[IMAGING-221] updateExifMetadataLossless restructures meta data (and problems with Maker Notes) - ASF JIRA

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Details

Type: Bug
Status: Open
Priority: Major
Resolution: Unresolved
Affects Version/s: None
Fix Version/s: 1.0.0-alpha6
Component/s: None
Labels:
None

Description

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.