I want to add video of 75 MB in my prezi. Should i add that much heavy size video?

Thank you.

Helo Vandana,
75MB is not a problem.  

The best is to convert the movie on YouTube. Then download it and add to prezi. You Tube will optimize the size.  The resolutions depens on the device you want to use.  720p is the lowest I recommend.

I dont play movies form the interent, connections problem can be very frustrating.  Portable prezi with movie is the safe option.