If I may pop in, I have had this issue in the past with recording from Media Players (VLC, Potplayer and Media Player Classic are my favourites [I cycle changing between them often due to personal ADHD heh])...
Sometimes it has occurred after a GPU Driver/Update or switching to a different GPU [I have no preference and enjoy both main manufacturers, 'stair-stepping' everytime I upgrade, between AMD and NVIDIA, back and forth]. Sometimes it has occurred after a Windows Automatic Update, or when the application updated itself to a newer version of the player/program.
For me, whenever it occurred, the solution I found was: to Enable (or turn back on) some kind of Accelerated Playback engine in the Media Player - so that it utilizes the GPU engine for playback.
For example, in VLC Media Player, in the Video Preferences, I would have to change the Output setting to OPENGL or DIRECT3D or similar. Then, Bandicam would detect/hook on to the VLC display once again, showing the trusty FPS display. If you wanted, you can then record from the VLC Player with Bandicam (to create GIFs, etc).
**I will create a 'Tutorial' Image, showing where I made the changes in VLC Media Player, as an example (using a Recording Test I did just tonight)**
Hopefully, this is all you have to do and it will work for you, too (and others!). HTH
- [Tutorial] Enabling Bandicam FPS Overlay on VLC Media Player (one method, choose OpenGL Output) - The Game Tips And More Blog.jpg (258.03 KiB) Viewed 3499 times
("Hope That Helps!") ~ Troy from The Game Tips And More Blog