Re: image hashes

[Alvaro del Castillo <acs openshine com>]

Hi John!

El jue, 25-08-2005 a las 16:11 +0100, John Leach escribió:
> Hi Alvaro,
> 
> this looks great.  sorry that I missed it.  I notice you don't generate
> the checksum on import and read your discussion on it.  I believe the
> overhead for the digest to be acceptable.
> 

Yes, I finally feel the same. I have measured a 10% addition in time
importing creating the MD5 but it is really useful when you start
importing from sources that have some directories that you have already
imported. Or when you have large collections with the same photos in
different directories.

> I did some tests on my P4 2Ghz SATA box importing my 12Gig of photos.
> Using md5sum I clocked around 200MB/s, which comes to about 60 seconds
> for 12Gig, whereas just the normal f-spot import took almost 30minutes.
> As about 1/3 of this seems to be disk I/O time, 60 seconds represents a
> 5% CPU overhead.
> 
> I'd consider this overhead as pretty trivial, assuming the digest is of
> use to people :)
> 
> Admittedly I've not considered the difference in speed between the
> md5sum tool and the c# md5 implementation.  Maybe that's the breaker.
> 
> 
> I also noticed the patch hasn't appeared in 0.1.0.  Has there been any
> discussion I've missed on this?  Is there a problem with the code?  Or
> with the feature?

I think that Larry hasn't reviewed the patch yet so we must wait a
little. Currently it is a not very intrusive patch. The worst thing is
changing the database schemas to add the new field.

I have it working in my F-Spot version at:

https://acs.barrapunto.org/svn/f-spot/

I have found this feature really useful in the past weeks using F-Spot.


Cheers

> 
> thanks,
> 
> John.
> 
> 
> 
> On Thu, 2005-08-25 at 11:32 +0200, Alvaro del Castillo wrote:
> > Hi John!
> > 
> > The MD5Sum is a patch that I have already done in June for implement the
> > duplicate photo detection feature as you can read in F-Spot list:
> > 
> > http://mail.gnome.org/archives/f-spot-list/2005-June/msg00046.html
> > 
> > Cheers
> > 
> > El sáb, 13-08-2005 a las 17:14 +0100, John Leach escribió:
> > > Hi,
> > > 
> > > could f-spot store a hash (say SHA1) of each photo in the database? This
> > > would help f-spot recognise images even if their filename+path is
> > > changed.  It could be of use in 3rd party programs too.  for example:
> > > <snip>
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