Can't find Frame Rate Mode of a VOB file

Hi everyone,

I'll be using VOB files from a DVD to create a short movie. I know I have to pay attention to the frame rate mode and make sure the video is not in VFR before editing in order not to have the audio desynchronized. But when I inspect the file using MediaInfo, VLC or FFmeg, I can find the frame rate (30 i/s) but it is not specified whether it is VFR or CFR.
What do you think ? Should I just consider it CFR then ?

Thanks for your insight