|
|
Thread Tools | Search this Thread |
10-09-2015, 10:50 AM | #1 |
Junior Member
Posts: 3
Karma: 10
Join Date: Oct 2015
Device: none
|
Epub to mobi using KindleGen creates really low quality images – advice needed!
My wife is about to self publish an eBook. It contains 60+ photos - mainly people and medical equipment. Most are 1200px wide and under 160KB in size.
I've so far built the epub file and everything looks good. I'm now trying to convert the epub to mobi format so we can sell it on the kindle store. I initially tried using KindleGen as I read this was the best way to do it. I used kindleGens no compression mode - i.e. C:\KindleGen\kindlegen.exe -c0 C:\KindleGen\Book\my_ebook.epub. After testing the mobi file it outputs on an older style e-ink Kindle reader (4th gen with the cursor pad), I discovered the images were very 'blocky' - backgrounds and skin textures are pixelated (Minecraft-style) or really blurry. If you zoom in on the image, the quality seems to improve slightly. I've tried setting the image sizes (via html) to pixels and percentages and have also left the size attribute out. I still get blocky images. I tried reformatting the actual image files down to 400px wide to help avoid any resizing problems and again no improvement. I then tried to use Calibre to do the conversion. And it improved things dramatically. No more blocky backgrounds or people! So now I'm left wondering:
|
10-10-2015, 02:55 AM | #2 | |
Grand Sorcerer
Posts: 5,584
Karma: 22735033
Join Date: Dec 2010
Device: Kindle PW2
|
Quote:
IIRC, there's an image resizing cutoff size somewhere between 64-128KB. If you resize your images yourself before compiling your book with KindleGen, KindleGen (usually) won't resize them again. However, there doesn't seem to be any fixed number, because KindleGen sometimes won't touch a 120KB image but will resize a 100KB image in the same book. You can down-convert your images to a specific size with ImageMagick (freeware command line tool). For example: Code:
convert -define jpeg:extent=128kb large.jpg small.jpg Many self-publishers have successfully submitted Calibre-generated Kindle books, however, KDP has been known to occasionally reject Calibre-generated Kindle books. |
|
10-10-2015, 06:32 AM | #3 | |||
Junior Member
Posts: 3
Karma: 10
Join Date: Oct 2015
Device: none
|
Thank you for the reply Doitsu. Very enlightening.
Quote:
I wonder if just uploading an epub2 to KDP and letting them handle the conversion achieves better results? I'm guessing not. Quote:
What's even better, a test image I included in the book that was 40KB seems to have been left alone - the image size remains the same. However, It's obviously still doing something with it as it looks just as blocky as the other images. KindleUnpack produces a folder called HDImages that contains my unmolested images. I'm guessing that on newer Kindle devices like the Fire my images at least look acceptable? Or is that just wishful thinking? Quote:
So basically my options are:
I never knew Amazon was this awesome |
|||
10-10-2015, 07:02 AM | #4 | ||||
Grand Sorcerer
Posts: 5,584
Karma: 22735033
Join Date: Dec 2010
Device: Kindle PW2
|
Quote:
Quote:
Quote:
Quote:
IMHO, a better solution would be to experiment with different image formats and conversion settings. If you resize all images down to about 80KB with an acceptable quality, KindleGen might leave them alone. |
||||
10-10-2015, 12:12 PM | #5 |
Junior Member
Posts: 3
Karma: 10
Join Date: Oct 2015
Device: none
|
Hi Doitsu, thanks for another awesome reply.
Scots blog was a great read. Although my wife's book in non-fiction, I'd rather it wasn't fixed width. I'm a web designer by trade, so the thought of a non-responsive book makes me shudder. It's bad enough I'm having to deal with a proprietary file format! I went ahead and uploaded the epub to KDP to see how their conversion handled the photos. As you hinted, the mobi they produced had the same overly compressed images. I guess their KindleGen is equally cr*p! The photos are just standard JPEG, edited in Photoshop. Compiling the mobi with low-res images just to make it look OK in old e-ink Kindle readers would suck. It would effectively force others with newer devices or the Kindle App to also have a low-res experience. I just noticed that any mobi file produced with the KindleGen is subject to a very restrictive terms of use - specifically, you can't sell the mobi file it produces outside of Amazon. Needless to say, we'll also be selling the book on our own website so this is yet another problem I wasn't expecting. On a positive note, the mobi file produced by Calibre did upload to KDP without being rejected. When I downloaded the resulting file, it hadn't compressed the images. Yippee! The only curious thing was when I unpacked it using the KindleUnpack plugin - it contained the mobi7 folder and the HDImages folder but no mobi8 folder. Not sure why. Given the restrictive nature of KindleGens terms of use, I think I'll persevere with Calibre. I should be ready to publish the book in the next week or two. When I do, I'll let you know how I get on. Once again, thank you for all your sage guidance. You're a legend (and a wizard!) |
10-10-2015, 12:42 PM | #6 | |
Grand Sorcerer
Posts: 5,584
Karma: 22735033
Join Date: Dec 2010
Device: Kindle PW2
|
Quote:
BTW, KindleGen generates a hybrid book file that contains both old and new formats and the ePub source files. Depending on the capabilities of the device/app you'll either see the old MOBI format or the new AZW3 format. |
|
10-11-2015, 06:16 AM | #7 |
Ex-Helpdesk Junkie
Posts: 19,422
Karma: 85397180
Join Date: Nov 2012
Location: The Beaten Path, USA, Roundworld, This Side of Infinity
Device: Kindle Touch fw5.3.7 (Wifi only)
|
I have heard that the main problem with uploading calibre-converted MOBI to the KDP is that it won't accept the newer AZW3 -- or dual-MOBI containing AZW3.
So effectively you are forcing all your readers to stick with MOBI (which has several disadvantages). As for selling MOBI on your website -- you can just upload calibre-converted AZW3 on your website, or offer people EPUB and let them convert it. As you've seen calibre does a darn fine job. I believe the HDImages are only used by the Kindle Fires (and are stripped out of files delivered to an E-Ink device). But you could double-check with KevinH at the KindleUnpack thread. KindleUnpack will always extract them from the raw source (if available), and allow you to overwrite the actual mobi7/KF8 with the HDImages versions. But that only helps someone who did the conversion on their computer, and wants to use KindleUnpack -- so it isn't a solution for selling on Amazon... Last edited by eschwartz; 10-11-2015 at 06:19 AM. |
10-11-2015, 06:25 AM | #8 |
mostly an observer
Posts: 1,515
Karma: 987654
Join Date: Dec 2012
Device: Kindle
|
I have uploaded epubs to the KDP since January 2012, and I've never had such a problem. They convert just beautifully in my experience. I've never used KindleGen because I never could get it to work on my computer. I do have Kindle Preview installed, and I believe that's pretty much the same thing, but again, I've never used it to convert an epub because I like to get as close to the publishing process as I can, and THEN preview the book.
I build my epubs in Sigil, never in Calibre, though I often use Calibre for the opposite purpose (converting library epubs to mobi so I can read them on my Fire tablet). Calibre-generated CSS just scares me. |
10-11-2015, 07:08 AM | #9 | |
Grand Sorcerer
Posts: 5,584
Karma: 22735033
Join Date: Dec 2010
Device: Kindle PW2
|
Quote:
|
|
Tags |
calibre, image quality, image quality conversion, kindlegen, mobi |
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Advice needed - how to best show several small images | patrik | Workshop | 5 | 09-04-2015 02:21 PM |
Warnings using KindleGen – epub to mobi | novation | Kindle Formats | 7 | 03-12-2012 12:51 PM |
epub to mobi using kindlegen - question | codrutoctavian | Workshop | 2 | 02-14-2012 03:35 PM |
kindlegen epub to mobi error | codrutoctavian | Kindle Formats | 2 | 02-14-2012 11:40 AM |
KindleGen: Epub to Mobi conversion | virtual_ink | Kindle Formats | 21 | 11-18-2011 08:00 AM |