[gdal-dev] New compression library based on gdal design

[Ivan Lucena]

Hi Jukka,

> To: gdal-dev at lists.osgeo.org
> From: jukka.rahkonen at mmmtike.fi
> Date: Fri, 21 Mar 2014 14:26:21 +0000
> Subject: Re: [gdal-dev] New compression library based on gdal design
> 
> Aaron Boxer <boxerab <at> gmail.com> writes:
> 
> > 
> > Hello,
> > I recently started developing an open source jpeg2000 compression library
> using opencl.
> > I would like to base the library design on the very successful gdal
> library design.
> > Can anyone recomend any resources to help me to grok the high level design
> of gdal?
> > 
> > Thanks so much,
> > Aaron
> 
> Hi,
> 
> I would like to see something that is open source and fast with JPEG2000. I
> think that it would be OK to support only a subset of JPEG2000 standard if
> the basic operations would be super fast. I took just a moment ago some
> timings for another purpose but they may be interesting. I converted the
> same 12000x12000 pixel image (432 MB uncompressed) with a few different methods:
> 
> GDAL (64-bit) from tiff to tiff: 3 seconds
> GDAL (64-bit) ECWJP2 (SDK 5.0) from lossless JPEG2000 to tiff: 21 seconds
> GDAL (64-bit) JP2KAK (SDK 7.3.2) from lossless JPEG2000 to tiff: 14 seconds
> Kakadu 7.3.2 (64-bit) kdu_expand from lossless JPEG2000 to tiff: 7 seconds.
> 
> The new library with opencl should be at least as fast as ECWJP2 with GDAL
> but the faster the better.
> 
> It is interesting to see that native Kakadu application was two times faster
> than GDAL with JP2KAK driver of the same Kakadu version. Of course the use
> case is very simple.

Your test image was in fact 12000x12000x3 (=432 MB). That might explains why, maybe the GDAL driver is dealing with one band at the time, requesting to run the decompression 2 times more than the other application.

> 
> -Jukka Rahkonen-
> 
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