Video frames from its video source were quickly brought to the screen while watching any TVs. Now ask, how fast the frames will be lifted? Generally, 12 FPS is normal for people’s eyes. But why 25 or 30 fps are used? Designers have decided for two reasons; how much will the frame rate be?
First of all, they noticed that if the frame rate and electrical frequency are not the same or subtropical, then the rolling hum (harmonic) can be repeated in the video. The refresh rate of the TV is depending on the mains power supply frequency. There are two types of electric frequency in the world, respectively 50Hz and 60Hz. The refresh rate is meant to tell how long the television will lift or refresh its screen image. Since we use 50Hz electrical frequency, our television refresh rate is 50. Accordingly, we use 25 FPS.
Secondly, the light wave which we used in the studio is dependent on the mains power supply frequency. In exactly the same way, if the camera’s frame rate and studio lighter waves are not consistent, then the rolling hum (harmonic) will be inserted in the video.
The above two reasons, the designers have decided that the fame rate will be 25 FPS (50Hz) and 30 FPS (60Hz). Typically, 50 Hz electric waves countries with PAL technique and 60 Hz electric wave countries use NTSC techniques. In different ways, it is one of the reasons PAL / NTSC techniques are used in different countries.