Author Topic: UTC/GMT Time correction in a voice note file from whatsapp  (Read 177 times)

tijuinem

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UTC/GMT Time correction in a voice note file from whatsapp
« on: February 09, 2020, 07:16:28 AM »
Hey guys.
I'm doing an important analysis on a file type .opus of the application for android whatsapp. It's a voice note as you can see from the extension. ( OGG FILE )

The question and my problem is that the metadata of the file says that it was recorded on a date with a correction of +2 hours. Actually it should only be an hour.
What could this be due to ?
There was no travel on that phone, no time change, etc.

Thank you in advance...

Quote
File Modification Date/Time     : 2019:10:15 14:16:18+02:00
File Access Date/Time           : 2020:02:07 11:17:47+01:00
File Inode Change Date/Time     : 2020:01:28 12:44:41+01:00
« Last Edit: February 09, 2020, 07:31:20 AM by tijuinem »

StarGeek

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Re: UTC/GMT Time correction in a voice note file from whatsapp
« Reply #1 on: February 09, 2020, 11:16:23 AM »
Those tags are not embedded information, they are entirely controlled by the operating system you are viewing the data on.  If you view them on a computer in a different time zone, they will change to reflect that time zone.  For example, viewing that on my computer, West Coast US, it would appear as 2019:10:15 05:16:18-07:00.  The computer you're are using (Mac?) believes that October 15, 2019 was daylight savings time.

While I don't know your country, a quick Google search indicates that Daylight Savings time for Central European Time (+01:00/+02:00) ended on October 27.  So that time zone appears correct to me.
Troubleshooting hints:
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tijuinem

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Re: UTC/GMT Time correction in a voice note file from whatsapp
« Reply #2 on: February 10, 2020, 04:42:05 AM »
thks for reply.
ok

I understand
So, if I had consulted that data a few months ago, it would have been +1? and likewise if I consult it when the time change is made again, it would be +1 again?

Phil Harvey

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Re: UTC/GMT Time correction in a voice note file from whatsapp
« Reply #3 on: February 10, 2020, 07:03:16 AM »
No.  If the file date is in the DST range then it will be +1 for daylight savings time.  It doesn't matter what the current date is.

- 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: UTC/GMT Time correction in a voice note file from whatsapp
« Reply #4 on: February 10, 2020, 11:05:13 AM »
Modern computers are aware of variations in time zones and will always display the proper time zone for that date.  So for CET, any date between March 31, 2019 and October 27, 2019 will show up as Central European Summer Time/CEST +02:00.  Outside of that range will be regular CET +01:00.

Semi-related, my favorite Computerphile video on time zones.
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: UTC/GMT Time correction in a voice note file from whatsapp
« Reply #5 on: February 10, 2020, 11:22:08 AM »
Good video.  Very true.

- 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 ($).

tijuinem

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Re: UTC/GMT Time correction in a voice note file from whatsapp
« Reply #6 on: February 11, 2020, 04:41:44 AM »

ok
then I don't give it much thought, I interpolate the results as the system says and it's solved.

Quote
File Modification Date/Time     : 2019:10:15 14:16:18+02:00

Modified on October 15, 2019 at 12:16:18 PM.


tijuinem

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Re: UTC/GMT Time correction in a voice note file from whatsapp
« Reply #7 on: February 14, 2020, 11:29:22 AM »
I'm confused again.
I think the correctl time was " 14:16:18" without regard to the time slot.
this data is merely indicative of reference.
I interpret. Is that correct?

StarGeek

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Re: UTC/GMT Time correction in a voice note file from whatsapp
« Reply #8 on: February 14, 2020, 11:37:15 AM »
Sorry for not reading your replies carefully.

ok
then I don't give it much thought, I interpolate the results as the system says and it's solved.

Quote
File Modification Date/Time     : 2019:10:15 14:16:18+02:00

Modified on October 15, 2019 at 12:16:18 PM.

No, you don't add/subtract time zones unless you are trying to get UTC time or figure out the time at a different time zone.  The time of 14:16:18 would be local time for Central European Summer Time/CEST.  The +02:00 indicates that the current time at that location is +2 hours ahead of UTC. 
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.

tijuinem

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Re: UTC/GMT Time correction in a voice note file from whatsapp
« Reply #9 on: February 15, 2020, 04:25:12 AM »
ok
perfect.
solved.
thks so much everyone.