Joakim Knudsen created IMAGING-221:
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Summary: updateExifMetadataLossless restructures meta data (and
problems with Maker Notes)
Key: IMAGING-221
URL: https://issues.apache.org/jira/browse/IMAGING-221
Project: Commons Imaging
Issue Type: Bug
Reporter: Joakim Knudsen
Attachments: original.JPG, original.html, test.JPG, test.html
ExifRewriter's *updateExifMetadataLossless* method causes the meta data of the
JPEG to be completely reordered after writing. This, in itself, might not be a
big concern, but it's a bit unexpected when the method is named "lossless".
More worryingly, I also find problems are introduced wrt. the Maker Notes tag
(odd offset).
I've produced an example of the problem in the attached JPEG file, using
ExifTool to validate/analyze the images before and after. The image is taken by
a Sony Xperia Z5 phone, and the "original.JPG" validates OK. After modifying
the contents of the UserComments tag (value: "Test") the modified image
produces a warning:
Verifying the attached photo using ExifTool gives the following output:
$ ./exiftool\(-k\).exe -validate -warning -a ../test.JPG
-- press RETURN --
Validate : 1 Warning (all minor)
Warning : [minor] Possibly incorrect maker notes
offsets (fix by -628?)
Using ExifTool's -htmldump option, it is easy to see how the meta data has been
affected.
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