[Digikam-devel] extragear/graphics/digikam/digikam

[Mikolaj Machowski]

On Saturday 13 June 2009 17:17:37 Gilles Caulier wrote:
> 2009/6/13 Marcel Wiesweg <marcel.wiesweg at gmx.de>:
> >> Result are better than PGF, from speed and space consumption point...
> >
> > For me results with JPEG are better as well.
> > I have an average size of 11KB per thumbnail (db file size / number of
> > stored thumbnails).
> > Most important for me: Subjectively, loading is faster than with PGF.
> > (With maximum number of icons visible - no sidebars, fullscreen, minimum
> > thumbnail size - I can mouse wheel scroll at a reasonable fast speed
> > without seeing missing thumbnails)
>
> Well, what better then ? JPEG as well with a compression ratio upper
> than 75 (default Qt = 75) ? I recommend 85 instead...
>
> Mik, do you have tried 85 JPEG quality ? And in this case, DB will be
> bigger : which size compared to PGF ?

JPEG Qt default (probably 75): 147MB for 15000 images
JPEG 85: 184MB
PGF 4: 243MB

>
> > For me creation time is not important, because this is done once, but
> > pregenerated thumbnail loading time, which is done everytime.
>
> Agree but it give info about algorithm optimization. For ex, JPEG2000
> is a mess in this case...
>
> I'm in contact with libPGF team. I will ask speed optimization
> question comparing to JPEG.
>