[gdal-dev] JP2ECW reversible compression issue with MapServer

[Jukka Rahkonen]

Hi,

I got inspired in making again some tests with jpeg2000. My environment is:

Mapserver MS4W with MapServer version 5.2.0
GDAL 1.5.2, released 2008/05/29

I was measuring MapServer speed with lossless vs.lossy JPEG2000 images and by
using either JP2ECW or JP2MrSID driver. I did not find any improvement in speed,
but accidentally I notised that when I used the JP2ECW driver I can not get full
quality image through MapServer. The output image looks like it were slightly
compressed even the originals are lossless. If I skip the JP2ECW driver and take
JP2MrSID driver Mapserver starts to deliver full quality images which are
identical with the output reached from GeoTIFF originals.

Question 1: Could this issue of getting lossy output from lossless JPEG2000
images be something worth making a trac issue, or is it known already, or do you
suppose I have made just some mistake in my test?

Question 2: MapServer is quite slow with JPEG2000 images. Do gdal developers
have ideas about how to make it faster? Any estimates about how much money would
be needed to make it 100 percent faster?  I believe that it is a realistic goal.