Weird question maybe re converters

Sorry first if this is in the wrong forum.
I have a question regarding dvd movies which are already converted.
I want to copy some of mine for a friend. They were originally converted by me with winavi and work perfectly on my dvd player.
However, I know from past experience, that her dvd player will ONLY play movies which have been converted with convertxtodvd (( have no idea why…but it’s true)
Is there any way I can “re-convert” my movies with convertxtodvd???

Regards to all