The marc-in-json<http://dilettantes.code4lib.org/blog/2010/09/a-proposal-to-serialize-marc-in-json/>format
is, as you might expect, a JSON serialization for MARC. A JSON
serialization for MARC is potentially useful in the same places where
MARC-XML would be useful (long records, utility of human-readable records,
etc.) without what many perceive to be the relative pain of working with
XML vs JSON.

It's currently supported across several implementations:

   - ruby's *marc* gem
   - php's *File_MARC*
   - java's *marc4j*
   - python's *pymarc*

There wasn't one for perl, so I wrote one :-)

MARC::File::MiJ<http://search.cpan.org/~gmcharlt/MARC-File-MiJ-0.01/lib/MARC/File/MiJ.pm>is
a perl module that allows MARC::Record to encode/decode marc-in-json.
It
also supplies a handler to MARC::File/MARC::Batch that will read
marc-in-json records from a newline-delimited-json (ndj) file (where each
line is a JSON object without unescaped newlines, ending with a newline).

marc-in-json encoding/decoding tends to be pretty
fast<http://robotlibrarian.billdueber.com/sizespeed-of-various-marc-serializations-using-ruby-marc/>,
since json parsers tend to be pretty fast, and uncompressed filesizes
occupy a middle-ground between binary marc and marc-xml. A sample file of
about 18k marc records looks like this:

  31M topics.mrc
  56M topics.ndj (newline-delimited JSON)
  93M topics.xml

 8.9M topics.mrc.gz
 7.9M topics.ndj.gz
 8.7M topics.xml.gz

​...so obviously it compresses pretty well, too.

I can take generic questions; bugs should go to
https://rt.cpan.org/Public/Bug/Report.html?Queue=MARC-File-MiJ

[ Note that there are many other possible JSON serializations for
MARC<http://jakoblog.de/2011/04/13/mapping-bibliographic-record-subfields-to-json/>,
including the (incompatible) one implemented in the
MARC::File::JSON<http://search.cpan.org/~cfouts/MARC-File-JSON-0.002/lib/MARC/File/JSON.pm>module]




-- 
Bill Dueber
Library Systems Programmer
University of Michigan Library