# Frames Per Second

Why Trust Techopedia

## What Does Frames Per Second Mean?

Frames per second (FPS) is a unit that measures display device performance in video captures and playback and video games. FPS is used to measure frame rate — the number of images consecutively displayed each second — and is a common metric used in video capture and playback when discussing video quality.

The human brain can only process about 10 to 12 FPS. Frame rates faster than this are perceived to be in motion. The greater the FPS, the smoother the video motion appears. Full-motion video is usually 24 FPS or greater.

Different video formats have different FPS rates. Slower FPS rates produce smaller computer files.

## Techopedia Explains Frames Per Second

Early silent films had frame rates between 16 to 24 FPS. The frame rate was highly variable because the cameras were hand-cranked. Filmmakers used this variability to their advantage and would slow or speed the frame rate to convey mood.

Although the frame rate of these early movies was high enough to sense motion, the video was still choppy. To reduce flickering, projectors used dual- and triple-blade shutters, which would display each frame two or three times. This would increase the flickering to 48 to 72 hertz, which was easier on the eyes. When sound film became available, the new videos continued to use 24 FPS in combinations with two- or three-blade shutters.

The concept of frame rate did not change substantially until the invention of the television. The frame rates of televisions were determined by the frequency of power of a cable wall outlet. In North America, Japan, and Korea it was 60 Hertz, and in most of the rest of the world 50 Hertz. This gave the televisions a frame rate of 60 FPS and 50 FPS respectfully. Neither format works well with 24 FPS. Videos designed for 60 FPS television use 30 FPS and 50 FPS televisions require 25 FPS videos. Each frame is shown twice to reduce flicker and accommodate the new speeds.

## Frame Rate vs Refresh Rate

In video production, frame rate is sometimes confused with refresh rate. Refresh rate is measured in hertz (Hz) and will vary according to the architecture of the display device. For example, if the device has a 60Hz refresh rate, it means that the screen is refreshing itself 60 times every second to compensate for jitter. This performance metric should not be confused with frame rate, which simply describes how many times per second the video source sends a new frame.