Uploaded image for project: 'Commons Imaging'
  1. Commons Imaging
  2. IMAGING-221

updateExifMetadataLossless restructures meta data (and problems with Maker Notes)

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Details

    • Bug
    • Status: Open
    • Major
    • Resolution: Unresolved
    • None
    • 1.0.0-alpha6
    • None
    • 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.

      Attachments

        1. mine.JPG
          3.25 MB
          Bruno P. Kinoshita
        2. mine.JPG.html
          63 kB
          Bruno P. Kinoshita
        3. mine-gps.JPG
          3.25 MB
          Bruno P. Kinoshita
        4. mine-metadata.JPG
          3.25 MB
          Bruno P. Kinoshita
        5. mine-original.JPG
          3.25 MB
          Bruno P. Kinoshita
        6. original.html
          64 kB
          Joakim Knudsen
        7. original.JPG
          3.25 MB
          Joakim Knudsen
        8. tagsmissing.png
          65 kB
          Joakim Knudsen
        9. test.html
          66 kB
          Joakim Knudsen
        10. test.JPG
          3.25 MB
          Joakim Knudsen

        Activity

          People

            kinow Bruno P. Kinoshita
            joakimk Joakim Knudsen
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            Dates

              Created:
              Updated: