Actually, I should clarify. The
corruption occurs on *read*, not *write*. Attached is a tiff file
converted from a PIZ compressed exr, also attached.
It's most noticeable in the alpha channel, although there's a
definite glitch in the red channel just above the plane.
- ½
On 13-06-18 12:44 PM, Piotr Stanczyk wrote:
Thanks.
Let me see if I can repro this. I presume that simply writing
out PIZ files should flare up.
Were you also seeing test failures?
I’m afraid mine are under
customer’s NDA.
It is rather common though, the
corruption was reported for alpha.
Juri
Is this
something that was quite deterministic in behaviour?
(Does anyone have an example of a corrupted image?)
Hi Halfdan,
Yep, we ran into
this one too. Was already the case for
OpenEXR 1.6/1.7.
Would be good to
know if it is fixed in 4.5.
Juri
Also, compiling the EXR2.0
library using gcc 4.2/4.3/4.4 with -O3 results
in the PIZ compression code producing
occasional garbage data (-O3 is the default
for cmake release builds). The workaround was
to build with -O2. gcc 4.6 and up seem ok. I
didn't test with gcc 4.5.
Unfortunately, I didn't have time to dig any
deeper as to whether this was an actual
optimizer bug, or whether there are some
spurious assumptions in the code leading to
it.
Just something to keep in mind.
- ½
On 13-06-17 09:35 PM, Piotr Stanczyk wrote:
Hi,
There have been a few usage cases reported
that exercised parts of the optimised
reading code path which unfortunately
revealed erroneous assumptions in the
source.
We have a fix for handling these, which
also extents to handling more general
cases, in a separate branch and will be
releasing that once we have built up more
usage cycles.
In the meantime, however, a v2.0.1 release
will be available shortly, which disables
the optimisation.
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