Motion vector

In video compression, a motion vector is the key element in the motion estimation process. It is used to represent a macroblock in a picture based on the position of this macroblock (or a similar one) in another picture, called the reference picture.

Visualized motion vectors. The foreground character's rotating downward head movement is visible, as well as the background character's slower upward head movement.

The H.264/MPEG-4 AVC standard defines motion vector as:

motion vector: a two-dimensional vector used for inter prediction that provides an offset from the coordinates in the decoded picture to the coordinates in a reference picture.[1][2]

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