Motion vector selection and prediction in video coding systems and methods

A computing device, comprising:

• a memory configured to store computer instructions;
• and
• a processor configured to execute the computer instructions to:
• obtain a coding block from an unencoded video frame of a sequence of video frames;
• select a coding mode from a plurality of coding modes for use in encoding the coding block, the plurality of coding modes include an inter-coding mode, a skip-coding mode, and a direct-coding mode;
• in response to selection of the inter-coding mode:
• divide the obtained coding block into a plurality of prediction blocks;
• and
• for each respective prediction block of the plurality of prediction blocks:
• select a motion-vector-prediction method from a plurality of motion-vector-prediction methods for use in encoding the respective prediction block;
• encode the respective prediction block based on the selected motion-vector-prediction method to generate a video data payload portion of an encoded bit-stream representative of the unencoded video frame for the respective prediction block;
• and
• provide a selected-motion-vector-prediction-method flag in a header portion of the respective encoded prediction block, wherein the selected-motion-vector-prediction-method flag indicates which of the plurality of motion-vector-prediction methods was selected for encoding the respective prediction block;
• in response to selection of the skip-coding mode or the direct-coding mode:
• set the obtained coding block as a current prediction block;
• obtain an ordered list of motion-vector candidates for the current prediction block;
• select a motion vector from the ordered list of motion-vector candidates for use in encoding the current prediction block;
• encode the current prediction block using the selected motion vector to generate a portion of the video data payload of the encoded bit-stream for the current prediction block;
• and
• provide a motion-vector-selection flag in the header portion of the encoded current prediction block, wherein the motion-vector-selection flag indicates a location in the ordered list of motion-vector candidates corresponding to the selected motion vector;
• and
• provide a coding-mode-selection flag in a header portion of the encoded bit-stream, wherein the coding-mode-selection flag indicates which of the plurality of coding modes was selected for encoding the coding block.

A non-transitory computer readable medium having stored contents that, when executed by a processor of a computing system, cause the computing system to perform actions, the actions comprising:

• obtaining a coding block from the unencoded video frame;
• selecting a coding mode from a plurality of coding modes for use in encoding the coding block, the plurality of coding modes include an inter-coding mode, a skip-coding mode, and a direct-coding mode;
• in response to selection of the inter-coding mode:
• dividing the obtained coding block into a plurality of prediction blocks;
• and
• for each respective prediction block of the plurality of prediction blocks:
• selecting a motion-vector-prediction method from a plurality of motion-vector-prediction methods for use in encoding the respective prediction block;
• encoding the respective prediction block based on the selected motion-vector-prediction method to generate a video data payload portion of the encoded bit-stream for the respective prediction block;
• and
• providing a selected-motion-vector-prediction-method flag in a header portion of the respective encoded prediction block, wherein the selected-motion-vector-prediction-method flag indicates which of the plurality of motion-vector-prediction methods was selected for encoding the respective prediction block;
• in response to selection of the skip-coding mode or the direct-coding mode:
• setting the obtained coding block as a current prediction block;
• obtaining an ordered list of motion-vector candidates for the current prediction block;
• selecting a motion vector from the ordered list of motion-vector candidates for use in encoding the current prediction block;
• encoding the current prediction block using the selected motion vector to generate a portion of the video data payload of the encoded bit-stream for the current prediction block;
• and
• providing a motion-vector-selection flag in the header portion of the encoded current prediction block, wherein the motion-vector-selection flag indicates a location in the ordered list of motion-vector candidates corresponding to the selected motion vector;
• and
• providing a coding-mode-selection flag in a header portion of the encoded bit-stream, wherein the coding-mode-selection flag indicates which of the plurality of coding modes was selected for encoding the coding block.