Conversion of .vsp projects to .mp4 was possible with the old Ulead Video Studio software through a share function, however nowadays achieving vsp to mp4 conversion can be troublesome.
After Corel acquired Ulead, it is perhaps possible that some successor products like Corel Video Studio can still handle old Ulead files, however, it is more likely that it can only with its own .vsp files and export them in the same manner.