Frame Rate

Frame rate is the number of still images (frames) displayed or captured per second in a video stream, usually measured in frames per second (fps). Common values include 24 fps (cinema), 30 fps (US broadcast), and 60 fps (high-motion content); video calling and streaming systems often run at 15–30 fps and adapt down when bandwidth or processing power is constrained. Frame rate is a critical accessibility parameter for sign language video: empirical studies have found that around 10 fps is the practical floor for intelligible conversational ASL, with fingerspelling tolerating somewhat higher rates and "just listening" segments tolerating much lower rates. Frame rate also matters for lip-reading, captioned video synchronisation, and seizure-safe content — WCAG 2.1 SC 2.3.1 limits flashes to no more than three per second to reduce photosensitive-epilepsy risk.