DDS Export error

[schabrackes]

Hello, 

first time posting here. I'm a casual GIMP user, mainly using it for creating Sim Racing Liveries. 

I recently experience an error message when exporting to DDS format using BC3/DXT5 or BC7. I'm on GIMP 3.2.4 using Linux, same happens on 3.2.2. Only 3.0.8 seems to work for BC3/DXT5 (BC7 is ot supported here). 

I tested also on my Windows 11 Laptop with Version 3.2.4, also doesn't work here. It also seems not to be a picture issues. Old pictures where the export to BC3/DXT5 worked before, will fail during export on 3.2.4 too. 

Any ideas based on the attached error message? Any hints are welcome. 


Michael

   
   
   

[CmykStudent_]

Hi! For bug reports, you'll have better luck posting on the official issue tracker: https://gitlab.gnome.org/GNOME/gimp/-/work_items

I helped implement BC7 export support in GIMP, so I'll take a look. So far I haven't been able to replicate - it all works fine for me. Unfortunately, the attachements you posted are not visible; could you report (or post them on the tracker)?

[schabrackes]

(05-14-2026, 08:10 PM)CmykStudent_ Wrote: Hi! For bug reports, you'll have better luck posting on the official issue tracker: https://gitlab.gnome.org/GNOME/gimp/-/work_items

I helped implement BC7 export support in GIMP, so I'll take a look. So far I haven't been able to replicate - it all works fine for me. Unfortunately, the attachements you posted are not visible; could you report (or post them on the tracker)?

Hi!

I did some more tests and was able to clearly reproduce it and - by the way - found a workaround. The issue happens when there is an addidtional channel beside the RGB (see picture below) once you delete that one the export to DDS (BC7 with MipMaps, ...) is working again: 

   

Here is the error message:

   

Shall I do a bug report? 

Regards,
Michael