Trouble with DRM ePub

[JSWolf]

I downloaded one of the free ePub eBooks available at BooksOnBoard and I used Adobe Digital Editions to transfer it to my 505. When I go to try to read it, I get it saying it's only 1 page and then I get a page error. What am I doing wrong?

[llasram]

Originally Posted by JSWolf

I downloaded one of the free ePub eBooks available at BooksOnBoard and I used Adobe Digital Editions to transfer it to my 505. When I go to try to read it, I get it saying it's only 1 page and then I get a page error. What am I doing wrong?

Epub DRM acts on a per-file basis, so you should be able to unzip the Epub book (renaming it to have a '.zip' extension if necessary on your platform). If the unzipped contents reveal something like just one giant HTML file then there's your problem -- the Reader version of ADE has an upper limit on the size of HTML files it will render. (I haven't tested what that exact size is -- perhaps one of the Adobe people could enlighten us?) Adobe warned about this in their Epub "Best Practices" guide, but I guess not all publishers were paying attention.

-Marshall

[JSWolf]

If anyone would like to try this same ePub eBook, then please do. It's free and the link to it is... http://www.booksonboard.com/index.ph...01840&v=buynow. The ePub edition is the free edition.

If anyone else can get it to work, please let me know.

[Zevs]

Originally Posted by JSWolf

If anyone would like to try this same ePub eBook, then please do. It's free and the link to it is... http://www.booksonboard.com/index.ph...01840&v=buynow. The ePub edition is the free edition.

If anyone else can get it to work, please let me know.

Hi JSWolf! I tried to download it and can confirm that in ADE it showe up OK, but in the Reader there is only one page and trying to read that give a page error.

I'm a bit confused though on what is ePub and not ePub. I thought those would have the ending .epub, but this file was called something else I think .etd ..??

Zevs

[JSWolf]

I had to download it using Internet Explorer. Then it downloaded fine and showed up in Digital Edition. I then tried to copy it to the 505 and it seemed to copy fine as I can read the copy from within the reader using eBook Library or Digital Editions. But when I use the reader itself, it doesn't work.

[llasram]

Originally Posted by JSWolf

If anyone else can get it to work, please let me know.

I took a look, and this book isn't going to work on the current Reader firmware until the publisher creates a new version. I checked Adobe's "EPUB Best Practices Guide" again and it explicitly notes that ADE will only handle contained files which are less than 300k uncompressed / 100k compressed. The DRM layer makes the ZIP compression level 0% (will e-book vendors start doing compression at the DRM layer?), leaving the compressed file size of the main book body well above ADE's limit.

I'd suggest e-mailing your the e-bookstore and/or the publisher to alert them of the issue.

-Marshall

[wallcraft]

Originally Posted by llasram

checked Adobe's "EPUB Best Practices Guide" again and it explicitly notes that ADE will only handle contained files which are less than 300k uncompressed / 100k compressed.

I assumed that this meant 300K uncompressed (with the compressed value as a guideline), but does it really mean the smaller of 300K uncompressed and 100K compressed? I can't see why the compressed size matters, unless DE stores the ebook in memory with compression.

[JSWolf]

So each individual xml file has to be a grand total of 300k, but the total ePub file can be large?

[kovidgoyal]

ADE should fallback to a a minimal CSS rendering mode (with support for say bold, italic, justification and nothing else) for larger files if displaying large files is impossible.

[=X=]

Originally Posted by JSWolf

I downloaded one of the free ePub eBooks available at BooksOnBoard and I used Adobe Digital Editions to transfer it to my 505. When I go to try to read it, I get it saying it's only 1 page and then I get a page error. What am I doing wrong?

I tried it and had the same problem.

As an aside I tried a Secure PDF and it was viable on the Reader.

=X=

[llasram]

Originally Posted by wallcraft

I assumed that this meant 300K uncompressed (with the compressed value as a guideline)

I'm just quoting what the Adobe documentation says . The could in fact see that the compressed size of the file in the ZIP container is greater than 100K and just immediately bail.

-Marshall

[llasram]

Originally Posted by JSWolf

So each individual xml file has to be a grand total of 300k, but the total ePub file can be large?

Yep, that's right. Overall EPUB file size is bounded only by the storage medium.

[llasram]

Originally Posted by kovidgoyal

ADE should fallback to a a minimal CSS rendering mode (with support for say bold, italic, justification and nothing else) for larger files if displaying large files is impossible.

That would certainly be better than an error which doesn't tell you what the real problem is! OTOH, EPUB support with arbitrary limitations is certainly better than no EPUB support at all.