SMPTE timecode is like a very special clock used in movies and TV shows. It helps keep track of where everything is in a movie or TV show like when someone speaks or when music starts playing.
It looks like numbers that go up and up, like 00:00:01:00 where the first two numbers are hours, the second two numbers are minutes, the third two numbers are seconds, and the final two numbers are frames. Frames are like little pictures put together to make the movement you see on the screen.
So, if you're watching a movie and you want to find a specific scene, you can look at the SMPTE timecode and know exactly where that scene starts and ends. It's like a secret code that only movie makers and editors know how to use. Cool, huh?