File size limits in Digital Editions

While the Best Practices document (over in the Adobe Developer Connection) had the recommendation that books be broken up into chapters, it wasn’t clear when you needed to break a document up further, or when a book was small enough so that one XHTML file was sufficient.

With the recent update to the document (version 1.0.2) we’ve given you information on how big the chapters can be.

Those limits on the file sizes are as follows:* XHTML/DTBook chapters: 300k uncompressed per chapter/100k compressed.* Images: 10M uncompressed.Note that these limits are for a single chapter document (or image) within the package, not a limitation on the size of the ePub document. The ePub can of course be much larger (limited by available storage space.)The limits are important for reading ePub documents on a mobile device.

5 Responses to File size limits in Digital Editions

  1. Do you think these ADE-specific requirements could be baked in epubcheck along with a –ade flag?

  2. Paul Norton says:

    Actually I’d rather see epubcheck be just validation and leave anything that is Adobe specific or anything that is subjective for a different tool (although it could be of the same form as epubcheck.) It could check for file limits and SWF objects that don’t have fall-backs for mobile devices. I’m sure we could come up with other things it could check for as well.

  3. Paul: That sounds fine.

  4. Mangal says:

    I want to know that how page numbers rendered on Adobe digital edition at the right of content.These page number are not consistent as per content.Please suggest me how i make page numbers consistent.Thanks

  5. Peter Sorotokin says:

    Page numbers can be controlled by adding a page map. See “EPUB Best Practices Guide” here