v0.51 crc32 checksum fail

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pim
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Joined: Sun Nov 06, 2011 12:11 pm

v0.51 crc32 checksum fail

Post by pim » Tue Apr 09, 2013 3:06 pm

Hi.
When merging old picture collections I found two different pictures with same crc32 according to XnView:

Image

Other crc32 tools show more believable values:

Code: Select all

[nabuko@nabuko cksum]$ cksum 183-8385_IMG.JPG 
323455275 433352 183-8385_IMG.JPG
[nabuko@nabuko cksum]$ cksum 184-8419_IMG.JPG 
315802252 743109 184-8419_IMG.JPG
Do you want to check original pictures?
Version 0.92 x64 (Sep 29 2018) - un*x

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xnview
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Re: v0.51 crc32 checksum fail

Post by xnview » Wed Apr 10, 2013 6:19 am

yes please send me the pictures?
Pierre.

pim
Posts: 27
Joined: Sun Nov 06, 2011 12:11 pm

Re: v0.51 crc32 checksum fail

Post by pim » Wed Apr 10, 2013 2:57 pm

Version 0.92 x64 (Sep 29 2018) - un*x

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xnview
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Re: v0.51 crc32 checksum fail

Post by xnview » Wed Apr 10, 2013 6:06 pm

ok, thanks. Strange i have not same crc32 on windows, and which settings do you have for a result with these 2 pictures?
There aren't similar...
Pierre.

pim
Posts: 27
Joined: Sun Nov 06, 2011 12:11 pm

Re: v0.51 crc32 checksum fail

Post by pim » Thu Apr 11, 2013 2:48 pm

Lets compare if we have identical files also by another tool:

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[nabuko@nabuko XnMP]$ md5sum 183-8385_IMG.JPG 
169fb6fba4638aa10e05f78b0c5b4581  183-8385_IMG.JPG
[nabuko@nabuko XnMP]$ md5sum 184-8419_IMG.JPG 
58ec190b6fb4b241cfafdeafcdb0ce72  184-8419_IMG.JPG
I'm getting the same result with default settings:

Code: Select all

[nabuko@nabuko XnMP]$ mv ~/.xnviewmp/ ~/.xnviewmp_bck
[nabuko@nabuko XnMP]$ xnviewmp
I just checked "Same file data" in "Search similar files" dialog. Nothing else.

And here is extract from terminal output since comparison starts:

Code: Select all

...

### ThumbLoaderThread :: stop() ok
QPixmap: It is not safe to use pixmaps outside the GUI thread
QPixmap: It is not safe to use pixmaps outside the GUI thread
QPixmap: It is not safe to use pixmaps outside the GUI thread
QPixmap: It is not safe to use pixmaps outside the GUI thread
QPixmap: It is not safe to use pixmaps outside the GUI thread
### MyBitmapView (35cf8a0) :: resizeEvent 244 64
### MyBitmapView (357da40) :: resizeEvent 244 64
LOAD BITMAP <//media/truecrypt1/PROGRAMY/Dropbox/Public/XnMP/184-8419_IMG.JPG>
GFF :: LoadThumbnail : 0 
LOAD BITMAP <//media/truecrypt1/PROGRAMY/Dropbox/Public/XnMP/183-8385_IMG.JPG>
GFF :: LoadThumbnail : 0 
=> 0 1 b4002e90 (0)
###### LOAD BITMAP </media/truecrypt1/PROGRAMY/Dropbox/Public/XnMP/184-8419_IMG.JPG>
### resetViewport (35cf8a0)  ==> 244 64  (85 64) 0 0
### resetViewport (35cf8a0)  ==> 244 64  (85 64) 0 0
###### LOAD BITMAP </media/truecrypt1/PROGRAMY/Dropbox/Public/XnMP/183-8385_IMG.JPG>
### resetViewport (357da40)  ==> 244 64  (48 64) 0 0
### resetViewport (357da40)  ==> 244 64  (48 64) 0 0
### MyBitmapView (357da40) :: resizeEvent 330 64
### resetViewport (357da40)  ==> 330 64  (48 64) 0 0
### MyBitmapView (35cf8a0) :: resizeEvent 330 64
### resetViewport (35cf8a0)  ==> 330 64  (85 64) 0 0
QSettings::endGroup: No matching beginGroup()
ThumbLoaderThread :: stop()
### ThumbLoaderThread :: stop() ok

...
Version 0.92 x64 (Sep 29 2018) - un*x

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xnview
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Re: v0.51 crc32 checksum fail

Post by xnview » Thu Apr 11, 2013 3:31 pm

Very strange, i've tested on windows and linux, and i don't have same crc with similar dialog
Pierre.

pim
Posts: 27
Joined: Sun Nov 06, 2011 12:11 pm

Re: v0.51 crc32 checksum fail

Post by pim » Thu Apr 11, 2013 4:22 pm

It is...
Have you tried both 32 bit or 64 bit version?
What crc32 checksums are you getting?

Setup in english: Initial settings, select dir, open dialog and select Method. Nothing else.
Image
Image
Image
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xnview
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Re: v0.51 crc32 checksum fail

Post by xnview » Thu Apr 11, 2013 6:21 pm

Ok, with same file data, the crc is not computed!
Pierre.

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Re: v0.51 crc32 checksum fail

Post by xnview » Fri Apr 12, 2013 6:10 am

Ok, i've tried with other tool, and the crc32 is the same for these 2 files :(
Pierre.

pim
Posts: 27
Joined: Sun Nov 06, 2011 12:11 pm

Re: v0.51 crc32 checksum fail

Post by pim » Fri Apr 12, 2013 3:04 pm

Today I checked those files at different computer with different OS under different XnView version but with the same result: v0.53
CRC32 checksum tool integrated into TotalCommander gives also same values (while in hexa):

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; Generated by WIN-SFV32 v1.0
; (Compatible: Total Commander 8.01)
183-8385_IMG.JPG B700F1BB
184-8419_IMG.JPG B700F1BB
Seems like it's time for another checksum method:-)
But at least you know it's not bug in your implementation but rather design flaw in crc32.
Version 0.92 x64 (Sep 29 2018) - un*x

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