Kobo ebooks with nonsense text

[Waylander]

Not sure whether this is better in the Kobo forum or the Calibre forum, but when I use the Obok de-drm function, most of my Kobo ebook purchases import fine. A couple, however, import with nonsense text and symbols instead of the actual content. Does anyone know why this is? It seems strange that it happens with some Kobo ebooks and not with others.

[Lys]

Originally Posted by Waylander

Not sure whether this is better in the Kobo forum or the Calibre forum, but when I use the Obok de-drm function, most of my Kobo ebook purchases import fine. A couple, however, import with nonsense text and symbols instead of the actual content. Does anyone know why this is? It seems strange that it happens with some Kobo ebooks and not with others.

When it happens, just delete the book from Calibre. Then close Calibre, close the Kobo App (if you have it open), reopen Calibre and import again the book (making sure you see the red lock next to the name of your book that indicates that Obok has detected the book has DRM).

[DNSB]

One possibility that comes to mind is that you are attempting to copy Kobo Plus ebooks from the Desktop app to calibre. That does not work. OTOH, if you download the books to your Kobo reader and then use Obok to copy them to your calibre library, that does seem to work.

Otherwise, what version of the DeDRM package are you using? You should be using the v10 version from NoDRM's GitHub.

[Lys]

Originally Posted by DNSB

One possibility that comes to mind is that you are attempting to copy Kobo Plus ebooks from the Desktop app to calibre. That does not work. OTOH, if you download the books to your Kobo reader and then use Obok to copy them to your calibre library, that does seem to work.

Otherwise, what version of the DeDRM package are you using? You should be using the v10 version from NoDRM's GitHub.

If I remember correctly from my month of promo subscription to Kobo Plus, when you check out a book using Kobo Plus program, you don't have the "download" option on the Kobo App, and Obok is never able to even list it on the list of books available (Obok only lists the books that are currently locally downloaded).

From my experience, sometimes Obok doesn't detect the book as DRM protected even when it is. Just a restart of Calibre and making sure you don't have Calibre and Kobo App open at the same time solves this issue. I never investigated much nor open a bug about it, though, since a restart always worked for me.

[ZodWallop]

Man, James Patterson can slap his name on anything and make it sell

[DNSB]

Originally Posted by Lys

If I remember correctly from my month of promo subscription to Kobo Plus, when you check out a book using Kobo Plus program, you don't have the "download" option on the Kobo App, and Obok is never able to even list it on the list of books available (Obok only lists the books that are currently locally downloaded).

Not quite correct. You do not have the Download option on the web page. However, you can download the ebooks to your Kobo ereader since that is pretty much a requirement to read them on the device. If you connect your Kobo ereader to calibre, you can select Device in calibre and Obok will show the books in the kepub directory on the device. From there you can select them and copy to calibre. You can also download them to the Kobo desktop app (Mac or Windows) and the iOS and Android apps though I have never tried to copy them from any of those using Obok.

Originally Posted by Lys

From my experience, sometimes Obok doesn't detect the book as DRM protected even when it is. Just a restart of Calibre and making sure you don't have Calibre and Kobo App open at the same time solves this issue. I never investigated much nor open a bug about it, though, since a restart always worked for me.

Been there, done that.

[Lys]

Originally Posted by DNSB

Not quite correct. You do not have the Download option on the web page. However, you can download the ebooks to your Kobo ereader since that is pretty much a requirement to read them on the device. If you connect your Kobo ereader to calibre, you can select Device in calibre and Obok will show the books in the kepub directory on the device. From there you can select them and copy to calibre. You can also download them to the Kobo desktop app (Mac or Windows) and the iOS and Android apps though I have never tried to copy them from any of those using Obok.

Sorry, I was unclear, I meant you don't have the option of downloading/transferring the book from the Desktop App (which is the prerequisite for using Obok + Desktop App). They appear in your Kobo Desktop App, but that's it

We are basically saying the same thing, though: in the case of Kobo Plus books, you can pick them up and put them in Calibre only by using a Kobo device and using Obok + Device combination (if they haven't changed something in the last months: my KP trial was almost a year ago ), no other options would work. But in case of using Kobo Desktop, Obok won't even be able to detect the book, so there's no risk to import in Calibre the file to start with in that case

[DNSB]

Originally Posted by Lys

Sorry, I was unclear, I meant you don't have the option of downloading/transferring the book from the Desktop App (which is the prerequisite for using Obok + Desktop App). They appear in your Kobo Desktop App, but that's it

We are basically saying the same thing, though: in the case of Kobo Plus books, you can pick them up and put them in Calibre only by using a Kobo device and using Obok + Device combination (if they haven't changed something in the last months: my KP trial was almost a year ago ), no other options would work. But in case of using Kobo Desktop, Obok won't even be able to detect the book, so there's no risk to import in Calibre the file to start with in that case

Some Kobo Plus books will work when copied from the Desktop app (Windows 11) but not all of them. You do have to download the books to the Desktop app but that is the case for all books.

[Waylander]

Thanks for the tips and advice everyone. Regarding DNSB's advice, I should've said I'm buying the books on the Kobo site, syncing my old Clara, and importing them from there. I can't think what the problem might be, other than that the Obok version I have isn't v10, so I'll download that from GitHub and give it another go. Also, ZodWallop's quip about James Patterson made me chuckle, so thankyou.

[Cootey]

Originally Posted by Waylander

Not sure whether this is better in the Kobo forum or the Calibre forum, but when I use the Obok de-drm function, most of my Kobo ebook purchases import fine. A couple, however, import with nonsense text and symbols instead of the actual content. Does anyone know why this is? It seems strange that it happens with some Kobo ebooks and not with others.

Is Kobo Desktop running when you use Obok? I have found that when Kobo Desktop is running, many books appear unlocked (DRM free) to Obok because the Kobo Desktop database is open. @Lys was referring to this. Quit Obok, then quit Kob Desktop and rerun Obok. It will only strip DRM from an ebook if the padlock icon is closed. Otherwise, you get gibberish as you describe.

This is how it works for me on my Mac. I don't need to quit Calibre, just the plug-in.

[chrisridd]

The way obok works is that it tries to decrypt the encrypted files with a couple of different symmetric encryption keys. There's no way to check if a key worked beyond peeking into the decrypted contents and looking for things like Unicode BOMs, XML fragments, or JFIF headers.

It got changed over time to test different things, and perhaps it now finds false positives.

https://github.com/noDRM/DeDRM_tools...k/obok.py#L589

[Cootey]

Originally Posted by chrisridd

The way obok works is that it tries to decrypt the encrypted files with a couple of different symmetric encryption keys. There's no way to check if a key worked beyond peeking into the decrypted contents and looking for things like Unicode BOMs, XML fragments, or JFIF headers.

It got changed over time to test different things, and perhaps it now finds false positives.

https://github.com/noDRM/DeDRM_tools...k/obok.py#L589

I always assumed that Obok passed the "unlocked" ebooks to Calibre as DRM free when they were actually still actively open in Kobo Desktop's DB because it was still running.


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[JSWolf]

It's better to download ePub and remove the DRM from there. That way you have ePub and that's easy to convert to KePub. So if you want ePub, you have ePub and if you want KePub, that's easy to do.

I know removing the DRM from ePub works.

[chrisridd]

Originally Posted by Cootey

I always assumed that Obok passed the "unlocked" ebooks to Calibre as DRM free when they were actually still actively open in Kobo Desktop's DB because it was still running.

No, but that's reminded me that obok also opens the Kobo Desktop's database, so having Kobo Desktop open at the same time is going to cause problems. I wonder if obok can detect that?

[JSWolf]

Simple solution. Forget about Obok. Download the ePub and remove the DRM from that.