Is there anyway to get units for ValueConv numeric values?

[Marcuse]

Hello, does anyone know if it is possible to get the unit of num|value? In the perfect world, maybe something like this:

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exiftool.exe -FileSize -ExposureTime -CreateDate -struct -l -j "C:\storage\samples\RAW_CANON_50D.CR2"
[{
  "SourceFile": "C:/storage/samples/RAW_CANON_50D.CR2",
  "FileSize": {
    "desc": "File Size",
    "unit": "byte",  ///** magic unit here **///
    "num": 18935626,
    "val": "18 MB"
  },
  "ExposureTime": {
    "desc": "Exposure Time",
    "unit": "fraction",  ///** magic unit here **///
    "num": 0.0125,
    "val": "1/80"
  },
  "CreateDate": {
    "desc": "Create Date",
    "unit": "date",  ///** magic unit here **///
    "val": "2008:09:17 15:13:40"
  },
etc...


It would be very useful for my current project which is not tied to specific file types or metadata groups or even media types. If I could get the values strongly typed it would really help with efficient db storage/queries and ui controls.

Thanks for any help or ideas.
-Max

[Hayo Baan]

Other than devising a table that maps tag to unit yourself, I don't think there is an automatic way. The unit of a value is directly coupled to the meaning of the tag, there is basically no conversion done, only formatting.

[Marcuse]

Ok, thanks. I have been digging around some more and according to http://www.exiftool.org/under.html all values (ValueConv with -n) get normalized to a unit before display formatting (PrintConv). I am going to look through the exifTool source, maybe I'll get lucky and find a handy tag-name:unit lookup I can port.

[Phil Harvey]

I don't think you'll have any luck with that, but feel free to look at the source anyway.

- Phil