Tablets, dedicated eReaders and smartphones present a further challenge, in that they do not all implement the display of a specific format in the same way. For example, the Amazon Kindle, which is the best-selling, most-used eReader, displays only in grayscale while the Barnes and Noble Nook supports color. In many cases the same ePub is implemented differently in different devices, requiring the use of either a lowest common denominator ePub, specific varieties of ePub for specific devices, or the ability to “gracefully degrade” content that cannot be displayed on a particular device.
Additionally, there are other limitations, primarily the ability to display video. Over time, this challenge will all but disappear, however, in the short term, not all devices will have access to video, and the Platform incorporates the intelligence to manage those devices appropriately.
Further, the DRM supported by these devices may be readily-available, proprietary, or not present. The most readily available device DRM is currently Adobe ACS4. This platform is available for license from Adobe, but has pricing that can be prohibitive in a library lending model. The DRM for Amazon Kindle, Mobipocket is proprietary and not available for private application – as such any files that are DRM encoded for delivery to the Kindle must go through Amazon. VML proposes that Follett include its own DRM to support a lending model in controlled environments.
Finally, the DRM on devices supports control of the content on that device – primarily to avoid un-authorized sharing across devices and to expire the content at some time after purchase. The library lending environment requires additional DRM control, such as how many times an eBook can be lent before the publisher right expires. This is designed into the system.