Conference ItemAbstract: This paper presents results of an analysis of different implementations of the JPEG2000 standard, specifically part 1: JP2, an image format that is currently popular within the digital preservation community. In particular we are interested in the effect different JPEG2000 codecs (encoders and decoders) have on image quality in response to lossy compression. We focus on three main codec libraries for analysis - Kakadu, JasPer and OpenJPEG - migrating 932 TIFF newspaper images to lossy JPEG2000 files using 2:1 and 4:1 compression ratios, and monitor image quality using PSNR. We look at the combination of encoder/decoder pairs and find that using OpenJPEG for both gives the best quality results, albeit with the slowest execution time. We also find that in some circumstances, particularly when a JasPer encoder is used, in order to retain image quality of the decoded image, the best choice of decoder may not be the same codec used to create the JPEG2000; based on these results, the encoding library is therefore recommended technical preservation metadata to retain.
Palmer, William; May, Peter; Cliff, Peter
ArticleAbstract: This article introduces the British Library’s Flashback project, which is exploring the practical challenges of preserving digital content currently stored on physical media (magnetic and optical disks). It reports on a Flashback proof of concept that conducted experiments on a sample of content from hybrid collection items dating from between 1980 and 2000. It describes some of the activities undertaken by the proof-of-concept stage of the project from July 2015 to February 2016, including the initial collection profiling and sampling of content, the extraction of content from the disks, and the project team’s experiments with identifying and applying preservation approaches to the content, which included both emulation and migration. It concludes with some general observations on the approaches taken by the proof of concept and shares some recent findings from the second phase of the project, which is concerned with the practical challenges of developing an implementation strategy for the Library’s capture and preservation of digital content currently stored on physical media.
Day, Michael; Pennock, Maureen; May, Peter; Davies, Kevin; Whibley, Simon; Kimura, Akiko; Halvarsson, Edith