Screens used to be fixed at 60 Hz, but many videos are 24 frames per second (fps), which can cause screen tearing, ghosting, and other issues. The solution is to repeat frames 1|2|3|4 of the video as 1A 1B|2A 2B 2C|3A 3B|4A 4B 4C, so that the 24 fps video corresponds to the 60 Hz screen.
However, this solution causes each frame to be displayed for varying lengths of time, and viewers may notice strange judder or other unsmooth sensations. There are two better ways: process the video, or make the display a multiple of the video frame rate.
AMD’s Fluid Motion Video frame interpolation technology in older graphics cards could smooth things out, and its successor is now AMD Fluid Motion Frames. In video players, you can use third-party plugins to invoke AMD graphics card frame interpolation. However, the disadvantage is that you need a suitable AMD graphics card and cannot optimize videos on web pages.
Another method is to modify the refresh rate of the display. A 60 Hz display usually supports a working range of 50 ~ 75 Hz, which can be modified with the software Custom Resolution Utility. This way, when playing 24 fps video, adjusting the display to 72 fps will smooth out the frame duration.
However, this problem is now gradually being alleviated by high refresh rate displays. 120 and 144 Hz displays are multiples of 24, so the effect should be good. For other displays that are not multiples of 24, as long as they have FreeSync variable refresh rate, and use some methods (such as frame doubling), the video can trigger the FreeSync variable refresh rate effect.
The first half mainly refers to the blog post “螢幕更新率Hz與影片幀率fps” by “黑米奇SVP”.
