Pattern-based motion vector derivation for video coding

An apparatus configured to decode video data, the apparatus comprising a processor in communication with memory, the processor being configured to execute instructions stored in the memory that cause the processor to:

• receive compressed video data related to a set of frames;
• derive a first motion vector for a current block, wherein the first motion vector is an unrefined motion vector;
• calculate, using a decoder-side predictor refinement technique according to the first motion vector, a second motion vector, wherein the second motion vector is a refined motion vector for the current block;
• perform motion compensation for the current block according to the second motion vector that is the refined motion vector, but not the first motion vector that is the unrefined motion vector for the current block;
• and
• derive a motion vector predictor for a second block different than the current block by using the first motion vector of the current block, but not the second motion vector that is the refined motion vector.

At least one non-transitory computer-readable storage medium encoded with a plurality of computer-executable instructions that, when executed, perform a method comprising:

• receiving compressed video data related to a set of frames;
• deriving a first motion vector for a current block, wherein the first motion vector is an unrefined motion vector;
• calculating, using a decoder-side predictor refinement technique according to the first motion vector, a second motion vector, wherein the second motion vector is a refined motion vector for the current block;
• performing motion compensation for the current block according to the second motion vector that is the refined motion vector, but not the first motion vector that is the unrefined motion vector for the current block;
• and
• deriving a motion vector predictor for a second block different than the current block by using the first motion vector of the current block, but not the second motion vector that is the refined motion vector.