How to play back video in real time?

hey there! im tying to make a environment with this green screen footage which i have imported as plane but sadly the play back rate is very choppy not able to judge the speed any help would be appreciated

I think you have to make a proxy. Try 25%.
Your frame rate should be 4 times better.

Or convert to a frame sequence outside of Blender as the proxy sometimes will not be an exact copy of the coloraturas in the original media. You can use a command line ffmpeg to blast through a video file and create a .bmp or perhaps .tif sequence. Although I haven’t tried it I’m told that half float compressed EXR is a good solution too.