Epub 3 feature support and conversion

I have a couple Epub 3 questions for folks who have experience using and directly editing epub 3 source files, and managing those files in Calibre.

What is the best concise summary you know for the differences between Epub 2 and 3, from a practical perspective of reading ebooks? Is this summary accurate?

For current model devices and apps that claim to support Epub 3--for example Android 8.x/9.x devices running apps like Fbreader or Moon+, and recent Kobo devices --is there any value in converting the epub source files in Calibre to Epub 3? Would this enable significant feature improvements that I'm not getting now with the default Epub 2*?

*Note: I did try this by converting a number of existing epub files and some purchased AZW3 and Epub books to Epub 3. From a user perspective, I can't tell a difference when reading in a Kobo Forma or my Android phone.

[Doitsu]

Originally Posted by maximus83

Is this summary accurate?

Yes.

Originally Posted by maximus83

Fbreader or Moon+, and recent Kobo devices

Last I checked, FBReader didn't support epub3 books and only the paid Moon+ version had limited epub3 support. I don't have a Kobo, but, AFAIK, you'll need to convert epub2 books to kepub books in order to select the Access NetFront epub3 engine. (For more information on the advantages of the kepub format, see this thread.)

Originally Posted by maximus83

is there any value in converting the epub source files in Calibre to Epub 3?

For most users, who don't use iBooks, the answer is no.

The Forma and all reading apps I've used on Android say they support Epub 3, including Moon+ paid, Google Play Books, and FBreader free. FBreader says on the Google play store they support "(including main features of ePub3)." So my device and app support should not be a problem.

I am already using the kepub format on my Forma and using Calibre to send that format to the Forma device specifically (I actually started the thread you linked to).

But I'm asking specifically if it's worth converting your epub format books in Calibre from Epub 2 to Epub 3 (independent of the process of sending .kepub format to Kobo devices, which Calibre does automatically when you have epub files in your library). Basically, I'm wondering if it's worth the trouble to convert all my epub source files to Epub 3, and if so, what feature differences would I see on current devices that say they would support it? It sounds like you're saying, not much.

[DNSB]

http://epubtest.org/testsuite/

Originally Posted by maximus83

Basically, I'm wondering if it's worth the trouble to convert all my epub source files to Epub 3, and if so, what feature differences would I see on current devices that say they would support it? It sounds like you're saying, not much.

Basically, even with commercially produced epub3 books other than the very few fixed layout versions, I've found little difference in the reading experience between using an epub2 renderer and an epub3 renderer. Fixed layout did require an .fxl.kepub.epub extension to work with the epub3 renderer on my Kobos while the RMSDK renderer made reading the fixed layout epub an "interesting" experience.

The few epub3 ebooks with embedded audio or video I've run into have generally not displayed any of that content on my eInk or ereader apps other than two that would only work with iBooks. Evidently Apple still hasn't found a standard to which they will not happily add proprietary extensions.

If you are really interested in testing your various apps/ereaders, you can check the EPUB3 Test Suite for the various test files and instructions on testing.

One thing I've noticed is that Google Play books, even with epubs that I purchased from them some years ago, have started enabling popup footnotes and better overall support around internal linking. Also I have less TOC problems on some of these books than I used to. I have to wonder--especially on the popup footnotes--if Google has actually reformatted some of those books to add that capability.