Why is the frame rate of the movie 24? Is it related to the reaction speed of human optic nerve?

Of course, the more frames are played per second, the smoother the video will look to users. Movies can make the audience feel smooth at a frame rate of 24 frames per second. Every increase of 1 frame on the basis of 24 frames will increase the cost by 5%. Therefore, the frame rates of SMPTE timecode of 24, 25 and 30 frames per second formulated by the American Society of Motion Picture and Television Engineers (SMPTE) are universal and used in different parts of the industry. The professional frame rate of movies is 24 frames per second, and that of American TV is 30 frames per second. The professional frame rate of TV in China is 25 frames.

Why is the frame rate of a movie 24 and that of a TV 25? Why is it that every time you want to discharge a movie on TV, you have to perform format conversion (inserting an extra frame means replaying a certain frame) instead of unifying it to 25 or 24? The reason why movies don't want to be changed to 25 frames is because people are satisfied with 24 frames per second, and changing to 25 frames will increase the cost; The reason why the TV doesn't want to change to 24 is that the frequency of alternating current in the power grid is 50Hz. If it is changed to other field frequencies, there will be beats when it is modulated by lights such as fluorescent lamps. Because everyone is unwilling to compromise, we can't reach an agreement, so we can only live in peace until now. So when we watch TV movies, we can always see extra pictures flashing.