for video the best shutter speed is double the framerate here in pal country it's 25fps so a shutterspeed of 50 is ideaal for smooth motion.
Higher shutterspeeds will give you choppier motion (even in natural light) so only good for very fast moving subjects
also it will give you strobe effect with a lot of lighting sourches and when shooting video walls etc...
you can get away with lower speeds but motion will become more blury/soft.
Canon eos C100+ ninjablade,3* XC10's,
7D, 40d, 17-40 f4L, 70-300L,24-105 f4L ,24-70 f2,8L, 100 f2,8L is macro , ef-s 10-22, samyang 8 f3,5 fisheye, sigma 18-35 f1,8 Art,sigma 50-100 f1,8 Art