#115 some GEM Raster (IMG/XIMG/TIMG) are not decoded correctly

[Roy Tam]

some sample files in https://sembiance.com/fileFormatSamples/image/gem/ are not decoded correctly.

[Piotr Fusik]

Which files do you mean? I see new.img not decoding at all and teststtt.img glitched.

[Roy Tam]

vision.img also looks strange but I didn't test it in genuine environment.

[Lonny Pursell]

Had a look at these 3 files.
new.img and vision.img appear to be "packed across lines/planes (solid run)" according to another application I sometimes use to test .img files. Not following the compression specifications.
I've seen this vision.img before, it's part of the Vision app and it's always been problematic.
teststtt.img has the bit planes arranged incorrectly. We talked about this variant a while back as I found the original app that created them and saved out some samples.
My opinion is these 3 files should be removed from that sample folder.
I keep such samples in a folder called \bad just in case I run into them again.

[Piotr Fusik]

Thanks, Lonny. What about the palettes in beauty.img and cndy8.img ?

[Lonny Pursell]

No way to know how these 2 were created, however they both look identical loaded into my app as well as the other app I test with. Poorly or wrongly created palettes my guess. I suspect they should look better than they do but the creator messed up the palette somehow.

[Piotr Fusik]

Thank you again! I think it might be Atari STE palette (where the high bit is the least-significant) converted incorrectly.
There's nothing to fix there. These files are damaged.