Efficient binary coding scheme for multimedia content descriptions

• US 7,398,275 B2
• Filed: 10/22/2001
• Issued: 07/08/2008
• Est. Priority Date: 10/20/2000
• Status: Expired due to Fees

• Current Assignee: Sony Corporation (Sony Group Corp.), Sony Electronics Inc. (Sony Group Corp.)
• Original Assignee: Sony Corporation (Sony Group Corp.), Sony Electronics Inc. (Sony Group Corp.)
• Inventors: Tabatabai, Ali, Rising, Hawley K. III, Visharam, Mohammed Z.
• Primary Examiner(s): Mofiz; Apu
• Assistant Examiner(s): Padmanabhan; Kavita
• Application Number:
  US10/029,758
• Publication Number:
  US 20020138514A1
• Time in Patent Office: 2,451 Days
• Field of Search: None
• US Class Current: 1/1
• CPC Class Codes: G06F 40/143 Markup, e.g. Standard Generalized Markup Language [SGML] or Document Type Definition [DTD]
• CPC Class Codes: G06F 40/149 Adaptation of the text data for streaming purposes, e.g. Efficient XML Interchange [EXI] format
• CPC Class Codes: H04N 21/2353 specifically adapted to content descriptors, e.g. coding, compressing or processing of metadata

Abstract

An encoding methodology encodes an instance document describing multimedia content by determining a context node in the content description and using a schema associated with the context node to determine the maximum number of children attributes and elements of the context node. Values for required attributes and elements are encoded into required attributes and required elements sections, respectively. Values for each optional attribute and optional element present in the content description are encoded into corresponding optional attributes and optional elements sections. In one aspect, a mask is encoded that indicates which of the optional attributes or optional elements are present in the content description. In another aspect, a count of the optional attributes or optional elements is used in place of the mask. A corresponding decode methodology extracts the values of the attributes and elements from the encoded instance document to re-create the content description.

Claims

1. A computerized method for encoding an instance document representing a content description, the method comprising:

determining a context node from a plurality of context nodes in the content description, the plurality of context nodes corresponding to description schemes for a particular multimedia content described by the instance document, wherein the plurality of context nodes are represented in the encoded instance document as a plurality of data structures;

obtaining a schema associated with the context node, the schema defining required attributes, optional attributes, required elements, and optional elements for the context node, with the optional attributes and optional elements having an order;

creating a required attributes section containing a value for each required attribute for the context node;

creating an optional attributes section containing a value for each optional attribute for the context node that appears in the content description;

creating a required elements section containing a value for each required element for the context node;

creating an optional elements section containing a value for each optional element for the context node that appears in the content description; and

generating the encoded instance document comprising the attributes and elements sections defined by the schema for each of the plurality of context nodes and a context-node reset code specifying an address for a next context node in the content description for each context node except a last context node, wherein the encoded instance document is a compressed representation of the instance document.

2. The computerized method of claim 1, wherein creating the optional attributes section comprises:

including a mask in a header of the optional attributes section, the mask indicating which of the optional attributes defined in the schema are present in the content description.

3. The computerized method of claim 2, wherein creating the optional attributes section further comprises:

including an order field in the header of the optional attributes section, the order field indicating that the optional attributes present in the content description correspond to the order of the optional attributes in the schema.

4. The computerized method of claim 1, wherein creating the optional attributes section comprises:

including an order field in a header of the optional attributes section, the order field indicating that the optional attributes present in the content do not correspond to the order of the optional attributes in the schema;

including a number field in the header of the optional attributes section, the number field indicating a count of the optional attributes present in the content description; and

associating an attribute identifier with the value of each optional attribute present in the content description.

5. The computerized method of claim 1, wherein creating the required elements section comprises:

associating an element identifier with the value for a required element if the schema defines a choice of values for the corresponding required element.

6. The computerized method of claim 1, wherein creating the required elements section comprises

including a terminator field for a required element in the required elements section if the schema defines the corresponding required element as an unbounded sequence.

7. The computerized method of claim 1, wherein creating the optional elements section comprises:

including a mask in a header of the optional elements section, the mask indicating which of the optional elements defined in the schema are present in the content description.

8. The computerized method of claim 7, wherein creating the optional elements section further comprises:

including an order field in the header of the optional elements section, the order field indicating the optional elements present in the content description correspond to the order of the optional elements in the schema.

9. The computerized method of claim 7, wherein creating the optional elements section further comprises:

associating a repeat field with the value of an optional element if the schema defines the corresponding optional element as having multiple occurrences.

10. The computerized method of claim 1, wherein creating the optional elements section comprises:

including an order field in a header of the optional elements section, the order field indicating that the optional elements present in the content do not correspond to the order of the optional elements in the schema;

including a number field in the header of the optional elements section, the number field indicating a count of the optional elements present in the content description; and

associating an element identifier with the value of each optional element present in the content description.

11. The computerized method of claim 10, wherein creating the optional elements section further comprises:

associating a repeat field with each value of an optional element if the schema defines the corresponding optional element as having multiple occurrences; and

associating the element identifier with only one value of the optional element if the schema defines the corresponding optional element as having multiple occurrences.

12. The computerized method of claim 1, wherein creating the required attributes section comprises:

associating an element identifier with the value of each required attribute.

13. The computerized method of claim 1, wherein creating the optional attributes section comprises:

associating an attribute identifier with the value of each optional attribute present in the content.

14. The computerized method of claim 1, wherein creating the required elements section comprises:

associating an element identifier with the value of each required element.

15. The computerized method of claim 14, wherein creating the required elements section further comprises:

including a terminator field for a required element in the required elements section if the schema defines the corresponding required element as an unbounded sequence.

16. The computerized method of claim 1, wherein creating the optional elements section comprises:

associating an element identifier with the value of each optional element present in the content description.

17. The computerized method of claim 16, wherein creating the optional elements section further comprises:

associating a repeat field with each value of an optional element if the schema defines the corresponding optional element as having multiple occurrences; and

associating the element identifier with only one value of the optional element if the schema defines the corresponding optional element as having multiple occurrences.

18. The computerized method of claim 1 further comprising:

creating the context-node reset code.

19. A computer-readable storage medium having executable instructions to cause a computer to perform a method comprising:

determining a context node from a plurality of context nodes in a content description, the plurality of context nodes corresponding to description schemes for a particular multimedia content described by an instance document, wherein the plurality of context nodes are represented in the encoded instance document as a plurality of data structures;

obtaining a schema associated with the context node, the schema defining required attributes, optional attributes, required elements, and optional elements for the context node, with the optional attributes and optional elements having an order;

creating a required attributes section containing a value for each required attribute for the context node;

creating an optional attributes section containing a value for each optional attribute for the context node that appears in the content description;

creating a required elements section containing a value for each required element for the context node;

creating an optional elements section containing a value for each optional element for the context node that appears in the content description; and

generating the encoded instance document comprising the attributes and elements sections defined by the schema for each of the plurality of context nodes and a context-node reset code specifying an address for a next context node in the content description for each context node except a last context node, wherein the encoded instance document is a compressed representation of the instance document.

20. The computer-readable medium of claim 19, wherein creating the optional attributes section comprises:

including a mask in a header of the optional attributes section, the mask indicating which of the optional attributes defined in the schema are present in the content description.

21. The computer-readable medium of claim 20, wherein creating the optional attributes section further comprises:

including an order field in the header of the optional attributes section, the order field indicating that the optional attributes present in the content description correspond to the order of the optional attributes in the schema.

22. The computer-readable medium of claim 19, wherein creating the optional attributes section comprises:

including an order field in a header of the optional attributes section, the order field indicating that the optional attributes present in the content do not correspond to the order of the optional attributes in the schema;

including a number field in the header of the optional attributes section, the number field indicating a count of the optional attributes present in the content description; and

associating an attribute identifier with the value of each optional attribute present in the content description.

23. The computer-readable medium of claim 19, wherein creating the required elements section comprises:

associating an element identifier with the value for a required element if the schema defines a choice of values for the corresponding required element.

24. The computer-readable medium of claim 19, wherein creating the required elements section comprises

including a terminator field for a required element in the required elements section if the schema defines the corresponding required element as an unbounded sequence.

25. The computer-readable medium of claim 19, wherein creating the optional elements section comprises:

including a mask in a header of the optional elements section, the mask indicating which of the optional elements defined in the schema are present in the content description.

26. The computer-readable medium of claim 25, wherein creating the optional elements section further comprises:

including an order field in the header of the optional elements section, the order field indicating that the optional elements present in the content description correspond to the order of the optional elements in the schema.

27. The computer-readable medium of claim 25, wherein creating the optional elements section further comprises:

associating a repeat field with the value of an optional element if the schema defines the corresponding optional element as having multiple occurrences.

28. The computer-readable medium of claim 19, wherein creating the optional elements section comprises:

including an order field in a header of the optional elements section, the order field indicating that the optional elements present in the content do not correspond to the order of the optional elements in the schema;

including a number field in the header of the optional elements section, the number field indicating a count of the optional elements present in the content description; and

associating an element identifier with the value of each optional element present in the content description.

29. The computer-readable medium of claim 28, wherein creating the optional elements section further comprises:

associating a repeat field with each value of an optional element if the schema defines the corresponding optional element as having multiple occurrences; and

associating the element identifier with only one value of the optional element if the schema defines the corresponding optional element as having multiple occurrences.

30. The computer-readable medium of claim 19, wherein creating the required attributes section comprises:

associating an element identifier with the value of each required attribute.

31. The computer-readable medium of claim 19, wherein creating the optional attributes section comprises:

associating an attribute identifier with the value of each optional attribute present in the content.

32. The computer-readable medium of claim 19, wherein creating the required elements section comprises:

associating an element identifier with the value of each required element.

33. The computer-readable medium of claim 32, wherein creating the required elements section further comprises:

including a terminator field for a required element in the required elements section if the schema defines the corresponding required element as an unbounded sequence.

34. The computer-readable medium of claim 19, wherein creating the optional elements section comprises:

associating an element identifier with the value of each optional element present in the content description.

35. The computer-readable medium of claim 34, wherein creating the optional elements section further comprises:

associating a repeat field with each value of an optional element if the schema defines the corresponding optional element as having multiple occurrences; and

associating the element identifier with only one value of the optional element if the schema defines the corresponding optional element as having multiple occurrences.

36. The computer-readable medium of claim 19, wherein the method further comprises:

creating the context-node reset code.

37. A system comprising:

a processor coupled to a bus;

a memory coupled to the processor through the bus; and

an encode process executed by the processor from the memory to cause the processor to

determine a context node from a plurality of context nodes in a content description, the plurality of context nodes corresponding to description schemes for a particular multimedia content described by an instance document, wherein the plurality of context nodes are represented in the encoded instance document as a plurality of data structures,

obtain a schema associated with the context node, the schema defining required attributes, optional attributes, required elements, and optional elements for the context node, with the optional attributes and optional elements having an order,

create a required attributes section containing a value for each required attribute for the context node,

create an optional attributes section containing a value for each optional attribute for the context node that appears in the content description,

create a required elements section containing a value for each required element for the context node,

create an optional elements section containing a value for each optional element for the context node that appears in the content description, and

generate the encoded instance document comprising the attributes and elements sections defined by the schema for each of the plurality of context nodes and a context-node reset code specifying an address for a next context node in the content description for each context node except a last context node, wherein the encoded instance document is a compressed representation of the instance document.

38. The system of claim 37, wherein the encode process further causes the processor, when creating the optional attributes section, to include a mask in a header of the optional attributes section, the mask indicating which of the optional attributes defined in the schema are present in the content description.

39. The system of claim 38, wherein the encode process further causes the processor, when creating the optional attributes section, to include an order field in the header of the optional attributes section, the order field indicating that the optional attributes present in the content description correspond to the order of the optional attributes in the schema.

40. The system of claim 37, wherein the encode process further causes the processor, when creating the optional attributes section, to

include an order field in a header of the optional attributes section, the order field indicating that the optional attributes present in the content do not correspond to the order of the optional attributes in the schema,

include a number field in the header of the optional attributes section, the number field indicating a count of the optional attributes present in the content description, and

associate an attribute identifier with the value of each optional attribute present in the content description.

41. The system of claim 37, wherein the encode process further causes the processor, when creating the required elements section, to associate an element identifier with the value for a required element if the schema defines a choice of values for the corresponding required element.

42. The system of claim 37, wherein the encode process further causes the processor, when creating the required elements section, to include a terminator field for a required element in the required elements section if the schema defines the corresponding required element as an unbounded sequence.

43. The system of claim 37, wherein the encode process further causes the processor, when creating the optional elements section, to include a mask in a header of the optional elements section, the mask indicating which of the optional elements defined in the schema are present in the content description.

44. The system of claim 43, wherein the encode process further causes the processor, when creating the optional elements section, to include an order field in the header of the optional elements section, the order field indicating that the optional elements present in the content description correspond to the order of the optional elements in the schema.

45. The system of claim 43, wherein the encode process further causes the processor, when creating the optional elements section, to associate a repeat field with the value of an optional element if the schema defines the corresponding optional element as having multiple occurrences.

46. The system of claim 37, wherein the encode process further causes the processor, when creating the optional elements section to

include an order field in a header of the optional elements section, the order field indicating that the optional elements present in the content do not correspond to the order of the optional elements in the schema,

include a number field in the header of the optional elements section, the number field indicating a count of the optional elements present in the content description, and

associate an element identifier with the value of each optional element present in the content description.

47. The system of claim 46, wherein the encode process further causes the processor, when creating the optional elements section, to

associate a repeat field with each value of an optional element if the schema defines the corresponding optional element as having multiple occurrences, and

associate the element identifier with only one value of the optional element if the schema defines the corresponding optional element as having multiple occurrences.

48. The system of claim 37, wherein the encode process further causes the processor, when creating the required attributes section, to associate an element identifier with the value of each required attribute.

49. The system of claim 37, wherein the encode process further causes the processor, when creating the optional attributes section, to associate an attribute identifier with the value of each optional attribute present in the content.

50. The system of claim 37, wherein the encode process further causes the processor, when creating the required elements section, to associate an element identifier with the value of each required element.

51. The system of claim 50, wherein the encode process further causes the processor, when creating the required elements section, to include a terminator field for a required element in the required elements section if the schema defines the corresponding required element as an unbounded sequence.

52. The system of claim 37, wherein the encode process further causes the processor, when creating the optional elements section, to associate an element identifier with the value of each optional element present in the content description.

53. The system of claim 52, wherein the encode process further causes the processor, when creating the optional elements section, to

associate a repeat field with each value of an optional element if the schema defines the corresponding optional element as have multiple occurrences, and

associate the element identifier with only one value of the optional element if the schema defines the corresponding optional element as have multiple occurrences.

54. The system of claim 37, wherein the encode process further causes the processor to create the context-node reset code.

55. A computerized method for decoding an encoded instance document representing a content description, the method comprising:

obtaining a schema associated with a context node in the instance document, the context node being one of a plurality of context nodes corresponding to description schemes for a particular multimedia content described by the instance document, the schema defining required attributes, optional attributes, required elements, and optional elements for the context node, with the optional attributes and optional elements having an order, wherein the plurality of context nodes are represented in the encoded instance document as a plurality of data structures, and wherein the encoded instance document is a compressed representation of the instance document comprising the attributes and elements sections defined by the schema for each of the plurality of context nodes and a context-node reset code specifying an address for a next context node in the content description for each context node except a last context node;

extracting a value for each required attribute from a required attributes section when present in the encoded instance document;

extracting a value for each optional attribute that appears in the content description from an optional attributes section when present in the encoded instance document;

extracting a value for each required element from a required elements section when present in the encoded instance document;

extracting a value for each optional element that appears in the content description from an optional elements section when present in the encoded instance document, and

generating the instance document from the values extracted from the compressed representation of the instance document.

56. The computerized method of claim 55, wherein extracting from the optional attributes section comprises:

extracting a mask from a header of the optional attributes section, the mask indicating which of the optional attributes defined in the schema are present in the content description.

57. The computerized method of claim 56, wherein extracting from the optional attributes section further comprises:

extracting an order field from the header of the optional attributes section, the order field indicating that the optional attributes present in the content description correspond to the order of the optional attributes in the schema.

58. The computerized method of claim 55, wherein extracting from the optional attributes section comprises:

extracting an order field from a header of the optional attributes section, the order field indicating that the optional attributes present in the content description do not correspond to the order of the optional attributes in the schema;

extracting a number field from the header of the optional attributes section, the number field indicating a count of the optional attributes present in the content description; and

extracting an attribute identifier associated with the value of each optional attribute present in the content description.

59. The computerized method of claim 55, wherein extracting from the required elements section comprises:

extracting an element identifier associated with the value of a required element if the schema defines a choice of values for the corresponding required element.

60. The computerized method of claim 55, wherein extracting from the required elements section comprises:

extracting a terminator field for a required element in the required elements section if the schema defines the corresponding required element as an unbounded sequence.

61. The computerized method of claim 55, wherein extracting from the optional elements section comprises:

extracting a mask from a header of the optional elements section, the mask indicating which of the optional elements defined in the schema are present in the content description.

62. The computerized method of claim 61, wherein extracting from the optional elements section further comprises:

extracting an order field from the header of the optional elements section, the order field indicating that the optional elements present in the content description correspond to the order of the optional elements in the schema.

63. The computerized method of claim 61, wherein extracting from the optional elements section further comprises:

extracting a repeat field associated with the value of an optional element if the schema defines the corresponding optional element as having multiple occurrences.

64. The computerized method of claim 55, wherein extracting from the optional elements section comprises:

extracting an order field from a header of the optional elements section, the order field indicating that the optional elements present in the content do not correspond to the order of the optional elements in the schema;

extracting a number field from the header of the optional elements section, the number field indicating a count of the optional elements present in the content description; and

extracting an element identifier associated with the value of each optional element present in the content description.

65. The computerized method of claim 64, wherein extracting from the optional elements section further comprises:

extracting a repeat field associated with the value of an optional element if the schema defines the corresponding optional element as having multiple occurrences; and

extracting the element identifier associated with only one value of the optional element if the schema defines the corresponding optional element as having multiple occurrences.

66. The computerized method of claim 55, wherein extracting from the required attributes section comprises:

extracting an element identifier associated with the value of each required attribute.

67. The computerized method of claim 55, wherein extracting from the optional attributes section comprises:

extracting an attribute identifier associated with the value of each optional attribute present in the content.

68. The computerized method of claim 55, wherein extracting from the required elements section comprises:

extracting an element identifier associated with the value of each required element.

70. The computerized method of claim 55, wherein extracting the optional elements section comprises:

extracting an element identifier associated with the value of each optional element present in the content description.

71. The computerized method of claim 70, wherein extracting from the optional elements section further comprises:

extracting a repeat field associated with each value of an optional element if the schema defines the corresponding optional element as having multiple occurrences; and

extracting the element identifier associated with only one value of the optional element if the schema defines the corresponding optional element as having multiple occurrences.

72. The computerized method of claim 55 further comprising:

extracting the context-node reset code.

69. The computerized method of 68, wherein extracting from the required elements section further comprises:

extracting a terminator field for a required element in the required elements section if the schema defines the corresponding required element as an unbounded sequence.

73. A computer-readable storage medium having executable instructions to cause a computer to perform a method comprising:

obtaining a schema associated with a context node in an instance document, the context node corresponding to a description scheme for a particular multimedia content described by an instance document, the schema defining required attributes, optional attributes, required elements, and optional elements for the context node, with the optional attributes and optional elements having an order, wherein the plurality of context nodes are represented in the encoded instance document as a plurality of data structures, and wherein the encoded instance document is a compressed representation of the instance document comprising the attributes and elements sections defined by the schema for each of the plurality of context nodes and a context-node reset code specifying an address for a next context node in the content description for each context node except a last context node;

extracting a value for each required attribute from a required attributes section when present in the encoded instance document;

extracting a value for each optional attribute that appears in the content description from an optional attributes section when present in the encoded instance document;

extracting a value for each required element from a required elements section when present in the encoded instance document;

extracting a value for each optional element that appears in the content description from an optional elements section when present in the encoded instance document; and

generating the instance document from the values extracted from the compressed representation of the instance document.

74. The computer-readable medium of claim 73, wherein extracting from the optional attributes section comprises:

extracting a mask from a header of the optional attributes section, the mask indicating which of the optional attributes defined in the schema are present in the content description.

75. The computer-readable medium of claim 74, wherein extracting from the optional attributes section further comprises:

extracting an order field from the header of the optional attributes section, the order field indicating that the optional attributes present in the content description correspond to the order of the optional attributes in the schema.

76. The computer-readable medium of claim 73, wherein extracting from the optional attributes section comprises:

extracting an order field from a header of the optional attributes section, the order field indicating that the optional attributes present in the content description do not correspond to the order of the optional attributes in the schema;

extracting a number field from the header of the optional attributes section, the number field indicating a count of the optional attributes present in the content description; and

extracting an attribute identifier associated with the value of each optional attribute present in the content description.

77. The computer-readable medium of claim 73, wherein extracting from the required elements section comprises:

extracting an element identifier associated with the value of a required element if the schema defines a choice of values for the corresponding required element.

78. The computer-readable medium of claim 73, wherein extracting from the required elements section comprises

extracting a terminator field for a required element in the required elements section if the schema defines the corresponding required element as an unbounded sequence.

79. The computer-readable medium of claim 73, wherein extracting from the optional elements section comprises:

extracting a mask from a header of the optional elements section, the mask indicating which of the optional elements defined in the schema are present in the content description.

80. The computer-readable medium of claim 79, wherein extracting from the optional elements section further comprises:

extracting an order field from the header of the optional elements section, the order field indicating that the optional elements present in the content description correspond to the order of the optional elements in the schema.

81. The computer-readable medium of claim 79, wherein extracting from the optional elements section further comprises:

extracting a repeat field associated with the value of an optional element if the schema defines the corresponding optional element as having multiple occurrences.

82. The computer-readable medium of claim 73, wherein extracting from the optional elements section comprises:

extracting an order field from a header of the optional elements section, the order field indicating that the optional elements present in the content do not correspond to the order of the optional elements in the schema;

extracting a number field from the header of the optional elements section, the number field indicating a count of the optional elements present in the content description; and

extracting an element identifier associated with the value of each optional element present in the content description.

83. The computer-readable medium of claim 82, wherein extracting from the optional elements section further comprises:

extracting a repeat field associated with the value of an optional element if the schema defines the corresponding optional element as having multiple occurrences; and

extracting the element identifier associated with only one value of the optional element if the schema defines the corresponding optional element as having multiple occurrences.

84. The computer-readable medium of claim 73, wherein extracting from the required attributes section comprises:

extracting an element identifier associated with the value of each required attribute.

85. The computer-readable medium of claim 73, wherein extracting from the optional attributes section comprises:

extracting an attribute identifier associated with the value of each optional attribute present in the content.

86. The computer-readable medium of claim 73, wherein extracting from the required elements section comprises:

extracting an element identifier associated with the value of each required element.

87. The computer-readable medium of claim 86, wherein extracting from the required elements section further comprises:

extracting a terminator field for a required element in the required elements section if the schema defines the corresponding required element as an unbounded sequence.

88. The computer-readable medium of claim 73, wherein extracting the optional elements section comprises:

extracting an element identifier associated with the value of each optional element present in the content description.

89. The computer-readable medium of claim 88, wherein extracting from the optional elements section further comprises:

extracting a repeat field associated with each value of an optional element if the schema defines the corresponding optional element as having multiple occurrences; and

extracting the element identifier associated with only one value of the optional element if the schema defines the corresponding optional element as having multiple occurrences.

90. The computer-readable medium of claim 73 further comprising:

extracting the context-node reset code, the context-node reset code specifying a different context node in the content description.

91. A system comprising;

a processor coupled to a bus;

a memory coupled to the processor through the bus; and

a decode process for an encoded instance document representing a content description, the decode process executed by the processor from the memory to cause the processor to

obtain a schema associated with a context node in the instance document, the context node being one of a plurality of context nodes corresponding to description scheme for a particular multimedia content described by an instance document, the schema defining required attributes, optional attributes, required elements, and optional elements for the context node, with the optional attributes and optional elements having an order, wherein the plurality of context nodes are represented in the encoded instance document as a plurality of data structures, and wherein the encoded instance document is a compressed representation of the instance document comprising the attributes and elements sections defined by the schema for each of the plurality of context nodes and a context-node reset code specifying an address for a next context node in the content description for each context node except a last context node,

extract a value for each required attribute from a required attributes section when present in the encoded instance document,

extract a value for each optional attribute that appears in the content description from an optional attributes section when present in the encoded instance document,

extract a value for each required element from a required elements section when present in the encoded instance document,

extract a value for each optional element that appears in the content description from an optional elements section when present in the encoded instance document; and

generate the instance document from the values extracted from the compressed representation of the instance document.

92. The system of claim 91, wherein the decode process further causes the processor, when extracting from the optional attributes section, to extract a mask from a header of the optional attributes section, the mask indicating which of the optional attributes defined in the schema are present in the content description.

93. The system of claim 92, wherein the decode process further causes the processor, when extracting from the optional attributes section, to extract an order field from the header of the optional attributes section, the order field indicating that the optional attributes present in the content description correspond to the order of the optional attributes in the schema.

94. The system of claim 91, wherein the decode process further causes the processor, when extracting from the optional attributes section, to

extract an order field from a header of the optional attributes section, the order field indicating that the optional attributes present in the content description do not correspond to the order of the optional attributes in the schema,

extract a number field from the header of the optional attributes section, the number field indicating a count of the optional attributes present in the content description, and

extract an attribute identifier associated with the value of each optional attribute present in the content description.

95. The system of claim 91, wherein the decode process further causes the processor, when extracting from the required elements section, to extract an element identifier associated with the value of a required element if the schema defines a choice of values for the corresponding required element.

96. The system of claim 91, wherein the decode process further causes the processor, when extracting from the required elements section, to extract a terminator field for a required element in the required elements section if the schema defines the corresponding required element as an unbounded sequence.

97. The system of claim 91, wherein the decode process further causes the processor, when extracting from the optional elements section, to extract a mask from a header of the optional elements section, the mask indicating which of the optional elements defined in the schema are present in the content description.

98. The system of claim 97, wherein the decode process further causes the processor, when extracting from the optional elements section, to extract an order field from the header of the optional elements section, the order field indicating that the optional elements present in the content description correspond to the order of the optional elements in the schema.

99. The system of claim 97, wherein the decode process further causes the processor, when extracting from the optional elements section, to extract a repeat field associated with the value of an optional element if the schema defines the corresponding optional element as having multiple occurrences.

100. The system of claim 91, wherein the decode process further causes the processor, when extracting from the optional elements section, to

extract an order field from a header of the optional elements section, the order field indicating that the optional elements present in the content do not correspond to the order of the optional elements in the schema,

extract a number field from the header of the optional elements section, the number field indicating a count of the optional elements present in the content description, and

extract an element identifier associated with the value of each optional element present in the content description.

101. The system of claim 100, wherein the decode process further causes the processor, when extracting from the optional elements section, to

extract a repeat field associated with the value of an optional element if the schema defines the corresponding optional element as having multiple occurrences, and

extract the element identifier associated with only one value of the optional element if the schema defines the corresponding optional element as having multiple occurrences.

102. The system of claim 91, wherein the decode process further causes the processor, when extracting from the required attributes section, to extract an element identifier associated with the value of each required attribute.

103. The system of claim 91, wherein the decode process further causes the processor, when extracting from the optional attributes section, to extract an attribute identifier associated with the value of each optional attribute present in the content.

104. The system of claim 91, wherein the decode process further causes the processor, when extracting from the required elements section, to extract an element identifier associated with the value of each required element.

105. The system of claim 104, wherein the decode process further causes the processor, when extracting from the required elements section, to extract a terminator field for a required element in the required elements section if the schema defines the corresponding required element as an unbounded sequence.

106. The system of claim 91, wherein the decode process further causes the processor, when extracting from the optional elements section, to extract an element identifier associated with the value of each optional element present in the content description.

107. The system of claim 106, wherein the decode process further causes the processor, when extracting from the optional elements section, to

extract a repeat field associated with each value of an optional element if the schema defines the corresponding optional element as having multiple occurrences, and

extract the element identifier associated with only one value of the optional element if the schema defines the corresponding optional element as having multiple occurrences.

108. The system of claim 91 wherein the decode process further causes the processor to extract the context-node reset code.