Intra prediction mode encoding/decoding method and apparatus for same

A video encoding method performed by a video encoding apparatus, the video encoding method comprising:

• determining an intra prediction mode of an encoding target unit;
• deriving neighbor prediction mode information from a left neighbor prediction mode and an upper neighbor prediction mode;
• and
• encoding the intra prediction mode of the encoding target unit based on the derived neighbor prediction mode information,
• wherein the left neighbor prediction mode is an intra prediction mode of a left neighbor unit adjacent to a left side of the encoding target unit and the upper neighbor prediction mode is an intra prediction mode of an upper neighbor unit adjacent to an upper side of the encoding target unit,
• wherein the neighbor prediction mode information includes a mode number of the left neighbor prediction mode and a mode number of the upper neighbor prediction mode,
• wherein the encoding of the intra prediction mode comprises
• determining a plurality of intra prediction modes for the encoding target unit based on the neighbor prediction mode information;
• encoding first information specifying whether the same intra prediction mode as the intra prediction mode of the encoding target unit exists among the plurality of intra prediction modes, into a bitstream;
• and
• encoding second information specifying the same intra prediction mode as the intra prediction mode of the encoding target unit among the plurality of intra prediction modes in case the same intra prediction mode as the intra prediction mode of the encoding target unit exists among the plurality of intra prediction modes, into the bitstream, and
• wherein, in case the left neighbor prediction mode is the same as the upper neighbor prediction mode, the plurality of intra prediction modes include a predetermined intra prediction mode.

A non-transitory computer-readable recording medium storing a bitstream generated by a video encoding method, the video encoding method comprising:

• determining an intra prediction mode of an encoding target unit;
• deriving neighbor prediction mode information from a left neighbor prediction mode and an upper neighbor prediction mode;
• and
• encoding the intra prediction mode of the encoding target unit based on the derived neighbor prediction mode information,
• wherein the left neighbor prediction mode is an intra prediction mode of a left neighbor unit adjacent to a left side of the encoding target unit and the upper neighbor prediction mode is an intra prediction mode of an upper neighbor unit adjacent to an upper side of the encoding target unit,
• wherein the neighbor prediction mode information includes a mode number of the left neighbor prediction mode and a mode number of the upper neighbor prediction mode,
• wherein the encoding of the intra prediction mode comprises
• determining a plurality of intra prediction modes for the encoding target unit based on the neighbor prediction mode information;
• encoding first information specifying whether the same intra prediction mode as the intra prediction mode of the encoding target unit exists among the plurality of intra prediction modes, into a bitstream;
• and
• encoding second information specifying the same intra prediction mode as the intra prediction mode of the encoding target unit among the plurality of intra prediction modes in case the same intra prediction mode as the intra prediction mode of the encoding target unit exists among the plurality of intra prediction modes, into the bitstream, and
• wherein, in case the left neighbor prediction mode is the same as the upper neighbor prediction mode, the plurality of intra prediction modes include a predetermined intra prediction mode.