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.