@ferran
It might help, even tho I do not have nvidia if you could supply some more details please.
a) just the snippet of
lspci -v
like mine...26:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Device 15d8 (rev c9) (prog-if 00 [VGA controller])
Subsystem: Micro-Star International Co., Ltd. [MSI] Device 7b86
that should allow us to truly identify your pci id against the very extensive nvidia range found here
http://pciids.sourceforge.net/v2.2/pci.idsIt is possible your device might still need firmware but lets see?
b) There are many ways of playing videos not all require firefox (FF) nor ffmpeg4
Can you supply a url to videos you can not play please.
If they are too naughty pm me if you like
eg I can watch youtube movies with no sound if I have not started pulseaudio with FF
ls /usr/local/tce.installed/ | grep ffmpeg
# no hits
c) In FF -> preferences -> General ....Have you checked the box for DRM
and then gone to
about:plugins
and checked you have OpenH264 and Widevine Content Decryption Module
cheers