mobi-asin and custom cover art?

[blaenk]

So I just realized that I could set the mobi-asin metadata identifier for a book within Calibre in order to enable the use of things like the Goodreads sharing feature.

The problem now is that the kindle seems to detect this identifier and decide to download and use the cover art from Amazon instead of the one that was already set for that book.

Is there a way to set the mobi-asin _and_ use custom cover art?

[susan_cassidy]

ASIN is the Amazon identifier, and that implies, I believe, Amazon's cover.

[eschwartz]

When the Kindle sees a book with an ASIN, it attempts to download the cover thumbnail from Amazon's servers. Usually, we are upset about that because there is no cover. And it will ONLY derive the thumbnail from the book's metadata if the book is a PDOC. Rather stupid and irritating...
(Without an ASIN -- to be exact, the exth 113 meta field -- you end up with a PDOC, and that ugly banner. Many people embed a fake ASIN to avoid that.)

You will have to manually place your own cover thumbnail in the [userstore]/system/thumbnails/ folder -- calibre will do this automatically, if you use calibre to send the book to the device.
Once a thumbnail exists, the Kindle will not try to replace it.

[blaenk]

Originally Posted by eschwartz

Usually, we are upset about that because there is no cover. And it will ONLY derive the thumbnail from the book's metadata if the book is a PDOC. Rather stupid and irritating...
(Without an ASIN -- to be exact, the exth 113 meta field -- you end up with a PDOC, and that ugly banner. Many people embed a fake ASIN to avoid that.)

Haha, what a coincidence then. Perhaps for me there _is_ a thumbnail because I set the correct ASIN and not a fake one? It did get a thumbnail for the correct book, just that it's a different one from the one I see in Calibre.

Originally Posted by eschwartz

You will have to manually place your own cover thumbnail in the [userstore]/system/thumbnails/ folder -- calibre will do this automatically, if you use calibre to send the book to the device.
Once a thumbnail exists, the Kindle will not try to replace it.

I'm sorry can you elaborate on this? It sounds to me like I can keep the mobi-asin (so that I could use goodreads) _and_ Calibre should place the thumbnail in system/thumbnails so that the kindle uses that thumbnail and not the one it downloads? Is this a setting somewhere in Calibre? I don't see a system/thumbnails folder. In fact I don't see a system folder at all, I'm pretty sure I used to see one. Perhaps it's because I'm on the latest version of the firmware? I'm using AZW3 and not MOBI, in case that matters.

Thanks a ton for your reply eschwartz.

[eschwartz]

Originally Posted by blaenk

Haha, what a coincidence then. Perhaps for me there _is_ a thumbnail because I set the correct ASIN and not a fake one? It did get a thumbnail for the correct book, just that it's a different one from the one I see in Calibre.

Not a coincidence, expected.
A fake ASIN points to nonexistent Amazon product pages, and thus there is no cover to download. The people who configure calibre to embed fake ASINs in order to get rid of the ugly "Personal" banner might end up with no covers at all.
Real ASINs point to existing cover thumbnails, you just prefer the thumbnail you manually embedded in the book.

I'm sorry can you elaborate on this? It sounds to me like I can keep the mobi-asin (so that I could use goodreads) _and_ Calibre should place the thumbnail in system/thumbnails so that the kindle uses that thumbnail and not the one it downloads? Is this a setting somewhere in Calibre? I don't see a system/thumbnails folder. In fact I don't see a system folder at all, I'm pretty sure I used to see one. Perhaps it's because I'm on the latest version of the firmware? I'm using AZW3 and not MOBI, in case that matters.

As long as you use the calibre send-to-device functionality, calibre should sideload a thdumbnail image for any non-PDOC (which means anything with a value, like an ASIN, in the exth 113 field).
For PDOCs, calibre won't bother since the Kindle generates PDOC covers from inside the book.
If you typically sideload books using your file browser, then calibre was never involved, and can't sideload the thumbnail. The Kindle sees a missing thumbnail, and since the book is not a PDOC it attempts to download a cover from the Amazon website.

The missing folder is likely because you are using windows -- Windows will hide a "system" folder in the root of a drive, on the logic that it is a protected system folder.
Tell Windows Explorer to stop hiding protected system folders, or type the folder name into the location bar.

Thanks a ton for your reply eschwartz.

Happy to help!

[blaenk]

Woah that's weird. I have "view hidden files and folders" on and I still don't see it, but typing it into the location bar does put me in it!

So yeah I see the thumbnails directory now. I've only ever sent books using Calibre. I think I see what the problem is though. I see the actual cover I want to use and that's named using a random (?) ID, e.g.:

thumbnail_d341a6a3-e5f8-4a7d-9d83-0d793f7893eb_EBOK_portrait.jpg

This was presumably sent the first time I sent the book, before I added the mobi-asin.

However, I also see the one that's now being used after adding the mobi-asin, and it contains the mobi-asin instead of that seemingly random ID:

thumbnail_1876963468_EBOK_portrait.jpg

This is presumably the one that the kindle downloaded.

So I'm not sure how I can get Calibre to (re?)send the thumbnail of that book but now using the mobi-asin ID so that that is picked up instead.

Does that make sense?

[blaenk]

I went through the process of adding a new book with a mobi-asin. I had the file explorer open to the thumbnails directory and I did see that Calibre sent the thumbnail file to that location, appropriately named, i.e. with the ASIN id instead of that seemingly random ID.

However, as soon as I open the kindle after transferring the book, it seems that the kindle downloads the cover art despite the thumbnail existing there, and thus overwrites the correct thumbnail that Calibre sent. If I then re-send the book using Calibre, thereby overwriting the kindle-downloaded cover with the correct cover, it does show the correct cover for a split second and then the kindle re-downloads the cover and overwrites it again.

[blaenk]

I tested some more and what I discovered is very surprising.

If I re-send the book through Calibre (so that it re-sends the cover art to the thumbnails directory), I do see that Calibre puts the correct cover art file in the thumbnails directory. I copy and paste that file to a folder on my computer as a backup. I then eject the kindle and it shows for a split second before being replaced by the downloaded one.

I then reconnect the kindle and it shows the newly downloaded one in the thumbnails directory instead of the one that Calibre sent, so yeah it was overwritten.

If I then _manually_ place the backup I made earlier of the file that Calibre placed, replacing/overwriting the one that kindle downloaded (which itself overwrote the original one that Calibre sent), then I eject, _then_ the kindle STOPS downloading and overwriting it!

It's very weird as I can't imagine what is different from Calibre putting it there and my putting it there manually, but the effect is reproducible: if Calibre sends it, the kindle downloads and overwrites the cover art that Calibre sent. If I place the cover art there manually (the same exact file, same name etc.) then the kindle doesn't overwrite it.

[blaenk]

So what I've narrowed the process down to is:

1. send to kindle via calibre. I do see the thumbnail placed by calibre there
2. open kindle. cover is shown then quickly replaced by downloaded cover
3. manually place the cover into the thumbnails directory again
4. open kindle. cover is not overwritten

I tried shortening the above by sending to the kindle and then manually placing the thumbnail in the thumbnails directory (even though kindle just did that) but the thumbnail is overwritten anyways.

It seems to me like the logic is "if the cover hasn't been downloaded, download it." This would explain two things:

1. after sending the book it is considered new, so the cover gets downloaded. afterward if I replace the cover art manually, it won't overwrite it because it's "already been downloaded"
2. it explains why re-sending the book via Calibre doesn't work, because each time I re-send it it is considered to be "new" again, so it re-downloads the cover art

So the trick would be to not let the kindle think that a new book is in fact new, but I doubt that's at all possible. Alternatively, it would be to set the flag (if there is any) that represents the cover having been downloaded already, so that the kindle won't go ahead and download it. I don't imagine this is possible though.

[eschwartz]

That is incredibly odd, and I don't believe anyone has ever seen that before!
I know on my Kindle Touch, I sideload all my Amazon-bought books, and calibre adds the covers which sometimes are different than the official ones, but anyway are in color, so I know which ones calibre sent. The Kindle has never overwritten them once a thumbnail exists.
The only thing I can think of is that Amazon changed something in the newest firmware -- although I would think other people would notice it as well!
And according to that logic, when you resend the book with calibre, the Kindle notices the timestamp changed and therefore the book is different -- and redownloads the cover art?



Some factoids for you :
The random UUID thumbnail is what you see when calibre creates embeds a random UUID in the exth 113 field -- that is why I don't like calling it the ASIN field, because it only sometimes is.

system files/folders are different from hidden files/folders, and Windows Explorer has a separate setting for them.

[odamizu]

@blaenk - Try turning off WiFi when transferring books via Calibre:

1. Turn off WiFi on your Kindle
2. Send to Kindle via Calibre
3. Open Kindle; cover used by Calibre should appear
4. Wait, I dunno, 5 minutes or so? Or until book is finished indexing, or whatever processes Kindles goes through with new books? Just give it a few minutes.
5. Turn on WiFi and see if cover is replaced

I'm working from fuzzy memory of when I was experimenting with sideloading books via Calibre (which I no longer do). I won't swear my fuzzy memory is accurate, but I seem to recall that when WiFi is off, you get the Calibre cover, and once Kindle finishes processing the book, it won't look for the cover from Amazon's servers. But again, this was a while ago and my memory is fuzzy.

[blaenk]

Originally Posted by eschwartz

And according to that logic, when you resend the book with calibre, the Kindle notices the timestamp changed and therefore the book is different -- and redownloads the cover art?

Yeah I'm not sure how the Kindle decides that a book is new. My guess is basically that it has some metadata table somewhere and for each book it has some flag that basically states (either directly or indirectly) whether the cover has been downloaded yet for that book (assuming there is a real (?) mobi-asin associated for it to download the cover). Each time I re-send the book, it either overwrites all metadata entries (including this flag) for that book that was just sent, or it treats that book as an entirely new book and thus new entry (perhaps it forms an identifier for the book based on the timestamp among other things).

So what I have to do is send the book once, allowing it to create this metadata and flag, let it download the cover, so that this flag is now set to 'true' (that it indeed has downloaded the cover) and then I manually sneak in the actual cover which indeed is color, i.e. the one that Calibre sends (but importantly, not sending the book via Calibre as this restarts the process). By then the kindle already has this flag to 'true' so it won't again overwrite the thumbnail.

It's unfortunate that I'm so close to having the best of both worlds here, both goodreads sharing and the covers I want (that I set through Calibre). However, this would be ridiculously tedious to do for each book on my kindle.

First I have to convert the book to AZW3 individually so that I have the AZW3 for the next step. Then I have to use the quality check plugin to add the mobi-asin field (to enable goodreads) (perhaps I could write a plugin that just does this as part of the metadata download process and copies it from the amazon identifier, without caring what store it came from which is the usual excuse for not integrating this into Calibre directly). Then I have to send the AZW3 to my kindle, disconnect, let it download and overwrite the cover, then I have to reconnect and manually replace the cover that kindle downloaded.

Originally Posted by eschwartz

system files/folders are different from hidden files/folders, and Windows Explorer has a separate setting for them.

I found the setting, thanks for the tip!

[blaenk]

Originally Posted by odamizu

@blaenk - Try turning off WiFi when transferring books via Calibre:

1. Turn off WiFi on your Kindle
2. Send to Kindle via Calibre
3. Open Kindle; cover used by Calibre should appear
4. Wait, I dunno, 5 minutes or so? Or until book is finished indexing, or whatever processes Kindles goes through with new books? Just give it a few minutes.
5. Turn on WiFi and see if cover is replaced

I turned airplane mode on and then connected it. I sent the book to the kindle, ejected, and what I saw was interesting. It showed the Calibre cover first, as usual, then it did the little animation for when the cover is replaced, but then it stayed on the same cover, presumably because it wasn't able to download the cover.

I then waited 5 minutes and disabled airplane mode. Then BAM the kindle downloaded and overwrote the cover. This seems to back up my theory.

[blaenk]

I suspect that not many have noticed this because the covers they use in Calibre probably match up with the ones that amazon downloads, so they probably don't notice that the kindle is overwriting the cover. I just happened to get (un?)lucky and tried it on a book that has a different cover on Amazon. It could also be a difference in what the firmware does too, for the latest PW2.

[odamizu]

Originally Posted by blaenk

... I then waited 5 minutes and disabled airplane mode. Then BAM the kindle downloaded and overwrote the cover ...

Thanks so much for reporting back on this! It has turned out to be helpful to me -- though I am sorry I could not be helpful to you.

I usually sideload via Dropbox, in which case WiFi is on and Kindle automatically retrieves the cover from Amazon. Occasionally I connect Kindle to computer and drag-and-drop over USB. If I forget to turn on WiFi, I get a generic cover. I thought the only way to get rid of the generic cover is to delete the book, turn on WiFi, and copy it over a second time. What a bother! I didn't realize that if I turn on WiFi, the generic covers will be replaced. Thanks!

EDIT: Um ... well, it didn't work. I just now transferred a couple books via USB, forgetting I had WiFi off, and got generic covers. I thought I could just turn on WiFi to have the covers overwritten ... but no. Nothing happened. Oh well <shrug>.