Method and device for image encoding and decoding, and recording medium having bit stream stored therein

A method of encoding an image, the method comprising:

• determining motion-constrained region information;
• determining motion information;
• and
• performing inter prediction based on the motion-constrained region information and the motion information,
• when the motion-constrained region information indicates that motion-constrained region is applied, a configuration of motion-constrained region of a reference picture used for inter prediction is equal to a configuration of motion-constrained region of a current picture, and
• when a reference sample value outside the motion-constrained region of the reference picture is required for the inter prediction, wherein the inter prediction is performed by using a sample value of a boundary of the motion-constrained region of the reference picture instead of the reference sample value outside the motion-constrained region of the reference picture.

A computer-readable non-transitory recording medium storing a bitstream formed by a method of encoding an image, the method comprising:

• determining motion-constrained region information;
• determining motion information;
• and
• performing inter prediction based on the motion-constrained region information and the motion information,
• when the motion-constrained region information indicates that motion-constrained region is applied, a configuration of motion-constrained region of a reference picture used for inter prediction is equal to a configuration of motion-constrained region of a current picture, and
• when a reference sample value outside the motion-constrained region of the reference picture is required for the inter prediction, wherein the inter prediction is performed by using a sample value of a boundary of the motion-constrained region of the reference picture instead of the reference sample value outside the motion-constrained region of the reference picture.