"Kung Fu Wing Chun - The Science of In-Fighting" is a 1982 documentary starring Wong Shun Leung who’s claim to fame is being a student of Yip Man and being credited as the man that taught Bruce Lee.
The documentary is a nice little introduction to the concepts of Wing Chun although it does suffer from having added sound effects. but that’s made tolerable by the seriously fresh soundtrack. It’s also a nice little testament to the fact that Wing Chun was somewhat popular even before “Ip Man” came out. There was a small pocket of cinema focusing on Wing Chun in 80’s, although it seems to have lost its momentum somewhat in the 90’s.