Why are HD movies noisy?

Theoretically, high-definition movies should be perfect and noiseless during production and transmission. But in fact, the film may be disturbed by some factors in the production and transmission process, resulting in noise. Here are some factors that may cause noise in HD movies:

1. Shooting equipment: Although modern camera and video camera technology are very advanced, the performance of the shooting equipment itself may still affect the quality of the final image. For example, if the camera or its sensor is not sensitive enough or handled improperly, it may cause noise in the image.

2. Lighting conditions: When shooting in low light, high-definition movies may also have noise. This is because cameras or video cameras need to amplify light to capture details, which may cause additional noise and interference in the image.

3. Post-processing: In the process of film production, many different processes and adjustments need to be made to the image. If it is not handled properly, noise may appear in the image. For example, over sharpening or over enhancing details may make the image look noisy.

4. Transmission and display: In the process of film transmission and display, noise may also appear. For example, if packet loss or signal interference occurs during transmission, it may lead to noise in the image. Similarly, if the quality of the display device is not good enough, it may also lead to additional noise and interference in the image.

It should be noted that some filmmakers deliberately add some noise to enhance the texture and authenticity of the film. For example, some filmmakers may use the "noise brush" technology to add some random black spots to the image to simulate the effect of movies. But if the noise is too much or too loud, it may affect the audience's viewing experience.