[gdal-dev] Open Jpeg 2.3.0 and OPJ_NUM_THREADS

[Even Rouault]

On mardi 31 octobre 2017 19:39:23 CET N. Farah wrote:
> Hi,
> 
> 
> In http://gdal.org/frmt_jp2openjpeg.html under 'Thread Support' section
> there is the following:
> 
> "Starting with GDAL 2.3, this multi-threading at code-block level is
> automatically enabled by GDAL".
> 
> 
> Was meant "Starting with OpenJpeg 2.3, ..." ?

No, was meant starting with GDAL 2.3 (the current dev version). And that requires openjpeg 
>= 2.2 as well.

> 
> If yes, was that enabling made in the 'OpenJpeg 2.3' library or was made in
> GDAL ?

openjpeg >= 2.2 (actually 2.1.2, but I restricted to 2.2 or later) brings multithreading decoding 
at codeblock level, and GDAL trunk automatically enables it.

So the doc is correct I think, but I know that those similar version numbers between GDAL 
and openjpeg can be confusing.

Bottom line: use the latest and greatest of both to get the better performance.

Even

-- 
Spatialys - Geospatial professional services
http://www.spatialys.com
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20171031/13f10790/attachment-0001.html>