On Fri, Mar 27, 2015 at 5:05 PM, Oliver Markowski <[email protected]>
wrote:
> Hey guys,
>
> this is my first post so please excuse me if this came up earlier!
>
> In my current tests it does not make a difference which exr compression i
> set.
>
But it does - filesize differs.
> the filesize differences are as follows:
> OFF 253.8 MB
> PIZ 251.3 MB
> ZIP 243.3 MB
> ZIPS 243.3 MB
> RLE 253.8
>
I have checked, and with git master and libopenexr6:amd64 1.6.1-8, i got
following results:
OFF 257M
PIZ 199M
ZIP 162M
ZIPS 162M
RLE 249M
So it definitely compresses it , albeit not too much, but that is to be
expected.
Why so bad compression ratio?
My explanation would be that all of those are lossless compression algos, so
it will likely differ between images with different "content".
And you can check that by setting some wrong values in exposure iop
(disable all other iops, they won't matter), e.g.
black = 1.0, exposure = -18EV
Then, i get following filesizes: (all exported images are completely black)
OFF 257M
PIZ 781K
ZIP 376K
ZIPS 376K
RLE 4.1M
So as you see, at least here, compression works, pretty well in fact :)
> This seems weird to me...could it be the exr libs that i have on my system
> or is this a bug? I am on Centos 7 and use OpenEXR-devel.x86_64 1.7.1-7.el7
>
Debian sid has older version, unfortunately:
$ dpkg -l |grep -i openexr
ii exrtools 0.4-1.2+b2
amd64 A collection of utilities for manipulating OpenEXR images
ii libilmbase6:amd64 1.0.1-6.1
amd64 several utility libraries from ILM used by OpenEXR
ii libopenexr-dev 1.6.1-8
amd64 development files for the OpenEXR image library
ii libopenexr6:amd64 1.6.1-8
amd64 runtime files for the OpenEXR image library
>
> thx for your help
> Oliver
>
>
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> Roman.
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