Calibre puts garbage JPG files on the Nook

HunterZ · 08-14-2010, 02:13 PM

So I've used Calibre 0.7.14 to put some EPUB-format books onto my stock Nook, and I noticed that along with the EPUB files it also uploads JPG files that just contain vertical lines in various colors. It looks like these are maybe supposed to be thumbnails of the book covers, but I guess something is going wrong with Calibre when it makes them. Anyone know what's up?

Thanks.

Edit: I've attached one of the JPG files so you can see what I'm talking about.

kovidgoyal · 08-14-2010, 02:35 PM

WHat operating system is this on?

HunterZ · 08-14-2010, 02:38 PM

Windows XP Pro SP3.

I browsed to the Calibre library folder tree on my hard drive and drive and found a full-size cover JPG that it extracted from the EPUB and it looks fine, so it seems to have just messed up the thumbnail conversion or something.

kovidgoyal · 08-14-2010, 03:04 PM

Works for me on linux, can somebody else using the nook with windows confirm this bug.

HunterZ · 08-15-2010, 03:14 PM

Maybe I should try booting Ubuntu and installing Calibre there and then have it access my library that I've created in the Windows version since you know that the Linux version will generate thumbnails properly.

I did compare Calibre's Nook driver code to the Apple driver code and noticed that they do thumbnails completely differently. I also noticed that almost none of the other drivers really do thumbnails at all.

HunterZ · 09-03-2010, 08:28 PM

I just updated to Calibre 0.7.17 and this is still happening (attaching a new screenshot). I also got a PM from another forum member who may be having the same issue; I encouraged him/her to post here as well.

Testing out the Linux version of Calibre is in progress; I installed Calibre on my Ubuntu disk but didn't have my Nook handy at the time.

Edit: Linux 0.7.17 seems to work fine, so it's definitely a Windows specific issue for me.

DoctorOhh · 09-03-2010, 08:51 PM

Quote:

Originally Posted by HunterZ

I just updated to Calibre 0.7.17 and this is still happening (attaching a new screenshot). I also got a PM from another forum member who may be having the same issue; I encouraged him/her to post here as well.

Since it seems that currently the 2 you are the exception to the rule. Talk with this other user and see if you both run some unique piece of software, graphics card or processor that is interfering with this process.

Quote:

Originally Posted by HunterZ

Testing out the Linux version of Calibre is in progress; I installed Calibre on my Ubuntu disk but didn't have my Nook handy at the time.

Since the two you run different versions of Windows I'm curious if Ubuntu will give you problems.

I'm also surprised that others haven't come forward with this error.

HunterZ · 09-03-2010, 08:53 PM

Updated previous post with screenshot of it working properly in Ubuntu 10.04 on the same machine that is having problems via Windows XP.

Edit: Oh, the person who PM'd me already posted a thread on this and he's using Vista: https://www.mobileread.com/forums/showthread.php?t=95983

So it looks like it can happen on both XP and Vista, but works fine on the same machine on Ubuntu.

DoctorOhh · 09-03-2010, 09:03 PM

Quote:

Originally Posted by HunterZ

Edit: Oh, the person who PM'd me already posted a thread on this and he's using Vista: https://www.mobileread.com/forums/showthread.php?t=95983

So it looks like it can happen on both XP and Vista, but works fine on the same machine on Ubuntu.

I referred him to you in that thread to see if you all could figure out what you each had in common that is causing this.

Good Luck.

HunterZ · 09-03-2010, 09:17 PM

I think I may have found a piece of the puzzle. The machine on which I run Calibre is my old desktop, so I've converted it to a sort of server/workstation that I log into via Remote Desktop. On a hunch, I decided to try connecting via VNC instead of Remote Desktop to see if that would affect anything, and interestingly it made Calibre's Nook cover thumbnail generation work properly (see screenshot).

My guess is that the library (or whatever) that Calibre is using to generate the cover thumbnails for the Nook is dependent on some video hardware feature that Remote Desktop doesn't emulate properly. UltraVNC captures the remote computer's video via different methods that apparently don't cause Calibre to malfunction.

DoctorOhh · 09-03-2010, 09:22 PM

Quote:

Originally Posted by HunterZ

My guess is that the library (or whatever) that Calibre is using to generate the cover thumbnails for the Nook is dependent on some video hardware feature that Remote Desktop doesn't emulate properly. UltraVNC captures the remote computer's video via different methods that apparently don't cause Calibre to malfunction.

That does indeed sound like a unique setup that you both might have been running, great work!

HunterZ · 09-03-2010, 09:28 PM

I've updated bug #4828 in the Calibre bug tracker with a link to this thread in hopes that it helps lead to a fix: http://bugs.calibre-ebook.com/ticket/4828

kovidgoyal · 09-03-2010, 10:30 PM

Interesting, thumbnail generation happens using Qt, I'll look into switching it to IMageMagick, if it does not take too much work.

WJMuldowney · 09-03-2010, 11:48 PM

Quote:

Originally Posted by kovidgoyal

Works for me on linux, can somebody else using the nook with windows confirm this bug.

Yes, same exact bug using Windows Vista.

DoctorOhh · 09-03-2010, 11:55 PM

Quote:

Originally Posted by WJMuldowney

Yes, same exact bug using Windows Vista.

Read the last few posts. Is your problem caused by the same source (see post 10)? The question is are you using a remote connection to your box?

08-14-2010, 02:13 PM	#1
HunterZ Member Posts: 15 Karma: 50 Join Date: Aug 2010 Location: Seattle Device: Nook	Calibre puts garbage JPG files on the Nook So I've used Calibre 0.7.14 to put some EPUB-format books onto my stock Nook, and I noticed that along with the EPUB files it also uploads JPG files that just contain vertical lines in various colors. It looks like these are maybe supposed to be thumbnails of the book covers, but I guess something is going wrong with Calibre when it makes them. Anyone know what's up? Thanks. Edit: I've attached one of the JPG files so you can see what I'm talking about. Attached Images Last edited by HunterZ; 08-14-2010 at 02:16 PM.

09-03-2010, 08:28 PM	#6
HunterZ Member Posts: 15 Karma: 50 Join Date: Aug 2010 Location: Seattle Device: Nook	I just updated to Calibre 0.7.17 and this is still happening (attaching a new screenshot). I also got a PM from another forum member who may be having the same issue; I encouraged him/her to post here as well. Testing out the Linux version of Calibre is in progress; I installed Calibre on my Ubuntu disk but didn't have my Nook handy at the time. Edit: Linux 0.7.17 seems to work fine, so it's definitely a Windows specific issue for me. Attached Thumbnails Last edited by HunterZ; 09-03-2010 at 08:52 PM.

09-03-2010, 08:53 PM	#8
HunterZ Member Posts: 15 Karma: 50 Join Date: Aug 2010 Location: Seattle Device: Nook	Updated previous post with screenshot of it working properly in Ubuntu 10.04 on the same machine that is having problems via Windows XP. Edit: Oh, the person who PM'd me already posted a thread on this and he's using Vista: https://www.mobileread.com/forums/showthread.php?t=95983 So it looks like it can happen on both XP and Vista, but works fine on the same machine on Ubuntu. Last edited by HunterZ; 09-03-2010 at 08:59 PM.

09-03-2010, 09:17 PM	#10
HunterZ Member Posts: 15 Karma: 50 Join Date: Aug 2010 Location: Seattle Device: Nook	I think I may have found a piece of the puzzle. The machine on which I run Calibre is my old desktop, so I've converted it to a sort of server/workstation that I log into via Remote Desktop. On a hunch, I decided to try connecting via VNC instead of Remote Desktop to see if that would affect anything, and interestingly it made Calibre's Nook cover thumbnail generation work properly (see screenshot). My guess is that the library (or whatever) that Calibre is using to generate the cover thumbnails for the Nook is dependent on some video hardware feature that Remote Desktop doesn't emulate properly. UltraVNC captures the remote computer's video via different methods that apparently don't cause Calibre to malfunction. Attached Thumbnails

Similar Threads
Thread	Thread Starter	Forum	Replies	Last Post
Calibre changes size of cover.jpg when copy to new Libary --> see PDF attached	icq70610	Calibre	5	10-02-2010 01:29 PM
JPG cover files not removed from Novel	js4c	Calibre	5	08-03-2010 09:27 PM
DR800 Couldn't we turn to the next image at one click when viewing jpg files?	bokjeid	iRex	3	07-22-2010 05:47 PM
Calibre leaving behind garbage in the filesystem?	tobidope	Calibre	3	07-13-2010 03:39 PM
calibre auto fetch non-scheduled job & puts out error msg	shinew	Calibre	2	02-23-2009 10:27 PM

08-14-2010, 02:35 PM	#2
kovidgoyal creator of calibre Posts: 43,858 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	WHat operating system is this on?

08-14-2010, 02:38 PM	#3
HunterZ Member Posts: 15 Karma: 50 Join Date: Aug 2010 Location: Seattle Device: Nook	Windows XP Pro SP3. I browsed to the Calibre library folder tree on my hard drive and drive and found a full-size cover JPG that it extracted from the EPUB and it looks fine, so it seems to have just messed up the thumbnail conversion or something.

08-14-2010, 03:04 PM	#4
kovidgoyal creator of calibre Posts: 43,858 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	Works for me on linux, can somebody else using the nook with windows confirm this bug.

08-15-2010, 03:14 PM	#5
HunterZ Member Posts: 15 Karma: 50 Join Date: Aug 2010 Location: Seattle Device: Nook	Maybe I should try booting Ubuntu and installing Calibre there and then have it access my library that I've created in the Windows version since you know that the Linux version will generate thumbnails properly. I did compare Calibre's Nook driver code to the Apple driver code and noticed that they do thumbnails completely differently. I also noticed that almost none of the other drivers really do thumbnails at all.

09-03-2010, 09:28 PM	#12
HunterZ Member Posts: 15 Karma: 50 Join Date: Aug 2010 Location: Seattle Device: Nook	I've updated bug #4828 in the Calibre bug tracker with a link to this thread in hopes that it helps lead to a fix: http://bugs.calibre-ebook.com/ticket/4828

09-03-2010, 10:30 PM	#13
kovidgoyal creator of calibre Posts: 43,858 Karma: 22666666 Join Date: Oct 2006 Location: Mumbai, India Device: Various	Interesting, thumbnail generation happens using Qt, I'll look into switching it to IMageMagick, if it does not take too much work.