Author Topic: Confused  (Read 75 times)

Paxapunch

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Confused
« on: August 06, 2020, 09:21:10 PM »
I have been running Exiftool for a while, but I am still learning and today very confused. I hope I can muddle through and describe my confusion.

Given a JPEG file with the FileCreationDate 2003:07:04 00:00:00 I change the date using the following command:

exiftool '-DateTimeOriginal=2004:04:14 11:11:11' -P -Overwrite_Original_In_Place dir/filename.ext

I then verify that the change took place using the following command:

exiftool -time:all -a -G0:1 -s dir/filename.ext

All files reside on my MacBook in internal SSD memory and are synchronized to an external HP Passport hard drive directly attached to my MacBook using the Goodsync application within a timeframe set to three seconds.

Now when I go to the external hard drive and look at the synchronized file with the -time:all command I see that the DateTimeOriginal has not changed. This data on the 'synchronized' file does not change if left for hours. However, without ever returning to the original directory or accessing the original file in any way, if I open the 'synchronized' file in Preview and manipulate it in some way such as performing a back and forth rotation then exit Preview voilĂ  the DateTimeOriginal is changed. Simply opening and closing the file in Preview does not make the change. I must manipulate the file in some way. Also quitting and restarting Finder does not cause the date to change... In fact, rebooting the MacOS system does not make the date change and when I reboot the system even manipulating the file in Preview will not change the data. After a reboot, it is like the data is lost... The original file is still changed, but the 'synchronized' file keeps the old information.

To me, this is very confusing... Must I really open and fakely manipulate every 'synchronized' file in order to ensure my backups are really identical?

Phil Harvey

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Re: Confused
« Reply #1 on: August 06, 2020, 09:33:15 PM »
This is a question for the Goodsync people to answer.  Apparently their software isn't syncing files as expected.

- Phil
...where DIR is the name of a directory/folder containing the images.  On Mac/Linux, use single quotes (') instead of double quotes (") around arguments containing a dollar sign ($).

StarGeek

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Re: Confused
« Reply #2 on: August 06, 2020, 09:41:59 PM »
Try running the command without the -P (preserve) option.  The sync software may be depending upon a difference in the timestamp to initiate the sync.
Troubleshooting hints:
* When posting, include your OS, Exiftool version, and type of file you're processing (MP4, JPG, etc).
* Double all percent signs (%) in a Windows batch file.
* If your GPS coords are negative, make sure and set the GpsLatitudeRef and GpsLongitudeRef tags correctly.

Paxapunch

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Re: Confused
« Reply #3 on: Today at 04:24:20 PM »
First and foremost, thanx for your response(s) which are exactly as expected...

Phil, been there done that... If you would really like to have a laugh and, by the way, a lesson in how to NOT treat customers I would be happy to quote the Goodsync support responses. Just let me know...

Stargeek, been there done that... No difference in the way things work. In fact, Goodsync support stated, in writing, that they specifically look for changes in the file modification date. So I ran a command that changed alldates AND the file modification date... didn't sync, didn't work. In addition, I set the Goodsync parameters to checksums which significantly slows things down... still didn't sync... Nothing changed from what I initially reported.

Both, this is part of Goodsync support response:

     GS does not care about EXIF data, as there is no such thing in file systems.
     if it is stored in file body, it is already copied.
     if it is stored in extended attributes, there is option to copy them.
     so you need to start with finding out where it is stored and then you decide how to copy it.
     If some programs change file body without changing file mod time or size, GS of course cannot detect it.

There's more, some not so nice, but nothing that helps.

BTW, unless you have something that you feel might help, I am not expecting any further response.

Have a great life and stay safe!
     

StarGeek

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Re: Confused
« Reply #4 on: Today at 04:46:40 PM »
The only other idea I have is maybe picking a rarely used tag and toggling it on and off to force a size change.
Troubleshooting hints:
* When posting, include your OS, Exiftool version, and type of file you're processing (MP4, JPG, etc).
* Double all percent signs (%) in a Windows batch file.
* If your GPS coords are negative, make sure and set the GpsLatitudeRef and GpsLongitudeRef tags correctly.

Phil Harvey

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Re: Confused
« Reply #5 on: Today at 05:49:09 PM »
You could use the Padding tag for that if you want.

- Phil
...where DIR is the name of a directory/folder containing the images.  On Mac/Linux, use single quotes (') instead of double quotes (") around arguments containing a dollar sign ($).

StarGeek

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Re: Confused
« Reply #6 on: Today at 06:04:22 PM »
This gives a 1 byte difference that flips back and forth.

Code: [Select]
C:\>exiftool -P -overwrite_original "-Padding<${Padding;$_=(length($_)>3)?'x':'xxxx'}" y:\!temp\Test4.jpg
    1 image files updated

C:\>exiftool -g1 -a -s -padding y:\!temp\Test4.jpg
---- ExifIFD ----
Padding                         : (Binary data 4 bytes, use -b option to extract)

C:\>exiftool -P -overwrite_original "-Padding<${Padding;$_=(length($_)>3)?'x':'xxxx'}" y:\!temp\Test4.jpg
    1 image files updated

C:\>exiftool -g1 -a -s -padding y:\!temp\Test4.jpg
---- ExifIFD ----
Padding                         : (Binary data 3 bytes, use -b option to extract)
Troubleshooting hints:
* When posting, include your OS, Exiftool version, and type of file you're processing (MP4, JPG, etc).
* Double all percent signs (%) in a Windows batch file.
* If your GPS coords are negative, make sure and set the GpsLatitudeRef and GpsLongitudeRef tags correctly.

Phil Harvey

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Re: Confused
« Reply #7 on: Today at 06:11:06 PM »
In EXIF, the value is stored in the IFD entry if it is 4 bytes or less.  So any value length of 0-4 bytes will result in the same sized file.  Changing between 4 and 5 bytes though will change the file size.

- Phil
...where DIR is the name of a directory/folder containing the images.  On Mac/Linux, use single quotes (') instead of double quotes (") around arguments containing a dollar sign ($).

StarGeek

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Re: Confused
« Reply #8 on: Today at 06:47:15 PM »
Ah, I didn't actually check the file size.
Troubleshooting hints:
* When posting, include your OS, Exiftool version, and type of file you're processing (MP4, JPG, etc).
* Double all percent signs (%) in a Windows batch file.
* If your GPS coords are negative, make sure and set the GpsLatitudeRef and GpsLongitudeRef tags correctly.