アナログ放送
The frame rate for motion picture film cameras was typically 24 frames per second (fps) with multiple flashes on each frame during projection to prevent flicker. Analog television and video employed interlacing where only half of the image (known as a video field) was recorded and played back/refreshed at once but at twice the rate of what would be allowed for progressive video of the same bandwidth, resulting in smoother playback, as opposed to progressive video which is more similar to how celluloid works. The field rate of analog television and video systems was typically 50 or 60 fields per second. Usage of frame rates higher than 24 fps for feature motion pictures and higher than 30 fps for other applications are emerging trends in the recent past. Filmmakers may capture their projects in a high frame so that it can be evenly converted to multiple lower rates for distribution.