bug in DWAA and DWAB compression schemes?

Mike Day <[email protected]> Fri, 29 Mar 2019 08:16:02 -0700
Newsgroups gmane.comp.video.openexr.devel
Message-ID <CAALNaN7A5JKpAbHLAL9zpWYn32VTudVEK2GZWxRBFo_FK5vDhQ@mail.gmail.com>
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Hi,

when an exr is written using either the DWAA or the DWAB compression
scheme, with a 3-channel image at least, any channel value over approx 2^16
seems to get output as 0. I wondered if this behaviour was intentional, or
if it would make more sense to clamp it to the max representable value.

Even clamping wouldn't be ideal, so would it make even more sense to have a
global multiplier to allow arbitrarily high output values (at the expense
of degrading the quality of the smaller values)?

Thanks,
Mike Day

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<div dir=3D"ltr">Hi,<div><br></div><div>when an exr is written using either=
 the DWAA or the DWAB compression scheme, with a 3-channel image at least, =
any channel value over approx 2^16 seems to get output as 0. I wondered if =
this behaviour was intentional, or if it would make more sense to clamp it =
to the max representable value.</div><div><br></div><div>Even clamping woul=
dn&#39;t be ideal, so would it make even more sense to have a global multip=
lier to allow arbitrarily high output values (at the expense of degrading t=
he quality of the smaller values)?</div><div><br></div><div>Thanks,</div><d=
iv>Mike Day</div><div><br></div></div>

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