What is the difference between the -m option and the -F option

[Tarn]

Hi Phil,

When I first began with ExifTool, I ran into a slight problem with a minor error regarding offsets. You showed me a fantastic way to repair these errors (and it has worked splendidly).

In poking around, I find that there is an "-F" option (FAQ number15 https://exiftool.org/faq.html#Q15). The documentation says that the -F "fixes" the offset. But that is what the -m option seems to do.

Is this a case were they both do the same thing, or do they do different, albeit similar things?

Thanks

[Phil Harvey]

Good question.

The maker note offset errors are a particularly insidious type of error that is sometimes difficult to correct automagically.  This is indicated by the "Possibly incorrect maker notes offsets (fix by XXX?)" warning.

Using -m on a file with this warning will cause the existing offsets to be honoured.  Using -F will cause the automagic correction (XXX) to be applied.  You can also specify your own offset (YYY) with -FYYY.  Often, -F is the right thing to do, but it depends on many factors, so if the maker note information is important to you and you see this warning then you should try both methods to see which works best with your files.

- Phil

[Tarn]

Thank you.

Oddly, I understood most of that.

[Phil Harvey]

Great.  I have updated FAQ 15 to include this description.

- Phil

[Tarn]

Thanks.