If you want all possible phones to be able to play your videos, then yes, converting to mobile is requierd. If you want only latest phones to be able to play your videos, then you dont need mobile. I will do some more research, maybe in the near future we can drop mobile (and use a mp4 file with baseline profile and level 3.0 by default).
How is it possible when using the responsive theme from mobile instead of the script searching for the MP4 at the /mobile folder to use the default folder.
You want on mobile device to play videos from /media/video/mp4