For ffmpeg from git you need libvdpau-1.4.
With libvdpau-1.3 I have segfault too.
And, old softhddevice from rofafor compiles with new ffmpeg??!
cuvid works fine, but it needs more memory, 2 GB of RAM is a bit for it, but vdpau works fine with 2 GB of RAM.
libvdpau is 1.4 -> https://gitlab.freedesktop.org/vdpau/libvdpau
Yes, compiles w. ffmpeg-git and works fine. Dont know, if i changed something in past.. sometimes i do;
however this one works fine. So ffmpeg and others are all working fine, including VLC.