Method for inducing prediction motion vector and apparatuses using same

A video encoding apparatus comprising:

• a prediction unit to generate a candidate prediction motion vector list by determining information on a plurality of spatial candidate prediction motion vectors from a neighboring prediction block to a prediction target block and determining information on a temporal candidate prediction motion vector based on the information on the plurality of spatial candidate prediction motion vectors;
• and
• an entropy encoding unit to encode prediction mode information indicating a prediction mode of the prediction target block, and encode information on a prediction motion vector used to perform inter prediction on the prediction target block among candidate prediction motion vectors comprised in the candidate prediction motion vector list in accordance with the prediction mode,
• wherein the information on the plurality of spatial candidate prediction motion vectors comprises at least one of first spatial candidate prediction motion vector availability information and a first spatial candidate prediction motion vector and at least one of second spatial candidate prediction motion vector availability information and a second spatial candidate prediction motion vector, and the information on the temporal candidate prediction motion vector comprises at least one of temporal candidate prediction motion vector availability information and the temporal candidate prediction motion vector,
• wherein when both the first spatial candidate prediction motion vector and the second spatial candidate prediction motion vector are available and the first spatial candidate prediction motion vector and the second spatial candidate prediction motion vector are different from each other, the prediction unit determines the temporal candidate prediction motion vector availability information such that the temporal candidate prediction motion vector is unavailable.

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

• prediction mode information indicating a prediction mode of a prediction target block;
• and
• information on a prediction motion vector used to perform inter prediction on the prediction target block among candidate prediction motion vectors comprised in a candidate prediction motion vector list;
• wherein the candidate prediction motion vector list is generated by determining information on a plurality of spatial candidate prediction motion vectors from a neighboring prediction block to the prediction target block and determining information on a temporal candidate prediction motion vector based on the information on the plurality of spatial candidate prediction motion vectors,
• wherein the information on the plurality of spatial candidate prediction motion vectors comprises at least one of first spatial candidate prediction motion vector availability information and a first spatial candidate prediction motion vector and at least one of second spatial candidate prediction motion vector availability information and a second spatial candidate prediction motion vector, and the information on the temporal candidate prediction motion vector comprises at least one of temporal candidate prediction motion vector availability information and the temporal candidate prediction motion vector,
• wherein when both the first spatial candidate prediction motion vector and the second spatial candidate prediction motion vector are available and the first spatial candidate prediction motion vector and the second spatial candidate prediction motion vector are different from each other, the temporal candidate prediction motion vector availability information is determined such that the temporal candidate prediction motion vector is unavailable.