My GDAL gdalinfo uses the hardware accelerated Kakadu based JPEG2000 code, which is up to 10 times faster than the software based Jasper based JPEG2000 code. So, why then does it take me with the faster GDAL Kakadu JPEG2000 the same time, several minutes, it takes William with the slower GDAL Jasper? Is Qgis (mistakenly) not using the faster Kakadu JP2KAK plugin that GDAL provides when Qgis is accessing .jp2 files, including .jp2 files referenced in a VRT? I would think that using Kakadu instead of Jasper for JPEG2000 could yield a 10 times speed up, but would, to me, not account for the 60 times speed up that Giovanni Manghi reports he is getting. William, At your convenience would you please try using the GDAL JP2KAK plugin and see if Qgis open the project faster than with Jasper? Greg
$ gdalinfo --version GDAL 1.6.3, released 2009/11/19 $ gdalinfo GeoJPEG2000/18stj/18stj940125.jp2 | head -1 Driver: JP2KAK/JPEG-2000 (based on Kakadu) The GDAL Kakadu JP2KAK plugin, compiled for 32 and 64 bit, under Mac OS X 10.6 can be downloaded from http://homepage.mac.com/gregcoats/jp2/images/gdal_JP2KAK.dylib.zip $ file /Library/Application\ Support/GDAL/1.6/PlugIns/gdal_JP2KAK.dylib /Library/Application Support/GDAL/1.6/PlugIns/gdal_JP2KAK.dylib: Mach-O universal binary with 2 architectures /Library/Application Support/GDAL/1.6/PlugIns/gdal_JP2KAK.dylib (for architecture i386): Mach-O bundle i386 /Library/Application Support/GDAL/1.6/PlugIns/gdal_JP2KAK.dylib (for architecture x86_64): Mach-O 64-bit bundle x86_64 On Jan 21, 2010, at 5:10 PM, William Kyngesburye wrote: > On Jan 21, 2010, at 3:45 PM, William Kyngesburye wrote: > >> Same setup as Greg (my binaries), takes a few minutes to open. >> >> A thought - gdalinfo on the jp2 tiles uses the ECW JP2 driver, which is a >> plugin on the Mac, but I wonder if the vrt is ignoring plugins and using the >> builtin jasper driver (slow). >> > I guess not - I disabled the ECW plugin and now it takes even longer.
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