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Introduction to PEF
Introduction to PEF
Today, anyone who comes in contact with braille is occasionally confronted
with braille files that do not emboss correctly. To amend this, you need
several skills. First you need to understand the text. This, in turn, means
that you need to know braille, the languages used and (sometimes) the topic
of the text. Secondly, you need knowledge about plausible character and
braille encoding combinations and how to adjust your software/embosser
accordingly. Depending on the differences between your current encoding
combination and the intended encoding combination, this process could
potentially involve hours of trial and error - if you are lucky enough to
have all these skills, that is.
A common, unambiguous exchange format is needed to efficiently share
braille in electronic form. There are several reasons behind the development
of PEF:
- To facilitate ordering of additional braille copies at a later point in
time
- To ensure readability of the material many years from now
- To reduce costs for embossing
- To enable easy file sharing (e.g. braille music) across regions having
different embosser settings or software
What is PEF?
The Portable Embosser Format (PEF) is a data format for representing
braille books, accurately and unambiguously.
PEF is a digital braille hardcopy - the PDF of braille books, if you
will.
PEF can be used for braille embossing and archiving anywhere in the world,
no matter where nor how it was produced. It allows new features to be added,
such as ink overlay or tactile graphics, thus enabling a completely automated
reproduction of advanced braille books.
PEF is built on XML, Unicode and Dublin Core. Three well known, widely
used and reliable technologies.
What about ASCII braille?
Many important aspects of ASCII braille are undefined. These aspects are
interpreted differently depending on the embosser and/or software used.
Furthermore, ASCII braille lacks even the most basic facilities to ensure
that it is possible to identify, verify, read and store. For example:
- ASCII braille depends on an alternate interpretation of regular ASCII
characters, but provides no means of how to differentiate one
interpretation from another.
- Common characters like .?()+$% and # render different braille patterns
depending on embosser and/or software locale. The reality is that one
can’t send an ASCII braille file to an embosser without braille
knowledge.
- A user keeping a collection of ASCII braille files cannot rely on
embedded metadata when searching or organizing, such as one can with for
example mp3-files. In fact, no additional information whatsoever can be
attributed to an ASCII file.
A stray file that has been taken out of context or transferred from one
computer to another can be very difficult to make sense of, even for a
skilled transcriber or braille user.
Why use PEF?
PEF takes care of these problems.
- A PEF file provides metadata, i.e. information about its contents that
can be used for tracing, tracking, organizing and searching.
- PEF is a proper file format, defined in a publicly available standard.
There is never any doubt about how to interpret or use the contents of a
PEF file.
- Publishing and republishing can be achieved quickly and easily, without
worrying about embosser or software settings.
Using PEF today
It is possible to use PEF today. Scripts in the Daisy Pipeline allow you
to:
- emboss a PEF file
- input an ASCII braille file and get a PEF file as output
- input a PEF file and get an ASCII braille file as output
- convert between different ASCII braille formats
Simple distribution
A package file prototype (a JAR file) has been developed that enables
instant embossing of PEF files on Windows, Mac and Linux platforms, without
any software installation (JRE 1.5 or newer must be available on the system).
The package file contains braille, embossing software and a fully accessible
web interface.
Through the web interface you can:
- set up the target embosser
- find information about the publication
- emboss the publication, in its entirety or a selection of pages
The embossing software is so small that it can be redistributed every time
a user asks for braille. In fact, it is often smaller than a PEF file on its
own.
Contact us
If your organization thinks that PEF is a good idea and wants to support
it, let us know.
Read more about PEF on the Daisy website
(http://www.daisy.org/projects/braille/braille_workarea/pef/pef-specification.html)
or contact joel.hakansson(at)tpb.se for more information.