Evaluating JPEG2000 for Cultural Heritage Organizations Gretchen Gueguen Digital Archivist 9/13/2011 Evaluating JPEG2000 for Cultural Heritage Organizations by Gretchen Gueguen is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License. Gretchen GueguenCreative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License

What Well Cover… What is JPEG2000 What are the advantages? What are the risks? How do I decide if JPEG2000 is the standard for me?

JPEG2000 Dry, dictionary definition: JPEG 2000 is an image compression standard and coding system. It was created by the Joint Photographic Experts Group committee in 2000 with the intention of superseding their original discrete cosine transform-based JPEG standard (created in 1992) with a newly designed, wavelet- based method.

JPEG2000 Format for still and moving images Smaller than some other high resolution formats Ability to compress through lossless or visually lossless algorithms Scalable display More robust embedded metadata Error resilience Supports images at least up to a terabyte

Risks Uptake in adoption, but not as fully compatible as TIFF or JPEG –Digitization –Display/handling Unfamiliarity to administrators and users Complexity can lead to long-term risks

Decision-making Evaluation Factors: Compression and savings possible Scalability vs. Derivatives Tools Available Conversion projects Adoption by peers

JPEG2000 compression True Lossless (reversible) –Can still achieve significant size reduction Visually Lossless (irreversible) –Lossy compression with no visible effect Lossy (irreversible) –Lossy compression with visible effects

Compressions and savings TIFF = 35 Mb 1:1/2:1 = 4.96 Mb (86% reduction) 4:1 = 4.56 Mb (87% reduction) 6:1 = 3.89 Mb (89% reduction) 10:1 = 2.87 Mb (92% reduction) 25:1 = 1.39 Mb (96% reduction) 50:1 = 0.72 Mb (98% reduction) 100:1 = 0.37 Mb (99% reduction) Source:

Compression rate Testing compression algorithms to get best trade-off –Even lossless can save a lot –At what point are your returns for further compression too small Size Compression rate

Evaluating compression Comparing Differences using Photoshop m/2010/10/guest-post-examining-losses- simple.htmlhttp://jpeg2000wellcomelibrary.blogspot.co m/2010/10/guest-post-examining-losses- simple.html image/documents/Comstock.pdfhttp:// image/documents/Comstock.pdf

Lossy Compression and Predictability

JPEG2000 Scalability

Scalability vs. Derivatives JPEG2000 can natively scale to different sizes Do you WANT to only have one copy? –Preservation master –Production master –Access copies (full, high, and/or medium resolutions) –Thumbnails

JPEG2000 Tools: Image Creation

JPEG2000 Tools: Display

JPEG2000 Tools Serve and Render –Kakadu + Djatoka (open source*) –LuraWave (commercial)

JPEG2000 Tools Online enhancement –Internet Archive BookReader (open source) –Library of Congress Newspaper Viewer (open-source)

JPEG2000 Tools Create or edit –Photoshop (commercial) j2k plugin for more advanced work –Newer versions of Silverfast (commercial) –GIMP (open source) lower level support

Backlog Conversions TIFF to JPEG2K backlog? –Infrastructure –Time Testing Migration QA

Adoption by Peers Library of Congress Internet Archive Wellcome Library Google LexisNexis Multiple Universities…

ECU Example JP2 master going forward. No backlog conversion (at this time) Scan as tiff due to software constraints, convert to JP2 during post-production clean-up phase Save the master in offline storage Deliver a derivative JP2 for access for maps and books in a zooming book viewer Use a GIF thumb because of load issues

UVa Example Uncompressed tiff as preservation master 186,000+ jp2 for access purposes only –Maps, books, and sheet music –Other things just in tiff at the moment, not available yet Two different lossy compression algorithms for access based on average compression toleration –One for large-scale maps –One for everything else Dynamically-generated thumbnails

Learn More… JP2K-UK Working Group Wiki JP2k at Wellcome Library Blog JPEG 2000 for the Practitioner Library of Congress JPEG2000 Workshop presentations UConn survey on JPEG2000 adoption rate DPBestFlow.org