Output video in opencv tracking fails unless opencv installed from source

[alexandroid000]

In open_cv/tracking.py if write=True in the track function, writing the output video doesn't work and gives the error Could not find encoder for codec id 27: Encoder not found due to this issue:

opencv/opencv-python#81

Don't have time to figure out an alternate encoding that will work, but putting this here for future reference / is a good small bug for someone to fix.