layers are the coded video sequence, picture, slice, and macroblock layers. level: A defined set of constraints on the values that may be taken by the syntax elements and variables of this Recommendation International Standard. The same set of levels is defined for all profiles, with most aspects of the definition of each level being in common across different profiles. Individual implementations may, within specified constraints, support a different level for each supported profile. In a different context, a level is the value of a transform coefficient prior to scaling (see the definition of transform coefficient level). list: A one-dimensional array of syntax elements or variables. list 0 (list 1) motion vector: A motion vector associated with a reference index pointing into reference picture list 0 (list 1). list 0 (list 1) prediction: Inter prediction of the content of a slice using a reference index pointing into reference picture list 0 (list 1). luma: An adjective specifying that a sample array or single sample is representing the monochrome signal related to the primary colours. The symbol or subscript used for luma is Y or L. NOTE - The term luma is used rather than the term luminance in order to avoid the implication of the use of linear light transfer characteristics that is often associated with the term luminance. The symbol L is sometimes used instead of the symbol Y to avoid confusion with the symbol y as used for vertical location. macroblock: A 16x16 block of luma samples and two corresponding blocks of chroma samples of a picture that has three sample arrays, or a 16x16 block of samples of a monochrome picture or a picture that is coded using three separate colour planes. The division of a slice or a macroblock pair into macroblocks is a partitioning. macroblock-adaptive frame/field decoding: A decoding process for coded frames in which some macroblocks may be decoded as frame macroblocks and others may be decoded as field macroblocks. macroblock address: When macroblock-adaptive frame/field de