Video signal processing method and apparatus

A video signal encoding method comprising:

• performing an intra prediction of a current block based on an extended angle mode;
• generating intra prediction mode information for the current block indicating one of a plurality of intra prediction modes including a basic angle mode corresponding to an angle within a preset angle range, based on the extended angle mode and a predetermined offset, wherein the extended angle mode is based on a sum of an index of the basic angle mode corresponding to the intra prediction mode information and a predetermined offset;
• and
• generating a bitstream including the intra prediction mode information,
• wherein the extended angle mode indicates a wide angle direction outside the preset angle range.

A non-transitory computer-readable medium storing a bitstream, the bitstream being decoded by a decoding method, the decoding method comprising:

• receiving intra prediction mode information for a current block indicating one of a plurality of intra prediction modes including a basic angle mode corresponding to an angle within a preset angle range;
• determining an extended angle mode based on a sum of an index of the basic angle mode corresponding to the intra prediction mode information and a predetermined offset;
• and
• obtaining a prediction sample of the current block based on the extended angle mode,
• wherein the extended angle mode indicates a wide angle direction outside the preset angle range.