[Gdal-dev] Re: MrSID Driver performances

[Gao, Peng]

Julien Demaria <dem <at> acri-st.fr> writes:

> 
> Hi,
> 
> First, Andrey thanks a lot for implementing block caching in the driver for 
> DSDK 4.xx, now decompress an RGB MrSID file is very faster ! 
> 
> I've made some tests on performances with the 4.xx driver on a big 
> 10000x10000 MrSID RGB file.
> The file has the version 1.0.1 (with mrsidinfo) and I suppose this is an 
> MG2 file ; I haven't got any big MrSID MG3 file for testing...
> 
> I found that the driver can be improved a lot simply by changing the blocks 
> size to 256x256 instead strips calculated with the 
> poImageReader->getStripHeight() DSDK method.
> With this changes my tests seem to be between 2 and 3 times more faster !
> 
> My tests are (on Win32 and Solaris) :
> - gdal_translate execution time
> - OpenEV visualisation (it's faster and more reactive)
> - a sort of gdal_translate in our software
> - visualisation time in our software
> 

Is there any progress made on this? Using a strip may be good for 
format translation,  but not so for viewing where the rectanglar
display is much smaller than the size of the image. I did some
GDAL performance test, it performs well for JP2 and Imagine, but
much slower for MrSID than another package I am using, even after I changed
the block size to the similar rectangler size. Is there any plan for a 
performance tuning?

Thanks,
Gao, Peng