It means impossible to do so theoreticallyDepends on the software used, on what cpu, at what cpu speed, using what codex, using what resolution, with what parameters, on what size file, using how many cores, with what size ram, using what speed ram, on what storage base, on what OS.....
There's absolutely no one-size-fits-all equation, All results are different as there are simply far too many variables and no solid yes or no answers