System and method of adaptive vertical search range tracking for motion estimation in digital video

A method of estimating a motion vector between video frames in a device, the video frames comprising a reference frame and a target frame, the method comprising:

• defining a fixed-size vertical search range for estimating the motion vector;
• storing the reference frame and the target frame of video in at least one memory;
• determining an offset value indicative of a directional shift of the fixed-size vertical search range;
• shifting the vertical search range based on the offset value;
• estimating a motion vector based on data in the shifted vertical search range;
• performing a plurality of cycles of motion estimation;
• wherein:
• the offset value is based at least in part on a search range of a preceding cycle;
• and
• determining the offset value includes:
• receiving the search range of the preceding cycle of motion estimation;
• generating a histogram based on the received search range;
• and
• determining the offset value based on the generated histogram.