Re: How to compare 2 images from command line
On 2 Sep 2008 , [EMAIL PROTECTED] entreated about freebsd-questions Digest, Vol 231, Issue 5: Yes, there's a huge difference between testing differences in images and testing differences in files. What do you mean by ...know if the display is working correctly.? Andrew 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. 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. JPG format will always be different because of the encoding/compression. I think you need to save to an uncompressed format like BMP. Maybe PNG has a mode that will work too. BMP has no info headers, just the raw data, so that won't be affected by the time of the save (at the least). -- DA Fo rsythNetwork Supervisor Principal Technical Officer -- Institute for Water Research http://www.ru.ac.za/institutes/iwr/ ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
How to compare 2 images from command line
Hi everyone, I'm trying to determine if 2 jpeg images are identical. The images are screenshots taken with scrot at different times. The point is to know if the display is working correctly. I tried to use 'diff' but without success, probably because of the metadata included in the image. I also tried the 'compare' command from imagemagick, but it produce an image containing the difference between the 2 images instead of telling me if both images are identical. So, my question is what are you using to determine if 2 images are identical? I'm using FreeBSD 7.0 and I need to be able to script this comparaison for an integration in Nagios. Thank you, Martin ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: How to compare 2 images from command line
/sbin/md5 image1.ext image2.ext ? On Tue, 2008-09-02 at 11:02 -0400, FreeBSD wrote: Hi everyone, I'm trying to determine if 2 jpeg images are identical. The images are screenshots taken with scrot at different times. The point is to know if the display is working correctly. I tried to use 'diff' but without success, probably because of the metadata included in the image. I also tried the 'compare' command from imagemagick, but it produce an image containing the difference between the 2 images instead of telling me if both images are identical. So, my question is what are you using to determine if 2 images are identical? I'm using FreeBSD 7.0 and I need to be able to script this comparaison for an integration in Nagios. Thank you, Martin ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED] -- Julien Cigar Belgian Biodiversity Platform http://www.biodiversity.be Université Libre de Bruxelles (ULB) Campus de la Plaine CP 257 Bâtiment NO, Bureau 4 N4 115C (Niveau 4) Boulevard du Triomphe, entrée ULB 2 B-1050 Bruxelles Mail: [EMAIL PROTECTED] @biobel: http://biobel.biodiversity.be/person/show/471 Tel : 02 650 57 52 ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: How to compare 2 images from command line
Tom Marchand a écrit : Hash the images and compare the hashes. -- Original message -- From: FreeBSD [EMAIL PROTECTED] Hi everyone, I'm trying to determine if 2 jpeg images are identical. The images are screenshots taken with scrot at different times. The point is to know if the display is working correctly. I tried to use 'diff' but without success, probably because of the metadata included in the image. I also tried the 'compare' command from imagemagick, but it produce an image containing the difference between the 2 images instead of telling me if both images are identical. So, my question is what are you using to determine if 2 images are identical? I'm using FreeBSD 7.0 and I need to be able to script this comparaison for an integration in Nagios. Thank you, Martin I just tried it and it doesn't work. The hashes are different. I can't say that I'm surprised since 'diff' is seeing a difference between the two identical images. Thanks for the suggestion ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: How to compare 2 images from command line
On Tue, Sep 2, 2008 at 10:23 AM, FreeBSD [EMAIL PROTECTED] wrote: Tom Marchand a écrit : Hash the images and compare the hashes. -- Original message -- From: FreeBSD [EMAIL PROTECTED] Hi everyone, I'm trying to determine if 2 jpeg images are identical. The images are screenshots taken with scrot at different times. The point is to know if the display is working correctly. I tried to use 'diff' but without success, probably because of the metadata included in the image. I also tried the 'compare' command from imagemagick, but it produce an image containing the difference between the 2 images instead of telling me if both images are identical. So, my question is what are you using to determine if 2 images are identical? I'm using FreeBSD 7.0 and I need to be able to script this comparaison for an integration in Nagios. Thank you, Martin I just tried it and it doesn't work. The hashes are different. I can't say that I'm surprised since 'diff' is seeing a difference between the two identical images. Thanks for the suggestion Yes, there's a huge difference between testing differences in images and testing differences in files. What do you mean by ...know if the display is working correctly.? Andrew ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: How to compare 2 images from command line
Andrew Gould a écrit : On Tue, Sep 2, 2008 at 10:23 AM, FreeBSD [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] wrote: Tom Marchand a écrit : Hash the images and compare the hashes. -- Original message -- From: FreeBSD [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] Hi everyone, I'm trying to determine if 2 jpeg images are identical. The images are screenshots taken with scrot at different times. The point is to know if the display is working correctly. I tried to use 'diff' but without success, probably because of the metadata included in the image. I also tried the 'compare' command from imagemagick, but it produce an image containing the difference between the 2 images instead of telling me if both images are identical. So, my question is what are you using to determine if 2 images are identical? I'm using FreeBSD 7.0 and I need to be able to script this comparaison for an integration in Nagios. Thank you, Martin I just tried it and it doesn't work. The hashes are different. I can't say that I'm surprised since 'diff' is seeing a difference between the two identical images. Thanks for the suggestion Yes, there's a huge difference between testing differences in images and testing differences in files. What do you mean by ...know if the display is working correctly.? Andrew 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. 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. Thank you for your interest ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: How to compare 2 images from command line
I'm trying to determine if 2 jpeg images are identical. The images are screenshots taken with scrot at different times. The point is to know if the display is working correctly. I tried to use 'diff' but without success, probably because of the metadata included in the image. I also tried the cmp does byte-to byte comparision. if you want to make sure uncompressed bitmaps are the same then uncompress (cmp) and then compare ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: How to compare 2 images from command line
On Tue, 02 Sep 2008 11:31:49 -0400, FreeBSD [EMAIL PROTECTED] 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... 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. -- Polytropon From Magdeburg, Germany Happy FreeBSD user since 4.0 Andra moi ennepe, Mousa, ... ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: How to compare 2 images from command line
In response to FreeBSD [EMAIL PROTECTED]: Andrew Gould a écrit : On Tue, Sep 2, 2008 at 10:23 AM, FreeBSD [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] wrote: Tom Marchand a écrit : Hash the images and compare the hashes. -- Original message -- From: FreeBSD [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] Hi everyone, I'm trying to determine if 2 jpeg images are identical. The images are screenshots taken with scrot at different times. The point is to know if the display is working correctly. I tried to use 'diff' but without success, probably because of the metadata included in the image. I also tried the 'compare' command from imagemagick, but it produce an image containing the difference between the 2 images instead of telling me if both images are identical. So, my question is what are you using to determine if 2 images are identical? I'm using FreeBSD 7.0 and I need to be able to script this comparaison for an integration in Nagios. Thank you, Martin I just tried it and it doesn't work. The hashes are different. I can't say that I'm surprised since 'diff' is seeing a difference between the two identical images. Thanks for the suggestion Yes, there's a huge difference between testing differences in images and testing differences in files. What do you mean by ...know if the display is working correctly.? Andrew 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. 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. Can you put the screenshots into some other format? As you mentioned, the jpeg format includes metadata, which might include the creation time and would cause every image to be unique from a filesystem view. For example, I don't believe bitmaps include metadata, which would cause them to be identical if the display were identical. -- Bill Moran http://www.potentialtech.com ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: How to compare 2 images from command line
Bill Moran a écrit : In response to FreeBSD [EMAIL PROTECTED]: Andrew Gould a écrit : On Tue, Sep 2, 2008 at 10:23 AM, FreeBSD [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] wrote: Tom Marchand a écrit : Hash the images and compare the hashes. -- Original message -- From: FreeBSD [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] Hi everyone, I'm trying to determine if 2 jpeg images are identical. The images are screenshots taken with scrot at different times. The point is to know if the display is working correctly. I tried to use 'diff' but without success, probably because of the metadata included in the image. I also tried the 'compare' command from imagemagick, but it produce an image containing the difference between the 2 images instead of telling me if both images are identical. So, my question is what are you using to determine if 2 images are identical? I'm using FreeBSD 7.0 and I need to be able to script this comparaison for an integration in Nagios. Thank you, Martin I just tried it and it doesn't work. The hashes are different. I can't say that I'm surprised since 'diff' is seeing a difference between the two identical images. Thanks for the suggestion Yes, there's a huge difference between testing differences in images and testing differences in files. What do you mean by ...know if the display is working correctly.? Andrew 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. 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. Can you put the screenshots into some other format? As you mentioned, the jpeg format includes metadata, which might include the creation time and would cause every image to be unique from a filesystem view. For example, I don't believe bitmaps include metadata, which would cause them to be identical if the display were identical. Thank you! It did the trick. I just converted the image from png (sorry it wasn't jpeg...) to bmp and it works with cmp. Even diff now recognize both images as identical. Thanks everyone for your support. Martin ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: How to compare 2 images from command line
Polytropon a écrit : On Tue, 02 Sep 2008 11:31:49 -0400, FreeBSD [EMAIL PROTECTED] 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. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: How to compare 2 images from command line
On Tue, Sep 2, 2008 at 10:31 AM, FreeBSD [EMAIL PROTECTED] wrote: Andrew Gould a écrit : On Tue, Sep 2, 2008 at 10:23 AM, FreeBSD [EMAIL PROTECTED]mailto: [EMAIL PROTECTED] wrote: Tom Marchand a écrit : Hash the images and compare the hashes. -- Original message -- From: FreeBSD [EMAIL PROTECTED] mailto:[EMAIL PROTECTED] Hi everyone, I'm trying to determine if 2 jpeg images are identical. The images are screenshots taken with scrot at different times. The point is to know if the display is working correctly. I tried to use 'diff' but without success, probably because of the metadata included in the image. I also tried the 'compare' command from imagemagick, but it produce an image containing the difference between the 2 images instead of telling me if both images are identical. So, my question is what are you using to determine if 2 images are identical? I'm using FreeBSD 7.0 and I need to be able to script this comparaison for an integration in Nagios. Thank you, Martin I just tried it and it doesn't work. The hashes are different. I can't say that I'm surprised since 'diff' is seeing a difference between the two identical images. Thanks for the suggestion Yes, there's a huge difference between testing differences in images and testing differences in files. What do you mean by ...know if the display is working correctly.? Andrew 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. 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. Thank you for your interest Are you simply trying to determine whether the mplayer has finished playing a movie (that you're not watching)? It seems to me that the fact that the image changes is not a good indication that mplayer is working correctly, only that the movie isn't running. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: How to compare 2 images from command line
andrew clarke a écrit : On Tue 2008-09-02 11:57:35 UTC-0400, FreeBSD ([EMAIL PROTECTED]) wrote: Can you put the screenshots into some other format? As you mentioned, the jpeg format includes metadata, which might include the creation time and would cause every image to be unique from a filesystem view. For example, I don't believe bitmaps include metadata, which would cause them to be identical if the display were identical. Thank you! It did the trick. I just converted the image from png (sorry it wasn't jpeg...) to bmp and it works with cmp. Even diff now recognize both images as identical. Before I read this I was going to suggest you could try removing the metadata using something like jhead. As it turns out, you say you're using PNG format images, not JPEGs, but perhaps there's an equivalent to jhead to work with metadata in PNG files - just as an alternative to converting each PNG to BMP (which could be CPU intensive). Regards Andrew Thank you for your almost-suggestion ;) The screenshot are taken once every 5 minutes and the conversion was pretty instant. I don't think it will be a problem in our case. Martin ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
Re: How to compare 2 images from command line
On Tue 2008-09-02 11:57:35 UTC-0400, FreeBSD ([EMAIL PROTECTED]) wrote: Can you put the screenshots into some other format? As you mentioned, the jpeg format includes metadata, which might include the creation time and would cause every image to be unique from a filesystem view. For example, I don't believe bitmaps include metadata, which would cause them to be identical if the display were identical. Thank you! It did the trick. I just converted the image from png (sorry it wasn't jpeg...) to bmp and it works with cmp. Even diff now recognize both images as identical. Before I read this I was going to suggest you could try removing the metadata using something like jhead. As it turns out, you say you're using PNG format images, not JPEGs, but perhaps there's an equivalent to jhead to work with metadata in PNG files - just as an alternative to converting each PNG to BMP (which could be CPU intensive). Regards Andrew ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to [EMAIL PROTECTED]
