Maniphest T66515

Loaded OpenEXR file is displayed all black in 2.80. Looks fine in 2.79
Closed, Resolved
Actions

Assigned To
Brecht Van Lommel (brecht)
Authored By
Dharma Teja Reddy Kasa (blenDTR)
Jul 7 2019, 7:15 AM
Tags
  • BF Blender
  • Compositing
  • Images & Movies
Subscribers
Brecht Van Lommel (brecht)
Dharma Teja Reddy Kasa (blenDTR)
Philipp Oeser (lichtwerk)
Robert Guetzkow (rjg)

Description

System Information
Operating system: Windows-10-10.0.17763 64 Bits
Graphics card: GeForce GTX 1060 6GB/PCIe/SSE2 NVIDIA Corporation 4.5.0 NVIDIA 417.35

Blender Version
Broken: version: 2.80 (sub 74), branch: master, commit date: 2019-07-05 06:13, hash: rB66684bdff30f
Worked: 2.79b (2018-03-22)

Short description of error
Compositing Node Tree - reading OpenEXR multilayer file content as black - no colors

Exact steps for others to reproduce the error
Image originally rendered in 2.79. When I load exr file for compositing, it looks fine in 2.79


Same file looks like below in 2.80 build

It's true for many exr's. I've attached single image and blend files to reproduce issue. Find them in following attachment

CompBug.zip13 MBDownload

Revisions and Commits

rB Blender
rBeee46769cefe Fix T66515, T67112, T61607: failure to read EXR files with single, named layer

Related Objects

Event Timeline

Dharma Teja Reddy Kasa (blenDTR) created this task.Jul 7 2019, 7:15 AM
Dharma Teja Reddy Kasa (blenDTR) added a project: Compositing.
Robert Guetzkow (rjg) added a subscriber: Robert Guetzkow (rjg).Jul 7 2019, 12:55 PM

I've got the same result in 2.79 and the current master build. Both show the broken result. Since loading your .exr file in an external image editing application and saving it as .hdr or .exr doesn't fix it, seems like the alpha hasn't been properly tagged in the file.

Dharma Teja Reddy Kasa (blenDTR) added a comment.Jul 7 2019, 1:30 PM

It remains true for some renders done using 2.8.
It's not same in all cases but it's random
Let me know if you need more data to debug.

Robert Guetzkow (rjg) added a comment.EditedJul 7 2019, 2:30 PM

Ignore my previous comment, I'm not sure what's going on here. Either Affinity Photo and LuminanceHDR both have broken OpenEXR implementation or Blender creates file that don't follow the spec. Affinity Photo can open the files and reads both RGB layer and alpha, but fails to save the data on export resulting in a blank alpha. LuminanceHDR complains that it can't find RGB data and refuses to load the file altogether. This happens for both your supposedly broken file and .exr files that can be properly read in Blender.

Either way I can't even get the "normal" .exr files saved by Blender to work outside of Blender when they have an alpha channel. That makes debugging a bit more complicated.

Can you share a .blend file that (sometimes) creates OpenEXR files that can't be properly read by Blender?

Philipp Oeser (lichtwerk) assigned this task to Brecht Van Lommel (brecht).Jul 8 2019, 2:58 PM
Philipp Oeser (lichtwerk) lowered the priority of this task from 90 to 50.
Philipp Oeser (lichtwerk) added a project: Images & Movies.
Philipp Oeser (lichtwerk) added subscribers: Brecht Van Lommel (brecht), Philipp Oeser (lichtwerk).

Hm, I'm getting this trying to import the file in Krita:

The image contains pixels with zero alpha and non-zero color channels. Krita has modified those pixels to have at least some alpha. The initial values will not be reverted on saving the image back.

If I render with a multilayer EXR file Output Node from blender I get those "bad" results if I add an Input to the node called Alpha, but leave this unconnected. If I then plug the Renderlayer alpha into the fileOutput Alpha, it seems fine...

BAD_film_transparent_disconnected_alpha.exr416 KBDownload

GOOD_film_transparent_connected_alpha_multilayer.exr425 KBDownload

Not sure how to handle the case where alpha is zero but pixels are not? changing alpha_mode to something else then premultiplied also doesnt seem to help here.
a bit on shaky ground, this is possibly not a bug, but will confirm for now and kindly ask @Brecht Van Lommel (brecht) for further guidance...

Dharma Teja Reddy Kasa (blenDTR) added a comment.Jul 8 2019, 7:24 PM

I'm attaching .blend as requested. One thing to note is output node setup is as follows when exr's were rendered. 

If I render with a multilayer EXR file Output Node from blender I get those "bad" results if I add an Input to the node called Alpha, but leave this unconnected

Rings some bell but not sure.

T66515.blend2 MBDownload

Philipp Oeser (lichtwerk) mentioned this in T67107: Open EXR Files Unreadable.Jul 17 2019, 11:43 AM
Brecht Van Lommel (brecht) changed the task status from Unknown Status to Resolved by committing rBeee46769cefe: Fix T66515, T67112, T61607: failure to read EXR files with single, named layer.Jul 17 2019, 8:57 PM
Brecht Van Lommel (brecht) added a commit: rBeee46769cefe: Fix T66515, T67112, T61607: failure to read EXR files with single, named layer.