Method and apparatus for image encoding and decoding using temporal motion information

An encoding method comprising:

• determining a first motion vector for a target block in a target picture;
• and
• performing inter prediction for the target block using the first motion vector,
• wherein the first motion vector of the target block is determined based on a second motion vector of a reference block in a first picture,
• the first picture is different from the target picture,
• a scaled motion vector of the reference block is determined by applying a first scaling to the second motion vector of the reference block,
• the scaled motion vector of the reference block is a motion vector from a position of the reference block in the first picture to a position of the target block in the target picture,
• the first scaling is performed based on a first distance and a second distance,
• the first distance is a distance between the first picture and a second picture,
• the second distance is a distance between the first picture and the target picture, and
• the second picture is a picture to which the reference block refers.

A non-transitory computer-readable recording medium storing a bitstream, the bitstream comprising:

• inter prediction information, wherein
• a first motion vector for a target block in a target picture is determined based on the inter prediction information,
• inter prediction for the target block is performed using the first motion vector,
• the first motion vector of the target block is determined based on a second motion vector of a reference block in a first picture,
• the first picture is different from the target picture,
• a scaled motion vector of the reference block is determined by applying a first scaling to the second motion vector of the reference block,
• the scaled motion vector of the reference block is a motion vector from a position of the reference block in the first picture to a position of the target block in the target picture,
• the first scaling is performed based on a first distance and a second distance,
• the first distance is a distance between the first picture and a second picture,
• the second distance is a distance between the first picture and the target picture, and
• the second picture is a picture to which the reference block refers.