Thanks smp, now I understood why... I'm on LE 8.2.4.
VC-1 works fine on my pi3 with the decoding code.
I am waiting to receive the code for the new Pi3 B+ in my e-mail to solve the problem.
I was hoping the new CPU could be able to play VC-1 without it
MPEG-2 (like DVB-T) in FullHD, works fine even without decoding code (but I bought it anyway).