You are in a multi-core/multi-CPU environment and top is working in IrixIrix mode. That means that your process (vlc) is performing a computation that keeps 1.2 CPUs/cores busy. That could mean 100%+20%, 60%+60%, etc.
Press 'I' (capital i, Shift+i) to switch to SolarisSolaris mode. You get the same value divided by the number of cores/CPUs.