10 January 2012
This will be my shortest blog post ever. Following up on my previous
blog post on a prototype JP2 validator and properties
(jpylyzer), there is now a comprehensive User Manual of the tool. Just
follow the link below:
Link to jpylyzer home page:
Meanwhile work on jpylyzer remains ongoing, so watch this space for
any updates on this.
Update February 2019: updated links in original blog post
Originally published at the Open Preservation Foundation blog
14 December 2011
A few months ago I wrote a blog
on a simple JP2 file structure checker. This led to some interesting
online discussions on JP2 validation. Some people asked me about the
feasibility of expanding the tool to a full-fledged JP2 validator.
Despite some initial reservations, I eventually decided to dedicate a
couple of weeks to writing a rough prototype. The first results of this
work are now ready in the form of the jpylyzer tool. Although I
initially intended to limit its functionality to validation (i.e.
verification against the format specifications), I quickly realised that
since validation would require the tool to extract and verify all header
properties anyway, it would make little sense not to include this
information in its output. As a result, jpylyzer is both a validator
and a properties extractor.
21 September 2011
As I already briefly mentioned in a previous blog
one of the objectives of the
SCAPE project is to develop an
architecture that will enable large scale characterisation of digital
file objects. As a first step, we are evaluating existing
characterisation tools. The overall aim of this work is twofold. First,
we want to establish which tools are suitable candidates for inclusion
in the SCAPE architecture. As the enhancement of existing tools is
another goal of SCAPE, the evaluation is also aimed at getting a better
idea of the specific strengths and weaknesses of each individual tool.
The outcome of this will be helpful for deciding what modifications and
improvements are needed. Also, many of these tools are widely used
outside of the SCAPE project, which means that the results will most
likely be relevant to a wider audience (including the original tool
01 September 2011
Over the last few weeks I’ve been working on the design of a workflow
that the KB is planning to use for the migration of a collection of
(mostly old) TIFF images to JP2. One major risk of such a migration is
that hardware failures during the migration process may result in
corrupted images. For instance, one could imagine a brief network or
power interruption that occurs while an image is being written to disk.
In that case data may be missing from the written file. Ideally we would
be able to detect such errors using format validation tools such as
JHOVE. Some time ago Paul Wheatley
reported that the BL at some point were dealing with corrupted,
incomplete JP2 files that were nevertheless deemed “well-formed and
valid” by JHOVE. So I started doing some experiments in which I
deliberately butchered up some images, and subsequently checked to what
extent existing tools would detect this.