there is a hissing/air release noise when the car is in drive. brake: no noise on 2009 Volkswagen Passat

There is a hissing/air release sound when my car is in drive and when I brake the noise stops.

Asked by for the 2009 Volkswagen Passat
Have the brake booster checked out. Before it gets worse!!
thank you very much. Is this normal or maybe a defect? thanks