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daemon mode for exiftool

Started by Archive, May 12, 2010, 08:54:06 AM

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[Originally posted by exiftool on 2007-07-13 19:21:59-07]

Hi Mike,

Great.  Glad this helps.

I've never heard of those formats, and haven't had any requests to support
them.  But unless they contain metadata, there isn't much reason to do
it (except maybe to extract the image dimensions or something like that).

- Phil

PH Edit: Read support was added for OpenEXR and Radiance images in ExifTool 8.73 on 2011-12-16.


[Originally posted by exiftool on 2007-07-13 19:36:28-07]

You got me thinking so I ran a quick test on my system here.
I timed the following two commands:

exiftool -listf
 exiftool -listg

The way ExifTool is implemented, the first command doesn't need to load
any of the format-specific modules, and it takes 0.100 sec on my
system.  The second command loads all modules to determine
the full group list, and takes 0.677 sec here.  The difference is mainly
due to the time required to load all the modules, but there is a bit
more CPU work done by -listg, so I hacked the code to remove this
and the time dropped to 0.622 sec.  So on my system (a 1.83 GHz Intel
Core Duo), the time to load all modules is 0.522 seconds.  That's pretty
hefty. (...and you want me to add more?... hehe)

- Phil


[Originally posted by mjc on 2007-07-13 19:50:08-07]

OpenEXR does have metadata, but I don't know anyone who uses the format. So it's just a curiosity...

- Mike


[Originally posted by metadatacrucher on 2009-01-23 21:35:16-08]

I do see a sense in an ExifTool Daemon. Imagine a non-Perl Web Application that wants to do metadata extraction for uploaded pics. Currently you have to call/exec exiftool on every uploaded pic which is a certain overhead - especially if you want to redirect the user to the results after the upload. A Daemon could improve performance in this case.

Can we expect any progress on this issue in near future?


[Originally posted by exiftool on 2009-01-24 00:14:06-08]

The short answer is:  No

Phil Harvey

Update: 2010-10-30 - ExifTool 8.36 implemented a -stay_open option which effectively gives this "daemon mode" functionality.

- Phil

Edit: As of 2013-12-01 there is a C++ Interface for ExifTool that is available.  This interface puts an object-oriented C++ interface around the ExifTool -stay_open feature.
...where DIR is the name of a directory/folder containing the images.  On Mac/Linux, use single quotes (') instead of double quotes (") around arguments containing a dollar sign ($).