error with showfoto jp2 image

[herb]

Hello Phil,

Since a short time I work with digikam on my windows 7 system.
Showfoto is part of digikam application. It is an image editor.
Accidentally I opened a *.jpg image (that contains only Exif metadata) and stored it as *.jp2 image.
Now Exiftool reports a warning: Unrecognized UUID EXIF box

IrfanView and also XnViewMP do also not show metadata. Only ShowFoto can read it.

Display of all metadata with option -v3 identified the following tags: ihdr, colr and uuid.
Sorry but it is not clear to me which parts are correct and which parts are wrong.

Please help me to identify whats wrong with metadata of this jp2 image.
I feeled free to send the image via mail.

Thanks for your help in advance.
Best regards
Herb

[Phil Harvey]

Hi Herb,

The UUID EXIF box should start with a standard TIFF header, but Digikam has apparently written a JPEG EXIF header in front of the TIFF header (six extra bytes: "Exif\0\0"), so ExifTool gives the warning and can't process the EXIF.

- Phil

[herb]

Hello Phil,

thanks for your quick reply.

I will open a bug report against digikam/showfoto.
Just to be sure and in order to give them additional information:
- the EXIF header in front of the TIFF header is against JP2 (and/or TIFF) standard
- this is the only error: removing this 6 byte will lead to a proper UUID EXIF box.

Thanks in advance
Best regards
Herb

[Phil Harvey]

Hi Herb,

In this case, ExifTool is defining the standard, because the UUID-EXIF box didn't exist before ExifTool wrote it.  I believe it was made in conjunction with a proposal to the JP2 group, but it looks like that proposal was never officially adopted.

So yes, removing the 6-byte header will lead to a proper UUID EXIF box because that is what ExifTool does.

- Phil

[herb]

Hello Phil,

thanks for your explanations.

I filed bug 370443 against digiKam on bugs.kde.org

On the other hand I attached a file with XMP metadata stored by digiKam.
Maybe it is of interest to you, how digiKam:ImageHistory tag is handled.

Best regards
Herb

[herb]

Hello Phil,

digiKam people did not accept my bug report. They forced me to file it directly against Exiv2 0.25.
Robin Mills is working for the FR #1242.

Best regards
Herb

[herb]

Hello Phil,

Thanks for the very good cooperation with Exiv2 people and thanks for the patch to read the "old version" of Exif box in *.jp2 images.

Best regards
Herb

[Phil Harvey]

You're welcome

- Phil