Method of encoding/decoding video signal using intra prediction and apparatus therefor

A video encoding method comprising:

• determining a reference sample line for a current block;
• deriving an intra prediction mode for the current block;
• and
• performing intra prediction of the current block, based on the reference sample line and the intra prediction mode,
• wherein the intra prediction mode is derived based on at least one of a first mode or a most probable mode (MPM) list,
• determining whether to encode a flag indicating whether the intra prediction mode is identical with the first mode based on an index of the reference sample line, wherein determining whether to parse the flag comprises:
• encoding the flag when the index of the reference sample line indicates an adjacent reference sample line, and
• refraining from encoding the flag when the index of the reference sample line indicates a non-adjacent reference sample line,
• wherein when the flag is encoded and indicates that the intra prediction mode is identical with the first mode, the intra prediction of the current block is to be derived without reference to the MPM list,
• wherein when the flag is not encoded, the intra prediction mode is to be derived without reference to the flag.

A video decoding device comprising an intra prediction unit configured to:

• determine a reference sample line for a current block;
• derive an intra prediction mode for the current block;
• and
• perform intra prediction of the current block, based on the reference sample line and the intra prediction mode,
• wherein the intra prediction mode is derived based on at least one of a first mode or a most probable mode (MPM) list,
• determine whether to parse a flag indicating whether the intra prediction mode is identical with the first mode based on an index of the reference sample line, wherein determining whether to parse the flag comprises:
• parsing the flag when the index of the reference sample line indicates an adjacent reference sample line, and
• refraining from parsing the flag when the index of the reference sample line indicates a non-adjacent reference sample line,
• wherein when the flag is parsed and the flag indicates that the intra prediction mode is identical with the first mode, the intra prediction of the current block is derived without reference to the MPM list, and
• wherein when the flag is not parsed, the intra prediction mode is derived without reference to the flag.