[gdal-dev] Fwd: [OpenJPEG] OpenJPEG 2.2.0 is out ! Faster and safer.

N. Farah nfarah at hotmail.com
Mon Aug 28 11:00:03 PDT 2017

Thanks Even for the quick response. I'll give it a try with setting OPJ_NUM_THREADS env variable to 8. Does it need to be used with GDAL_NUM_THREADS ? Any url to read about those two env variables ?

The two dataset i used:



p.s: i'm using GDAL 2.1.2


From: Even Rouault <even.rouault at spatialys.com>
Sent: Monday, August 28, 2017 1:40:31 PM
To: N. Farah
Cc: gdal-dev at lists.osgeo.org
Subject: Re: [gdal-dev] Fwd: [OpenJPEG] OpenJPEG 2.2.0 is out ! Faster and safer.




> I rebuilt GDAL (older version: 2.1.2) using this new open jpeg 2.2.0

> (https://github.com/uclouvain/openjpeg/releases/download/v2.2.0/openjpeg-v2

> .2.0-linux-x86_64.tar.gz)


> and tried to convert two jp2 dataset to tiff (gdal_translate):


> - bluemarble_4km.jp2: (10800 x 5400 pixels). 37.3 mb file size.


> - usgsLanSat.jp2: (8627 x 7745 pixels). 48 mb file size.

Do you know if they use JPEG2000 tiling ?



> Tests were run on virtual machine with ‘Ubuntu 16.04’ operation system, 18

> gb RAM and 2 CPU processors.



> These results were not expected since the new openJpeg should be faster than

> the previous one. Could this be cause by 'gdal_translate' not using threads

> that the new openjpeg uses for performance boost ?

By default, GDAL will now enable openjpeg thread support. So you need to set the OPJ_NUM_THREADS environment variable. That said, you should already get significant performance improvements even without enabling multi-threading. I'm not sure why you don't get them.

I'd be interested if you could share those images.



Spatialys - Geospatial professional services

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