Frame rate is how many frames per second a video shows — usually written as fps. The number alone is technical, but the choice changes how the video feels. 24 fps is the cinema standard for almost a century: it's the lowest rate that still feels like motion to a viewer, gives the trademark "cinematic" look thanks to natural motion blur, and saved a lot of film stock back when celluloid was expensive.
60 fps is the standard for sports, gaming, screencasts, action footage on YouTube — anything where you want every fast movement to be sharp and trackable. 30 fps lives somewhere in between (the old NTSC TV legacy in North America). High-end production goes to 120 fps for slow motion or super-smooth playback on premium TVs.
Two business considerations. First, doubling the frame rate roughly doubles the bitrate at the same visual quality — a real cost on a CDN. Second, the "soap opera effect" — when films are upscaled to 60 fps by TVs — is widely disliked because viewers have learned to associate 24 fps with "film" and higher with "live TV"; the choice is therefore part of brand and aesthetic, not just a technical knob.
