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Image-ExifTool
Posted on 2006-11-11 00:00:59-08 by geve
Makernotes Sanyo
Some Sanyo camera's have (I assume) a software fault. For example the C4, J2 and J4 calculted the offset pointer for makernotes 12 to high
For example your picture sanyo-C4.jpg results in sanyo-C4.html and should look like sanyo-C4.rmaker
p.e. Exif tool tag "MakerNotes_05 DigitalZoom" points to h'05cc and is located at h'05c0, see rmaker file "Makernote field-6".
Q1: should Exiftool handle software faults?
Q2: and rewriting the data should it repair, or make the same mistakes?

Ger
Direct Responses: 3489 | Write a response
Posted on 2006-11-11 03:11:00-08 by exiftool in response to 3486
Re: Makernotes Sanyo
Hi Ger,

Thanks for pointing out this problem. My philosophy is that ExifTool should handle problems like this and duplicate them when rewriting the image. (Believe me, there are far worse things that makers do with their offsets than this!) I will take a look at my Sanyo samples and see if I can come up with a general way to fix this. If not, I will resort to recognizing individual models if necessary. Give me a few days to think about it.

- Phil
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Posted on 2006-11-13 15:43:39-08 by exiftool in response to 3489
Re: Makernotes Sanyo
I have looked into this. The current version of ExifTool will read and write these maker notes properly if you use the -F option. I will add a patch to fix the maker notes offsets automatically for this camera model and the update will appear in ExifTool 6.56 when it is released. Normally a warning would be issued when ExifTool detects a possible problem with the maker notes offsets (as a clue that you should try -F), but some other manufacturers leave 12 bytes of unused data at the end of the IFD, which looks exactly like a 12-byte offset error, so the warning message was being suppressed for this case.

So if you use the -F option (and without the -F option with ExifTool 6.56 or greater), the error in the offsets will be preserved when the file is rewritten. This is in keeping with my philosophy of trying to preserve the original structure of the image.

- Phil
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