[Qgis-user] Weekly builds and JP2 files

[Even Rouault]

Selon Jonathan Moules <jonathanmoules at warwickshire.gov.uk>:

> I'm wondering - is there a reason that the JP2Open is distributed with
> QGIS/GDAL given it seems to do a terrible job? At least it does with all
> the ones I've tested against. Could the JP2ECW be distributed as the
> default instead?

It depends on the images. On tiled JPEG2000, the OpenJPEG library is usable,
although admitedly much slower than JP2ECW or JP2KAK. On single tile JPEG2000
images, the performance of OpenJPEG is really terrible since it will decompress
the whole image even if a subwindow is asked.
I'm sure the OpenJPEG developers would welcome funding and/or patches to improve
the performance of the library. We need a performant free and open source
JPEG2000 decoder. The proprietary alternatives are workaround.

>
> (again, I'm using the weekly build here).
> Cheers,
> Jonathan
>
>
>
> On 18 December 2013 15:35, Andre Joost <andre+joost at nurfuerspam.de> wrote:
>
> > Am 17.12.2013 20:47, schrieb Jukka Rahkonen:
> >
> >
> >
> >> If there are several drivers for JPEG2000 GDAL is using the first on the
> >> list. You can skip a driver by setting GDAL_SKIP environment. Thus, if I
> >> would like to have a try with JP2OpenJPEG I should run SET
> >> GDAL_SKIP=JP2ECW
> >> first. No idea really how and where I should do it so that QGIS starts
> >> with
> >> that setting.
> >>
> >
> > From the menue, Settings -> Options, GDAL tab, lets you select or deselect
> > every driver. QGIS 2.0.1 32bit standalone has JP2ECW and JP2Open, while
> > OSGEO4W QGIS-dev only has the second one, unless you loaded the ecw package
> > separately.
> >
> > Greetings,
> > André Joost
> >
> >
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> >
>
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