What is "frame extraction" in movies? What are the specific examples?

Frame extraction in movies is through sudden cassette or frame skipping during movie playing, which is usually seen in old movies. Now that film movies have been reformed into digital movies, there will be no such thing. For example, Wong Kar-wai's "Chongqing Forest" used the frame extraction effect at the beginning. A normal action removed some frames, for example, only 12 frames were played in one second, and 24 frames were also played, so that the frame extraction effect could form a sense of stagnation.

Simulate the process of taking a photo every once in a while and forming a video after joining, that is, low-speed shooting. It will feel different from simply fast-forwarding. The effect of video frame extraction is often confused with time-lapse photography and low-speed photography.

Main advantages:

Reduce the frame rate to reduce the stored data, such as the original 1 sec 25 frames and 25M data, to 1 sec 8 frames and 8M data. In the uncompressed video transmission, it will cause the visual feeling of picture jam, which will be used in special occasions with extremely limited bandwidth or only static images. The biggest advantage of frame extraction and storage is to save storage space.

Nowadays, with the trend of high definition, the occupation of bandwidth and hard disk space is greatly challenged. Although the hard disk is getting bigger and bigger, once the system is equipped with many cameras, storage is still a big part of the cost. Smart cameras can automatically reduce the storage frame rate without changing the background, without losing data and avoiding excessive redundant data and information.