Thank you very much for your quick answer and for the links, Chef .
Now that It seems I wasn' t mistaken about TMPGEnc(DVD Author), I would say that it also handles video_ts files and , among other possibilities , is incredibly easy for creating chapters . You can also adjust audio when necessary (a pity Dolby AC3 is not free ). It also includes a burning tool but I then prefer Nero Recode .
I will now go and give a look at the sites you kindly forwarded to me .
Best regards ,