Mr.SID performance

[Benjamin Thelen]

Hi,


I have rather bad performance displaying Mr.SID raster data with
mapserver 4.2.5 via gdal 1.2.5 - about 15 sec. I'm talking about
8-bit, 144000x14000, 6.1 MB compressed Mr.SID files, each uncompressed
(tiff) 187 MB.


I tried various methods displaying these images. Irfan View with
Mr.SID plug-in needs about 15 sec to load a Mr.SID image, but then
Irfan View is even faster than Mr.SID Viewer, interesting, isn't it?!
Quite interesting too is the different memory management. Irfan View
or PaintShop need 195 MB of RAM, Mr.SID Viewer at loading time only
4MB, what also means, that at first the quality of the image is quite
worse and then it get's better. But even then Mr.SID Viewer only needs
16 MB of RAM!


Does anybody have an idea how to tweak performance?


Thank's in advance,
Benjamin