[APP] Kinbo – Mobile-first Manga/E-book Optimizer (Android)

[GigaCat]

Hi everyone,

I wanted to share a project I’ve been working on called Kinbo.

I’m a huge fan of Kindle Comic Converter (KCC), but I often found myself wanting to prep manga or PDFs while away from my desktop. I built Kinbo to bring that same optimization pipeline directly to Android so I could handle everything on my phone right after a download.

Main Features:

• Smart Margin Cropping: Automatically detects and trims borders to maximize art on 6" and 7" screens.
• Spread Splitting: Logic to detect and split double-page spreads into portrait or rotate them.
• Native KEPUB Export: Built-in support for Kobo’s KEPUB format.
• AI Upscaling: On-device sharpening for lower-resolution scans.
• Batch Processing: Handles entire folders or series in the background.

Current Limitations:
Please note that AZW3 and MOBI are not yet supported. I’m currently focusing on the EPUB/KEPUB and PDF pipelines first.

Technical Note:
The app is built in Kotlin. I’ve implemented a parallel processing pipeline to keep it stable even on mid-range devices without hitting the Android Low Memory Killer.

Google Play Store:
https://play.google.com/store/apps/d...inbo.converter

Looking forward to your thoughts!

[Evil_Crab]

Any chance you can add "Rainbow eraser" feature from KCC? Colored eink screens are prone to rainbow artifacts in dithered greyscale images, such as manga.

Also, "update in place" feature and profiles for Boox devices would be handy when using the app on Android e-readers to directly optimize manga grabbed with Mihon.

[GigaCat]

Originally Posted by Evil_Crab

Any chance you can add "Rainbow eraser" feature from KCC? Colored eink screens are prone to rainbow artifacts in dithered greyscale images, such as manga.

Also, "update in place" feature and profiles for Boox devices would be handy when using the app on Android e-readers to directly optimize manga grabbed with Mihon.

Great timing! I was actually working on this feature. I have already pushed the update with rainbow effect remover and custom gamma support. It's in review and will go live within a few hours. As for the BOOX device profile, I will add them within next few days. Meanwhile you can use custom resolution switch to match the exact pixel resolution of your BOOX device.

Also can you please explain what you mean by "update in place"? I think I am misunderstanding it.

Thanks for using the app and the feedback. Feel free to request for any new features.

[Evil_Crab]

By "update in place" I meant overwriting original files with the optimized ones. Right now, if you select the same folder for both input and output, KinBo will save optimized files with " (1)" suffix, so to actually replace original files with the optimized ones, you have to export them to some other folder and then replace the original ones via file manager.

And a couple more pieces of feedback:
1. By default, on Boox devices, text on some buttons is unreadable, although it can be fixed via eink tweaks: https://imgur.com/a/AfTlOvh
2. It would be nice to have an explanation of what some of the options do (e.g., Manga mode).

[GigaCat]

Originally Posted by Evil_Crab

By "update in place" I meant overwriting original files with the optimized ones. Right now, if you select the same folder for both input and output, KinBo will save optimized files with " (1)" suffix, so to actually replace original files with the optimized ones, you have to export them to some other folder and then replace the original ones via file manager.

And a couple more pieces of feedback:
1. By default, on Boox devices, text on some buttons is unreadable, although it can be fixed via eink tweaks: https://imgur.com/a/AfTlOvh
2. It would be nice to have an explanation of what some of the options do (e.g., Manga mode).

Great info. I had no idea readability was even an issue. For now I held off the update due to a minor bug. Will update with all the fixes in couple of days.