that's may be a bit of a problem with Debian 9: solid but not very quick with updates.
I am coming from Raspbian Jessie Light, upgraded to Stretch Lite.
so, with my new machine, I went for Debian.
may be I should consider a different distro
for some reason, I don't like Mint, nor Ubuntu.
any suggestions ??
updated SMPlayer and the problem is solved.
thanks