ePUB Files - the Essentials for Electronic Publishing
We are often asked whether a training document, book or other document can be augmented with embedded video and/or audio and/or other interactive elements. The brief answer for standards-compliant PDFs is that video and audio can be provided but only via explicit links with the media files hosted on a server somewhere in the cloud - i.e. linked rather than embedded. However, for HTML5-based technologies such as web-based display and for many ePUB documents the answer is "yes", as explained further below:
Using ePUB instead of PDF - what are the pros and cons?
"ePUB is the distribution and interchange format standard for digital publications and documents based on Web Standards. ePUB defines a means of representing, packaging and encoding structured and semantically enhanced Web content - including XHTML, CSS, SVG, images, and other resources - for distribution in a single-file format. ePUB allows publishers to produce and send a single digital publication file through distribution and offers consumers interoperability between software/hardware for unencrypted reflowable digital books and other publications." International Digital Publishing Forum (http://idpf.org/epub).
In addition to reflowable text (text font size selection amends the layout of the text displayed on screen) ePUB files may include advanced features including:
- optional fixed format page layouts
- video and audio media embedding
- pop-up widget embedding
- interactive questions/answers
Some ePUB readers can display all of the above facilities, whereas others may be restricted to a subset. Note that there are a number of different ePUB standards and specialist ePUB creation tools may or may not be able to produce all the advanced features described above. The Wikipedia page on ePUB (https://en.wikipedia.org/wiki/EPUB) provides a useful summary of the history, structure and use of ePUB files, with a partial list of ePUB readers and ePUB editor software.
Creating ePUB files
ePUB format files can be hand edited (rather like editing a web page using HTML, CSS and XML), but very few ePUB files are generated in this way. In most cases ePUB files are created using the Export to ePUB facilities provided by specialist document creation software. These output files may then be augmented with media or other "extensions" using specialist ePUB editors.
In general you cannot convert PDF files to ePUB - although many tools claim to do this for you the formats are so different that only the simplest of PDFs will convert in a satisfactory manner - most just end up as a mess.
Products for creating ePUB eBooks include Adobe InDesign (https://www.adobe.com), Calibre (https://calibre-ebook.com/), Pubcoder (https://www.pubcoder.com/), Help and Manual (https://www.helpandmanual.com/index.html), Sigil (https://sigil-ebook.com/) and many others. For Kindle eBooks there are free Amazon-provided "Creator" tools for PCs and Macs - see https://kdp.amazon.com/en_US/help/topic/G200735480 for more details. For iBooks there is the Apple iBooks Author product (https://www.apple.com/uk/ibooks-author/). Note that Kindle uses non-standard (proprietary) variants of the official ePUB standards.
If you have an ePUB file created and saved on your computer, you can rename it from having an .ePUB file extension to a .zip file extension and then open the zip file to see exactly how the various parts of the file are included within the packed document.
Distributing ePUB files
Once you have an ePUB file ready for distribution you then need to decide on how you will distribute it. There are several options:
- make the file available as a standard ePUB file without any form of protection
- upload the ePUB file to a service that provides ePUB file hosting with Digital Rights Management (DRM) protection - for example to the Google Books service, Amazon Kindle Direct Publishing service, or one of the many third party services that use the Adobe eBook Platform (https://www.adobe.com/solutions/ebook.html).
- Convert the ePUB file to an app (ideally with protection against hacking) and distribute the app via the main app stores and/or via direct download - this does not typically provide any DRM protection, but copy protection can be provided (e.g. using Google Play Licensing)
- Convert the file to an encrypted ePUB file with DRM protection using a bespoke service
In most cases it is preferable to have some level of protection of the files, so use of DRM-enabled ePUB is the norm for commercial publications - the security is relatively weak generally so care is needed when selecting the method of distribution, the price (if any) that the publication is offered at, and the risk of the item being copied.
In summary - the main advantages of ePUB over PDF is the range of additional facilities that can be included in the single "package" and the suitability for smaller mobile devices like small tablets and mobile phones. The main disadvantages are the relatively weak security and limited permissioning controls, even for documents with traditional DRM. And it assumes the source document and associated resources are available in ePUB format.
We assist training organizations, educational publishers and others in the selection and implementation of PDF, Print-on-demand and ePUB-based publishing solutions. If you have any questions about our services please Contact us