2.39: Error opening png file

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Stepa_ua
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Joined: Sat Nov 26, 2016 12:06 am

2.39: Error opening png file

Post by Stepa_ua »

I use Win7 x64. After the XnView updating to version 2.39 I have found out that it is impossible to open one of graphic files.

The error of reading is shown only on this file, other png files open without problems.
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XnTriq
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Re: 2.39: Error opening png file

Post by XnTriq »

Welcome to the forum, Stepa_ua.

I can confirm that XnView Classic v2.37 and v2.39 as well as MP v0.83 don't like SoftJig.png. I had no problem viewing it with v1.99 though, and TweakPNG gives it a clean bill of health.

Update:
p136095.png
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xnview
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Re: 2.39: Error opening png file

Post by xnview »

The error is 'IDAT: invalid distance too far back', from Libpng they recommand to use "contrib/tools/pngfix", "pngcrush" to fix such bad file.
Pierre.
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XnTriq
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Re: 2.39: Error opening png file

Post by XnTriq »

xnview wrote:The error is 'IDAT: invalid distance too far back', from Libpng they recommand to use "contrib/tools/pngfix", "pngcrush" to fix such bad file.
Thanks for the hint!

Code: Select all

pngcrush.exe X:\in\SoftJig.png X:\out\SoftJig.png

  Recompressing IDAT chunks in X:\in\SoftJig.png to X:\out\SoftJig.png
   Total length of data found in critical chunks            =     13573
While converting X:\in\SoftJig.png to X:\out\SoftJig.png:
  pngcrush caught libpng error:
   IDAT: invalid distance too far back

   Critical chunk length, method  12 (ws 15 fm 0 zl 0 zs 0) =        99

Code: Select all

pngcrush.exe -fix X:\in\SoftJig.png X:\out\SoftJig.png

  Recompressing IDAT chunks in X:\in\SoftJig.png to X:\out\SoftJig.png
   Total length of data found in critical chunks            =     13573
   Critical chunk length, method   1 (ws 15 fm 0 zl 4 zs 0) =     17795
   Critical chunk length, method   2 (ws 15 fm 1 zl 4 zs 0) >     17795
   Critical chunk length, method   3 (ws 15 fm 5 zl 4 zs 1) >     17795
   Critical chunk length, method   4 (ws 15 fm 0 zl 9 zs 1) =     13445
   Critical chunk length, method   7 (ws 15 fm 0 zl 9 zs 0) >     13445
   Best pngcrush method        =   4 (ws 15 fm 0 zl 9 zs 1) =     13445
     (0.94% critical chunk reduction)
     (0.94% filesize reduction)
p136130.png
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helmut
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Re: 2.39: Error opening png file

Post by helmut »

xnview wrote:The error is 'IDAT: invalid distance too far back', from Libpng they recommand to use "contrib/tools/pngfix", "pngcrush" to fix such bad file.
Thank you for checking, Pierre. Perhaps XnView can display a more detailed error message which points to the problem.
Stepa_ua
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Re: 2.39: Error opening png file

Post by Stepa_ua »

Thank you! This file is really easy to fix by using Pngcrush or OptiPNG.