902 Any idea how PB 90x chooses cover thumbnails

Bonex · 02-26-2011, 06:06 PM

Hi there!

Is there anybody who knows how the new models choose the image to use as cover thumbnail in Files/Library view?
Of the epubs I have, there are many showing the correct image, but there are some that show some random image taken from the ebook.
I tried to compare the opf files of those that work with those that don't but I can't find anything wrong. Both seem perfectly fine to me.

troll05 · 02-26-2011, 06:50 PM

Most probably: by chance

No, serious. I've given up to find out a reason why this happens, cause I have absolutely no idea. At first I thought it might be because some books use Calibre imported covers and others had their own, but has to be something else.

Bonex · 02-27-2011, 09:03 AM

I discovered that if you put into the epub an image with the filename ending with "cover.jpg" it is used as thumbnail even if it's not declared into the opf.
This does not explain the random right/wrong image anyway because in those ebooks I checked the cover are always called in the form Author_ISBN-number_etc.jpg

EDIT: No... my mistake. It has to be declared and what matters is the position of its declaration (see below).

jackie_w · 02-27-2011, 10:53 AM

I did extensive testing of this mystery with epubs on my PB360. I eventually found an answer which has had a 100% success rate so far on a PB360 running firmware v15.2.

I found that if I examined the <manifest> section in the .opf file inside the epub, the epubs which didn't work invariably had the cover image item a long way down the manifest list (around 50 or more). It's almost as if the PB stopped looking for a cover part-way through the manifest. If I moved the cover image item to the top of the manifest list the problem was fixed.

However, if you've already sent the epub to the reader, it is not enough to just resend the epub, to overwrite the original, because the PB "remembers" the old thumbnail (or lack thereof). You first need to delete the book from the PB before connecting to the PC, so that the PB deletes the old thumbnail. If you then reconnect and resend the epub the thumbnail is extracted correctly.

I didn't find that the name of the cover image mattered at all, just its position in the manifest

Of course, PB firmware being as 'quirky' as it is, may mean that each different version has its own solution to this problem

troll05 · 02-27-2011, 01:07 PM

As I said, most probably by chance

jackie_w · 02-27-2011, 03:46 PM

Quote:

Originally Posted by troll05

As I said, most probably by chance

You may mock. I have total confidence that I have the answer to MY particular PB problem.

troll05 · 02-27-2011, 04:10 PM

I'm sure you are right, but with computers you never know...

Bonex · 02-28-2011, 11:51 AM

Quote:

Originally Posted by jackie_w

I found that if I examined the <manifest> section in the .opf file inside the epub, the epubs which didn't work invariably had the cover image item a long way down the manifest list (around 50 or more). It's almost as if the PB stopped looking for a cover part-way through the manifest. If I moved the cover image item to the top of the manifest list the problem was fixed.

Yesss!! That's it! I tried it and it works!!

No need to delete the file first with the 902. I have simply overwritten it and when I disconnected the reader from the PC the covers were there.

jackie_w · 02-28-2011, 11:03 PM

Quote:

Originally Posted by Bonex

No need to delete the file first with the 902. I have simply overwritten it and when I disconnected the reader from the PC the covers were there.

That's interesting. Sounds like there's been an improvement to the firmware. Perhaps the 902 detects that the book is newer than the thumbnail and automatically re-extracts it. I wish my PB360 did that.

02-26-2011, 06:06 PM	#1
Bonex Connoisseur Posts: 63 Karma: 10 Join Date: Oct 2010 Device: KDXG, Kobo Glo, Kobo Aura HD	Any idea how PB 90x chooses cover thumbnails Hi there! Is there anybody who knows how the new models choose the image to use as cover thumbnail in Files/Library view? Of the epubs I have, there are many showing the correct image, but there are some that show some random image taken from the ebook. I tried to compare the opf files of those that work with those that don't but I can't find anything wrong. Both seem perfectly fine to me. Last edited by Bonex; 02-26-2011 at 06:08 PM.

02-27-2011, 09:03 AM	#3
Bonex Connoisseur Posts: 63 Karma: 10 Join Date: Oct 2010 Device: KDXG, Kobo Glo, Kobo Aura HD	I discovered that if you put into the epub an image with the filename ending with "cover.jpg" it is used as thumbnail even if it's not declared into the opf. This does not explain the random right/wrong image anyway because in those ebooks I checked the cover are always called in the form Author_ISBN-number_etc.jpg EDIT: No... my mistake. It has to be declared and what matters is the position of its declaration (see below). Last edited by Bonex; 02-28-2011 at 12:06 PM.

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02-26-2011, 06:50 PM	#2
troll05 Harmless idiot Posts: 3,411 Karma: 2154829 Join Date: Nov 2010 Location: Zuhause Device: PB622, Nexus7, Sony PRS 350, Tolino und nur noch wenig toter Baum:(	Most probably: by chance No, serious. I've given up to find out a reason why this happens, cause I have absolutely no idea. At first I thought it might be because some books use Calibre imported covers and others had their own, but has to be something else.

02-27-2011, 10:53 AM	#4
jackie_w Grand Sorcerer Posts: 6,246 Karma: 16539642 Join Date: Sep 2009 Location: UK Device: ClaraHD, Forma, Libra2, Clara2E, LibraCol, PBTouchHD3	I did extensive testing of this mystery with epubs on my PB360. I eventually found an answer which has had a 100% success rate so far on a PB360 running firmware v15.2. I found that if I examined the <manifest> section in the .opf file inside the epub, the epubs which didn't work invariably had the cover image item a long way down the manifest list (around 50 or more). It's almost as if the PB stopped looking for a cover part-way through the manifest. If I moved the cover image item to the top of the manifest list the problem was fixed. However, if you've already sent the epub to the reader, it is not enough to just resend the epub, to overwrite the original, because the PB "remembers" the old thumbnail (or lack thereof). You first need to delete the book from the PB before connecting to the PC, so that the PB deletes the old thumbnail. If you then reconnect and resend the epub the thumbnail is extracted correctly. I didn't find that the name of the cover image mattered at all, just its position in the manifest Of course, PB firmware being as 'quirky' as it is, may mean that each different version has its own solution to this problem

02-27-2011, 01:07 PM	#5
troll05 Harmless idiot Posts: 3,411 Karma: 2154829 Join Date: Nov 2010 Location: Zuhause Device: PB622, Nexus7, Sony PRS 350, Tolino und nur noch wenig toter Baum:(	As I said, most probably by chance

02-27-2011, 04:10 PM	#7
troll05 Harmless idiot Posts: 3,411 Karma: 2154829 Join Date: Nov 2010 Location: Zuhause Device: PB622, Nexus7, Sony PRS 350, Tolino und nur noch wenig toter Baum:(	I'm sure you are right, but with computers you never know...

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