[digiKam-users] EXIF in PNG not recognized

[Rainer J.H. Brandt]

Hi,

I imported PNG files with EXIF data like this into Digikam 7.0:

ExifTool Version Number         : 11.70
File Name                       : rh_01_01.png
Directory                       : rh_01
File Size                       : 9.3 MB
File Modification Date/Time     : 2021:03:12 09:19:36+01:00
File Access Date/Time           : 2021:03:12 09:29:25+01:00
File Inode Change Date/Time     : 2021:03:12 09:26:57+01:00
File Permissions                : rw-r--r--
File Type                       : PNG
File Type Extension             : png
MIME Type                       : image/png
Image Width                     : 2669
Image Height                    : 1811
Bit Depth                       : 8
Color Type                      : RGB
Compression                     : Deflate/Inflate
Filter                          : Adaptive
Interlace                       : Noninterlaced
Exif Byte Order                 : Big-endian (Motorola, MM)
X Resolution                    : 72
Y Resolution                    : 72
Resolution Unit                 : inches
Modify Date                     : 1958:02:01 10:00:00
Y Cb Cr Positioning             : Centered
Exif Version                    : 0232
Date/Time Original              : 1958:02:01 10:00:00
Create Date                     : 1958:02:01 10:00:00
Components Configuration        : Y, Cb, Cr, -
Flashpix Version                : 0100
Color Space                     : Uncalibrated
Image Size                      : 2669x1811
Megapixels                      : 4.8

In the right side bar Metadata/EXIF is empty,
and in the Dates hierarchy the files are listed under 2021.

What went wrong?
Thanks, Rainer

--
Email: [hidden email]   Telefon: [phone]   Mobiltelefon: 0172/9593205
Brandt & Brandt Computer GmbH     Am Wiesenpfad 6     53340 Meckenheim
Geschäftsführer: Rainer J.H. Brandt und Volker A. Brandt
Handelsregister: Amtsgericht Bonn, HRB 10513

[Maik Qualmann]

PNG files do not show any abnormalities here with digiKam-7.2.0, Exif
metadata, if available, are displayed. Please send a test PNG to my private
mail.

Maik

Am Freitag, 12. März 2021, 10:55:07 CET schrieb Rainer J.H. Brandt:

> Hi,
>
> I imported PNG files with EXIF data like this into Digikam 7.0:
>
> ExifTool Version Number         : 11.70
> File Name                       : rh_01_01.png
> Directory                       : rh_01
> File Size                       : 9.3 MB
> File Modification Date/Time     : 2021:03:12 09:19:36+01:00
> File Access Date/Time           : 2021:03:12 09:29:25+01:00
> File Inode Change Date/Time     : 2021:03:12 09:26:57+01:00
> File Permissions                : rw-r--r--
> File Type                       : PNG
> File Type Extension             : png
> MIME Type                       : image/png
> Image Width                     : 2669
> Image Height                    : 1811
> Bit Depth                       : 8
> Color Type                      : RGB
> Compression                     : Deflate/Inflate
> Filter                          : Adaptive
> Interlace                       : Noninterlaced
> Exif Byte Order                 : Big-endian (Motorola, MM)
> X Resolution                    : 72
> Y Resolution                    : 72
> Resolution Unit                 : inches
> Modify Date                     : 1958:02:01 10:00:00
> Y Cb Cr Positioning             : Centered
> Exif Version                    : 0232
> Date/Time Original              : 1958:02:01 10:00:00
> Create Date                     : 1958:02:01 10:00:00
> Components Configuration        : Y, Cb, Cr, -
> Flashpix Version                : 0100
> Color Space                     : Uncalibrated
> Image Size                      : 2669x1811
> Megapixels                      : 4.8
>
> In the right side bar Metadata/EXIF is empty,
> and in the Dates hierarchy the files are listed under 2021.
>
> What went wrong?
> Thanks, Rainer

[Rainer J.H. Brandt]

Maik Qualmann writes:
> PNG files do not show any abnormalities here with digiKam-7.2.0, Exif
> metadata, if available, are displayed. Please send a test PNG to my private
> mail.
Done.  Thanks for investigating.
Rainer
--
Email: [hidden email]   Telefon: [phone]   Mobiltelefon: 0172/9593205
Brandt & Brandt Computer GmbH     Am Wiesenpfad 6     53340 Meckenheim
Geschäftsführer: Rainer J.H. Brandt und Volker A. Brandt
Handelsregister: Amtsgericht Bonn, HRB 10513

[Maik Qualmann]

Exiftool shows a few metadata, including a date. A test with the Exiv2 CLI
tool shows no metadata and the message no Exif metadata available. Since the
problem can be reproduced with the Exiv2 CLI tool, you should report the
problem together with the test image as a bug to Exiv2.

Maik

Am Freitag, 12. März 2021, 13:22:17 CET schrieb Rainer J.H. Brandt:
> Maik Qualmann writes:
> > PNG files do not show any abnormalities here with digiKam-7.2.0, Exif
> > metadata, if available, are displayed. Please send a test PNG to my
> > private
> > mail.
>
> Done.  Thanks for investigating.
> Rainer

[Rainer J.H. Brandt]

Thanks, Maik.

> Exiftool shows a few metadata, including a date. A test with the Exiv2 CLI
> tool shows no metadata and the message no Exif metadata available. Since the
> problem can be reproduced with the Exiv2 CLI tool, you should report the
> problem together with the test image as a bug to Exiv2.
I see that a very similar bug report was made in October 2020:
https://github.com/Exiv2/exiv2/issues/1343

I'm currently learning how to build Exiv2 so that I can reproduce the
problem and test.  Anyway, I will talk to the Exiv2 people.

Cheers, Rainer

[Rainer J.H. Brandt]

Hi all,

I wrote:
> I'm currently learning how to build Exiv2 so that I can reproduce the
> problem and test.  Anyway, I will talk to the Exiv2 people.

I did that and learned that although I used exiftool to store the dates in
my image, that wasn't EXIF data, but was stored in a "tEXt" chunk of the
PNG file.

So I used exiv2 for another attempt to add the creation date as EXIF data to
my image file.  That worked, and after a refresh on the album, DigiKam
recognizes it, too.  Very nice.

However, in the "Dates" view within DigiKam, the image still doesn't appear
in the period given by the creation date.  DigiKam still shows it in the
period given by the image file date.  That must be a bug, right?

Thanks, Rainer

[Maik Qualmann]

You have to read in the metadata of the image again, Menu-> Item-> Reread
Metadata from file.

Maik

Am Sonntag, 14. März 2021, 20:51:13 CET schrieb Rainer J.H. Brandt:

> Hi all,
>
> I wrote:
> > I'm currently learning how to build Exiv2 so that I can reproduce the
> > problem and test.  Anyway, I will talk to the Exiv2 people.
>
> I did that and learned that although I used exiftool to store the dates in
> my image, that wasn't EXIF data, but was stored in a "tEXt" chunk of the
> PNG file.
>
> So I used exiv2 for another attempt to add the creation date as EXIF data to
> my image file.  That worked, and after a refresh on the album, DigiKam
> recognizes it, too.  Very nice.
>
> However, in the "Dates" view within DigiKam, the image still doesn't appear
> in the period given by the creation date.  DigiKam still shows it in the
> period given by the image file date.  That must be a bug, right?
>
> Thanks, Rainer

[Rainer J.H. Brandt]

Maik wrote:
> You have to read in the metadata of the image again, Menu-> Item-> Reread
> Metadata from file.
[...]
> > So I used exiv2 for another attempt to add the creation date as EXIF data to
> > my image file.  That worked, and after a refresh on the album, DigiKam
> > recognizes it, too.  Very nice.
> >
> > However, in the "Dates" view within DigiKam, the image still doesn't appear
> > in the period given by the creation date.  DigiKam still shows it in the
> > period given by the image file date.  That must be a bug, right?

That worked, thank you.

I was confused because I thought DigiKam might use data that it knew.
(Sorry for that rant :-)

Thanks, Rainer