Predictor candidates for motion estimation search systems and methods

A tangible, non-transitory, computer-readable medium that stores instructions executable by one or more processors in a video encoding pipeline, wherein the instructions comprise instructions to:

• instruct, using the one or more processors, the video encoding pipeline to retrieve source image data corresponding with a coding unit in a first image frame;
• instruct, using the one or more processors, the video encoding pipeline to determine an adjacent inter-frame prediction mode used to prediction encode a pixel block directly adjacent the coding unit in the first image frame, wherein the adjacent inter-frame prediction mode comprise a first motion vector that identifies a first pixel position in a second image frame;
• instruct, using the one or more processors, the video encoding pipeline to determine a first predictor inter-frame prediction mode corresponding with a prediction unit in the coding unit by offsetting the first motion vector of the adjacent inter-frame prediction mode in a first direction to identify a second pixel position different from the first pixel position, wherein a first pixel area comprises the second pixel position;
• instruct, using the one or more processors, the video encoding pipeline to determine a second predictor inter-frame prediction mode corresponding with the prediction unit by offsetting the first motion vector of the adjacent inter-frame prediction mode in a second direction to identify a third pixel position different from the first pixel position, wherein a second pixel area comprises the third pixel position;
• instruct, using the one or more processors, the video encoding pipeline to, in response to an overlap between the first pixel area and the second pixel area greater than a first threshold:
• in response to the overlap greater than a second threshold, replace the second predictor inter-frame prediction mode with another initial candidate inter-frame prediction mode that identifies a fourth pixel position, wherein a third pixel area comprises the fourth pixel position;
• and
• in response to the overlap less than the second threshold, determining a fourth pixel area comprising a fifth pixel position identified by offsetting a second motion vector of the second initial candidate inter-frame prediction mode such that the overlap is less than the first threshold;
• instruct, using the one or more processors, the video encoding pipeline to determine a final candidate inter-frame prediction mode based at least in part on a first motion estimation search in the first pixel area and a second motion estimation search in the second pixel area, the third pixel area, or the fourth pixel area;
• instruct, using the one or more processors, the video encoding pipeline to determine a prediction mode to be applied to other image data to determine a prediction sample of the prediction unit based at least in part on a rate-distortion cost associated with the final candidate inter-frame prediction mode;
• and
• instruct, using the one or more processors, the video encoding pipeline to output encoded image data generated to indicate the prediction mode and a prediction residual resulting from comparison of the prediction sample and the source image data.

A method comprising:

• receiving, using a video encoding pipeline, source image data corresponding with a prediction unit in a first image frame;
• determining, using the video encoding pipeline, a first candidate inter-frame prediction mode that identifies a first pixel position in a second image frame;
• determining, using the video encoding pipeline, a first pixel search area comprising a first plurality of pixel positions in the second image frame based at least in part on the first pixel position identified by the first candidate inter-frame prediction mode;
• determining, using the video encoding pipeline, a second candidate inter-frame prediction mode that identifies a second pixel position in the second image frame;
• determining, using the video encoding pipeline, a second pixel search area comprising a second plurality of pixel positions in the second image frame based at least in part on the second pixel position identified by the second candidate inter-frame prediction mode;
• determining, using the video encoding pipeline, number of pixel positions in the second image frame that overlap between the first pixel search area and the second pixel search area;
• adjusting, using the video encoding pipeline, the second pixel search area to reduce the number of pixel positions in the second image frame that overlap between the first pixel search area and the second pixel search area when the number of pixel positions that overlap is greater than a lower threshold, wherein adjusting the second pixel search area comprises:
• replacing the second candidate inter-frame prediction mode with a third candidate inter-frame prediction mode that identifies a third pixel position different from the second pixel position identified by the second candidate inter-frame prediction mode such that the second pixel search area comprises a third plurality of pixel positions in the second image frame surrounding the third pixel position when the number of pixel positions that overlap is greater than an upper threshold;
• and
• offsetting a motion vector of the second candidate inter-frame prediction mode such that the number of pixel positions that overlap is no longer greater than the lower threshold when the number of pixel position that overlap is not greater than the upper threshold;
• performing, using the video encoding pipeline, a motion estimation search in the first pixel search area and the second pixel search area to facilitate determining a prediction mode to be applied to other image data to determine prediction sample corresponding with the prediction unit;
• and
• outputting, using the video encoding pipeline, encoded image data that indicates the prediction mode and a prediction residual resulting from comparison of the prediction sample and the source image data.