Issue with loading DWAB compressed EXR images


We met an issue with loading DWAB compressed EXR images. The DWAB format could be correctly loaded via HioOIIO, but not anymore since USD switched to built-in OpenEXR image reading in commit SHA 2d8a47d7.

The commit only introduced the OpenEXRCore library, which does’t support DWAB yet. But after doing experiments, we found that by using the OpenEXR library, DWAB format EXR images can be loaded correctly.

I’m wondering if there is any plan to introduce the OpenEXR library into USD for better EXR image support. Or before OpenEXRCore adding DWAB support, is there any alternative way to work around this?


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Hi Shaochun! dwab is expected to be supported by OpenEXRCore. Perhaps there is a dwab mode unaccounted for, or other bug. Could you post a problematic dwab for testing please?

TestDWAB.usdz (265.7 KB)
Hi Nick. Test EXR attached. As attachment of extension exr/zip is not allowed, I zip the test image and changed the extension to usdz. Please unzip it with any compressing app before testing with it.
During the loading process of this image no error would be reported, but nothing would be rendered out.
Thank you,

Ah apologies. I missed adding zip to the default extension list. Should be added now.

I have repro, I can see that your image is supposed to a environment map, and it is rendered as black.

The image is there, but the dimensions are incorrect, and the values are also incorrect. I’ve confirmed with the OpenEXR team that there is a bug in recent OpenEXR itself that your file has exposed.

Thank you for providing that information quickly!

There is a fix pending, it’s waiting for the OpenEXR team to verify correctness.