AV Prototype Project Working Documents

Extension Schemas for the
Metadata Encoding and Transmission Standard

Main Revision February 2003, Added Information January 2004


Introduction
Table Showing Arrangement of Schemas
Introduction. The Library of Congress Audio-Visual Prototyping Project (hereafter AV Project) will use the emerging Metadata Encoding and Transmission Standard (METS) to encode the metadata for digital objects. The METS website includes an Overview and Tutorial about the primary schema that is intended to serve as a framework document and explains that users may select extension schemas in order to provide additional metadata. The table below indicates the arrangement of the primary and extension schemas proposed for use in the AV Project as of February 2003.

In the table, there are links to schema xsd files and to a data dictionary for the various attributes and elements. Please note that the data dictionary is really for the relational database in which the metadata is initially captured and from which the XML instances are generated.

The audio-file technical information (schema, data dictionary) owes a great debt to work being carried out as a part of the Harvard University Library Digital Initiative and as an activity of the Audio Engineering Society. The same source provided the impetus for the digiprov schema (see also data dictionary) presented here, although this version is somewhat simplified from the Harvard-AES example (see digiprov explanation). The text technical metadata (schema, documentation, and data dictionary) is the work of Jerome McDonough, Elmer Bobst Library, New York University. The video-file technical information (schema, data dictionary) is very tentative and awaits improvement by video engineering specialists.


Table Showing Arrangement of METS Primary Schema and Extension Schemas Proposed for AV Project.
Primary Schema Extension schema and comment
<mets>       For more information, visit the METS website.
  <dmdSec>

Descriptive Metadata Section

  MODS Schema For more information, visit the MODS website.
  <amdSec>

Administrative Metadata Section

<techMD>

Technical Metadata (about "files")

AMD Schema
(same schema as under sourceMD)

DB data dict (file data only)

Information specific to audio files, e.g., sampling frequency.
      MIX Schema

DB data dict

Information specific to image files, e.g., bits per pixel, color space. For more information, visit the MIX website.

Note: for the time being, the AV Project is using a variant of MIX, with some added enumerated values and other slight changes.

      Text techical metadata (same schema as under sourceMD)

Documentation

DB data dict

Information specific to text files, e.g., character set, encoding used.
      VMD Schema
(same schema as under sourceMD)

DB data dict (file data only)

Information specific to video files, e.g., bit rate, compression codec.
    <rightsMD>

Rights and Access Management Metadata

RMD Schema

DB data dict

Rights, restrictions, and/or other categorizing information that can be used to support rights-management and/or access-management systems.
    <sourceMD>

Metadata about the Source for the File in this METS object

AMD Schema
(same schema as under techMD, above)

DB data dict (file and physical)

Descriptive terms from MAVIS for reference.

Information specific to audio items presented for file-format migration or to be digitized, e.g., channel or track specifications, sampling frequency.
      IMD Schema
(for use when source is physical item)

DB data dict (IMD, file and physical)


MIX Schema
(same schema as under techMD above; for use when source is a digital file)

DB data dict (MIX)
Information specific to items scanned to produce images (IMD), e.g., type or condition, ot items presented for file-format migration (MIX).

Note: for the time being, the AV Project is using a variant of MIX, with some added enumerated values and other slight changes.

      Text techical metadata (same schema as under techMD, above)

Documentation

DB data dict

Information specific to text files presented for file-format migration, e.g., character set, encoding.

Note: the project assumes that scanning a paper items with typography produces an image, and that text conversion methodology is covered in digiProvMD (below).

      VMD Schema
(same schema as under techMD, above)

DB data dict (file and physical)

Descriptive terms from MAVIS for reference.

Information specific to video items presented for file-format migration or to be digitized, e.g., bit rate, tape stock information.
    <digiProvMD>

Metadata about the Process Used to Create the File

PMD schema

Explanation

DB data dict

About the events/steps/processes that occurred in reformatting or migrating entities.
  <behaviorSec>

Behavior Section

    Section designed to identify digital object behaviors; for example as may be used in the FEDORA repository architecture.
  <fileGrp>

File Groups Section

    The inventory of files that are part of this digital object, with location pointers.
  <structMap>

Structural Map Section

    The metadata required to present and navigate this digital object.
</mets>        


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