Frame rate
Frame rate (fps)
How many video frames are shown per second. Common rates: 23.976, 24, 25, 29.97, 30, 60. Affects subtitle timing precision.
In depth
Frame rate is the count of distinct video frames displayed per second, measured in fps. Cinema is traditionally 24 fps; broadcast NTSC is 29.97; broadcast PAL and most European broadcast is 25; web and most short-form social is 30 or 60. Subtitle timing is generally specified in real-time (HH:MM:SS,mmm) — frame rate matters when you convert SRT timing back into video frames or when you change the playback rate of a video without re-timing the captions.
When to use it
Pay attention to frame rate when converting between broadcast and digital deliverables, when an editor pulls a 23.976 fps source down to 24 fps, or when SRT timing seems progressively off relative to video.
Frequently asked
Why are some videos 23.976 fps and not 24?+
23.976 fps (24 × 1000/1001) was introduced for NTSC color compatibility. Broadcast TV in North America still uses derivatives of this rate.
Do I need to re-time subtitles when changing frame rate?+
Only if the playback duration changes. Most editors retime by speeding the audio (which changes runtime) — the SoCaptions frame-rate converter tool handles SRT re-timing for any pair of rates.