Different image signature between versions of IM7

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mbrijun
Posts: 14
Joined: 2019-05-05T10:06:02-07:00
Authentication code: 1152

Different image signature between versions of IM7

Post by mbrijun »

Hi,

I have noticed that IM7 is producing an inconsistent signature of the same image. There seem to be 2 separate issues:

1. Q8 and Q16 produces a different signature - this was fixed in 7.0.8-45, but seems to have crept back in.

Code: Select all

C:\Users\Martynas>magick identify -verbose u:\test\test.jpg
  <...>
    signature: 1776a54869f543618008dcf0ba21fdf09d507aa672693ef8b5989d63356c22b3
  <...>
  Version: ImageMagick 7.0.9-25 Q8 x64 2020-02-21 http://www.imagemagick.org

C:\Users\Martynas>magick identify -verbose u:\test\test.jpg
  <...>
    signature: 76188816c3b309a82c2a3f931eaa45d98db4ea7b6fdc79f7f5a19f20e0485e39
  <...>
  Version: ImageMagick 7.0.9-25 Q16 x64 2020-02-21 http://www.imagemagick.org

2. Different versions of IM7 (same Q value) produce a different signature.

Code: Select all

C:\Users\Martynas>magick identify -verbose u:\test\test.jpg
  <...>
    signature: 1776a54869f543618008dcf0ba21fdf09d507aa672693ef8b5989d63356c22b3
  <...>
  Version: ImageMagick 7.0.9-25 Q8 x64 2020-02-21 http://www.imagemagick.org

C:\Users\Martynas>magick identify -verbose u:\test\test.jpg
Image: u:\test\test.jpg
  <...>
    signature: 91460fb1d8dd878bbfb0ea82281c46aa7493b82bf11ac5ca47120adb403d8728
  <...>
  Version: ImageMagick 7.0.8-45 Q8 x64 2019-05-13 http://www.imagemagick.org

Code: Select all

C:\Users\Martynas>magick identify -verbose u:\test\test.jpg
  <...>
    signature: 76188816c3b309a82c2a3f931eaa45d98db4ea7b6fdc79f7f5a19f20e0485e39
  <...>
  Version: ImageMagick 7.0.9-25 Q16 x64 2020-02-21 http://www.imagemagick.org

C:\Users\Martynas>magick identify -verbose u:\test\test.jpg
  <...>
    signature: 91460fb1d8dd878bbfb0ea82281c46aa7493b82bf11ac5ca47120adb403d8728
  <...>
  Version: ImageMagick 7.0.8-45 Q16 x64 2019-05-13 http://www.imagemagick.org

User avatar
magick
Site Admin
Posts: 11254
Joined: 2003-05-31T11:32:55-07:00

Re: Different image signature between versions of IM7

Post by magick »

Thanks for the problem report. We can reproduce it and will have a patch to fix it in GIT master branch @ https://github.com/ImageMagick/ImageMagick later today. The patch will be available in the beta releases of ImageMagick @ https://www.imagemagick.org/download/beta/ by sometime tomorrow.

mbrijun
Posts: 14
Joined: 2019-05-05T10:06:02-07:00
Authentication code: 1152

Re: Different image signature between versions of IM7

Post by mbrijun »

Thank you, I can confirm that ImageMagick 7.0.9-26 Q8 now returns the same signature as 7.0.8-45.

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