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Pocketbook InkPad Overview: eBook Formats

Pocketbook has long boasted that their ebook readers support an impressive number of file formats, including PDF, Epub, Mobi, FB2, and while that’s nifty and all I for one have always wondered how well all those formats actually worked on Pocketbook’s devices.

And now that I have the InkPad, I decided to find out.

Pocketbook’s 8″ ebook reader has iffy software, but the hardware is good enough that I feel it’s worth my time to critique the software features and how well the various file formats are supported.

Table of Contents
[—ATOC—] [—TAG:h2—]

The following post is Part One of X of my review of the InkPad, and I will add more detail as I write other parts of my review or at the request of readers.

According to Pocketbook, the complete list of supported formats include:

  • PDF, Epub, Mobi, DJVU, FB2,, Doc, Docx, rtf, prc, tcr, txt, chm, & html

This of course leaves out the image formats (JPG, TIFFF, BMP, PNG) and audio format (MP3), which I intend to cover in a post on the InkPad’s apps.

Let’s start with PDF.


This is one of the Inkpad’s best and worst features. While text based PDFs look great on the InkPad’s 8″ screen, graphic novels are slow to render (2 seconds per page, or more). Text to Speech also didn’t work more than a single time.

I tested a 10MB graphic novel, and several other PDFs of various sizes. So long as the PDFs weren’t image intensive they worked just fine.

I found 8.5×11 PDFs to be quite readable with the margin cropping option set to automatic. That removed the need for zooming in most situations.


  • Zoom: Pinch, manual
  • Scrolling
  • Dictionary
  • Note taking
  • Bookmark
  • Search
  • Text to Speech (it doesn’t work)
  • Screen Rotation (4 directions)
  • Margin Cropping: manual, automatic
  • Zoom Options: width, whole page, reflow, & column

For the sake of completeness: I tested English language PDFs, but not (so far as I know) ones with unusual embedded fonts. So I might have missed something.


Epub is one of the more common formats and its various flavors (Kobo, Apple, etc) make up a significant share of the global ebook market. With that in mind, you would think that Epub would be the best supported format.

Frankly, it’s not.

I noticed while reading that the Epub renderer repeatedly forgot what it had just shown on screen. In other words, most of the times that I tried to use the left page turn button to go back through what I just read, instead of seeing text I saw a blank page. Pressing the page turn button again sometimes moved another page back, but sometimes it did nothing.

It was also slow to turn the page. In comparison to my  my Kindle Paperwhite (2013), which was showing an ebook I bought from Amazon, the InkPad took noticeably longer to turn the page.There were also times where the InkPad simply froze.


  • Dictionary
  • Note taking
  • Bookmark
  • Search
  • TTS
  • Table of Contents (including separate TOCs for notes and bookmarks)
  • Screen Rotation (4 directions)
  • Margins: 3 options
  • Line spacing: 3 options
  • Hyphenation
  • Fontface: Several dozen offered
  • Font Sizes: 16 pt to 90 pt

Mobi & PRC

While I am sure that some ebook users look at the Mobi support and think that the InkPad is the answers to their need for a single platform which supports both Epub and DRM-free Kindle ebooks, I’m going to have to burst your bubble.

The InkPad supports Mobi, but it does not support much in the way of formatting. It won’t show you the formatting created by the publisher, just a very basic text layout. It also cannot show you the cover, but it does support the external TOC.


  • Dictionary
  • Note taking
  • Bookmark
  • Search
  • TTS
  • Table of Contents

From what I can tell, the Mobi files are rendered using code different from Epub files. They share some details, including font sizes, line spacing, and margin options, but I have noticed that the Mobi files didn’t have the same issue with left page turns.

They also had a "back button" which I didn’t see with the Epub files; it enabled me to go back to the inline TOC, for example. And the InkPad was faster at turning the age in a Mobi file than it was in an Epub file.


Similar to the incomplete Mobi support, the InkPad doesn’t completely support these office formats. It will open the files and display the text, but certain details like formatting, page breaks, and a TOC are ignored.

Or at least, those details were ignored in the test files I created with Libre Office; I can’t say for sure whether they will be respected in office files created with other apps.

Most of the features available for the ebook formats worked with the office formats.


Originally Microsoft’s help file format, the CHM format has never been very common. It can still sometimes be found with Windows apps, but I don’t think it’s in widespread use any more. In fact, Microsoft doesn’t really support it any more; Windows can open the file but it uses the a frame design that hasn’t been updated since 2002 (I checked the about page).

The page turn speed was comparable to my Kindle Paperwhite (2013) which was showing an ebook I bought from Amazon.

The InkPad can open the files, but most of the formatting is ignored. The TOC works, though, and you do get the same features as the office formats mentioned above.


I freely confess that I know little about this format this morning, and after having used it I still don’t know much. Described online as a compressed image format, the files I tested more closely resembled a PDF-like file format.  The text was in fixed layout like a PDF, and there was actual text and not just page images. (The search worked, for example.)

The page turn speed was somewhat slower than my Kindle Paperwhite (2013).

I don’t think DJVu is terribly useful, but it does work to some degree.  To be honest, I can’t tell you how well it worked; I was only able to find a handful of files from a single source so I don’t know whether the imperfect performance was the quality of the files or the InkPad.


  • Zoom: Pinch, manual
  • Dictionary
  • Note taking
  • Bookmark
  • Search
  • Margin Cropping: manual, automatic
  • Zoom Options: width, whole page, & column


I had similar issues with testing this format. Originally developed for FBReader (a Russian ebook app), this format is from a US perspective incredibly obscure. I was able to find one file I could read. To be more exact, I found one file in English; if I were able to read Russian I could have used any of a few dozen files.

The page turn speed was comparable to my Kindle Paperwhite (2013), which was showing an ebook I bought from Amazon.

The FB2 support closely matched the support for Epub, though I am not sure whether the formatting was displayed correctly. I can also add that I did not encounter Epub’s missing text bug.


  • Dictionary
  • Note taking
  • Bookmark
  • Search
  • TTS
  • Table of Contents
  • Screen Rotation (4 directions)
  • Margins: 3 options
  • Line spacing: 3 options
  • Hyphenation
  • Fontface: Several dozen offered
  • Font Sizes: 16 pt to 90 pt

Not Tested

Due to my inability to find a test file, I did not try TCR. I also did not test html beyond a cursory test to confirm the files opened; I lack test files with inline formatting or CSS embedded in the header.


In summary, Pocketbook’s software offers good support for PDF and FB2, marginal support for Mobi and office doc formats, and flawed support for Epub. That list of supported formats doesn’t sound nearly as impressive as it did this morning.

Update: On the other hand, when viewed from a reader’s position the format support is better than a critical review would suggest. I’m in the middle of putting the final touches on my review of the InkPad, and I wanted to add that the limited support for the many formats is worth more than I thought. I’m reading a couple ebooks in Mobi format on the InkPad and I am enjoying myself.

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DeeDee November 17, 2014 um 3:19 am

I have an old Pocketbook 611 basic and for epub the adobe app sucked – it couldn’t recognize some of the encodings and it counted fixed number of pages – I would press the page turn button 3-4 times before it counts a page and after the device is turned off it remembers only the page and not which part of it, so I read some parts of the text twice. The preinstalled fbreader and coolreader3 (I installed it) don’t have those issues. Coolreader is too good and I almost never use the default apps, and it shows the publisher’s formatting, but for a test of format support it’s only fair to use the default apps.

Joel November 17, 2014 um 8:19 am

Is it hard to install Coolreader?
And is there other appps to install?

DeeDee November 17, 2014 um 8:52 am

For my device (Pocketbook 611) it was relatively easy – download a .zip file, extract, copy in the root folder and I had to edit a config file to include coolreader in the list of available. Google device name and coolreader – there are topics on mobilereads with instructions. But I’m not sure if it’s available for the InkPad.

Name (required) November 17, 2014 um 8:39 am

I had one of old generations of PocketBook – the PocketBook 360. I also have PocketBook 623 Touch Lux. I had the chance to test PocketBook Ultra 650 and declined offer to buy it, despite discount.

I personally consider the 5 inch PB360 to be one of the best readers of its time. If it had front-lit screen I would be using it even now. It had fantastic body that you could slip into a pocket and it had a plastic lid that did not add to the bulk of the device.
The software was just perfect [FOR MY NEEDS].
It had large number of customization options, including side-loading fonts, pictures displayed when the device is of [sometimes called screensavers], third-party apps (including things like Linux terminal) and third-party versions of built-in binaries – most notably fbreader. You could also remap all 7 hardware keys, each key for two functions (short press and long press) from a very long list of available functions). No hacking needed. PocketBook company released tools for creating user dictionaries, themes (files that let you completely redefine user interface – main page, library, menus …) and even an SDK – Software Development Kit, together with sources for some apps, such as fbreader. They even sponsored development of apps – server organized a competition for themes, apps, games with generous prizes supplied by PocketBook.
I call those times "The Good Old Times" (TM).

One of many configuration options was the extensions.conf file where you could define your own apps for opening each supported format (with third-party apps adding support for things like cbz files). Then in the library you could just hold the OK button and then select "Open with" menu and select from a list of apps.
For the epub, you could use the built-in fbreader, AdobeReader and third-party apps like fbreader180 and Coolreader. AdobeReader displayed the epubs the way they were formatted by publisher. Full justification, atrocious fonts, and other things. FBReader was developed primarily for reading FB2 files. FB2 files do not describe formatting, they describe books structure. FB2 is xml format that has some 37 well defined formatting groups, such as Heading1, Heading2, BodyText, quote, verse, bold, italics … . It is then up to user to configure how he wants to display the book. I LOVED that feature. I opened the epub in fbreader and it displayed the book left aligned, with minimal margins, using my favourite font regardless of what insane things publisher set. When I needed to see original formatting, which was very rarely, I opened the epub in AdobeReader.
Third-party FBReader 180 had very large number of configuration options and could turn pages using the built-in acclelerometer. You just flicked your wrist.
Mobi, rtf, html and other formats are opened by – they are internally converted to FB2 format – this conversion is part of the FB2 parser. So it is up to user to set up how he wants to read the book. Kindle does something similar. Whatever the formatting in the original file you upload to Amazon, it always displays in one of small handful of built-in Kindle fonts, full justification (that I personally can not stand [on a small e-ink display]), three sizes of margins …
Sorry for the long nostalgic rant, but you need to see the history and reasons behind some unusual features.

Fact forward to newer version of firmware (4.something) and newer hardware, such as PB623.
I guess that the legendary programmers that wrote software specification for the first generation and designed system architecture, where *everything* is opened to the user either as an option or at least through the config file have left the company.
I think that configuration features we see now is just an inertia, and the openness is not primary concern.
They screwed up formatting in fbreader for epubs and now fbreader ignores my settings for justification, margins and other things. Why do they need to preserve formatting in fbreader when AdobeReader (with its full support for publisher formatting) is the default reading app?
Fortunately, I can install Coolreader to 4.xy firmware and use that to read epubs.
They did introduce a few interesting features, such as DropBox integration, but those are used only very rarely in comparison with fbreader and other features that they managed to screw up.

The Inkpad came with the 4.4 firmware. DO NOT UPDATE TO 5.xy.

Fast forward to firmware 5.xy – the one you had the pleasure use in PocketBook Ultra 650.
The user interface is even more "Kindlified" (and I use this as a highest insult) then in version 4.
Users at are revolting, because they updated their InkPads to firmware 5 and THERE IS NO WAY BACK. There is no 4.4 that you could download to be able to downgrade once you update to 5. Forkosigan who is responsible for distribution of PocketBook readers to Europe has promised the firmware for downgrade, but couldn’t tell when. In the meanwhile people are pissed off royally.

Nate Hoffelder November 17, 2014 um 9:27 am

I like the PB 360 as well; it has the best form factor of all of the smaller ereaders. Now if only Pocketbook would release an updated model.

As for the InkPad, I updated to the v5.4 firmware. I honestly think it was an improvement.

Name (required) November 17, 2014 um 11:43 am

Can the homepage in v5.4 be switched into a list mode like it was in the 4.4 or is it still 3x picture that you have to swipe to see further books – nine in total? In 4.4 I have 9 most recently read books on main page (with menu minimized) and 20 in total after a swipe.

Can the bottom status-line in a reading app in 5.4 display more than just a page number? If I want to see things like battery status, time … do I have to have top status line as well?

Can you install Coolreader to v5.4? It can be installed in 4.4. With screwed-up fbreader for reading epubs it has been a lifesaver for me.

There are some other … aehm … differences, but I do not want to make you biased.

You see, I have been using firmware 4.4 for some time in my PB 623 and I have had the opportunity to experience firmware 5.2 on PocketBook Ultra.
Guess which one I personally prefer? 😉

Nate Hoffelder November 17, 2014 um 11:50 am

I can’t find a way to change to the list view you mention, and there are no options for the status bar at the bottom of the screen.

I was also unable to find a copy of CoolReader other than the one on a Russian site behind a registration wall.

Name (required) November 18, 2014 um 10:19 am

I was hoping they would address some of the issues I have seen in 5.2 firmware.

If you need help downloading files from Russian speaking servers just ask.

freighter November 19, 2014 um 5:25 am

Could you tell us about the screen quality and build quality? Also, how is the battery life and lighting. Software can be improved but hardware stays the same.

Nate Hoffelder November 19, 2014 um 6:33 am

Yep. That’s going to be in the main section of the review, which I will be writing next weekend.

Name (required) November 19, 2014 um 2:52 pm

Here is address for Coolreader that can be installed to firmware 4.4

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Michael December 21, 2014 um 3:27 pm

The 4.4 firmware is now available on the support website ?
Therefore a downgrade to 4.4 should be possible.

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Yep. I’ve downgraded. I don’t like the interface but the reading app offers more options and has darker text.

I’m still working on installing additional apps.

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