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Bug #892

-T does not seem to have an effect

Added by Tomáš Hnyk over 8 years ago. Updated over 8 years ago.

Status:
Closed
Priority:
Normal
Assignee:
Robin Mills
Category:
documentation
Target version:
0.24
Start date:
13 Mar 2013
Due date:
% Done:

100%

Estimated time:
1.00 h

Description

This is on Ubuntu 12.10, exiv2 0.23 001700 (64 bit build).

Either I do not understand the -T option or it does not work.
I have a scanned picture and I want to have Exif.Image.DateTime and Image timestamp set. I do set the Exif.Image.DateTime:
exiv2 -g Exif.Image.DateTime -Pv photo.jpg
2004:06:20 00:00:00

Then I verify there is no timestamp:
exiv2 photo.jpg
File name : photo.jpg
File size : 171249 Bytes
MIME type : image/jpeg
Image size : 1100 x 1680
Camera make :
Camera model :
Image timestamp :
Image number :
Exposure time :
Aperture :
Exposure bias :
Flash :
Flash bias :
Focal length :
Subject distance:
ISO speed :
Exposure mode :
Metering mode :
Macro mode :
Image quality :
Exif Resolution :
White balance :
Thumbnail : None
Copyright :
Exif comment :

I try to update the timestamp:
exiv2 -T -v photo.jpg
File 1/1: photo.jpg
Updating timestamp to 2004:06:20 00:00:00

However, when I try to verify whether it was updated, it seems it has not:
exiv2 photo.jpg
File name : photo.jpg
File size : 171249 Bytes
MIME type : image/jpeg
Image size : 1100 x 1680
Camera make :
Camera model :
Image timestamp :
Image number :
Exposure time :
Aperture :
Exposure bias :
Flash :
Flash bias :
Focal length :
Subject distance:
ISO speed :
Exposure mode :
Metering mode :
Macro mode :
Image quality :
Exif Resolution :
White balance :
Thumbnail : None
Copyright :
Exif comment :

History

#1

Updated by Robin Mills over 8 years ago

Tomáš

Thank you for using exiv2 and bringing your concern to our attention. I believe the purpose of the -T option is to set the time-stamp in the filesystem from the metadata in the image. Here's what I see on Cygwin:

518 rmills@nv10042:~ $ exiv2 -pt ~/foo.jpg | grep Date
Exif.Image.DateTime                          Ascii      20  2012:08:07 16:00:28
Exif.Photo.DateTimeOriginal                  Ascii      20  2009:12:29 08:34:12
Exif.Photo.DateTimeDigitized                 Ascii      20  2009:12:29 08:34:12
519 rmills@nv10042:~ $ touch ~/R.jpg
520 rmills@nv10042:~ $ ls -alt ~/R.jpg
-rwxr-xr-x 1 rmills Domain Users 2205140 Mar 13 09:52 /home/rmills/R.jpg
521 rmills@nv10042:~ $ exiv2 -T ~/foo.jpg
522 rmills@nv10042:~ $ ls -alt ~/foo.jpg
-rwxr-xr-x 1 rmills Domain Users 2205140 Dec 29  2009 /home/rmills/foo.jpg
523 rmills@nv10042:~ $
So it doesn't add metadata to the image, it changes the timestamp on the disk.

If you want to add new metadata to the image, you can add modify and change tags. For example:

525 rmills@nv10042:~ $ exiv2 -M"set Exif.Image.DateTime 2013-03-13 10:09" foo.jpg
533 rmills@nv10042:~ $ exiv2 -pt foo.jpg | grep -i time
Exif.Image.DateTime                          Ascii      17  2013-03-13 10:09
Exif.Photo.ExposureTime                      Rational    1  1/200 s
Exif.Photo.DateTimeOriginal                  Ascii      20  2009:12:29 08:34:12
Exif.Photo.DateTimeDigitized                 Ascii      20  2009:12:29 08:34:12
Exif.CanonCs.Selftimer                       Short       1  Off
Exif.CanonCs.DriveMode                       Short       1  Single / timer
534 rmills@nv10042:~ $

If you want to write a tag such as Exif.Image.DateTime from the timestamp on the filesystem, I think you'll need a script or batch file to do that.

If you'd like me to write the script or batch file, please attach a file and details of your platform (Windows/Mac/Linux/Cygwin/MinGW) and the version of exiv2 being used. You can find the version with the command: exiv2 --version

If I've haven't understood what you want, please explain again and I'll try to help.

#2

Updated by Tomáš Hnyk over 8 years ago

Thanks for the quick reply. Oh, i see, and it is even in the man page, it talks about "file timestamp". Mea culpa.

I would actually want to set the "Image timestamp :" in the output of exiv2 foo.jpg but I am unable to find how to do it, exiv2 -M"set Image timestamp 2013-03-13 10:09" foo.jpg throws an error on me.

#3

Updated by Tomáš Hnyk over 8 years ago

Never mind, I need to update DateTimeOriginal: exiv2 -M"set Exif.Photo.DateTimeOriginal 2013-03-13 10:09

You can close this now, and thanks for the swift reaction!

#4

Updated by Robin Mills over 8 years ago

  • Category set to documentation
  • Status changed from New to Assigned
  • Assignee set to Robin Mills
  • Target version set to 0.24
  • % Done changed from 0 to 100
  • Estimated time set to 1.00 h

You've got it!

When you use the command $ exiv2 foo.jpg, it prints a sanitized list of the metadata, so it shows the date as:

Image timestamp : 2009:12:29 08:34:12
However when you use $ exiv2 -pt foo.jpg, it shows the "real" keys:
509 rmills@nv10042:~ $ exiv2 -pt foo.jpg | grep -i date
Exif.Image.DateTime                          Ascii      17  2013-03-13 10:09
Exif.Photo.DateTimeOriginal                  Ascii      20  2009:12:29 08:34:12
Exif.Photo.DateTimeDigitized                 Ascii      20  2009:12:29 08:34:12
510 rmills@nv10042:~ $
You'll need to use "real" keys to set metadata.

#5

Updated by Robin Mills over 8 years ago

  • Status changed from Assigned to Resolved
#6

Updated by Robin Mills over 8 years ago

  • Status changed from Resolved to Closed

I'm going to close this one now. No code change required. This issue only required explaining to Tomáš how the -T option works. So, not a bug!

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