Sent to Kindle App - Won't Accept Epub

[John F]

Originally Posted by jhowell

Amazon is inconsistent in naming. I have seen MOBI7 and FF7 used in Amazon’s documentation. KF7 seems a reasonable name to me.

There was a post by someone who worked for Amazon that confirmed KFX is short for kindle format 10.

I have no idea what happened to number 9.

Number 9. Number 9. Number 9.

[Quoth]

Originally Posted by j.p.s

amazon still sells periodical issues and subscriptions, which are available as mobi and not available as KF8/azw3.

Possibly due to format issues. The magazine series I bought for a year was OK on the Kindle DXG, but was somewhat messed up (but readable on the Kobo H2O) when converted to epub, so a variation of KF7.

I did get some downloads recently targeted for PW3 (using Download to PC for USB transfer) that were KF7 in .azw, at least one was .mobi
On one occasion a .azw wouldn't open in Calibre via Add until renamed to .mobi and all were regular ebooks, not subscription, fixed layout or magazines etc.

@JSWolf Mobi is a family of formats. KF7 is a particular format usually in a .mobi or .azw file. The .prc file from the last version of Mobipocket Creator might be KF7 or very similar to it.

[Quoth]

Originally Posted by John F

Number 9. Number 9. Number 9.

Or 1 to 6. But AFAIK the Kindle starts with version 7 of Mobipocket ebooks.

The oldest Mobipocket format seems to be one of the two pdb formats used on the Palm PDA. The Mobipocket app for my Palm Z22 PDA reads either pdb format Calibre can create, but not .prc from my Mobipocket creator on XP, though all the Kindles I have can read the .prc but not the pdb, which is pretty much just plain text with a TOC and extra space, no indent, on paragraph breaks which is annoying on a 160 x 160 pixel screen.

Even ancient Sony eink with LRF was a big advance on Palm PDAs. Win CE PDAs and Symbian phones with Mobipocket to read the ebooks.
The 5" Sony PRS-350 is superior to any Kindle without KF8 and to the Kindle Basic. The Sony series before that had the optional upgrade from LRF to epub.

[JSWolf]

Originally Posted by Quoth

Possibly due to format issues. The magazine series I bought for a year was OK on the Kindle DXG, but was somewhat messed up (but readable on the Kobo H2O) when converted to epub, so a variation of KF7.

It's Mobi (shorthand for Mobipocket), not KF7. There is no KF7. Amazon and/or Mobipocket never used the term KF7 for the format.

[jhowell]

The file format version or FFV number was part of the original MOBI format created by Mobipocket and purchased by Amazon. It provides a way for reader software to know whether or not it is capable of properly interpreting the content of a particular book. The version number was incremented each time new features were added to MOBI format.

Books are not simply assigned the latest version number. When a book was converted to MOBI the particular features present in that book were used to determine the version number assigned to it. That way old reader software could be used for newer books as long as those books didn't use any recently added features.

As far as I know even the oldest Kindle is capable of handling FF version 7 and so version numbers 7 or less are effectively treated the same. Despite that Amazon's kindlegen software still produces the correct version number for MOBI format based on the features it contains, so newly created MOBI files can still have a version number less than 7.

I haver never seen a complete list of features are associated with each version. This is the best I have come up with so far:

• 0-2 I have never encountered MOBI files with these version numbers.
• 3 Documented as indexes for images
• 4 EXTH, FCIS, FLIS, orthographic index, names index
• 5 RESC, multi-byte overlap trailing bytes in content records (Mobipocket Reader 4.8 - 2005)
• 6 NCX index, multiple flows, non-overlap trailing bytes in content records, DRM V2, always produced by calibre for MOBI
• 7 audio, video, UTF-16 Unicode in indexes, ingestion by kindletool (prcgen/mobigen v5.0, Mobipocket Reader 5 - 2006)
• 8 KF8 based on HTML5 and CSS3
• 9+ No V9 was ever released and KFX (Kindle format 10) is a totally different format

[JSWolf]

Originally Posted by jhowell

[*] 9+ No V9 was ever released and KFX (Kindle format 10) is a totally different format

When KFX is created, is the CSS kept separate of is it merged into the HTML code?

[jhowell]

Originally Posted by JSWolf

When KFX is created, is the CSS kept separate of is it merged into the HTML code?

KFX uses its own data representation (Amazon Ion) that corresponds loosely to a simplified version of HTML and CSS. The HTML/CSS provided by the publisher is highly processed during conversion and so the resulting KFX formatting usually bears little resemblance to it. It it somewhat similar to the way that calibre flattens CSS during conversion, but much more extreme.

[Quoth]

Originally Posted by jhowell

The file format version or FFV number was part of the original MOBI format created by Mobipocket and purchased by Amazon.

• 0-2 I have never encountered MOBI files with these version numbers.
• 3 Documented as indexes for images
• 4 EXTH, FCIS, FLIS, orthographic index, names index
• 5 RESC, multi-byte overlap trailing bytes in content records (Mobipocket Reader 4.8 - 2005)
• 6 NCX index, multiple flows, non-overlap trailing bytes in content records, DRM V2, always produced by calibre for MOBI
• 7 audio, video, UTF-16 Unicode in indexes, ingestion by kindletool (prcgen/mobigen v5.0, Mobipocket Reader 5 - 2006)
• 8 KF8 based on HTML5 and CSS3
• 9+ No V9 was ever released and KFX (Kindle format 10) is a totally different format

Excellent. So most refloawable ebooks in .mobi, .prc or .azw (not azw3) are really No. 6, AKA KF6, compatible as there is no audio or video.
I think KFX had two aims: adaptable DRM and less bandwidth / incremental download on so called Whispernet?

The First Kindle was 2007 and Amazon bought Mobipocket in 2005, the year the first Sony eink came out:

[version] 7 audio, video, UTF-16 Unicode in indexes, ingestion by kindletool (prcgen/mobigen v5.0, Mobipocket Reader 5 - 2006)

So looks like 7 came out after Amazon bought MobiPocket but during Kindle Development. Hence all Kindles can do version 7 AKA KF7, but probably not doing video sensibly. Also did ALL the Kindles at least to B008 (KK3) and B009 (DXG) have 3.5mm jack audio and even speakers?