Comment # 20 on bug 1219494 from Michael Pujos

Yes libvpl is conceived as aneasy replacement for libmfx (aka Intel Media SDK).
Quoting FFmpeg QuickSync documentation
(https://trac.ffmpeg.org/wiki/Hardware/QuickSync):

"The library is the successors of libmfx. It will support Intel's platform >=
Alder Lake and will add new features. libvpl.so is compatible with MSDK's
runtime (libmfxhw64.so) and libmfx.so also has forward compatibility with
oneVPL's runtime (libmfx-gen.so)." 

But there is a big catch ! libvpl is only compatible with >= Alder Lake CPUs
(Aka Intel's 12th gen) if the Intel Media SDK (libmfx) is not installed!

I could test this on my Skylake (8th gen) laptop with ffmpeg-6 from Packman.
The Packam version already removed libmfx and enabled libvpl. 
I'm familiar with FFmpeg QSV transcoding and could test that the Packman ffmpeg
version (compiled against only libvpl) is working fine for QSV transcoding.
However, I have libmfx installed. If I rename its main lib
(/usr/lib64/libmfxhw64.so.1.35) to simulate mfx not installed without actually
uninstalling libmfx, QSV transcoding via ffmpeg-6/libvpl does not work anymore!

So by removing libmfx, you are removing QSV support for all Intel CPU below
Alder Lake. 

All of this is confirmed by this chart:

https://github.com/Intel-Media-SDK/MediaSDK?tab=readme-ov-file#media-sdk-support-matrix


So the legacy libmfx is really needed. Please don't remove it :(.