Resulting in:
 * { error: { "statusCode" : 415 } }
 */

SyncMediaResource interface

The SyncMediaResource interface provides a number of operations to access the metadata of a media resource. Next, we give the Web IDL description of the SyncMediaResource interface for synchronous requests and describe the different operations that are part of it. The MediaResource defines a constructor that can be called to construct the object based on an identifier of the media resource and optionally some metadata sources. The mediaResource argument identifies the media resource, for which the implementation of this API should try to find relevant metadata sources. Optionally, references to metadata sources can be passed using an array of objects, each implementing the MetadataSource interface. This interface holds two attributes, namely an URI identifying the metadata source (metadataSource) and the name of the actual metadata format (sourceFormat). An example, how to create this object can be found here.

MediaAnnotation[] getMediaProperty (DOMString[] propertyNames, optional DOMString fragment, optional DOMString sourceFormat, optional DOMString subtype, optional DOMString language)
This operation allows retrieval of the metadata of a specific property, several or all properties in a synchronous manner. The passed array holds the requested properties and a array of objects is returned. If the array is empty, every property holding values will be requested and returned. The returned objects implement the MediaAnnotation interface (see Section 4.3). Depending on the requested property, the returned objects implement a different subtypes (inheriting from the MediaAnnotation interface). Requesting "title" gives back an array of objects implementing the Title interface, requesting "creator" results in objects implementing the Creator interface and so on. These subtypes are described in Section 4.4. The operation returns a MediaAnnotation array holding the requested properties. If an error occurs during retrieval, a MediaAnnotation object with the corresponding status code (e.g., 400, 404 or 415) will be generated and inserted at the first position of the array. An example can be found here.

In this section the MediaAnnotations interface is used in the interface definitions. It serves as a container to hold general values about properties enabling an iteration over a set of different properties. Its explanation can be found in Section 4.4

DOMString[] propertyNames
This argument holds the requested properties as an array. If the array is empty, each property holding values will be returned.
optional DOMString fragment
This argument contains a URI identifying the specific media fragment for which the metadata is requested. The URI MUST conform to the URI for Media Fragment[[!MEDIA-FRAGMENTS]] specification. This parameter is optional.
optional DOMString sourceFormat
This argument identifies a specific metadata format. It SHOULD use the metadata format identifiers defined in the Ontology for Media Resources 1.0 specification. If a metadata format is defined, only the metadata available in the corresponding metadata format is retrieved. This parameter is optional.
optional DOMString language
This argument allows to identify the language of the metadata. Values for the metadata will only be returned if it is available in the specified language. Recommended best practice is to use BCP 47 [[BCP47]]. This parameter is optional.
DOMString[] getOriginalMetadata(DOMString sourceFormat)
This operation allows retrieval of the original metadata according to the specified source format in a synchronous manner. The operation returns a DOMString array holding the status code of the request at the first and the original metadata at the second position. An example can be found here.
DOMString sourceFormat
This argument identifies a specific metadata format. It SHOULD use the metadata format identifiers defined in the Ontology for Media Resources 1.0 specification. If a metadata format is defined, only the metadata available in the corresponding metadata format is retrieved.

Examples in Javascript

The examples in this section use getMediaProperty() to get an object implementing the MediaAnnotation interface. The noErrorStatus function ensures that no error is present and the requested properties carry values.

We give some JavaScript examples on how to use the synchronous MediaResource interface and it's operations.

Example for synchronous getMediaProperty:

syncMediaResource = mediaResource.createMediaResource("http://www.imdb.com/title/tt0133152/",
                          new Array(), 2);
title = syncMediaResource.getMediaProperty(["title"], "", "", "");

if (noErrorStatus(title[0].statusCode) == true) {
   ...
}						

/** Resulting in:
 * [ { "Title" : {
 *         "propertyName" : "title",
 *         "value" : "Planet of the apes",
 *         "language" : en-us",
 *         ...,
 *         "statusCode" : 200
 *         }
 * },
 * { "Title" : {
 *         "propertyName" : "title",
 *         "value" : "Planet der Affen",
 *         "language" : "de-de",
 *         ...,
 *         "statusCode" : 200
 *         }
 * },
 * { ...
 * } ]
 */

Example for synchronous getOriginalMetadata:

syncMediaResource = mediaResource.createMediaResource("http://www.w3.org/2008/WebVideo/Annotations/wiki/images/9/93/MAWG-Stockholm-20090626.JPG",
                         new Array(), 2);
dcMetadata = syncMediaResource.getOriginalMetadata("DC");

if (noErrorStatus(dcMetadata[0].statusCode) == true) {
    ...
}

/** Resulting in:
 * [ { "statusCode" : 200
 * },
 * {"originalMetadata" : "<metadata xmlns='http://example.org/myapp/'
 *                                        xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance'
 *                                        xsi:schemaLocation='http://example.org/myapp/ http://example.org/myapp/schema.xsd'
 *                                        xmlns:dc='http://purl.org/dc/elements/1.1/'>
 *                                          <dc:title>DC title</dc:title>
 *                                  </metadata>"
 * } ]
 */

MediaAnnotation interface

MediaAnnotation interface is used as the return type of MediaResource.getMediaProperty operation. It is a container to hold general values about properties enabling an iteration over a set of different properties. Depending on the requested property, this interface will be enlarged by more specific attributes.

As several properties are complex types, specific derived types of MediaAnnotation have been defined, added these properties with the appropriate types. However, MediaAnnotation can be used as a generic return type to access a printable string representation of the property (in the value attribute). It also includes a status code. In case of general errors, the first element of the returned MediaAnnotation array contains the global error code, otherwise the status can be given for each of the returned properties.

The following design considerations have been used for specifying the derived types for each of the properties:

attribute DOMString propertyName
The name of the property MUST be specified and SHOULD correspond to the property names defined in the Ontology for Media Resources 1.0 specification.
attribute DOMString value
This attribute MUST be filled with an printable string representation.
attribute DOMString language
This attribute SHOULD hold the language of the metadata. The attribute is empty if language is not applicable for a specific property. Recommended best practice is to use BCP 47 [[BCP47]].
attribute DOMString sourceFormat
This attribute allows to specify the metadata source from which the metadata was retrieved. It SHOULD use the metadata format identifiers defined in the Ontology for Media Resources 1.0 specification.
attribute DOMString fragmentIdentifier
This attribute SHOULD be an URI determining the fragment for which the metadata is relevant.
attribute DOMString mappingType
This attribute specifies the kind of mapping as discussed in the semantic level mappings. The value of this attribute SHOULD be one of the mapping characteristics.
attribute short statusCode
This attribute MUST specify the status code for the associated property (e.g., 264 indicating a structured return value).

Example in JavaScript

The noErrorStatus function ensures that no error is present and the requested properties carry values. The MediaAnnotation interface will be never instantiated - only the implementing subtypes will be created. These MUST be filled at least with the parameters specified in the MediaAnnotation interface and MAY be filled with the specific attributes.

mediaAnnotation = image.getMediaProperty(["title"], "", "", "");

if (noErrorStatus(mediaAnnotation[0].statusCode) == true) {                    
   ...
}

/** Resulting in:
 * [ { "Title" : {
 *         "propertyName" : "title",
 *         "value" : "Gone with the Wind",
 *         "language" : "en-us",
 *         "sourceFormat" : "mpeg7",
 *         "fragmentIdentifier" : "http://www.example.com/video.ogv#t=10,20",
 *         "mappingType" : "Exact match",
 *         "statusCode" : 200
 *         } 
 * } ]

Properties

This section describes the different properties that can be requested through the MediaResource.getMediaProperty() operation. When invoking this operation, objects implementing the MediaAnnotation interface are returned that represent the specified property. All properties are represented with an interface inherited from the MediaAnnotation interface (following the design guidelines described above).

Several of the following return type interfaces can hold the value of the property as both URI (i.e., a pointer to a controlled vocabulary) or as free text. The URI is preferred, and the respective attribute of the return value shall be filled whenever possible (i.e., when the information is included in or can be constructed from the source metadata).

In the following, for each property, a (synchronous) JavaScript example illustrates the usage of the property specific attributes. In any case, the genereal attributes of the MediaAnnotation interface could be also requested.

Identification Properties

Identifier

When the MediaResource.getMediaProperty operation is invoked with "identifier" as a value of the propertyName parameter, an object implementing the Identifier interface is returned representing the identifier property (defined in the Ontology for Media Resources 1.0 specification).

attribute DOMString identifierLink
This attribute holds a URI identifying the media resource.

Example in JavaScript

id = image.getMediaProperty(["identifier"]);
                                     
/** Resulting in:
 * [ { "Identifier" : {
 *         "propertyName" : "identifier",
 *         "identifierLink" : "urn:uuid:36a87260-1102-11df-8a39-0800200c9a66",		    
 *         "statusCode" : 200
 *         } 
 * } ]
 */

Title

When the MediaResource.getMediaProperty operation is invoked with "title" as a value of the propertyName parameter, an object implementing the Title interface is returned representing the title property (defined in the Ontology for Media Resources 1.0 specification).

attribute DOMString titleLabel
This attribute hold the title as a plain string.
attribute DOMString typeLink
This attribute holds the type of the title as a URI.
attribute DOMString typeLabel
This attribute holds the type of the title as a plain string.

Example in JavaScript

title = song.getMediaProperty(["title"]);
		    
/** Resulting in:
 * [ { "Title" : {
 *         "propertyName" : "title",
 *         "titleLabel" : "Artificial Horizon" ,
 *         "typeLink" : "http://www.ebu.ch/metadata/cs/ebu_ObjectTypeCodeCS.xml#21",
 *         "typeLabel" : "Album title",
 *         "statusCode" : 200
 *         }
 * } ]
 */
					

Language

When the MediaResource.getMediaProperty operation is invoked with "language" as a value of the propertyName parameter, an object implementing the Language interface is returned representing the language property (defined in the Ontology for Media Resources 1.0 specification).

attribute DOMString languageLink
This attribute represents the language of the media resource as a URI.
attribute DOMString languageLabel
This attribute represents the language of the media resource as a plain string, which can be filtered on in the getMediaProperty operation. Recommended best practice is to use BCP 47 [[BCP47]].

Example in JavaScript

language = video.getMediaProperty(["language"]);
	
/** Resulting in:
 * [ { "Language" : {
 *         "propertyName" : "language",
 *         "languageLabel" : "en-us",		    
 *         "statusCode" : 200
 *         }
 * } ]
 */

Locator

When the MediaResource.getMediaProperty operation is invoked with "locator" as a value of the propertyName parameter, an object implementing the Locator interface is returned representing the locator property (defined in the Ontology for Media Resources 1.0 specification).

attribute DOMString locatorLink
This attribute specifies the location of the media resource by a URI.

Example in JavaScript

locator = image.getMediaProperty(["locator"]);

/** Resulting in:
 * [ { "Locator" : {
 *         "propertyName" : "locator",
 *         "locatorLink" : "http://www.w3.org/2008/WebVideo/Annotations/wiki/images/9/93/MAWG-Stockholm-20090626.JPG",		    
 *         "statusCode" : 200
 *         } 
 * } ]
 */

Creation Properties

Contributor

When the MediaResource.getMediaProperty operation is invoked with "contributor" as a value of the propertyName parameter, an object implementing the Contributor interface is returned representing the contributor property (defined in the Ontology for Media Resources 1.0 specification).

attribute DOMString contributorLink
This attribute represents the contributor (i.e., the agent making the contribution) as a URI.
attribute DOMString contributorLabel
This attribute represents the contributor (i.e., the agent making the contribution) as a plain string
attribute DOMString roleLink
This attribute represents the role of the contributor as URI.
attribute DOMString roleLabel
This attribute represents the role of the contributor as a plain string.

Example in JavaScript

contributor = video.getMediaProperty(["contributor"]);

/** Resulting in:
 * [ { "Contributor" : {
 *         "propertyName" : "contributor",
 *         "contributorLink" : "http://en.wikipedia.org/wiki/Tim_Burton",
 *         "contributorLabel" : "Tim Burton",
 *         "roleLink" : "http://www.imdb.com/name/nm0000318/",
 *         "roleLabel" : "director",		    
 *         "statusCode" : 200
 *         } 
 * } ]
 */

Creator

When the MediaResource.getMediaProperty operation is invoked with "creator" as a value of the propertyName parameter, an object implementing the Creator interface is returned representing the creator property (defined in the Ontology for Media Resources 1.0 specification).

attribute DOMString creatorLink
This attribute represents the creator (i.e., the agent participating in the creation of the media resource) as a URI.
attribute DOMString creatorLabel
This attribute represents the creator (i.e., the agent participating in the creation of the media resource) as a plain string.
attribute DOMString roleLink
This attribute represents the role of the creator as URI.
attribute DOMString roleLabel
This attribute represents the role of the creator as a plain string.

Example in JavaScript

creator = video.getMediaProperty(["creator"]);

/** Resulting in:
 * [ { "Creator" : {
 *         "propertyName" : "creator",
 *         "creatorLink" : "http://dbpedia.org/resource/William_Shakespeare",
 *         "creatorLabel" : "William Shakespeare",
 *         "roleLink" : "http://www.ebu.ch/metadata/cs/ebu_RoleCodeCS.xml#22.5",
 *         "roleLabel" : "playwright",		    
 *         "statusCode" : 200
 *         }
 * } ]
 */

MADate

When the MediaResource.getMediaProperty operation is invoked with "date" as a value of the propertyName parameter, an object implementing the Date interface is returned representing the date property (defined in the Ontology for Media Resources 1.0 specification). This property has been renamed from "Date" into "MADate" since the appearance of naming conflicts is possible in web applications.

attribute DOMString date
This attribute represents date related to the media resource. A date value MUST be represented using one of the specific date/time data types of XML Schema, depending on the available precision: gYear gYearMonth, date, dateTime, or dateTimeStamp.
attribute DOMString typeLink
This attribute defines the category of date (e.g. creation date, broadcast date, release date, date recorded and date edited) as a URI.
attribute DOMString typeLabel
This attribute defines the category of date (e.g. creation date, broadcast date, release date, date recorded and date edited) as a plain string.

Example in JavaScript

maDate = video.getMediaProperty(["date"]);

/** Resulting in:
 * [ { "MADate" : {
 *         "propertyName" : "date",
 *         "date": "2009-06-26T15:30:00",
 *         "typeLink" : "urn:smpte:ul:06.0E.2B.34.01.01.01.02.07.02.01.10.02.03.00.00",
 *         "typeLabel" : "modification date",
 *         "statusCode" : 200
 *         }
 * } ]
 */
					

Location

When the MediaResource.getMediaProperty operation is invoked with "location" as a value of the propertyName parameter, an object implementing the Location interface is returned representing the location property (defined in the Ontology for Media Resources 1.0 specification).

attribute DOMString locationLink
This attribute identifies the location as a URI.
attribute DOMString locationLabel
This attribute identifies the location by its name as a plain string.
attribute double longitude
This attribute holds the longitude of the location, w.r.t. the coordinate system specified by the coordiateSystem attribute (default is WGS84).
attribute double latitude
This attribute holds the latitude of the location, w.r.t. the coordinate system specified by the coordiateSystem attribute (default is WGS84).
attribute double altitude
This attribute holds the altitude of the location, w.r.t. the coordinate system specified by the coordiateSystem attribute (default is WGS84).
attribute DOMString coordinateSystemLabel
This attribute identified the coordinate system used by its name.
attribute DOMString coordinateSystemLink
This attribute identified the coordinate system used by a URI.

Example in JavaScript

location = video.getMediaProperty(["location"]);

/** Resulting in:
 * [ { "Location" : {
 *         "propertyName" : "location",
 *         "locationLink" : "http://en.wikipedia.org/wiki/San_Jose,_California",
 *         "locationLabel" : "San Jose",
 *         "longitude" : 37.33986481118008,
 *         "latitude" : -121.88507080078125,
 *         "altitude" : 0,
 *         "coordinateSystemLabel" : "WGS84",
 *         "coordinateSystemLink" : "http://www.w3.org/2003/01/geo/wgs84_pos#Point",
 *         "statusCode" : 200
 *         }
 * } ]
 */
					

Content Properties

Description

When the MediaResource.getMediaProperty operation is invoked with "description" as a value of the propertyName parameter, an object implementing the Description interface is returned representing the description property (defined in the Ontology for Media Resources 1.0 specification).

attribute DOMString descriptionLabel
This attribute contains a description of the content of the media resource.

Example in Javascript

description = image.getMediaProperty(["description"]);

/** Resulting in:
 * [ { "Description" : {
 *         "propertyName" : "description",
 *         "descriptionLabel" : "Group picture of the W3C MAWG at the F2F meeting in Stockholm.",
 *         "statusCode" : 200
 *         }
 * } ]
 */
					

Keyword

When the MediaResource.getMediaProperty operation is invoked with "keyword" as a value of the propertyName parameter, an object implementing the Keyword interface is returned representing the keyword property (defined in the Ontology for Media Resources 1.0 specification).

attribute DOMString keywordLabel
This attribute contains a keyword describing the content as a plain string.
attribute DOMString keywordLink
This attribute contains a URI representing a keyword describing the content.

Example in Javascript

keyword = image.getMediaProperty(["keyword"]);

/** Resulting in:
 * [ { "Keyword" : {
 *         "propertyName" : "keyword",
 *         "keywordLabel" : "meeting with people from outside the organisation",
 *         "keywordLink" : "http://sw.opencyc.org/2008/06/10/concept/en/MeetingWithOrganizationalOutsiders",		    
 *         "statusCode" : 200
 *         }
 * }, 
 * { "Keyword" : {
 *         "propertyName" : "keyword",
 *         "keywordLabel" : "standardisation",
 *         "keywordLink" : "http://purl.org/vocabularies/princeton/wn30/synset-standardization-noun-1",		    
 *         "statusCode" : 200
 *         } 
 * } ]
 */
					

Genre

When the MediaResource.getMediaProperty operation is invoked with "genre" as a value of the propertyName parameter, an object implementing the Genre interface is returned representing the genre property (defined in the Ontology for Media Resources 1.0 specification).

attribute DOMString genreLabel
This attribute represents the genre of the media resource as a plain string.
attribute DOMString genreLink
This attribute represents the genre of the media resource as a URI.

Example in Javascript

genre = image.getMediaProperty(["genre"]);

/** Resulting in:
 * [ { "Genre" : {
 *         "propertyName" : "genre",
 *         "genreLabel" : "Sports",
 *         "genreLink" : "http://www.ebu.ch/metadata/cs/ebu_ContentGenreCS.xml#3.1.1.9"		    
 *         "statusCode" : 200
 *         } 
 * } ]
 */

Rating

When the MediaResource.getMediaProperty operation is invoked with "rating" as a value of the propertyName parameter, an object implementing the Rating interface is returned representing the rating property (defined in the Ontology for Media Resources 1.0 specification).

attribute double ratingValue
This attribute contains the value of the rating.
attribute DOMString ratingSystemLabel
This attribute identifies the rating system by a plain string.
attribute DOMString ratingSystemLink
This attribute identifies the rating system as a URI.
attribute double minimum
This attribute specifies the minimum rating value in the rating system.
attribute double maximum
This attribute specifies the maximum rating value in the rating system.

Example in Javascript

rating = image.getMediaProperty(["rating"]);

/** Resulting in:
 * [ { "Rating" : {
 *         "propertyName" : "rating",
 *         "ratingValue" : 10.0,
 *         "ratingSystemLabel" : "John Doe",
 *         "ratingSystemLink" : "http://individuals.example.com/JohnDoe",
 *         "minimum" : 0,
 *         "maximum" : 10.0,		    
 *         "statusCode" : 200
 *         } 
 * } ]
 */

Relational Properties

Relation

When the MediaResource.getMediaProperty operation is invoked with "relation" as a value of the propertyName parameter, an object implementing the Relation interface is returned representing the relation property (defined in the Ontology for Media Resources 1.0 specification).

attribute DOMString targetLink
This attribute identifies the related resource by a URI.
attribute DOMString targetLabel
This attribute identifies the related resource by a plain string.
attribute DOMString typeLink
This attribute specifies the type of relationship by a URI.
attribute DOMString typeLabel
This attribute specifies the type of relationship by a plain string.

Example in Javascript

relation = image.getMediaProperty(["relation"]);

/** Resulting in:
 * [ { "Relation" : {
 *         "propertyName" : "relation",
 *         "targetLink" : "http://www.w3.org/2008/WebVideo/Annotations/wiki/Image:MAWG-Stockholm-20090626_thumb.JPG",
 *         "targetLabel" : "Group picture of MAWG in Stockholm",
 *         "typeLink" : "http://www.ebu.ch/metadata/cs/ebu_HowRelatedCS.xml#19",
 *         "typeLabel" : "thumbnail",		    
 *         "statusCode" : 200
 *         }
 * } ]
 */

Collection

When the MediaResource.getMediaProperty operation is invoked with "collection" as a value of the propertyName parameter, an object implementing the Collection interface is returned representing the collection property (defined in the Ontology for Media Resources 1.0 specification).

attribute DOMString collectionLink
This attribute holds the name of the collection from which the media resource originates as URI.
attribute DOMString collectionLabel
This attribute holds the name of the collection from which the media resource originates as a plain string.

Example in Javascript

collection = image.getMediaProperty(["collection"]);

/** Resulting in:
 * [ { "Collection" : {
 *         "propertyName" : "collection",
 *         "collectionLink" : "http://individuals.example.com/JohnDoe/myWorkPictures/",
 *         "collectionLabel" : "My Work Pictures",		    
 *         "statusCode" : 200
 *         } 
 * } ]
 */

Rights Properties

Copyright

When the MediaResource.getMediaProperty operation is invoked with "copyright" as a value of the propertyName parameter, an object implementing the Copyright interface is returned representing the copyright property (defined in the Ontology for Media Resources 1.0 specification).

attribute DOMString copyrightLabel
This attribute contains the copyright statement as a plain string.
attribute DOMString holderLabel
This attribute identifies the copyright holder by a plain string.
attribute DOMString holderLink
This attribute identified the copyright holder by a URI.

Example in Javascript

copyright = image.getMediaProperty(["copyright"]);

/** Resulting in:
 * [ { "Copyright" : {
 *         "propertyName" : "copyright",
 *         "copyrightLabel" : "All images in the collection are copyrighted by John Doe.",
 *         "holderLabel" : "John Doe",
 *         "holderLink" : "http://individuals.example.com/JohnDoe",		    
 *         "statusCode" : 200
 *         } 
 * } ]
 */

Policy

When the MediaResource.getMediaProperty operation is invoked with "policy" as a value of the propertyName parameter, an object implementing the Policy interface is returned representing the policy property (defined in the Ontology for Media Resources 1.0 specification).

attribute DOMString statementLink
This attribute contains a URI of the policy statement.
attribute DOMString statementLabel
This attribute contains a plain string of the policy statement.
attribute DOMString typeLink
This attribute identifies the type of the policy as a URI.
attribute DOMString typeLabel
This attribute identifies the type of the policy as a URI as a plain string.

Example in Javascript

policy = image.getMediaProperty(["policy"]);

/** Resulting in:
 * [ { "Policy" : {
 *         "propertyName" : "policy",
 *         "statementLink" : "http://creativecommons.org/licenses/by/2.5/",
 *         "statementLabel" : "Attribution 2.5 Generic (CC BY 2.5)",
 *         "typeLabel" : "license",		    
 *         "statusCode" : 200
 *         }
 * } ]
 */

Distribution Properties

Publisher

When the MediaResource.getMediaProperty operation is invoked with "publisher" as a value of the propertyName parameter, an object implementing the Publisher interface is returned representing the publisher property (defined in the Ontology for Media Resources 1.0 specification).

attribute DOMString publisherLink
This attribute represents the publisher as a URI.
attribute DOMString publisherLabel
This attribute represents the publisher as a plain string.

Example in Javascript

publisher = image.getMediaProperty(["publisher"]);

/** Resulting in:
 * [ { "Publisher" : {
 *         "propertyName" : "publisher",
 *         "publisherLabel" : "ACME",
 *         "publisherLink" : "http://company.example.com/ACME",		    
 *         "statusCode" : 200
 *         } 
 * } ]
 */

TargetAudience

When the MediaResource.getMediaProperty operation is invoked with "targetAudience" as a value of the propertyName parameter, an object implementing the TargetAudience interface is returned representing the targetAudience property (defined in the Ontology for Media Resources 1.0 specification).

attribute DOMString audienceLink
This attribute identifies the target audience by a URI.
attribute DOMString audienceLabel
This attribute identifies the target audience by a plain string.
attribute DOMString classificationSystemLink
This attribute specifies the classification system by a URI.
attribute DOMString classificationSystemLabel
This attribute specifies the classification system by a plain string.

Example in Javascript

targetAudience = image.getMediaProperty(["targetAudience"]);

/** Resulting in:
 * [ { "TargetAudience" : {
 *         "propertyName" : "targetAudience",
 *         "audienceLink" : "http://www.mpaa.org/ratings/what-each-rating-means#NC-17",
 *         "audienceLabel" : "No One 17 and Under Admitted",
 *         "classificationSystemLink" : "http://www.mpaa.org/ratings",
 *         "classificationSystemLabel" : "MPAA",		    
 *         "statusCode" : 200
 *         }
 * } ]
 */

Fragments Properties

Fragment

When the MediaResource.getMediaProperty operation is invoked with "fragment" as a value of the propertyName parameter, an object implementing the Fragment interface is returned representing the fragment property (defined in the Ontology for Media Resources 1.0 specification).

attribute DOMString identifier
This attribute identifies the fragment as Media Fragment URI (temporal, spatial or track).
attribute DOMString roleLink
This attribute identifies the role of the fragment as a URI, which can be filtered on in the getMediaProperty operation.
attribute DOMString roleLabel
This attribute identifies the role of the fragment as a plain string, which can be filtered on in the getMediaProperty operation.

Example in Javascript

fragment = movie.getMediaProperty(["fragment"]);

/** Resulting in:
 * [ { "Fragment" : {
 *         "propertyName" : "fragment",
 *         "identifier" : "http://www.example.com/video.ogv#t=10,20",
 *         "roleLabel" : "chapter",		    
 *         "statusCode" : 200
 *         }
 * } ]
 */

NamedFragment

When the MediaResource.getMediaProperty operation is invoked with "namedFragment" as a value of the propertyName parameter, an object implementing the NamedFragment interface is returned representing the namedFragment property (defined in the Ontology for Media Resources 1.0 specification).

attribute DOMString identifier
This attribute identifies a named fragment by a Media Fragment URI.
attribute DOMString label
This attribute contains a plain text label of a named media fragment, which can be used to contruct a Media Fragment URI fro a named fragment.

Example in Javascript

namedFragment = movie.getMediaProperty(["namedFragment"]);

/** Resulting in:
 * [ { "NamedFragment" : {
 *         "propertyName" : "namedFragment",
 *         "identifier" : "http://www.example.com/video.ogv#t=30,35",
 *         "label" : "kissScene",
 *         "statusCode" : 200
 *         } 
 * } ]
 */

Technical Properties

FrameSize

When the MediaResource.getMediaProperty operation is invoked with "frameSize" as a value of the propertyName parameter, an object implementing the FrameSize interface is returned representing the frameSize property (defined in the Ontology for Media Resources 1.0 specification).

attribute double width
This attribute represents the width of the frame.
attribute double height
This attribute represents the height of the frame.
attribute DOMString unit
This attribute represents the unit of the frame width/height. The default value is pixels.

Example in Javascript

frameSize = image.getMediaProperty(["frameSize"]);

/** Resulting in:
 * [ { "FrameSize" : {
 *         "propertyName" : "framesize",
 *         "width" : 3072,
 *         "height" : 2304,
 *         "unit" : "pixels",		    
 *         "statusCode" : 200
 *         } 
 * } ]
 */

Compression

When the MediaResource.getMediaProperty operation is invoked with "compression" as a value of the propertyName parameter, an object implementing the Compression interface is returned representing the compression property (defined in the Ontology for Media Resources 1.0 specification).

attribute DOMString compressionLink
This attribute specifies the compression type of the media resource by a URI.
attribute DOMString compressionLabel
This attribute specifies the compression type of the media resource as a plain string.

Example in Javascript

compression = video.getMediaProperty(["compression"]);

/** Resulting in:
 * [ { "Compression" : {
 *         "propertyName" : "compression",
 *         "compressionLabel" : "H.264/AVC",
 *         "compressionLink" : "urn:example-org:codingnames2010#ITU-H264",		    
 *         "statusCode" : 200
 *         } 
 * } ]
 */

Duration

When the MediaResource.getMediaProperty operation is invoked with "duration" as a value of the propertyName parameter, an object implementing the Duration interface is returned representing the duration property (defined in the Ontology for Media Resources 1.0 specification).

attribute double duration
This attribute represents the duration of the media resource (in seconds) as an double value.

Example in Javascript

duration = video.getMediaProperty(["duration"]);
		    
/** Resulting in:
 * [ { "Duration" : {
 *         "propertyName" : "duration",
 *         "duration" : 3600,		    
 *         "statusCode" : 200
 *         } 
 * } ]
 */

Format

When the MediaResource.getMediaProperty operation is invoked with "format" as a value of the propertyName parameter, an object implementing the Format interface is returned representing the format property (defined in the Ontology for Media Resources 1.0 specification).

attribute DOMString formatLink
This attribute identifies the MIME type of the media resource by a URI.
attribute DOMString formatLabel
This attribute specifies the MIME type of the media resource.

Example in Javascript

format = image.getMediaProperty(["format"]);

/** Resulting in:
 * [ { "Format" : {
 *         "propertyName" : "format",
 *         "formatLabel" : "image/jpeg",
 *         "formatLink" : "http://dbpedia.org/resource/JPEG",		    
 *         "statusCode" : 200
 *         } 
 * } ]
 */

SamplingRate

When the MediaResource.getMediaProperty operation is invoked with "samplingRate" as a value of the propertyName parameter, an object implementing the SamplingRate interface is returned representing the samplingRate property (defined in the Ontology for Media Resources 1.0 specification).

attribute double samplingRate
This attribute specifies the samplingrate (in Hz) as a double.

Example in Javascript

samplingrate = audio.getMediaProperty(["samplingRate"]);

/** Resulting in:
 * [ { "SamplingRate" : {
 *         "propertyName" : "samplingRate",
 *         "samplingRate" : 44100,		    
 *         "statusCode" : 200
 *         } 
 * } ]
 */

FrameRate

When the MediaResource.getMediaProperty operation is invoked with "frameRate" as a value of the propertyName parameter, an object implementing the FrameRate interface is returned representing the frameRate property (defined in the Ontology for Media Resources 1.0 specification).

attribute double frameRate
This attribute specifies the framerate (in fps) as a double value.

Example in Javascript

framerate = video.getMediaProperty(["frameRate"]);

/** Resulting in:
 * [ { "FrameRate" : {
 *         "propertyName" : "frameRate",
 *         "frameRate" : 30,		    
 *         "statusCode" : 200
 *         } 
 * } ]
 */

AverageBitRate

When the MediaResource.getMediaProperty operation is invoked with "averageBitRate" as a value of the propertyName parameter, an object implementing the AverageBitRate interface is returned representing the averageBitRate property (defined in the Ontology for Media Resources 1.0 specification).

attribute double averageBitRate
This attribute specifies the average bitrate (in kbps) as a double value.

Example in Javascript

bitrate = video.getMediaProperty(["averageBitRate"]);

/** Resulting in:
 * [ { "AverageBitRate" : {
 *         "propertyName" : "averageBitRate",
 *         "averageBitRate" : 45.06,		    
 *         "statusCode" : 200
 *         }
 * } ]
 */

NumTracks

When the MediaResource.getMediaProperty operation is invoked with "numTracks" as a value of the propertyName parameter, an object implementing the NumTracks interface is returned representing the numTracks property (defined in the Ontology for Media Resources 1.0 specification).

attribute short number
This attribute specifies the number of tracks as an integer value.
attribute DOMString typeString
This attribute specifies the type of the tracks that are counted as a plain string (e.g., audio, subtitle).

Example in Javascript

numTracks = video.getMediaProperty(["numTracks"]);

/** Resulting in:
 * [ { "NumTracks" : {
 *         "propertyName" : "numTracks",
 *         "number" : 2,
 *         "typeString" : "audio",		    
 *         "statusCode" : 200
 *         }
 * } ]
 */

MetadataSource interface

MetadataSource interface is used to identify other metadata sources.

attribute DOMString metadataSource
An URI identifying the metadata source.
attribute DOMString sourceFormat
The name of the actual metadata format. It SHOULD use the metadata format identifiers defined in the Ontology for Media Resources 1.0 specification.

Examples in Javascript


metadataSources = new MetadataSource("http://www.w3.org/2008/WebVideo/Annotations/drafts/metadata_formats/DC_example1.xml","dc");

API Status Codes

This section introduces a set of status codes for the defined API to indicate the system behavior. As described in section 4.4, the status code is returned as one of the attributes of the MediaAnnotation object returned by a method call to the API. These status codes are used on the API level, and applied to either client side or server side implementations.

Later versions of this document may include additional status codes.

Numerical Code Textual Description Example
200 OK property delivered correctly
204 No Content property retrieved without content
206 Partial Content only a subset of the available data stored in the result set
400 Bad Request syntactical error
404 Not Found the queries resource is not found
415 Unsupported Media Type get duration call on an image data store
462 Property not defined in Source Format location is not defined in MediaRSS
500 Internal Server Error internal library (e.g., extractor) crashes
562 Property not supported only a subset of properties implemented

Usage examples

Usage as JavaScript API

This part illustrates some examples how to use this API using JavaScript in actual implementations. Moreover, in these examples it is assumed that the implementation of this API knows where to find the metadata that corresponds to a specific media resource (if necessary the location of the metadata can be configured by the use of the MetadataSource interface). The implementation should provide the mappings of different metadata formats to the core properties of the Ontology for Media Resources 1.0 specification.

Example 1: Return the name of the director of the movie "Apocalypse now".
			
//search the video array for the one with title "Apocalypse now" 
for (var i = 0; i < mediaResourceVideoArray.length; i++) { 

    //request for the titles of the video, the variable "titles"
    //will be filled with an array of MediaAnnotation objects. 
    titles = mediaResourceVideoArray[i].getMediaProperty(["title"], "", "", ""); 
    
    //check if the request is finished correctly
    if (noErrorStatus(titles[0].statusCode) == true) {

        for (var j = 0; j < titles.length; j++) { 

            //check if the title matches 
            if (titles[j].titleLabel == "Apocalypse Now") {

                //request for the director of the video, the variable "results" 
                //will be filled with an array of MediaAnnotation objects. 
                tempResults = mediaResourceVideoArray[i].getMediaProperty(["contributor"], "", "", "");

		for (var k = 0; k < tempResults.length; k++) {
                    if (tempResults[i].roleLabel == "director") {
                        result = tempResults[i];
		        break;
		    }
		}  
            } 
        } 
    }
}

/** Resulting in:
 * [ { "Contributor" : {
 *         "propertyName" : "contributor",
 *         "value" : "Francis Ford Coppola",
 *         ...,		    
 *         "statusCode" = 200
 *         }
 * } ]
 */	
Example 2: Retrieve the title of the second song from the album "Joshua Tree" by U2.
//get the id of the second song using the fragments property 
tracks = albumMediaResource.getMediaProperty(["fragment"], "", "", "");
trackIdentifier = tracks[1].identifier; 

//use this identifier to get the mediaResource object that represents the track 
mediaResource = new MediaResource(); 
if (mediaResource.getSupportedModes() == 2 || mediaResource.getSupportedModes() == 3) {
    syncMediaResource = mediaResource.createMediaResource(trackIdentifier, new Array(), 2);
}

//get the title of the track 
title = syncMediaResource.getMediaProperty(["title"], "", "", "");

/** Resulting in:
 * [ { "Title" : {
 *         "propertyName" : "title",
 *         "value" : "I Still Haven't Found What I'm Looking For",
 *         ...,		    
 *         "statusCode" = 200	  
 *         } 
 * } ]
 */
Example 3: Return the genre of the movie "Apocalypse Now".
genre = movie.getMediaProperty(["genre"], "", "", "en-us"); 

/** Resulting in: 
 * [ { "Genre" : {
 *         "propertyName" : "genre",
 *         "value" : "Action",
 *         ...,		    
 *         "statusCode" = 200
 *         }
 * },
 * { "Genre" : {
 *         "propertyName" : "genre",
 *         "value" : "Drama",
 *         ...,		    
 *         "statusCode" = 200
 *         }
 * },
 * { ...
 *  } ]
 */

Usage as Web Service

This part illustrates how this API could be implemented using web services. Note that, Web IDL currently does not provide bindings for web services. The given examples correspond to the examples given in Section 4.5 for each property.

The following examples illustrate how to request values for the different properties.

Security Considerations

This specification defines a API to access metadata information related to media resources on the Web. These APIs will provide means for requesting metadata information, which can already be accessed in one or different formats, either as separate document or embedded in media resources. As such, this API introduces no additional security issue.

One should nevertheless note that some metadata could be used to access personal information about someone without declaration of agreement. For example, temporal and geographic information about a media resource could indirectly provide information about its creator.

There are related activities and technical documents in W3C working on this topics, such as Policy Requirements [[POLICY-REQS]] in DAP WG, ODRL 1.1 [[ODRL11]], P3P 1.1 [[P3P11]] and PLING Wiki [[PLING-WIKI]].

Web IDL description

Follow this link to download the WebIDL description as IDL file.

module mawg {

    interface MediaResource {
        short getSupportedModes();
        MediaResource createMediaResource(in DOMString mediaResource,
                          in optional MetadataSource[] metadataSources, in optional short mode);
    };

    interface AsyncMediaResource : MediaResource {
        void getMediaProperty(in DOMString[] propertyNames, in PropertyCallback successCallback,
                          in ErrorCallback errorCallback, in optional DOMString fragment,
                          in optional DOMString sourceFormat, in optional DOMString language );
        void getOriginalMetadata (in DOMString sourceFormat, in MetadataCallback successCallback,
                          in ErrorCallback errorCallback);
    };

    interface PropertyCallback {
        void handleEvent (in MediaAnnotation[] mediaAnnotations);
    };

    interface MetadataCallback {
        void handleEvent (in DOMString[] metadata);
    };

    interface ErrorCallback {
        void handleEvent (in DOMString errorStatus);
    };
    
    interface SyncMediaResource : MediaResource {
        MediaAnnotation[] getMediaProperty(in DOMString[] propertyNames,
                            in optional DOMString fragment, in optional DOMString sourceFormat,
                            in optional DOMString language);
        DOMString[] getOriginalMetadata (in DOMString sourceFormat);
    };
    
    interface MetadataSource {
        attribute DOMString metadataSource;
        attribute DOMString sourceFormat;
    };
    
    interface MediaAnnotation {
        attribute DOMString propertyName;
        attribute DOMString value;
        attribute DOMString language;
        attribute DOMString sourceFormat;
        attribute DOMString fragmentIdentifier;
        attribute DOMString mappingType;
        attribute short     statusCode;
    };

    interface Identifier : MediaAnnotation {
        attribute DOMString identifierLink;
    };

    interface Title : MediaAnnotation {
        attribute DOMString titleLabel;
        attribute DOMString typeLink;
        attribute DOMString typeLabel;
    };

    interface Language : MediaAnnotation {
        attribute DOMString languageLink;
        attribute DOMString languageLabel;
    };  

    interface Locator : MediaAnnotation {
        attribute DOMString locatorLink;
    };

    interface Contributor : MediaAnnotation {
        attribute DOMString contributorLink;
        attribute DOMString contributorLabel;
        attribute DOMString roleLink;
        attribute DOMString roleLabel;
    };

    interface Creator : MediaAnnotation {
        attribute DOMString creatorLink;
        attribute DOMString creatorLabel;
        attribute DOMString roleLink;
        attribute DOMString roleLabel;
    };

    interface MADate : MediaAnnotation {
        attribute DOMString date; 
        attribute DOMString typeLink;
        attribute DOMString typeLabel;
    };

    interface Location : MediaAnnotation {
        attribute DOMString locationLink;
        attribute DOMString locationLabel;
        attribute double    longitude;
        attribute double    latitude;
        attribute double    altitude;
        attribute DOMString coordinateSystemLabel;
        attribute DOMString coordinateSystemLink;
    };

    interface Description : MediaAnnotation {
        attribute DOMString descriptionLabel;
    };

    interface Keyword : MediaAnnotation {
        attribute DOMString keywordLink;
        attribute DOMString keywordLabel;
    };

    interface Genre : MediaAnnotation {
        attribute DOMString genreLink;
        attribute DOMString genreLabel;
    };

    interface Rating : MediaAnnotation {
        attribute double ratingValue;
        attribute DOMString ratingSystemLink;
        attribute DOMString ratingSystemLabel;
        attribute double    min;
        attribute double    max; 
    };

    interface Relation : MediaAnnotation {
        attribute DOMString targetLink;
        attribute DOMString targetLabel;
        attribute DOMString typeLink;
        attribute DOMString typeLabel;
    };

    interface Collection : MediaAnnotation {
        attribute DOMString collectionLink;
        attribute DOMString collectionLabel;
    };

    interface Copyright : MediaAnnotation {
        attribute DOMString copyrightLabel;
        attribute DOMString holderLink;
        attribute DOMString holderLabel;
    };

    interface Policy : MediaAnnotation {
        attribute DOMString statementLink;
        attribute DOMString statementLabel;
        attribute DOMString typeLink;
        attribute DOMString typeLabel;
    };

    interface Publisher : MediaAnnotation {
        attribute DOMString publisherLink;
        attribute DOMString publisherLabel;
    };

    interface TargetAudience : MediaAnnotation {
        attribute DOMString audienceLink;
        attribute DOMString audienceLabel;
        attribute DOMString classificationSystemLink;
        attribute DOMString classificationSystemLabel;
    };

    interface Fragment : MediaAnnotation {
        attribute DOMString identifier;
        attribute DOMString roleLink;
        attribute DOMString roleLabel;
    };

    interface NamedFragment : MediaAnnotation {
        attribute DOMString identifier;
        attribute DOMString label;
    };

    interface FrameSize : MediaAnnotation {
        attribute double width;
        attribute double height;
        attribute DOMString unit;
    };

    interface Compression : MediaAnnotation {
        attribute DOMString compressionLink;
        attribute DOMString compressionLabel;
    };

    interface Duration : MediaAnnotation {
        attribute double duration;
    };

    interface Format : MediaAnnotation {
        attribute DOMString formatLink;
        attribute DOMString formatLabel;
    };

    interface SamplingRate : MediaAnnotation {
        attribute double samplingRate;
    };

    interface FrameRate : MediaAnnotation {
        attribute double frameRate;
    }; 

    interface AverageBitRate : MediaAnnotation {
        attribute double averageBitRate;
    };

    interface NumTracks : MediaAnnotation {
        attribute short  number;
        attribute DOMString typeString;
    };
		
};
			

Change log

Note: The following subsections lists all significant changes applied to the API for Media Resources 1.0 specification received in LC.

-- General changes ---

---[LC 2406] 2001-09-10 ---

---[LC 2410] 2001-09-10 ---

---[LC 2419] 2001-09-10 ---

---[LC 2394] 2001-09-10 ---

The following subsection lists all significant changes applied to the API for Media Resources 1.0 specification. These have been decided during the 10th Face-to-face meeting hosted by Apple in Silicon Valley, Ca, USA.

The following subsection lists all significant changes applied to the API for Media Resources 1.0 specification. These have been decided during the 12th Face-to-face meeting hosted by JOANNEUM, Graz, Austria.

Acknowledgements

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 (JOANNEUM RESEARCH), Tobias Bürger ((public) Invited expert), Eric Carlson (Apple, Inc.), Pierre-Antoine Champin (Université de Lyon), Ashish Chawla ((public) Invited expert), Jaime Delgado (Universitat Politècnica de Catalunya), Jean-Pierre Evain ((public) Invited expert), Martin Höffernig (JOANNEUM RESEARCH), Philip Jägenstedt (Opera Software), Ralf Klamma ((public) Invited expert), WonSuk Lee (Samsung Electronics Co., Ltd.), 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), Chris Poppe (IBBT), Victor Rodríguez (Universitat Politècnica de Catalunya), Felix Sasaki (Potsdam University of Applied Sciences), David Singer (Apple, Inc.), Florian Stegmaier ((public) Invited expert), John Strassner ((public) Invited expert), Joakim Söderberg (ERICSSON), Mari Carmen Sutárez-Figueroa ((public) Invited expert) Thai Wey Then (Apple, Inc.), Ruben Tous (Universitat Polittécnica de Catalunya), Raphaël Troncy (EURECOM), 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.