Las Vegas, early June in the early 2000s they used to hold “JuneFest”. $10 to get in for the day, all day outdoor event with everyone from REO Speedwagon, Joan Jett and Jethro Tull to Kansas, Jefferson Starship and Bad Company and more. It was a who’s who and who’s still alive of the classic rock genre in 2003. But it was one hell of an event. I think it got killed due to lax id checks at the vendors and some violence and heat related injuries.
Most camera sensors can only be read one line at a time. This means that the second line isn’t captured until the first line is completed. This goes for all of the remaining lines on the sensor of which there are thousands. For example a 24 megapixel camera might have around 4000 lines of pixels to capture.
The image processor captures the state of the top line and moves on to the next. By the time it’s captured the 2nd line, if the subject has moved, that line is no longer aligned with what was captured in the first line. Continue this 3998 more times and you have a frame of a video where the bottom of the frame is further ahead than the top of the frame.
To slow this down to a human understandable scale, while watching a video close one eye, then open it and close the other. By the time you’ve opened the second eye and closed the first things have moved. Just don’t do it while driving.