System and method for video coding

An image encoder comprising:

• a splitter which, in operation, receives and splits an original picture into blocks,
• a first adder which, in operation, receives the blocks from the splitter and predictions from a prediction controller, and subtracts each prediction from its corresponding block to output a residual,
• a transformer which, in operation, performs a transform on the residuals outputted from the adder to output transform coefficients,
• a quantizer which, in operation, quantizes the transform coefficients to generate quantized transform coefficients,
• an entropy encoder which, in operation, encodes the quantized transform coefficients to generate a bitstream,
• an inverse quantizer and transformer which, in operation, inverse quantizes the quantized transform coefficients to obtain the transform coefficients and inverse transforms the transform coefficients to obtain the residuals,
• a second adder which, in operation, adds the residuals outputted from the inverse quantizer and transformer and the predictions outputted from the prediction controller to reconstruct the blocks, and
• the prediction controller coupled to an inter predictor, an intra predictor, and a memory, wherein the inter predictor, in operation, generates a prediction of a current block based on a reference block in an encoded reference picture and the intra predictor, in operation, generates a prediction of a current block based on an encoded reference block in a current picture, wherein the inter predictor, in operation,
• predicts a first set of pixels for a first partition of a current picture with a first motion vector;
• predicts a second set of pixels for a second partition with a second motion vector;
• weights pixels of the first set of pixels and the second set of pixels for a first portion in which the first partition is overlapped with the second partition;
• stores for the first portion one of the first motion vector and the second motion vector in response to a first condition;
• stores for the first portion both of the first motion vector and the second motion vector in response to a second condition different from the first condition;
• and
• encodes the first partition using at least the weighted pixels.

An image encoding method, comprising:

• predicting a first set of pixels for a first partition of a current picture with a first motion vector;
• predicting a second set of pixels for a second partition with a second motion vector;
• weighting pixels of the first set of pixels and the second set of pixels for a first portion in which the first partition is overlapped with the second partition;
• storing for the first portion one of the first motion vector and the second motion vector in response to a first condition;
• storing for the first portion both of the first motion vector and the second motion vector in response to a second condition different from the first condition;
• and
• encoding the first partition using at least the weighted pixels.