METHOD OF GENERATING A FILE DESCRIBING A BITSTREAM, CORRESPONDING DEVICE AND COMPUTER PROGRAM PRODUCT

• US 20100281177A1
• Filed: 03/27/2007
• Published: 11/04/2010
• Est. Priority Date: 03/28/2006
• Status: Active Grant

• Current Assignee: Orange S.A.
• Original Assignee: Orange S.A.
• Inventors: Devillers, Sylvain
• Granted Patent: US 8,583,815 B2
• Time in Patent Office: Days
• US Class Current: 709/231
• CPC Class Codes: G06F 16/9577 Optimising the visualization of content, e.g. distillation of HTML documents

Abstract

Method of generating a file describing a bit stream, corresponding device and computer program product. The invention relates to a method of generating a description file (14) of a bit stream (11), from a description scheme (15) describing a structure and a content that are compliant with a predetermined format and comprising a set of attributes and elements, the bit stream (11) consisting of a plurality of fields. According to the invention, such a method comprises: a step for assigning at least one value of at least one identified field of the stream to at least one variable defined by an attribute of the description scheme, called assignment attribute; a step for storing said variable; a step for determining at least one characteristic of at least one element of the description file, from an evaluation of a conditional expression relating to said value; a step for generating a portion of the description file according to the characteristics determined in the determination step.

Claims

1. Method for the generation of a description file describing a bitstream from a description schema describing a structure and a content compliant with a predetermined format and comprising a set of attributes and elements, said bitstream being formed by a plurality of fields, wherein said method comprises:

assigning at least one value of at least one identified field of said stream to at least one variable defined by an attribute of said description schema, called an assignment attribute;

storing said at least one variable;

determining at least one characteristic of at least one element of said description file from an evaluation of a conditional expression relating to said at least one value;

generating a portion of said description file as a function of said characteristic or characteristics determined during said determining step.

2. Method for the generation of a description file according to claim 1, wherein the assignment attribute comprises at least one parameter comprising at least said variable.

3. Method for the generation of a description file according to claim 1, wherein said identified field corresponds to a field in process of being read in said bitstream.

4. Method for the generation of a description file according to claim 2, wherein at least one of said parameters comprises a triplet comprising said variable and at least two pieces of information on identification belonging to the group comprising at least:

a start-of-field position in said bitstream,

an end-of-field position in said bitstream,

a field length in said bitstream,

said pieces of information on identification enabling said identified field to be identified.

5. Method for the generation of a description file according to claim 1, wherein the evaluation step makes reference to said variable.

6. Method for the generation of a description file according to claim 1, wherein said at least one characteristic belongs to the group comprising at least:

a type of an element;

a length of an element;

a number of occurrences of an element.

7. Method for the generation of a description file according to claim 1, wherein said bitstream is a scalable multimedia stream.

8. Method for the generation of a description file according to claim 1, wherein the description file is of the Bitstream Syntax Description type and said description schema is of the Bitstream Syntax Schema type according to the MPEG-21 Part 7 standard.

9. Device for generation of a file describing a bitstream from a description schema describing a structure and a content compliant with a predetermined format and comprising a set of attributes and elements, said bitstream being formed by a plurality of fields, wherein said device comprises:

means of assigning at least one value of at least one identified field of said stream to at least one variable defined by an attribute of said description schema, called an assignment attribute;

means of storing said at least one variable;

means of determining at least one characteristic of at least one element of said description file from an evaluation of a conditional expression relating to said at least one value;

means of generating a portion of said description file as a function of said characteristic or characteristics determined during said determining step.

10. Computer program product recorded on a computer-readable carrier and comprising program code instructions for the execution of a method of generating a description file describing a bitstream from a description schema, when said program is executed on a computer, wherein the description schema describes a structure and a content compliant with a predetermined format and comprises a set of attributes and elements, said bitstream being formed by a plurality of fields, wherein said method comprises:

assigning at least one value of at least one identified field of said stream to at least one variable defined by an attribute of said description schema, called an assignment attribute;

storing said at least one variable;

determining at least one characteristic of at least one element of said description file from an evaluation of a conditional expression relating to said at least one value;

generating a portion of said description file as a function of said characteristic or characteristics determined during said determining step.

11. A description file describing a bitstream stored on a computer-readable carrier, wherein the description file comprises:

a description of a bitstream from a description schema describing a structure and a content compliant with a predetermined format and comprising a set of attributes and elements, said bitstream being having a plurality of fields;

at least one value of at least one identified field of said stream assigned to at least one variable defined by an attribute of said description schema, called an assignment attribute, wherein the at least one variable is stored;

at least one characteristic of at least one element of said description file determined from an evaluation of a conditional expression relating to said at least one value;

wherein a portion of said description file is a function of said at least one characteristic.

12. Method for the adaptation of scalable multimedia contents characterized in that it comprises a phase of generation of a description file (14) describing a bitstream from a description schema describing a structure and a content compliant with a predetermined format and comprising a set of attributes and elements, said bitstream being formed by a plurality of fields, wherein said method comprises:

assigning at least one value of at least one identified field of said stream to at least one variable defined by an attribute of said description schema, called an assignment attribute;

storing said at least one variable;

determining at least one characteristic of at least one element of said description file from an evaluation of a conditional expression relating to said at least one value;

generating a portion of said description file as a function of said characteristic or characteristics determined during said determining step.