What is "reference frame"

n. a system that uses coordinates to establish position [syn: coordinate system, frame of reference, reference system]

Reference frame may refer to:

• Frame of reference, in physics
• Reference frame (video), frames of a compressed video that are used to define future frames

Reference frames are frames of a compressed video that are used to define future frames. As such, they are only used in inter-frame compression techniques. In older video encoding standards, such as MPEG-2, only one reference frame – the previous frame – was used for P-frames. Two reference frames (one past and one future) were used for B-frames.