AVI is a wrapper format, and many different codecs can be used on the contained audio and video streams. There are utility programs that will tell you which codecs are used in an AVI file. Installing VFW drivers (Video For Windows) in Windows 3.x allows decoding of many commonly used video compressions for the AVI wrapper from around the time of Win3; but there may be later codecs (e.g., DivX, XviD, etc.) for which a Win3 decoder was never made.

FYI, for modern Windows, installing something like ffdshow adds support for many older codecs.

+1

http://win31.de/esoft.htm

@ripsaw8080: okay.
@jo22: I already found that webpage. I couldn't find the right app there.

As to not being able to play the *.avi files in Windows 10: https://codecguide.com/download_kl.htm - Fixed! 😀

Peter Swinkels wrote on 2022-05-10, 18:20:

@jo22: I already found that webpage. I couldn't find the right app there.

Hi! It's "Video for Windows 1.1, 1.39 M: You'll need Video for Windows to play AVI movies."
http://www.gaby.de/ftp/pub/win3x/vfw11.zip

And, optionally..
"Intel Indeo Video Codecs: Video-Codecs 3.2 and 4.1 for Windows 3.1x including installation guide in German."
http://www.gaby.de/ftp/pub/win3x/codecs/index.htm

- These files must simply be copied over and then two entries or so in system.ini or win.ini must be made.

Good luck! 🙂✌️

@jo22:
Video for Windows worked. I will try your second suggestion at a later date. Thank you!

EDIT:
Both work.