Variable bit rate (VBR) compression

While many video compression schemes are ‘constant bit rate’ – designed to produce fixed data rates irrespective of the complexity of the video, VBR offers the possibility of fixing a constant picture quality by varying the bit-rate of, typically, MPEG-2 or MPEG-4 compressed video according to the needs of the pictures. This allows the images that require little data, like still or slow moving video sequences, to use less data and to use more for those that need it where there is more detail or/and movement; so maintaining a constant quality. This reduces the need for storage on DVDs, while delivering better overall quality, or more efficient allocation of total available bit-rate in a multi-channel broadcast multiplex.

See also: Constant bit rate, DVD, Statistical multiplexing