A mode for compressing color information in digital video formats. See chroma subsampling.
Under the Whyte notation system, a steam locomotive that has four leading wheels arranged in a leading truck, two driving wheels and two trailing wheels.
It is generally designed as a 4-2-2 engine, but some old types are still running with only three axles, the 2-2-2.
Thus 4-4-2 represents a bogie engine with four-coupled wheels and one pair of trailing wheels, the wellknown Atlantic type; 4-2-2 represents a bogie engine with a single pair of driving-wheels and a pair of trailing wheels; 0-4-4 represents an engine with four-coupled wheels and a trailing bogie, and 4-4-o an engine with four-coupled wheels and a leading bogie.
A general description of the chief peculiarities of various kinds of locomotives is given in the following analysis of types: (I) " Single-driver " type, 4-2-2 or 2-2-2.