EPUB -> CBZ Conversion?

[Cactus Chef]

I did a thread search before posting this, and I see alot of articles on converting CBZ -> EPUB, but nothing on the reverse.

My use-case is that I have a bunch of digital comics I purchased from a vendor (we'll call them "Rainforest") and then stripped the DRM to get an EPUB. I'd prefer to just have them as generic CBR/CBZ files, though, so that I can leverage the dedicated comic-book reader apps on my tablet.

I've found that I can manually make a CBZ file from a comic source EPUB by just yanking the "Images" directory out of the extracted EPUB, zipping it up, and renaming it to a .CBZ extension. This is trivial to do, but quite time-consuming.

Has anyone created a plugin/conversion option that would let me do this within Calibre? I am sure this might result in some missing metadata, but I did try googling around, and as far as I'm aware there is no established "standard" for CBR/CBZ files for metadata files, etc. It looks like it's literally just a Zip Archive or RAR Archive of images, with the first chronologically-named image serving as the comic's cover.

If I'm wrong on this front, I'd appreciate any info about the CBR/CBZ standard.

[BetterRed]

What you have written accords with my understanding of CBZ/CBR.

You could convert the EPUB to ZIP. My default comic book viewer, Honeyview, can open ZIPs, and it ignores non image files, I'd be surprised if other comic viewers weren't similar.

I can't think of a built in way to rename a ZIP to CBZ from within calibre - you'd need to copy the ZIP somewhere, rename it to CBZ and then add it to the book and delete the ZIP. This is what I'd do - open the book folder, drag the ZIP to the desktop, close the book folder, rename the ZIP to CBZ, drag it back to the Book details panel and then delete the ZIP.

For a bunch of books you could use the command line ebook-convert tool to do the EPUB ->ZIP conversion, and do the ZIP->CBZ rename in a .BAT or Powershell script. See ==>> Command Line Interface

BR

[Fiat_Lux]

Originally Posted by Cactus Chef

I did a thread search before posting this, and I see alot of articles on converting CBZ -> EPUB, but nothing on the reverse.

My use-case is that I have a bunch of digital comics I purchased from a vendor (we'll call them "Rainforest") and then stripped the DRM to get an EPUB. I'd prefer to just have them as generic CBR/CBZ files, though, so that I can leverage the dedicated comic-book reader apps on my tablet.

I've found that I can manually make a CBZ file from a comic source EPUB by just yanking the "Images" directory out of the extracted EPUB, zipping it up, and renaming it to a .CBZ extension. This is trivial to do, but quite time-consuming.

Has anyone created a plugin/conversion option that would let me do this within Calibre? I am sure this might result in some missing metadata, but I did try googling around, and as far as I'm aware there is no established "standard" for CBR/CBZ files for metadata files, etc. It looks like it's literally just a Zip Archive or RAR Archive of images, with the first chronologically-named image serving as the comic's cover.

If I'm wrong on this front, I'd appreciate any info about the CBR/CBZ standard.

Play around with Embed Comic Metadata.
I have no idea if it does what you want, but it can do things that are not implied by either the name, or description.

[bustacap]

i know this thread is quite old but i found it through google and it may help others who are still looking for the same thing.
over the last few months i wrote a program that automatically turns epub manga and comics into cbz files, including correct reading order and direction, page alignment, metadata like chapters and more.
it started out as a python program, then a c# console program and is now a c# gui program. so if anyone is still interested in a niche use case like this, please try it out.
https://github.com/bust4cap/epub2cbz-gui

[DNSB]

Out of curiosity, what are the advantages of epub2cbz compared to KCC (Kindle Comic Converter) for a epub to cbz conversion?

[bustacap]

Originally Posted by DNSB

Out of curiosity, what are the advantages of epub2cbz compared to KCC (Kindle Comic Converter) for a epub to cbz conversion?

kcc does it the other way around, so from cbz to epub.
it cant convert from epub

[DNSB]

Originally Posted by bustacap

kcc does it the other way around, so from cbz to epub.
it cant convert from epub

The last time I looked at KCC, it could take a ePub input file and output a CBZ file. I just tested an input ePub and KCC output a CBZ sized to fit the screen on a Libra Colour (selected output device).

[bustacap]

Originally Posted by DNSB

The last time I looked at KCC, it could take a ePub input file and output a CBZ file. I just tested an input ePub and KCC output a CBZ sized to fit the screen on a Libra Colour (selected output device).

what kcc version are you using?
i tested all versions from the newest 6.2.0 to as far back as 2019 and they all say "unsupported file type" when trying to import/convert an epub file. all their documentation also doesnt mention epub as a valid import type

[bustacap]

kcc source code confirms that the only valid import file types are "'.pdf', '.cb7', '.7z', '.cbz', '.zip', '.cbr', '.rar'"

[DNSB]

Originally Posted by bustacap

what kcc version are you using?
i tested all versions from the newest 6.2.0 to as far back as 2019 and they all say "unsupported file type" when trying to import/convert an epub file. all their documentation also doesnt mention epub as a valid import type

A bit weird since while I did have to change the dropdown to all files on the file selector, once I did that, I could select an ePub files as the input, CBZ as the output and all seemed to work okay.

[bustacap]

Originally Posted by DNSB

A bit weird since while I did have to change the dropdown to all files on the file selector, once I did that, I could select an ePub files as the input, CBZ as the output and all seemed to work okay.

seems to be more of a bug with the file picker than an intended feature. when you drop the files into the window, the error message pops up correctly.
anyway, back to the differences. doing it this way, kcc just extracts the images folder and renames the files to its kcc naming scheme. it doesnt include any metadata like chapters, it doesnt respect proper reading order or page alignment or anything. it just extracts the images and renames them

[bustacap]

i also did a quick speedtest with 10 test files.
kcc took around 3:30 minutes total with the setting "disable processing"
epub2cbz took less than 6 seconds total with every option enabled

[DNSB]

Thanks for the feedback. My daughter is the one who uses KCC and so far she has been happy enough with the results. I'll point her at epub2cbz and see what she thinks of it.