Why can the video behind the characters move when making a movie or MV? Can people stand still?

This is called post-keying technology in movies or TV! It is to use software to cut out a solid color to realize the channel. The cut color part is transparent, and you can see the background video material at the lower level.

So in China, when shooting, the characters need to stand in front of the blue or green background to do the action. Why do you use blue or green? Because people basically don't have this color. Of course, people can't wear blue clothes. That man's clothes are also transparent. ) This can well remove the blue cloth around people. These are all done in later software, such as the most common PREMIERE or AE software. Then you can change things from other videos on the next floor of this video. Once synthesized, you will see that the person in front is moving and the background changes casually. Typical is the weather forecast. The electronic map of people and background is this keying technology. Please note that the forecaster always puts it on the map with his finger. The only difference is that this effect of TV stations is mostly real-time keying. At that time, the keying synthesis was completed in real time in the computer at the same time! They don't wait for time, but most of them are synthesized by software after shooting.

Therefore, when shooting, we should pay attention to the fact that the color cloth or board must be pure, especially the cloth is ready-made, and there must be no wrinkles and shadows, because as long as there are color shades or traces on the cloth, it will have an impact on the key-taking effect behind it. It should also be noted that after entering the later software, it is not necessary to dig immediately, but to adjust the contrast and saturation of the color first. The purpose is to make the color of cloth or board more vivid and pure. Then the effect of digging out will be better. The most difficult part of the buttoning effect lies in the relationship between people's boundaries and backgrounds, because most people's edges have some colored cloth or color reflection, so this is your technology. Software can help you deal with the edges. However, the efforts are not entirely dependent on the software. The comprehensive ability and how to dig under what adjustment conditions are the combination of experience and technology. The so-called veterans. Ha ha!

Interestingly, in foreign countries, they use green cloth or something to take pictures, but not blue, because foreigners' eyes and pupils are blue. Ha ha! Your eyes will be gouged out, hehe!