Video encoding/decoding method and device, and recording medium having bitstream stored therein

An image encoding method comprising:

• determining an intra prediction mode of a current block;
• deriving a reference sample of intra prediction for the current block from a plurality of reference sample lines;
• generating a prediction block by performing intra prediction for the current block based on the intra prediction mode and the reference sample;
• and
• deriving a reconstructed block for the current block based on the prediction block of the current block,
• wherein the deriving the reference sample of intra prediction for the current block comprises:
• determining whether an upper boundary of the current block is an upper boundary of a current coding tree block or not;
• and
• selecting a reference sample line for deriving the reference sample among the plurality of reference sample lines based on the determination, and
• wherein, in case the upper boundary of the current block is the upper boundary of the current coding tree block, the reference sample is derived using a first reference sample line adjacent to the current block among the plurality of reference sample lines.

A non-transitory computer-readable recording medium storing a bitstream which is received and decoded by an image decoding apparatus and used to reconstruct an image,

• wherein the bitstream comprises information on prediction of a current block,
• the information on prediction of the current block is used to derive an intra prediction mode of the current block,
• a reference sample used for the intra prediction is derived from a plurality of reference sample lines,
• the intra prediction mode of the current block is used to generate a prediction block by performing intra prediction for the current block, and
• the prediction block of the current block is used to derive a reconstructed block,
• wherein a reference sample line used for deriving the reference sample is selected from the plurality of reference sample lines based on whether an upper boundary of the current block is an upper boundary of a current coding tree block,
• wherein, in case the upper boundary of the current block is the upper boundary of the current coding tree block, the reference sample is derived using a first reference sample line adjacent to the current block among the plurality of reference sample lines.