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MARC DISCUSSION PAPER NO. 2021-DP08

DATE: May 27, 2021
REVISED:

NAME: Cleaning Up Redundancies Related to Fields 34X in the MARC 21 Bibliographic Format

SOURCE: OCLC, in consultation with Music Library Association (MLA) and Online Audiovisual Catalogers (OLAC)

SUMMARY: This paper proposes narrowing the definition of Bibliographic field 340 (Physical Medium) subfield $f, currently defined for "Production Rate/Ratio," to be specifically for microform "Reduction Ratio," reducing redundancies and confusion about more recently defined fields and subfields that are now specifically suitable for several historical uses of subfield $f.

KEYWORDS: KEYWORDS: Aspect Ratio (BD); Digital File Characteristics (BD); Digital Graphic Representation (BD); Encoded Bitrate (BD); Encoding Format (BD); Field 340 (BD); Field 344 (BD); Field 345 (BD); Field 347 (BD); Field 352 (BD); Format of the Digital Image (BD); Moving Image Characteristics (BD); Physical Medium (BD); Playing Speed (BD); Production Rate/Ratio (BD); Projection Characteristics of Moving Image (BD); Projection Speed (BD); Reduction Ratio (BD); Sound Characteristics (BD); Subfield $b, in field 345 (BD); Subfield $b, in field 347 (BD); Subfield $c, in field 344 (BD); Subfield $c, in field 345 (BD); Subfield $f, in field 340 (BD); Subfield $f, in field 347 (BD); Subfield $q, in field 352 (BD); Transmission Speed (BD); Vocabulary Encoding Schemes (BD)

RELATED: 2016-DP10, 2016-DP22, 2020-DP03, 2020-DP04, 2020-DP14, 2021-DP04; 94-17, 2003-05, 2011-08, 2017-05, 2020-04, 2020-05, 2021-07, 2021-10.

STATUS/COMMENTS:
05/27/21 – Made available to the MARC community for discussion.

06/29/21 – Results of MARC Advisory Committee discussion: There was widespread agreement, even among those with some concerns, that cleaning up the documented redundancies would reduce confusion and make for clearer MARC records.  For those who wondered if such effort to clean up mostly legacy records for microforms was worthwhile, there was a clarification that the main beneficiaries would be non-microform resources, which now have specific fields and subfields defined for their respective speeds, bitrates, and aspect ratios.  Building upon a notion mentioned in the discussion paper, the suggestion was made and accepted that the proposal include separate subfields in field 340 for both "reduction ratio value" and "reduction ratio designation."  The paper will return as a proposal.


Discussion Paper No. 2021-DP08: Cleaning Up Redundancies Related to Fields 34X

1. BACKGROUND

1.1. Bibliographic Field 340

Field 340 is currently defined in the Bibliographic format as follows:

Field Definition and Scope:
Physical description information for an item that requires technical equipment for its use, and/or more granular description information of an item's material properties to facilitate access and discovery or to support collection management.
Coded physical information is contained in field 007 (Physical Description Fixed Field) and field 008 (Fixed-Length Data Elements). The field is repeated for each subfield $3 (Materials specified).
Multiple values from the same source vocabulary may be recorded in the same field in separate occurrences of subfields. Terms from different source vocabularies are recorded in separate occurrences of the field.

The current text of the repeatable subfield $f states:

$f - Production rate/ratio (R)
Normal rate or ratio at which the information in the material must be used to be meaningful (e.g., how many revolutions per minute for recordings, the magnification for photographic reductions).

340 ##$3case files$aaperture cards$b9 x 19 cm.$dmicrofilm$f48x.

In 2011, several new 34X fields were introduced to allow for the recording of specific technical characteristics for sound, moving images, and digital files. In three of these fields, there are now subfields whose definitions needlessly overlap with the definition of field 340 subfield $f. In one case, the current definition of field 340 subfield $f explicitly duplicates the more specialized intention of the newer field and subfield.

1.2. Bibliographic Field 344

Field 344 is currently defined in the Bibliographic format as follows:

Field Definition and Scope:
Technical specifications relating to the encoding of sound or the absence of sound in a resource.
Multiple values from the same source vocabulary may be recorded in the same field in separate occurrences of subfields. Terms from different source vocabularies are recorded in separate occurrences of the field.

The current text of the repeatable subfield $c in field 344 reads:

$c - Playing speed (R)
The speed at which an audio carrier must be operated to produce the sound intended.

344 ##$aanalog$2rdatr
344 ##$c78 rpm

This definition is an explicit duplication of how field 340 subfield $f is currently defined: "Normal rate or ratio at which the information in the material must be used to be meaningful (e.g., how many revolutions per minute for recordings, the magnification for photographic reductions)." In RDA, the redundancy of field 340 subfield $f and field 344 subfield $c is documented in the "playing speed" MARC 21 Bibliographic element reference.

In two other fields, the duplications are more implicit than explicit but would nonetheless benefit from clarification.

1.3. Bibliographic Field 345

Bibliographic field 345, introduced as “Projection Characteristics of Moving Image” in 2011 and renamed as “Moving Image Characteristics” in 2020, is currently defined as follows:

Field Definition and Scope:
Specifications relating to a moving image resource.
Multiple values from the same source vocabulary may be recorded in the same field within separate subfield occurrences. Terms from different source vocabularies are recorded in separate occurrences of the field.

The current texts of the repeatable subfields $b, $c, and $d in field 345 read:

$b - Projection speed (R)
The speed at which a device must be operated to produce the moving image intended.

345 ##$aCinerama$2rdapf
345 ##$b24 fps

$c - Aspect ratio value (R)
A numerical ratio of the width to the height of a moving image.

345 ##$c16:9$dwide screen

$d - Aspect ratio designator (R)
A general description of the ratio of the width to the height of a moving image.

345 ##$dletterboxed$dmixed aspect ratio

The most obvious duplication here is subfield $b, “Projection Speed,” but because field 340 subfield $f has traditionally dealt with both rate/speed and ratio, it may be prudent to take field 345 subfields $c and $d into consideration, as well. In RDA, the redundancy of field 340 subfield $f and field 345 subfield $b is documented in the "projection speed" MARC 21 Bibliographic element reference.

1.4. Bibliographic Field 347

Bibliographic field 347, introduced in 2011, is currently defined as follows:

Field Definition and Scope:
Technical specification relating to the digital encoding of text, image, audio, video, and other types of data in a resource. This information could also be recorded in field 300 (Physical Description) $b (Other physical details).
Multiple values from the same source vocabulary may be recorded in the same field in separate occurrences of subfields. Terms from different source vocabularies are recorded in separate occurrences of the field.

The current text of the repeatable field 347 subfield $f, originally defined as “Transmission speed” and renamed in 2014, reads:

$f - Encoded bitrate (R)
The speed at which streaming audio, video, etc., is designed to play.

347 ##$aaudio file$2rdaft
347 ##$bMP3
347 ##$f32 kbps

Again, a clarification seems to be in order.

Field 347 is also defined in the MARC Holdings format, but Holdings does not define field 340, so there is no chance of similar confusion.

1.5. Bibliographic Fields 347 and 352

The current text of the repeatable field 347 subfield $b, "Encoding format," reads:

347 - Digital File Characteristics (R)

$b - Encoding format (R)
A schema, standard, etc., used to encode the digital content of a resource.

347 ##$atext file$2rdaft
347 ##$bPDF

347 ##$avideo file$2rdaft
347 ##$bBlu-Ray

Bibliographic field 352 is currently defined as follows:

Field Definition and Scope:
Description of the method of referencing and the mechanism used to represent graphic information in a data set. This information consists of the type of storage technique used, the number of items in the data set, and the format in which the data is stored.

The current text of the nonrepeatable subfield $q, introduced in 2003, reads:

$q - Format of the digital image (NR)
Name of the format in which the digital image is stored.

352 ##$aVector :$bPoint$c(13671),$bstring$c(20171),$bGT-polygon composed of chains$c(13672) ;$qARC/INFO export.
352 ##$aRaster :$bpixel$d(5,000 x$e5,000) ;$qTIFF.

Although the definitions of field 352 and subfield $q are understood to be limited to the digital format of a cartographic data set, the redundancy of subfield $q with the encoding format of field 347 subfield $b is recognized in RDA in the "encoding format" MARC 21 Bibliographic element reference.

Within the context of the other 34X changes arising in this paper, it seems that this overlap deserves at least a discussion.

2. DISCUSSION

MARC Proposal No. 2011-08 (2011) had suggested the possible augmentation of field 340 to identify each general carrier characteristic then found in RDA with a particular subfield of field 340. In Section 2.3 of that proposal, subfield $f was explicitly identified with RDA 3.15, "Reduction ratio." That proposal led to the addition of Bibliographic fields 344, 345, 346, and 347, as well as subfields $j through $o to field 340. At that time, the definition of field 340 subfield $f already accounted for reduction ratio but was not tightened up sufficiently to remove references to playing speeds that would henceforth be covered by the newly defined fields and subfields

The suggestion here is to finally align subfield $f with what appeared to be the 2011 intention, renaming it "Reduction Ratio," narrowing its definition, and removing the potential confusion with more specific subfields.

The current field 340 subfield $f:

340 - Physical Medium (R)

$f - Production rate/ratio (R)
Normal rate or ratio at which the information in the material must be used to be meaningful (e.g., how many revolutions per minute for recordings, the magnification for photographic reductions).

Adapting the RDA definition of "reduction ratio" and taking stylistic cues from the definitions of subfields $n (Font Size) and $p (Illustrative Content), we propose the following:

340 - Physical Medium (R)

$f – Reduction ratio (R)
A general and/or specific indication of the size of a micro-image in relation to the original from which it was produced.
Reduction ratio may be expressed in general terms (e.g., low reduction, ultra high reduction), numerically as a reduction designation (e.g., 16x, 90x), or numerically as a ratio (e.g., 16:1, 90:1).

The RDA Reduction Ratio Designation Value Vocabulary maintains a controlled vocabulary of the five "concepts for a numerical ratio of the size of a micro-image in relation to the original from which it was produced." The "low reduction" and "ultra high reduction" examples are taken from this vocabulary. When this vocabulary is used, subfield $2 is coded "rdarr".

Slight variations on this idea have also been suggested, although at this point in the histories of both MARC 21 and microform reproduction they might be deemed excessive. Working from the recent example of field 345 subfield $c being defined for the numerical "Aspect ratio value" and subfield $d for the descriptive "Aspect ratio designator," field 340 subfield $f could be even more narrowly defined. Taking the second paragraph of the proposed field 340 subfield $f definition above, the verbal general terms and the numerical expressions could be divided into separate subfields. Alternatively, the verbal general terms, the numerical reduction designation, and the numerical reduction ratio could be three separate subfields.  In each case, subfield $f could be limited to, say, the verbal terminology, and either a new single subfield defined for the two numerical expressions or each numerical expression being assigned its own new subfield.  If any of these variations attract support, they can be worked up in a resulting proposal, with examples.

If deemed useful, guidance from field 340 subfield $f to the current homes of elements that are no longer so coded could be added to subfield $f.

In the 2021 April 1 analysis of the 509,146,170 bibliographic records in WorldCat, field 340 was found in 7,824.583 of them (1.54% of all WorldCat records), and in turn subfield $f appeared in 27,549 of those (0.35% of all fields 340). Roughly 2,600 of those subfields $f currently contain identifiable reduction ratios, about 45 contain identifiable moving image projection speeds, and smaller numbers contain identifiable aspect ratios. Small numbers contain data that are not obviously related to any current or past definition of subfield $f and/or would require individual investigation. The remaining 24,000 to 25,000 contain sound recording playing speeds. OCLC would be able to clean up and/or convert most or all of the subfields $f in WorldCat. To provide some context, here are the current WorldCat statistics on the four fields and seven subfields discussed:

3. PROPOSED CHANGES

In the MARC 21 Bibliographic Format, rename field 340 subfield $f and revise the definition as follows:

340 - Physical Medium (R)

$f – Reduction ratio (R)
A general and/or specific indication of the size of a micro-image in relation to the original from which it was produced.
Reduction ratio may be expressed in general terms (e.g., low reduction, ultra high reduction), numerically as a reduction designation (e.g., 16x, 90x), or numerically as a ratio (e.g., 16:1, 90:1).

4. EXAMPLES


4.1. Bibliographic 340 subfield $f examples

Example 1: Bibliographic 340 subfield $f example with numerical reduction designator

340 ##$3case files$aaperture cards
340 ##$3case files$b9 x 19 cm
340 ##$3case files$dmicrofilm
340 ##$3case files$f48x

Example 2: Bibliographic 340 subfield $f example with numerical reduction ratio

340 ##$3case files$aaperture cards
340 ##$3case files$b9 x 19 cm
340 ##$3case files$dmicrofilm
340 ##$3case files$f48:1

Example 3: Bibliographic 340 subfield $f example with term from the RDA Reduction Ratio Designation vocabulary

340 ##$3case files$aaperture cards
340 ##$3case files$b9 x 19 cm
340 ##$3case files$dmicrofilm
340 ##$3case files$fhigh reduction$2rdarr

4.2. Bibliographic 340 subfield $f audio recording playing speed now in field 344 subfield $c

Former use of field 340 subfield $f

340 ##$f33 1/3 rpm

Conversion to field 344 subfield $c

344 ##$c33 1/3 rpm

4.3. Bibliographic 340 subfield $f moving image projection speed now in field 345 subfield $b

Former use of field 340 subfield $f

340 ##$f24 fps

Conversion to field 344 subfield $b

345 ##$b24 fps

4.4. Bibliographic 340 subfield $f moving image aspect ratio value now in field 345 subfield $c

Former use of field 340 subfield $f

340 ##$f16:9

Conversion to field 344 subfield $c

345 ##$c16:9

4.5. Bibliographic 340 subfield $f moving image aspect ratio designator now in field 345 subfield $d with VES identifier in subfield $2

Former use of field 340 subfield $f

340 ##$fwide screen

Conversion to field 344 subfield $d

345 ##$dwide screen$2rdaar

4.6. Bibliographic 340 subfield $f digital file encoded bitrate now in field 347 subfield $f

Former use of field 340 subfield $f

340 ##$f32 kbps

Conversion to field 347 subfield $f

347 ##$f32 kbps

4.7. Bibliographic 352 subfield $q format of the digital image now in field 347 subfield $b encoding format

Former use of field 352 subfield $q

352 ##$qPDF

Conversion to field 347 subfield $b

347 ##$bPDF

5. BIBFRAME DISCUSSION

Better definition and alignment with RDA will improve conversion from MARC to BIBFRAME since BIBFRAME is aligned with RDA.

6. QUESTIONS FOR DISCUSSION

6.1. Are the potential points of confusion caused by the overlapping definitions noted in this paper serious enough to be worth trying to clean up, for the sake of working catalogers, in looking forward to linked data, or for any other reasons?

6.2. Has the benefit of resolving the overlap between Bibliographic field 340 (Physical Medium) subfield $f (Production rate/ratio) and field 344 (Sound Characteristics) subfield $c (Playing speed) been adequately presented? (See 1.2.)

6.3. Has the benefit of resolving the overlap between Bibliographic field 340 (Physical Medium) subfield $f (Production rate/ratio) and field 345 (Moving Image Characteristics) subfield $b (Projection speed) been adequately presented? (See 1.3.)

6.4. Has the benefit of resolving the overlap between Bibliographic field 340 (Physical Medium) subfield $f (Production rate/ratio) and field 345 (Moving Image Characteristics) subfields $c (Aspect ratio value) and $d (Aspect ratio designator) been adequately presented? (See 1.3.)

6.5. Has the benefit of resolving the overlap between Bibliographic field 340 (Physical Medium) subfield $f (Production rate/ratio) and field 347 (Digital File Characteristics) subfield $f (Encoded bitrate) been adequately presented? (See 1.4.)

6.6. Has the benefit of resolving the overlap between Bibliographic field 347 (Digital File Characteristics) subfield $b (Encoding format) and field 352 (Digital Graphic Representation) subfield $q (Format of the digital image) been adequately presented? (See 1.5.)

6.7. Would it be useful to add guidance from Bibliographic field 340 (Physical Medium) subfield $f (Production rate/ratio) to any of the preferred fields and subfields?

6.8. If the decision is made to redefine Bibliographic field 340 (Physical Medium) subfield $f from its current “Production Rate/Ratio” to “Reduction Ratio,” is there any additional value in limiting the numerical expression of the reduction ratio to either the reduction designation form (e.g., 16x, 90x) or the reduction ratio form (e.g., 16:1, 90:1), and if so, which?

6.9. If the decision is made to limit the definition of Bibliographic field 340 (Physical Medium) subfield $f, is there any additional value in limiting it further to verbal reduction terms (such as "low reduction") and defining either one additional subfield for both numerical options or two additional subfields, one for the numerical reduction designation (such as "16x") and one for the numerical reduction ratio (such as "16:1")?

6.10. Are there any potential consequences of the contemplated changes that this paper does not take into consideration?


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