Method and apparatus for encoding video, and method and apparatus for decoding video

An apparatus of decoding image, the apparatus comprising:

• an entropy decoder which extracts information that indicates an intra prediction mode applied to a current block to be decoded from a bitstream;
• a reference pixel determining unit which determines reference pixels from among neighboring pixels adjacent to the current block and filtered neighboring pixels filtered from the neighboring pixels, based on a size of the current block and an intra prediction mode of the current block;
• an intra prediction performing unit which performs intra prediction in the intra prediction mode on the current block using the extracted information and the determined reference pixels,
• wherein the image is hierarchically split from a plurality of maximum coding units, according to information about a maximum size of a coding unit, into coding units of coded depths according to depths,
• wherein a coding unit of a current depth is one of rectangular data units split from a coding unit of an upper depth,
• wherein the coding unit is split into coding units of a lower depth, independently from neighboring coding units, and
• wherein the coding unit of the current depth is split into at least one prediction unit.