Is the PDF experience better with a text layer?

[El Duderino]

First off, I've yet to install KOReader so these are pre-install questions...

KOReader has an OCR function, which is awesome, but how accurate do you find it? I suspect it depends on the image quality? Also, with a Kobo Aura (original), will the OCR process chew through the CPU causing battery drain and sluggish behaviour?

Before installing KOReader, I've been ingesting PDF's into Calibre, but only those with a text layer. I'm looking for as close to an e-pub experience as possible, so my assumption is Reflow works best with text layer as opposed to OCR'd image layer.

Is this assumption anywhere close to accurate?

Thanks!

[Ken Maltby]

KOReader is an additional reading program that you can add to what Kobo supplied as the stock readers. Your installing KSM8 and KOReader will not effect your existing Kobo software. There is an issue of how the Kobo Firmware Updates can make it necessary to use the properly updated KSM8.

KOReader includes a number of features to make reading PDFs less of a pain, but a 6" device is still Not the best thing to try and read full page PDF documents on.

I am not much of a PDF user myself, the few I do use (Like the Navy Dive Manual and the Army First Aid FM) are readable with reflow off, on my AuraHD. Hopefully someone with more PDF experience will be able to better address your questions.

Luck;
Ken

[johnnyb]

Originally Posted by El Duderino

First off, I've yet to install KOReader so these are pre-install questions...

KOReader has an OCR function, which is awesome, but how accurate do you find it? I suspect it depends on the image quality? Also, with a Kobo Aura (original), will the OCR process chew through the CPU causing battery drain and sluggish behaviour?

Before installing KOReader, I've been ingesting PDF's into Calibre, but only those with a text layer. I'm looking for as close to an e-pub experience as possible, so my assumption is Reflow works best with text layer as opposed to OCR'd image layer.

Is this assumption anywhere close to accurate?

Thanks!

The OCR will definitely affect your battery somewhat (it is based on the free tesseract OCR). The good news is, it is not necessary for the reflow feature at all. Reflow works with the k2pdfopt engine which actually rearranges the picture level of the PDF. So reflow will work any any PDF that you feed into it. The output quality depends largely on the picture quality of the PDF, and it is (like always) advisable to clean up your PDFs a bit before reading. There are various tools to do just that, like “briss” or “ScanTailor” (both help crop out margins and separate double pages, the former is quick and easy, the latter is really thorough and a bit more complicated) and “Tesseract” OCR which should help you with cleaning up your scans.
If you want to see how Koreader reflows your PDFs before installing, give “k2pdfopt” a try.

[El Duderino]

Thank you both for the enlightenment. In my research, KOReader is what I need to install if I want to read imported PDF's that I consider "undeniable, must-reads without an Epub variant".

Unfortunately, some have a text layer, others are comprised of fuzzy image scans, while many have unorthodox column structuring.

Based on your advice, I should do the following?

1. Install KSM8/KOReader
2. Run each PDF through Bliss
3. Import PDF's to Calibre
4. Load PDF's to device
5. Enjoy better reading experience
6. Look for KOReader to break when Kobo OTA updates occur
7. Update KOReader manually

Is that about right?

I'm having a helluva time trying to figure out the best approach to installing KOReader. Are the instructions/links the same in 2017 for Aura (original) as they were in 2013, 2015, etc?

Do I follow the first post in this thread only? https://www.mobileread.com/forums/sh...d.php?t=216960

There seems conflicting information regarding installation if one looks hard enough...

[Ken Maltby]

There are installation guidance in both the project WiKi and in the sticky threads at the top of the KOReader Forum here. The "installation" of KOReader is just a matter of copying over the KOReader folder, from the download, into the .adds folder on your device. The installation of KSM8 and any needed updates (depending on the Kobo firmware on your device) takes more consideration but is well explained in the KSM8 thread.

KOReader is not likely to "break" by the Kobo firmware updates, but KSM may be affected and need reinstallation or even a new update, to work with the firmware change.

Luck;
Ken

[johnnyb]

If you catch an update to the Kobo firmware before it is automatically installed, you can use KSM to install that update non-destructively. This is also why I would recommend istalling KSM as opposed to the fmon method.
Koreader installation is really just a copy and paste job to the .adds folder.
Tip: create a hidden .PDF (or anything else) folder on your Kobo and make that the standard for your files. That way new additions to your Kobo will not be automatically imported into Nickel. If you do not want to have hidden files all the time on your computer, create an alias of the hidden .PDF folder and place that on your desktop. No need to go through calibre at all.

[El Duderino]

Thank you both, that clears up most of the confusion in my mind.

Bypassing Calibre and Nickel altogether is an intriguing option. To be clear johnnyb, this hidden folder method is intended for PDF's only?

I'm wondering if the Kobo Start Menu (KSM) always has to be navigated when the device is turned on. I use the Sleep Wake cover, and 99% of the time am going back to an EPUB, so when I turn on the device or wake from sleep, I'd like to avoid having to press "Launch Nickel" or whatever to reach the Kobo firmware all the time. Is that possible?

Also, for anyone looking for an overview of KOReader, there's this video: https://www.youtube.com/watch?v=i2oSOeAnD10

[johnnyb]

Originally Posted by El Duderino

Thank you both, that clears up most of the confusion in my mind.

Bypassing Calibre and Nickel altogether is an intriguing option. To be clear johnnyb, this hidden folder method is intended for PDF's only?

You're welcome!
The method is intended for any files that you don't want Nickel to see.
You could also call it "Books" and then differentiate between different types within. To be clear: this is just to facilitate the use of both Koreader and Nickel at the same time. If you never start up Nickel it doesn't matter whether it will see your PDFs or not.
As for bypassing Nickel completely: ususally, when you're on Koreader, sending the device to sleep should do just that. When you wake it up, it resumes with Koreader automatically. Only when you turn it off completely will you be sent back to KSM to make your selection. There may be scripts that you could have KSM launch that facilitate booting to Koreader, but I haven't tried anything of that sort yet.

[Ken Maltby]

The main point of using a "hidden" folder for your books is to avoid the processing into the kobo SQLite database. KOReader can handle books and formats that would corrupt Kobo's database.

When waking from sleep (with or without the cover) you return to the page you went to sleep on. Only when you actually poweroff, or exit KOReader do you return to the KSM menu. KOReader can be set to "Show hidden files" and "Start with last opened file". In this way you will be on the page you were last reading, when ever you start KOReader.

KSM can be set to "Auto select" KOReader, after a number of seconds you define.

Luck;
Ken

[El Duderino]

OK thanks, I'll try and parrot back what you told me, and throw in a couple suppositions...

KSM is the e-reader equivalent of Grub 2 for computers. It allows dual-booting, and you can choose a default firmware (Nickel or KOReader) which gets auto-selected when you turn the device on from an off state.

Settings in both Nickel and KOReader control when your device gets turned off after a sleep duration. When you wake the device from a sleeping state, it returns to the page in the book in the firmware you were last in.

KOReader allows you the flexibility to choose your defaults, whereas Nickel (Kobo firmware) sets these for you (outside of what you can choose in "Settings").

Settings in KSM allow you to choose which is the default firmware, duration before auto-select, along with other options.

Sorry for the back and forth, I'm just afraid of bricking my Aura original. It's arguably the best e-reader Kobo ever made, and don't know how hard they are to replace these days.

[Ken Maltby]

A firmware update gone bad would be much more likely to brick the device than the installation of these additional programs. There is nothing that happens in installing these programs that affects the device's OS or would not be corrected with a "factory" reset.

Luck;
Ken

[El Duderino]

Ken, so do you always update Kobo firmware using KSM with "partial update" checked?

[Ken Maltby]

I would if I was updating the Kobo firmware, but I very rarely use Nickel or the stock reading software. When I do it is only to check on issues mentioned here or at Github. Sense I don't use the stock software, Kobo's efforts to "improve" them or more likely tie the device more tightly to their web store, are of no use to me (and given some of the problems the 4.x firmwares introduced) I am still using the 3.05 firmware.

The partial update protects the tiny bit of KSM code that a firmware update would overwrite.

Luck;
Ken

[El Duderino]

Thank again for the clarity Ken. I may be where you are someday and ditch Nickel entirely. Baby steps.

[Alan_S]

Originally Posted by El Duderino

KSM is the e-reader equivalent of Grub 2 for computers. It allows dual-booting, and you can choose a default firmware (Nickel or KOReader) which gets auto-selected when you turn the device on from an off state.

I don't know what grub 2 is, but it isn't what you describe.

There's no dual booting. You use in all cases (with or without KSM) firmware that comes with Kobo device.

Some updates update only nickel (that's how original software for reading on Kobos is named), some update firmware also. Not all updates contain firmware. Or, maybe they do, but it isn't necessary.

KSM is software, application that intercepts auto-loading of nickel and which gives many other options (too many to name all you get with KSM). It is in no way firmware, it just intercepts some scripts contained in firmware.

Koreader is just like nickel, ebook reading application, a program, software.

From KSM you choose which reading software you want to use on your device, I know of three programs: nickel, koreader, coolreader.

It is just like you can install on your computer more than one software for any task (let's say image viewer). It is not like you install on your computer windows, linux, unix, or some other OS.

And because of this, it is much safer. There's no messing with different firmwares, OSes or whatever complicating. Just choosing which program you want to use for reading.