Method for evaluating xpath-like fragment identifiers of audio-visual content

• US 20060020631A1
• Filed: 07/15/2005
• Published: 01/26/2006
• Est. Priority Date: 07/16/2004
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Lucie Amielh, Myriam Elisa, Cheong Wan, Ernest Yiu
• Granted Patent: US 7,984,037 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G06F 16/745 the internal structure of a single video sequence
• CPC Class Codes: G11B 27/105 of operating discs
• CPC Class Codes: Y10S 707/913 Multimedia

Abstract

A method of retrieving a plurality of resource fragments from a audio-visual resource that is encoded using a hierarchical addressing model for the class of resources of which the audio-visual resource is a member is disclosed. The method comprises inputting a URI reference (1407) comprising a Universal Resource Identifier (1401) and a complex fragment identifier (1402) comprising a plurality of audio-visual resource specific location steps. Thereafter the method comprises a step of locating the audio-visual resource using the Universal Resource Name, and establishing (2023) a logical representation (2040) of the structure of the audio-visual resource. Then the method iteratively evaluates the fragment identifier location steps (1110) against the logical representation (2040) to resolve the complex fragment identifier (1402) into a set of explicit fragment references (1406) configured to explicitly address each of the plurality of resource fragments.

Claims

1. A method of retrieving a plurality of resource fragments from a audio-visual resource that is encoded using a hierarchical addressing model for the class of resources of which the audio-visual resource is a member, the method comprising the steps of:

inputting a URI reference comprising a Universal Resource Identifier and a complex fragment identifier comprising a plurality of audio-visual resource specific location steps;

locating the audio-visual resource using the Universal Resource Identifier;

establishing a logical representation of the structure of the audio-visual resource; and

iteratively evaluating the fragment identifier location steps against the logical representation to resolve the complex fragment identifier into a set of explicit fragment references configured to explicitly address each of the plurality of resource fragments of the audio-visual resource.

2. A method according to claim 1, wherein:

the logical representation is a tree of nodes derived from an XML equivalent document representation of the audio-visual resource;

each said location step comprises an axis, a node test and zero or more predicates; and

the method further comprises the step of representing the XML equivalent document as a tree of nodes; and

the iteratively evaluating step comprises the steps of;

establishing a set of said nodes dependent upon a current location step;

projecting the currently established node set to the axis specified by the current location step;

evaluating the node test of the current location step to select the projections of the nodes on the axis;

applying the predicate to refine the selected node set; and

repeating the establishing, projecting, evaluating and applying steps for all the location steps in the complex fragment identifier, to thereby resolve the complex fragment identifier into said set of explicit fragment references.

3. A method according to claim 2, wherein the iteratively evaluating step is performed by an XPath evaluator that is extended by incorporation of node-tests and predicate functions necessary to support spatio-temporal axes of the hierarchical addressing model for the class of resources of which the audio-visual resource is a member.

4. A method according to claim 3, wherein said extension to the XPath evaluator comprises:

addition of at least one of XML attributes and XML elements to the node set representing the explicit fragment references to denote a time point and a time interval.

5. A method according to claim 3, wherein said extension to the XPath evaluator comprises:

addition of at least one of XML attributes and elements to the node set representing the explicit fragment references to denote shape, spatial location, spatial extent and/or spatial transformation over time.

6. An apparatus for retrieving a plurality of resource fragments from a audio-visual resource that is encoded using a hierarchical addressing model for the class of resources of which the audio-visual resource is a member, the apparatus comprising:

means for inputting a URI reference comprising a Universal Resource Name and a complex fragment identifier comprising a plurality of audio-visual resource specific location steps;

means for locating the audio-visual resource using the Universal Resource Name;

means for establishing a logical representation of the structure of the audio-visual resource; and

means for iteratively evaluating the fragment identifier location steps against the logical representation to resolve the complex fragment identifier into a set of explicit fragment references configured to explicitly address each of the plurality of resource fragments.

7. An apparatus according to claim 6, wherein:

the logical representation is an XML equivalent document representation of the audio-visual resource;

each said location step comprises an axis, a node test and zero or more predicates; and

the means for the iterative evaluation step comprises;

means for representing the XML equivalent document as a tree of nodes;

means for establishing a set of said nodes dependent upon a current location step;

means for projecting the currently established node set to the axis specified by the current location step;

means for evaluating the node test of the current location step to select the projections of the nodes on the axis;

means for applying the predicate to refine the selected node set; and

means for repeating the establishing, projecting, evaluating and applying steps for all the location steps in the complex fragment identifier, to thereby resolve the complex fragment identifier into said set of explicit fragment references.

8. An apparatus for retrieving a plurality of resource fragments from a audio-visual resource that is encoded using a hierarchical addressing model for the class of resources of which the audio-visual resource is a member, the apparatus comprising:

a memory for storing a program; and

a processor for executing the program, said program comprising;

code for inputting a URI reference comprising a Universal Resource Name and a complex fragment identifier comprising a plurality of audio-visual resource specific location steps;

code for locating the audio-visual resource using the Universal Resource Name;

code for establishing a logical representation of the structure of the audio-visual resource; and

code for iteratively evaluating the fragment identifier location steps against the logical representation to resolve the complex fragment identifier into a set of explicit fragment references configured to explicitly address each of the plurality of resource fragments.

9. An apparatus according to claim 8, wherein:

the logical representation is an XML equivalent document representation of the audio-visual resource;

each said location step comprises an axis, a node test and zero or more predicates; and

the code for the iterative evaluation step comprises;

code for representing the XML equivalent document as a tree of nodes;

code for establishing a set of said nodes dependent upon a current location step;

code for projecting the currently established node set to the axis specified by the current location step;

code for evaluating the node test of the current location step to select the projections of the nodes on the axis;

code for applying the predicate to refine the selected node set; and

code for repeating the establishing, projecting, evaluating and applying steps for all the location steps in the complex fragment identifier, to thereby resolve the complex fragment identifier into said set of explicit fragment references.

10. A computer program product including a computer readable medium having recorded thereon a computer program for directing a processor to execute a method for retrieving a plurality of resource fragments from a audio-visual resource that is encoded using a hierarchical addressing model for the class of resources of which the audio-visual resource is a member, the program comprising:

code for inputting a URI reference comprising a Universal Resource Name and a complex fragment identifier comprising a plurality of audio-visual resource specific location steps;

code for locating the audio-visual resource using the Universal Resource Name;

code for establishing a logical representation of the structure of the audio-visual resource; and

code for iteratively evaluating the fragment identifier location steps against the logical representation to resolve the complex fragment identifier into a set of explicit fragment references configured to explicitly address each of the plurality of resource fragments.

11. A computer program product according to claim 10, wherein:

the logical representation is an XML equivalent document representation of the audio-visual resource;

each said location step comprises an axis, a node test and zero or more predicates; and

the code for the iterative evaluation step comprises;

code for representing the XML equivalent document as a tree of nodes;

code for establishing a set of said nodes dependent upon a current location step;

code for projecting the currently established node set to the axis specified by the current location step;

code for evaluating the node test of the current location step to select the projections of the nodes on the axis;

code for applying the predicate to refine the selected node set; and

code for repeating the establishing, projecting, evaluating and applying steps for all the location steps in the complex fragment identifier, to thereby resolve the

complex fragment identifier into said set of explicit fragment references.