[gdal-dev] Question on GDAL using libjpegturbo.

[Even Rouault]

Daniele,

There's generally nothing particular to do to make GDAL run against libjpeg-
turbo. libjpeg-turbo has been the default libjpeg on Ubuntu since a long time. 
Not sure about CentOS. libjpeg-turbo can be built to be compatible with IJG 
libjpeg ABI, 6b or 7 if I remember well (this is a ./configure switch of 
libjpeg-turbo). So if your GDAL is built against standard libjpeg, you need to 
make sure to build libjpeg-turbo with the same ABI as the standard libjpeg. 
Otherwise you'd need to rebuild GDAL against libjpeg-turbo. You can do that 
with ./configure --with-jpeg=/path/to/install/prefix/of/libjpeg-turbo

Even

> Hi List,
> we are doing some performance tests with gdal operations (translate, warp,
> ...) and we are rewriting our output files as GeoTIFF with JPEG compression
> and YCBCR Photometric interpretation.
> We would like to involve libjpegturbo on that so I have a couple of
> questions on the topic.
> Before starting the new tests we have built a standard GDAL 2.1 version (on
> Centos 7) and did some "benchmarks".
> 
> Now we would like redo the tests using libjpegturbo.
> 1) Should we re-build GDAL once libjpegturbo is installed on the machine?
> In that case, is there any explicit setting to be provided to ./configure
> or any output message from the ./configure confirming that libjpegturbo
> will be used?
> 2) is there any CPL_DEBUG similar env var to be configured to better know
> what is happening when running the gdal utilities in relation to the
> libjpegturbo usage?
> 
> I have already taken a look to the GDAL JPEG format page but it doesn't say
> too much.
> 
> *"It is also possible to use the JPEG driver with the libjpeg-turbo, a
> version of libjpeg, API and ABI compatible with IJG libjpeg-6b, which uses
> MMX, SSE, and SSE2 SIMD instructions to accelerate baseline JPEG
> compression/decompression"*
> Thanks in advance.
> Cheers,
> Daniele

-- 
Spatialys - Geospatial professional services
http://www.spatialys.com