You cannot mix different standards easily on one DVD. The main video / movie would have to be doubled. It's hardly ever done. A separate DVD must be made for each standard. However a single DVD that has region restrictions turned off may be played anywhere in the world on a computer. Each video standard requires a separate version of a DVD and separate versions of menus must be made.
US / Canadan / Some Asia and Japan - NTSC (National Television System Committee) 525 lines & 60 frames / sec
Europe - PAL (Phase Alternating Line) 625 lines & 50 fields / sec (sub types with different Color sub carrier frequency, video bandwidth and sound carrier frequency are B,G,H,I,D,N and M)
France & Middle East - SECAM (Sequential Couleur Avec Memoire or Sequential Colour with Memory) 625 lines & 50 frames / sec but transmits the colour information sequentially.
A very good site for more details is: Alken M.R.S. worldwide video conversions