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noDRM / DeDRM_tools

DeDRM tools for ebooks
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Add support for comixology #86

Open Ever4engel opened 2 years ago

Ever4engel commented 2 years ago

can you please try to support comixology? it serve a higher resolution compared to the simple kindle books

AdmiralAsshat commented 2 years ago

How would you get Comixology books into a single file to decrypt in the first place? IIRC, you can only get a single file when using the Kindle for PC/Mac apps. In the Comixology Android/IOS app, the comic is stored in a bunch of fragmented files that no one has reverse engineered to recombine yet.

j-howell commented 2 years ago

I have looked comics downloaded using the latest version of the Comixology app on iOS and Android. The files it downloads are identical to those downloaded if the Kindle app is used instead. They are in KFX format using the latest unbroken DRM.

As far as I know using a recent version of Kindle for PC with KFX disabled is the best option for obtaining high quality comics from Amazon/Comixology at the moment. It will download as two files, the main one with standard def images and an add-on file with high def images. The AZW6 Image Merge plugin for calibre can be used to combine them.

ElleKayEm commented 2 years ago

Recent Kindle for PC? Ones that support KFX but can still have KFX disabled? Any idea about Kindle for Mac?

j-howell commented 2 years ago

Recent Kindle for PC? Ones that support KFX but can still have KFX disabled?

Yes.

Any idea about Kindle for Mac?

I believe it will work but I am not sure.

Ever4engel commented 2 years ago

As far as I know using a recent version of Kindle for PC with KFX disabled is the best option for obtaining high quality comics from Amazon/Comixology at the moment. It will download as two files, the main one with standard def images and an add-on file with high def images. The AZW6 Image Merge plugin for calibre can be used to combine them.

I asked someone experienced with azw6. Azw6 max hight is 1920 whereas cmx is way beyond that, he said, i have cmx samples that have 2500px sometimes beyond that.

Ever4engel commented 2 years ago

How would you get Comixology books into a single file to decrypt in the first place? IIRC, you can only get a single file when using the Kindle for PC/Mac apps. In the Comixology Android/IOS app, the comic is stored in a bunch of fragmented files that no one has reverse engineered to recombine yet.

Honestly can't tell because the old app requests/files were unobfuscated, not the case now

j-howell commented 2 years ago

I asked someone experienced with azw6. Azw6 max hight is 1920 whereas cmx is way beyond that, he said, i have cmx samples that have 2500px sometimes beyond that.

As far as I can tell the CMX-HD format has been retired. The Comixology apps now use the same KFX format as the Kindle apps.

Based on their size KFX comics on iOS and Android do use higher resolution images than AZW6 format supports. I took a look at one comic Gunnerkrigg Court Vol. 6: Dissolve. The file size on the Amazon product page is listed as 534,554 KB. Kindle for iOS and the iOS Comixology app both download that comic as 375 KFX files totaling the expected 534,554 KB in size. In comparison the files from Kindle for PC are 68,998 KB (KF8/AZW3) and 209,606 KB (HD-CONT/AZW6).

Unfortunately Amazon has been very aggressive about protecting KFX. They have implemented dozens of hidden DRM algorithms in their apps, adding new ones over time. When one is broken they immediately switch to another already handled by the existing apps. If anyone has broken the current KFX DRM algorithm they are probably keeping it to themselves so that it doesn't become obsolete.

Using AZW6 from Kindle for PC is the best option available for the foreseeable future.