DWAA minimum tile size?

Here is a strange behavior (easy to repro for those of you who might have a copy of OIIO lying around):

    # works
    oiiotool --pattern checker 512x512 1 -d half -compression dwaa -tile 16 16 -o test.exr

    # fails
    oiiotool --pattern checker 512x512 1 -d half -compression dwaa -tile 8 8 -o test.exr

Just writing a simple tiled 1-channel half exr file with dwaa (or dwab) compression. It succeeds with 16x16 tiles but fails with 8x8, wherein writeTiles() throws an exception with the following message:

    > Failed to write pixel data to image file "test.bb700d14.temp.exr". Data compression (zlib) failed.


Curiously, if I instead make a 3-channel file,

    oiiotool --pattern checker 512x512 3 -d half -compression dwaa -tile 8 8 -o test.exr

that succeeds (also fine with 4x4, 2x2, 1x1 tile size). Using zip compression is fine. I can only make it fail with the specific combination of 1 channel images + dwaa/dwab compression + tile size < 16.

Anybody have any insight, or has this bug been reported before?

Here's the OIIO issue if anyone wants to follow up there or reference it:
https://github.com/OpenImageIO/oiio/issues/1844

--
Larry Gritz
[email protected]