How to compare 2 images from command line
freebsd at optiksecurite.com
Tue Sep 2 15:59:53 UTC 2008
Polytropon a écrit :
> On Tue, 02 Sep 2008 11:31:49 -0400, FreeBSD <freebsd at optiksecurite.com> wrote:
>> I want to determine if Mplayer is working correctly. The best way to be
>> sure is to check if the display on the screen is changing. That's the
>> purpose of the screenshots.
> And this works? I always thought mplayer would output the video
> stream via DRI / DRM, so on the screenshot, nothing would be seen...
Yes it works. I don't know how scrot takes it's screenshot but it does
it well ;)
>> The screenshots are taken by Nagios every 5
>> minutes and the new screenshot is compared with the preceding one. But,
>> by now, it doesn't work because every tool we try is seeing a diffence
>> between 2 identical images.
> The images may be identical in content, but it's completely possible
> that other data (others than the pictural information) is coded into
> the file, for example date and time of creation, so the files may be
> different, while the pictures they show are identical.
> It would be useful first to "decompile" the files - create a new file
> that only contains pictural information, nothing more.
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