LC METS Profile

Library of Congress Audio Compact Disc METS Profile

XML Version of Profile Document

Abstract

The Library of Congress Compact Disc METS Profile specifies how METS documents representing audio compact discs within Library of Congress digital library projects should be encoded. The term "compact disc" applies both to items issued as single discs and also to items issued as multiple disc sets. The distinctive features of the profile are: 1) the use of MODS to express the logical structure of the compact disc (by means of a hierarchy of relatedItem type="constituent" elements), 2) the use of the METS structMap to express the physical structure of the compact disc (by means of a hierarchy of typed div elements, and 3) a straightforward correlation of the two differing hierarchies by means of XML ID/IDREF links.

URI

//www.loc.gov/mets/profiles/00000007.xml

Date

2005-06-08T17:31:00

Contact

Morgan Cundiff
Network Development and MARC Standards Office, Library of Congress
101 Independence Avenue, Washington DC, 20540

Related Profile

No related profiles.

Extension Schema

Metadata Object Description Schema (MODS)
//www.loc.gov/standards/mods/v3/mods-3-0.xsd

Description Rules

The content data used in the MODS section of a METS document must conform to AACR2.

Controlled Vocabularies

Library of Congress Subject Headings
Library of Congress
Controlled subject headings used in the MODS section of a METS document must be formulated according to the Library of Congress Subject Headings (LCSH).

Library of Congress Classification
Library of Congress
//www.loc.gov/catdir/cpso/lcc.html

NACO Authority File
Library of Congress
http://authorities.loc.gov/
Controlled name and title headings used in the MODS section of a METS document must be formulated according to the NACO Authority File.

MARC Country Codes
Library of Congress
//www.loc.gov/marc/countries/
Country codes used in the MODS section of a METS document must use MARC country code list.

ISO 639-2 Language Codes
Library of Congress
//www.loc.gov/standards/iso639-2/
Language codes used in the MODS section of a METS document must use ISO 639-2 bibliographic codes.

MARC Relator Codes
Library of Congress
//www.loc.gov/marc/relators/
Relator codes or terms used in the MODS section of a METS document must use MARC relator list.

Target Audience Codes
Library of Congress
//www.loc.gov/marc/sourcecode/target/
Terms used in the MODS section of a METS document must use the MARC target audience list.

MARC Code List for Organizations
Library of Congress
//www.loc.gov/marc/organizations/
Source codes used in the MODS section of a METS document must use MARC organization list.

Structural Requirements

METS Root Element

metsRootElement Requirement 1

The METS root element must have an attribute PROFILE="//www.loc.gov/mets/profiles/00000007.xml".

Example 1.

Descriptive Metadata Section

dmdSec Requirement 1

A document must contain one and only one Descriptive Metadata Section (dmdSec) with a wrapped (mdWrap) MODS bibliographic record. The mods element must have an ID attribute.

Example 2.

dmdSec Requirement 2

If a compact disc contains one and only one work, and that work has no logical sub-parts to be described, then the MODS record will contain no relatedItem TYPE=constituent elements. Note: this will not often be the case. A typical case where it would occur would be a compact disc with only one title and one track (i.e. no physical or logical subdivisions).

Plese note: the term "work" is being used here as shorthand for the FRBR concept of "manifestation" of an abstract work. The work is in the form of a recorded performance as issued on a given audio compact disc.

Example 3.

dmdSec Requirement 3

If there is more than one work recorded on the compact disc, the MODS element must contain one Related Item (relatedItem) child element for each work. Each relatedItem element must have an ID attribute and a type="constituent" attribute.

Example 4.

dmdSec Requirement 4

If a work has logical sub-parts, those sub-parts may be represented with relatedItem TYPE=constituent child elements. Examples of logical sub-parts of a work are the movements of a musical work, the acts and scenes of a dramatic work, etc. The logical structure of a work will thus be represented as a heirarchy of relatedItems. All relatedItem TYPE=constituent elements must be given an ID attribute and must have a titleInfo child element.

Note that the profile makes no further descriptive cataloging requirements either in terms of content (i.e. particular descriptive data) or content designation (particular MODS elements and attributes). That being said, it should be obvious (given that the mods element and the relatedItem element both have the same content model) that there is the possibilty of providing more extensive description for each relatedItem. If, and to what extent, this possibility is expoited, is considered to be outside the scope of the profile. Rather, it is an issue of local cataloging practice.

It should also be noted that because the mods element and the relatedItem type="constituent" child elements represent the logical heirarchy of the compact disc (i.e. as an XML tree structure), then it becomes possible to consider that information can be inherited from one level of the heirarchy to another. For instance, in Example 5, it is clear that the partName with value "Allegro molto appassionato, presto" is a part of the work with title "Concerto in E minor, op. 64" by virtue of the child-to-parent relationship in the XML tree. Again, if, and to what extent, this kind of potential for inheritance is exploited is beyond the scope of the profile and is a matter of cataloging practice.

Example 5.

Administrative Metadata Section

amdSec Requirement 1

The profile does not require administrative metadata.

File Section

fileSec Requirement 1

The content files referenced by the fptr elements (in the structMap) must point to the appropriate files in the File Section (fileSec). The profile makes no further requirements regarding the fileSec element.

Structure Map

structMap Requirement 1

The physical structure of the compact disc will be represented in the Structure Map (structMap) section of the METS instance. The document will have one and only one structMap. The structMap element will have one and only one top level div TYPE="cd:compactDiscObject" child element. The top-level div element of the structMap will have a DMDID attribute that points to the mods element.

Example 6.

structMap Requirement 2

The primary physical component of a compactDiscObject is one or more compact discs. Accordingly, the div TYPE="cd:compactDiscObject" element must have one or more div TYPE="cd:disc" child elements. When there is more than one disc, the div TYPE="cd:disc" elements must occur in document order that corresponds to the physical order of the discs (Disk 1, Disk 2, etc.). A compactDiscObject may also contain physical components for the container cover, and for an inserted booklet. The div TYPE="cd:compactDiscObject" element may therefore also contain zero or one div TYPE="cd:cover" elements and/or zero or more div TYPE="cd:booklet" elements. The examples that follow will first treat the div TYPE="cd:disc" element with audio content and then move to the div TYPE="cd:cover" element and the div TYPE="cd:booklet" elements and a discussion of image and text content.

Example 7.

structMap Requirement 3

The div TYPE="cd:disc" elements will have one or more div TYPE="cd:track" child elements. The div TYPE="cd:track" elements should occur in document order that corresponds to the physical order of the tracks on the compact disc.

If the track is not further divided (i.e. the audio content of the track corresponds to a relatedItem in the mods record), then the div TYPE="cd:track" element will contain a div TYPE="cd:audio" child element. Each div TYPE="cd:audio" element will contain one or more fptr (File Pointer) elements, each with a FILEID attribute that points to the appropriate file element in the fileSec (File Section). Also in this case, each div TYPE="cd:track" element must have an ID attribute and a DMDID attribute that points to the corresponding relatedItem element in the mods record.

If, however, the track is further divided into logical segments, see the next requirement on the use of div TYPE="cd:trackSegment" child elements.

Example 8.

structMap Requirement 4

The div TYPE="cd:track" elements may have zero or more div TYPE="cd:trackSegment" child elements. The div TYPE="cd:trackSegment" element should be used in cases where a compact disc track contains more than one logical part. Each div TYPE="cd:trackSegment" element must have a DMDID attribute that points to the corresponding relatedItem element in the mods record. Each div TYPE="cd:trackSegment" element will have a div TYPE="cd:audio" child element.

Each div TYPE="cd:audio" element will in turn have one or more fptr (File Pointer) elements. Each fptr element will in turn contain an area child element with a FILEID attribute that points to the appropriate file in the fileSec (File Section). The area element will also use the BETYPE (Beginning and End Type) attribute with value "TIME", the BEGIN attribute, and the EXTENT attribute to indicate the starting time and the duration of the associated audio file segment.

Example 9 shows a fragment of an operatic work as an illustration of the use of the div TYPE="cd:trackSegment" element. The work contains two acts and each act in turn contains two scenes so there are four logical sub-parts to be correlated to the appropriate audio segments. The disc, however, contains only two physical tracks (with each track containing two scenes). The div TYPE="cd:trackSegment" is used to correlate the segment of each track to the corresponding relatedItem element. Note that the div TYPE="cd:trackSegment" element is associated with the corresponding time segment of the appropriate file element by using the area element and the BETYPE, BEGIN, ande EXTENT attributes

Example 9.

structMap Requirement 5

The parent div element of all div TYPE="cd:audio" elements will have a DMDID attribute linking the parent div to the appropriate relatedItem element. These parent div elements will always be either div TYPE="cd:track" or div TYPE="cd:trackSegment". Notice (in the example below) that there is a correspondence between the three lowest-level relatedItem elements (in document order) and the three div elements that are parents of div TYPE="cd:audio" elements (in document order). (The phrase "lowest-level relatedItem elements" means relatedItem elements that contain no child relatedItem elements.)

Example 10.

structMap Requirement 6

A compactDiscObject may also contain image and text content in addition to audio content. Digital images may exist for the disc label, the container cover, and for an inserted booklet. A div TYPE="cd:image" element will always contain one or more fptr elements that point to the appropriate file elements.

In the case of container or cover images, the profile does not require a particular sequence of images. However, as a matter of practice, the images may be arranged in a reasonable document order with the front cover image occuring first. With the div TYPE="cd:image" element it may be useful to add a LABEL attribute containing additional structural information. For example, div TYPE="cd:image" LABEL="front cover" as in the following example.

Example 11.

structMap Requirement 7

Text files may exist for a transcription of the text on the disc label, a transcription of the text on the container cover, a transcription of the text from an inserted booklet, or a transcription of the text from an audio program. A text file is associated with a particular physical component div element by nesting it as a child of that element. For example, for a text file containing a transcription of audio program for a particular track, div TYPE="cd:track" element would contain a div TYPE="cd:text" child element. For the purpose of illustration, an example of each of these possibilities is presented below. Note that each div TYPE="cd:text" element contains a fptr element with FILEID attribute pointing to the appropriate file element. The text file will typically be an XML document conforming to the TEILITE DTD.

Example 12.

structMap Requirement 8

The last example provides an overview of the structMap showing all possibilities for div TYPE hierarchies. It also provides an easy reference for the complete compact disc profile div TYPE "vocabulary" (e.g. div TYPE="cd:compactDiscObject").

Example 13.

Technical Requirements

Content Files

Audio Files

The master audio files referenced by conforming documents must be in WAVE Audio File Format. See Digital Formats for Library of Congress Collections: WAVE Audio File Format at http://www.digitalpreservation.gov/formats/fdd/fdd000001.shtml.

Still Image Files

The master image files referenced by conforming documents must be in TIFF Revision 6.0 format. See Digital Formats for Library of Congress Collections: TIFF, Revision 6.0 at http://www.digitalpreservation.gov/formats/fdd/fdd000022.shtml.

Text Files

Master text files referenced by conforming documents must be in XML format. See Digital Formats for Library of Congress Collections: XML (Extensible Markup Language) at http://www.digitalpreservation.gov/formats/fdd/fdd000075.shtml.