Thank you, Janet55, for your answer. That's good info. At the moment, I have already a DVD creator and the solution proposed by Nikorr works fine and it is free. So I think I'll go on with that one. The only drawback is the time for convertion: about 3 hours.
However, I did not know there were DVD creators basically modifying the format input-output and I'll for sure take that into account when renewing some softwares.
Have a nice day.
Ya, converting video takes time, there is no way around it except to have a mess of ram, and a good cpu. 3 hours is perfectly normal for good quality conversion on most systems