This is a textual representation of a lightning talk done on Feb 26th at Code4Lib 2008.
When the video of the talk is up (thanks, Noel!) I’ll link it here, too. The video is now available, and that article includes an update on progress since the this article was posted.
OhioLINK has a collection of JPEG2000 images as an access format that were generated for use in our DLXS-based content system. We are in the process of migrating those collections to DSpace and were looking for a mechanism to leverage the existing JPEG2000 files and not have to generate new derivatives. We are also considering the use of JPEG2000 as a preservation format, and would find it attractive to use the same image format for both access copies and preservation copies. We looked at Zoomify, but to perform its scaling function it generates JPEG tiles at several resolutions and storing those tiles can triple or quadruple disk space requirements. Or, one could use the ‘enterprise’ version of Zoomify and its proprietary PFF format or the equally proprietary MrSID format. We didn’t want to be locked into either of these scenarios. Our solution is to create a web application that mimics the directory-of-JPEG-tiles solution, but to dynamically generate the tiles our of a JPEG2000 master.
The free version of Zoomify reads JPEG tiles out of a directory structure that looks like this:
The shim mimics that directory structure. It parses the URL of the request and dynamically creates the appropriate JPEG tile (or metadata file) out of the JPEG2000 image.
The source code is available from the Subversion access). We plan to integrate it into DSpace 1.5 as part of the Ohio Digital Resource Commons, and I may create a Fedora disseminator to serve up the tiles as well.(
Thanks go out to Keith Gilbertson and John Davison on the OhioLINK staff for their help in making this work as well as Stu Hicks and François d’Erneville for being a sounding board for these ideas.
The text was modified to update a link from http://code4lib/conference/2008 to http://code4lib.org/conference/2008 on January 28th, 2011.
The text was modified to update a link from http://www.kakadusoftware.com/Purchasing.html to http://www.kakadusoftware.com/index.php?option=com_virtuemart&Itemid=19&vmcchk=1&Itemid=19 on January 28th, 2011.(This post was updated on 27-Jan-2011.)