Video compression

Notions: video is basically a three-dimensional array of color pixels. Two dimensions serve as spacial (horizontal and vertical) directions of the (moving) pictures and one dimension represents the time domain. A frame is a set of all pixels that (approximately) correspond to a single point in time. Basically, a frame is the same as a (still) picture. However, in interlaced video, the set of horizontal lines with even numbers and the set with odd numbers are grouped together to fields. The term picture can refer to a frame or a field.

Method: Video data contains spatial and temporal redundancy. Video compression removes this redundancy lossy. Usually this is achieved by:

• Image compression techniques to remove spatial redundancy from frames and
• Motion compensation techniques to remove temporal redundancy.

See also:

• video codecs
• MPEG video