Data decompression (zlib) failed

[diffuus]

This is an error I get sometimes when I try to open an Corona CXR in the Corona Image Editor:
"Error reading pixel data from image file "...". Data decompression (zlib) failed.
It happens at random. Sometimes I render 6 images from the same scene and just one is corrupt. And when I re-render the file with the same settings, there is no error.

I am at the point I no longer dare to render images overnight in CXR format.

Is this a known problem?

[maru]

Hi, I am not really familiar with this error. I will do my best to find out what it indicates.

[maru]

According to my initial findings, this simply means that the CXR file is corrupted for some reason.
This is not related in any way to Corona or the CIE, but rather to the information stored in the CXR file itself (which is based on the Open EXR libraries).

Most common cause of this is hardware error. To verify this, you could run some kind of HDD and RAM benchmark, to see if everything is fine. Are you experiencing any other problems when reading/writing files, even with other applications than Corona/3ds Max?

Could you also send us any CXR file which is corrupted like this? You can use this uploader - https://corona-renderer.com/upload
The file will be only accessible to our team, and it will be only used for debugging.

Thanks!

[diffuus]

I have send a corrupted file via the dropbox link.
"loenhout_06.cxr"
My files are saved on a Samsung 850 PRO 512 GB.
These CXR are quite big, so the chance on having an error on a bad disk increases, but i have more than 30.000 files on that disk and i have never had any error besides the CXR errors. I have checked the disk with HD Tune and did not find any errors.

Thx for looking at the file.

[maru]

Thanks for the file. We are looking into this.

[MarekB]

Hi,

Thanks for the report, how exactly did you create the file? Did you save it from VFB? If so, was the rendering still running while you were saving the file?
Also is it possible to share the scene with us using the private uploader? https://corona-renderer.com/upload

[diffuus]

The files with the errors are saved by a slave as a result of a backburner network job.
It didn't happen a lot, so i did not check if it was always the same slave that gave the error.
For the moment I am using TGA instead of CXR and had no more errors. (I don't dare to use CXR overnight anymore)
I don't have the exact copy of the scene that caused the error of the file i uploaded, this file has been saved over by a more recent. I can provide this recent one if you like?

[maru]

Just an update: we have this logged in our task tracker with a few examples, so we are planning to fix it, but it seems that the issue could be more complex - for example it could be related to OpenEXR itself.
(internal note: id=217367096)
(internal note: id=221254576)

[MarekB]

The files with the errors are saved by a slave as a result of a backburner network job.
It didn't happen a lot, so i did not check if it was always the same slave that gave the error.
For the moment I am using TGA instead of CXR and had no more errors. (I don't dare to use CXR overnight anymore)
I don't have the exact copy of the scene that caused the error of the file i uploaded, this file has been saved over by a more recent. I can provide this recent one if you like?

Any scene where the problem is reproducible would be highly appreciated.
Also, some more detailed description of the process which leads to the problem would greatly help.