帧Frame

帧是时间采样的点——把连续的运动切成一秒一个一个瞬间，每一张就是一帧。

• 帧率 = 每秒采几个瞬间：24 / 30 / 60——切得越密，运动越连贯（见 帧率 · 时间分辨率）。
• 帧间的运动不在文件里：靠人眼把它补回来；快速运动下的残影和抖动，就是采样不够密的痕迹（见 采样）。
• 慢放的秘密：把 24fps 放慢 4 倍，每秒只剩 6 帧——帧是有限的快照，慢放靠它自然变卡，或靠软件造帧。

A frame is a point of temporal sampling — continuous motion cut into so-many instants per second; each still is one frame.

• Frame rate = instants per second: 24 / 30 / 60 — the denser the cut, the smoother the motion (see Frame rate · Temporal resolution).
• Motion between frames is not in the file: your eye fills it in; smear and judder on fast movement are the traces of sampling that is too sparse (see Sampling).
• The secret of slow motion: slow 24fps down 4× and six frames a second remain — frames are finite snapshots; slow them and they stutter naturally, unless software invents more.