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4.2 Medium of performance

Posted By Kirk-Evan Billet, Friday, April 24, 2015
Updated: Thursday, May 14, 2015

Working group members: Anna Alfeld, Sophie Rondeau, Kirk-Evan Billet (group leader)


This section examines the current state of MARC-to-Bibframe transformation for medium of performance data.

Testing procedure

Individual members of the working group assembled test files of between 1 and 16 MARC bibliographic records, converted them to MARC-XML, and ran them through the Library of Congress transformation service available at Several records were passed through the new MarcNext utility, showing quite similar results. Some of the test files were also passed through Zepheira’s transformation tool.

Individual test files were limited to notated music, performed music as audio, or performed music as video. Compilation records were included for both performed music and notated music, and an effort was made to address various aspects of medium of performance such as partial statements and alternative mediums. In total, 111 records were processed.

Bibframe vocabulary

In the current published Bibframe vocabulary, two properties are designated for medium of performance data: musicMedium and musicMediumNote. Both have exactly the same description: “Instrumental, vocal, and/or other medium of performance for which a musical resource was originally conceived, written or performed.” The expected value is URI for the former and string for the latter. The example given for musicMediumNote carries a string (“voices (4)”) from MARC 130 ‡m in a record for an expression for 4 recorders ( This example is consistent with the vocabulary’s placement of music medium properties in its “Title information” category; however, such placement does not reflect usage patterns for medium of performance statements (as a facet of the resource) as opposed to medium terms used as part of an access point. (No example is given for musicMedium.)

Overview of MARC-to-Bibframe mapping


MARC Subfield Codes



‡a ‡b

not retained


‡a Medium of performance


‡b Soloist

not retained

‡d Doubling instrument


‡p Alternative medium of performance


‡n Number of performers of the same medium

not retained

‡s Total number of performers

not retained

‡v Note

not retained






carried as part of bf:authorizedAccessPoint



medium information not separately treated




Testing results

Analysis of RDF output from testing carefully considers statements of medium of performance as distinct from medium terms added as part of an access point. However, as can be seen in the above mapping, transformation tools do not necessarily make this distinction. This analysis also acknowledges a related project, currently underway, with the goal of programmatic conversion of strings in MARC field 650 and codes in 048 into LCMPT terms in 382. Ideally, though not necessarily, such conversion would take place prior to MARC-to-Bibframe transformation. Thus, data from MARC 382 are the main focus of this analysis.

Current transformations are generally unsatisfactory on three levels: 1) data loss, 2) failure to delimit terms, and 3) failure to distinguish medium terms as part of an authorized access point (AAP) from actual statements of medium of performance.

Data loss

  1. Soloist mediums coded in 382 ‡b are simply ignored under transformation.

  2. Semantics of subfield adjacency in 382 are lost under transformation.

  3. Doubled (382 ‡d) and alternative (382 ‡p) mediums are carried under transformation, but they are treated the same as principal mediums (382 ‡a); thus they simply appear in addition to the corresponding principal mediums. The semantic loss of the doubling or alternative relationship to the principal medium is unsatisfactory in itself; further, it results in a distortion of overall medium of performance statement.

  4. Number (382 ‡n) for each medium and total number (382 ‡s) are both ignored under transformation.

  5. Note-type data recorded in 382 ‡v are ignored under transformation.

Failure to delimit terms

While it is necessary to express medium of performance as a single statement incorporating all constituent mediums, the merging of all medium terms into a single Bibframe element without delimiting individual terms in any way perpetuates yet another string situation. It is not clear how the resulting element is intended to be used or linked. This problem is especially pronounced when a medium of performance statement includes one or more compound terms, for example:

bass voice bass clarinet double bass

Conflict between medium mapped from medium of performance statement (382) and medium term(s) mapped from portion of AAP (240 ‡m)

This conflict is most evident in arrangements that include medium of performance in the AAP. In such cases, transformation yields two bf:musicMediumNote elements—one for the original (from 240 ‡m) and one for the expression (from 382)—with no way to tell which is which.

example (ocn881522545):

240 10 Berceuses, ‡m violin, piano, ‡n op. 16, ‡r D major; ‡o arranged

382 01 clarinet ‡n 1 ‡a piano ‡n 1 ‡s 2 ‡2 lcmpt


violin, piano

clarinet piano

For a concerto with orchestral part arranged for piano, if coded correctly (382 for expression with soloist in ‡b), the resulting Bibframe data will have two bf:musicMediumNote elements: one for the original work and one for piano alone (because 382 ‡b is ignored). In this case, both resulting medium elements will be inaccurate.

example (ocn903519991):

240 10 Concertos, ‡m clarinet, orchestra, ‡n no. 2, op. 5, ‡r F minor; ‡o arranged

382 01 ‡b clarinet ‡n 1 ‡a piano ‡n 1 ‡s 2 ‡2 lcmpt

clarinet, orchestra


This kind of conflict also results in things like the combination of 1) “instrumental ensemble” from AAP, and 2) actual instruments from the medium of performance statement (minus those in 382 subfields that are ignored).


240 10 Concertos, ‡m harpsichord, instrumental ensemble

382 01 ‡b harpsichord ‡n 1 ‡a flute ‡n 1 ‡a oboe ‡n 1 ‡a clarinet ‡n 1 ‡a violin ‡n 1 ‡a cello ‡n 1 ‡s 6 ‡2 lcmpt

harpsichord, instrumental ensemble

flute oboe clarinet violin cello

In all of the above cases, internal comma(s) within subfield ‡m are retained.

Zepheira transformation

While this analysis considers the Library of Congress transformation tool as its baseline, several differences in Zepheira output should be noted. Data loss from MARC 382 is not as severe with Zepheira: solo mediums are retained and so designated, alternative mediums retain their semantic distinction, and numbers and notes (‡v) are also retained. However, doubling mediums are ignored. Zepheira output delimits medium terms (with quotation marks), thus keeping together compounds like “bass clarinet.” Zepheira has extended the Bibframe vocabulary to accommodate several aspects of medium of performance, for example by adding the properties alternativeMedium, featuredMedium, and numberOfPerformers. Medium codes from MARC 048 are actually carried—though not mapped to any Bibframe property—potentially enabling a post-transformation conversion to LCMPT. A particularly unsatisfactory side to Zepheira transformation is the practice of grouping 382 data from multiple 382 fields together by subfield rather than keeping the elements of each 382 together.


  1. Ideally, conversion of strings in MARC 650 and codes in 048 into LCMPT terms in 382 should occur prior to MARC-to-Bibframe transformation.

  2. Transformation rules should be adjusted so that data elements and semantics currently lost under transformation are carried.

  3. If medium terms are to be carried into a single Bibframe element, individual terms should be delimited in some way so that matching terms to their corresponding URIs will be possible. It may also be worthwhile to explore the possibility of incorporating such an enrichment process into transformation.

  4. Some way of preserving the meaning conveyed by subfield adjacency within MARC 382 should be sought. For example, an alternative medium immediately following a solo medium should be recognizable as an alternative solo medium.

  5. MARC-to-Bibframe transformation should distinguish between statements of medium of performance and medium terms as part of access points. This recommendation does not discount the possibility of other use of medium terms from access points.

  6. If “round-trip” transformation back to MARC becomes a desired option, it will be necessary to extend the Bibframe vocabulary, since current transformations map both statements of medium of performance and medium terms given as part of an access point to the same Bibframe property (bf:musicMediumNote).

  7. MARC-to-Bibframe transformation also needs to distinguish between a complete medium of performance for the musical work/expression (382 01) and a partial medium of performance statement (382 11).

  8. The issue of sequence associated with medium of performance must also be considered during transformation. Linking specific medium of performance statements with their respective works is essential to achieving the full potential of these vocabularies. It must be acknowledged, however, that these links are not present in current MARC data. For a detailed discussion on the issue of sequence, see Report 3.3 Sequence.

Tags:  BIBFRAME  Data Migration  MARC  medium of performance 

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