Can't open .AVI files on USB device

Longtime digikam user on Linux...I have a new installation of LinuxMint 
22.3 and digikam 8.2.0. I've made no changes to the default Linux 
installation, nor to digikam.

When I attempt to view photos & videos on an SD card (from a trail 
camera), using the Import function, it pulls up a preview window that 
shows all photos and videos on the SD card. All JPG photos look fine, 
and all .MP4 play fine. But the .AVI files just have a blank thumbnail 
with a "Failed to load image" message.

If I download the .AVI videos into my photo albums, they will play just 
fine in digikam. So the problem seems limited to previewing .AVI files 
on a USB-mounted SD card before Importing. Any thoughts on what I might 
need to do?

This worked perfectly prior to the upgrades I made.

Thanks