how to get frame number of a playing video ?

hi everybody , I have a problem please help me if any solution is available I want to play a video with unity UI system and depend on the time which the player click I want to do some actions , I mean I need to find out which frame is the video on now , or how much has passed from the video , is there any way to find out ? I thought about using a timer but is there any other way? excuse me for my poor English