A frame is a complete video image. In the 2:1 interlaced scanning format of the
RS-170 and CCIR formats, a frame is made up of two separate fields of
262.5 or 312.5 lines interlaced at 60 or 50 Hz to form a complete
frame, which appears at 30 or 25 Hz. In video cameras with a
progressive scan, each frame is scanned line-by-line and not
interlaced; most are also displayed at 30 and 25 Hz.