Joint motion vector coding

A method of coding video data, comprising:

• developing a plurality of coding hypotheses each having a motion vector identifying a source of prediction for a current pixel block,
• predicting a motion vector for a first one of the coding hypotheses,
• determining a difference between the developed motion vector for the first coding hypothesis and the predicted motion vector for the first coding hypothesis, and
• outputting, with coded data of the current pixel block, data representing the difference between the developed motion vector for the first coding hypothesis and the predicted motion vector for the first coding hypothesis.

A video coding system, comprising:

• a predictor that:
• develops motion vectors identifying prediction references for each of a plurality of coding hypotheses,
• predicts a motion vector for a first one of the coding hypotheses from the motion vector of a second coding hypothesis,
• determines a difference between the developed motion vector for the first coding hypothesis and the predicted motion vector for the first coding hypothesis;
• a pixel block encoder that codes a current pixel block differentially with respect to a predicted pixel block developed by the motion vectors for the first and second hypotheses;
• and
• a syntax unit that outputs coded data of the current pixel block including data representing the difference between the developed motion vector for the first coding hypothesis and the predicted motion vector for the first coding hypothesis, and data representing the second hypothesis.

A method of decoding coded video data, comprising:

• responsive to a motion vector prediction residual supplied in coded video data for a first coding hypothesis applied to a current pixel block, predicting a motion vector for the first coding hypothesis from motion vector data supplied in the coded video data for a second coding hypothesis applied to the current pixel block,
• recovering a motion vector for the first coding hypothesis from the predicted motion vector and the motion vector prediction residual,
• developing a prediction pixel block for the current pixel block for the first coding hypothesis using the recovered motion vector, and
• decoding the current pixel block using the developed prediction pixel block.

A method of decoding coded video data, comprising:

• predicting a motion vector for a first coding hypothesis for a current pixel block,
• predicting a motion vector for a second coding hypothesis for a current pixel block,
• responsive to a motion vector prediction residual supplied in coded video data:
• developing a first recovered motion vector from the predicted motion vector for the first coding hypothesis and the motion vector prediction residual,
• developing a second recovered motion vector from the predicted motion vector for the second coding hypothesis and the motion vector prediction residual,
• predicting a motion vector for a second coding hypothesis for a current pixel block, developing a first prediction pixel block for the current pixel block using the first recovered motion vector, and
• developing a second prediction pixel block for the current pixel block using the second recovered motion vector, and
• decoding the current pixel block using the first and second prediction pixel blocks.

A video decoding system, comprising:

• a predictor that:
• responsive to a motion vector prediction residual supplied in coded video data for a first coding hypothesis applied to a current pixel block, predicting a motion vector for the first coding hypothesis from motion vector data supplied in the coded video data for a second coding hypothesis applied to the current pixel block,
• recovering a motion vector for the first coding hypothesis from the predicted motion vector and the motion vector prediction residual,
• developing a prediction pixel block for the current pixel block for the first coding hypothesis using the recovered motion vector;
• and
• a pixel block decoder that decodes a current pixel block differentially with respect to prediction pixel block developed by the predictor and coded pixel block data.

Computer readable medium storing program instructions that, when executed by a processing device, cause the processing device to perform a method of coding video data, comprising:

• developing a plurality of coding hypotheses each having a motion vector identifying a source of prediction for a current pixel block,
• predicting a motion vector for a first one of the coding hypotheses from the motion vector of a second coding hypothesis,
• determining a difference between the developed motion vector for the first coding hypothesis and the predicted motion vector for the first coding hypothesis, and
• outputting, with coded data of the current pixel block, data representing the difference between the developed motion vector for the first coding hypothesis and the predicted motion vector for the first coding hypothesis.

Computer readable medium storing program instructions that, when executed by a processing device, cause the processing device to perform a method of coding video data, comprising:

• developing a plurality of coding hypotheses each having a motion vector identifying a source of prediction for a current pixel block,
• predicting a motion vector for a first one of the coding hypotheses,
• determining a difference between the developed motion vector for the first coding hypothesis and the predicted motion vector for the first coding hypothesis, and
• outputting, with coded data of the current pixel block, data representing the difference between the developed motion vector for the first coding hypothesis and the predicted motion vector for the first coding hypothesis.