Method of decoding moving pictures in intra prediction

A method of decoding an image, the method comprising:

• deriving, via an intra-predictor, an intra prediction mode;
• generating, via the intra-predictor, reference pixels on an unavailable position if there exist unavailable reference pixels of a current block;
• determining, via the intra-predictor, whether reference pixels of the current block are filtered or not based on the derived intra prediction mode and a block size of the current block;
• filtering the reference pixels of the current block using a filter if it is determined that the reference pixels of the current block are filtered, wherein two or more filters are used based on the block size of the current block such that a filter with a broad bandwidth is applied to a large block;
• and
• generating, via the intra-predictor, a prediction block of the current block according to the derived intra prediction mode of the current block and the reference pixels,
• wherein the filter is selected based on the block size of the current block and a difference between reference pixels, and
• wherein the reference pixels of the current block are not filtered in a vertical mode.