APNX
APNX is a new file format for Amazon Kindle 3 and is used to store the page numbers as related to a paper version of the book. This can allow referencing page numbers in an academic document.
Contents |
[edit] Overview
APNX provides a method to achieve an exact match between the eBook pages and a specific edition of the paper book. It is also possible to generate approximate matches automatically in some cases using a program. Once the APNX file is generated there is no way to know if it is an exact match or just an approximate one.
[edit] The format
The file format has been decoded by MobileRead user:User_none The file begins with a header similar to below.
{"contentGuid":"8d3d16e0","asin":"B002RHGYOA","cdeType":"EBOK","fileRevisionId":"1296868639127"} ) = {"asin":"1906694184","pageMap":"(4,a,1)"}
Following this header is a list of 4 byte sequences of big endian ints. They are in an increasing order. The total number of the 4 byte sequences is 573. The first 3 ints are all 0 which leads me to believe they are padding. The total number of pages within the book are 570 (as shown on the Kindle itself). The apnx file is a list of file locations where each is the beginning of a new page.
A more in-depth & up to date look at user-none's work on the APNX format is available in Calibre's docs.
[edit] Kindle publishing
KindleGen version 1.2 does not generate an APNX file directly; it creates a PAGE section in the MobiPocket file which is then stripped and converted to an APNX file by Amazon's publishing service. The KindleGen input can use either a NCX pageList or page-map xml.
Kindle Previewer, as of version 1.5, does not display page numbers. In addition, Kindle for PC and Kindle for Mac, while they do display page numbers using .apnx files, are unable to read them from a MobiPocket file generated by KindleGen. This makes testing the page number feature somewhat problematic for publishers.
[edit] For more information
- NCX describes the format for the page numbers description in the source file.
- MobileRead forum - discussion on this new feature and how to add them to Calibre.
- MobileRead forum - on APNX generation.
- Amazon discussion of this feature
