Why are there two black edges on the top and bottom of the movie?

At present, the general blockbusters are 2.35: 1 or 2.4: 1, and there are many low-cost films, and almost none of them are 16:9. By the way, the picture proportions of these videos are as follows:

4: 3 image ratio

From the day the film was born, the proportion of pictures in the film has been developing and changing. The original and transmitted picture is 4: 3 (1.33: 1). This ratio established the mainstream position 50 years ago in the last century, and now it looks very uncomfortable, because the human eye is horizontal, it will be more comfortable to see things that are wide and flat, and it will receive more information, while the ratio of 4: 3 is too "square". The ratio of 4: 3 is still used for two reasons. The first reason is that the picture ratio of traditional TV is 4: 3, and the second reason is that the ratio of traditional movies is also 4: 3. Therefore, now DVD will also provide a picture ratio of 4: 3 to adapt to the film playing on traditional TV.

1.85 picture scale: 1

After 1950s, the widescreen with the picture ratio of 1.85: 1 was born. This kind of widescreen is called university widescreen. In order to match this picture ratio, traditional movies will use a barrier to block a part of the film up and down when shooting movies, so that the picture ratio conforms to 1.85: 1. Then, when the movie is shown, the projection size of the picture is adjusted to present a widescreen effect. However, there is an obvious disadvantage in realizing this picture ratio, that is, the height of the film is not fully utilized and a lot of effective film space is wasted. At present, many DVD packages are printed with the words "1.85: 1", which refers to the picture ratio of the film.

2.35: 1 picture ratio

? After the 1970s, a kind of widescreen with a picture ratio of 2.35: 1 was born, which was scientifically called "deformed widescreen". It didn't take long for this deformed wide-screen movie to become the mainstream. Because such a picture ratio is most in line with the viewing habits of the human eye, it can also fully show the spectacular scene. Although it is also a traditional film shooting, the use of a special optical lens has become a widescreen without blocking the film, so the widescreen of 2.35: 1 avoids the shortcoming of wasting the effective space of the film. At present, many DVD packages are printed with the words "2.35: 1", which refers to the picture ratio of the film.

16: 9 picture scale

At present, the popular picture ratio of16: 9 (1.78:1) is mainly because the TV industry wants to imitate the wide screen of movies. Because the picture ratio of 16: 9 occupies a place in the current TV industry, some wide-screen movies of 16: 9 were born today. But at present, many people confuse 16: 9 and 1.85: 1 in DVD. In fact, the word "16: 9" on the DVD package means that the film is suitable for playing on 16: 9 broadband TV, but the actual picture ratio of the film is 1.85: 1. Now you should understand the meaning of the four picture proportion numbers printed on the DVD package. 4: 3 means that the movies provided in DVD are suitable for playing on traditional TV; 16: 9 means that the movies provided in DVD are suitable for playing on broadband TV; 1.85: 1 indicates that the picture ratio of movies provided by DVD is1.85:1; 2.35: 1 means that the picture ratio of movies provided by DVD is 2.35: 1. ?