Fast forward playback

The process of displaying a sequence, or parts of a sequence, of pictures in display-order faster than real-time.

Fast reverse playback

The process of displaying the picture sequence in the reverse of display order faster than real-time.

FFT

Fast Fourier Transform

Field

For an interlaced video signal, a field is the assembly of alternate lines of a frame. Therefore an interlaced frame is composed of two fields a top field and a bottom field.

Field period

The reciprocal of twice the frame rate.

Flag

A variable which can take one of only two values.

Forbidden

The term forbidden when used in the clauses defining the coded bitstream indicates that the value shall never be used. This is usually to avoid emulation of start codes.

Forced updating

The process by which macroblocks are intra coded from time-to-time to ensure that mismatch errors between the inverse DCT processes in encoders and decoders cannot build up excessively.

Forward compatibility

A new coding standard is forward compatible with an existing coding standard if new decoders (designed to operate with the new coding standard) continue to be able to decode bitstreams of the existing coding standard.

Forward motion vector

A motion vector that is used for motion compensation from a reference picture at an earlier time in display order.

Frame

A frame contains lines of spatial information of a video signal. For progressive video, these lines contain samples starting from one time instant and continuing through successive lines to the bottom of the frame. For interlaced video a frame consists of two fields, a top field and a bottom field. One of these fields will commence one field period later than the other.

Frame period

The reciprocal of the frame rate.

Frame rate

The rate at which frames are be output from the decoding process.

Future reference picture

A future reference picture is a reference picture that occurs at a later time than the current picture in display order.