1. A method comprising: loading a set of pixel values into memory to define a first search space, the first search space defining a first plurality of columns of candidate video blocks to be compared to a first video block to be encoded during a first iteration of a motion estimation routine; performing the first iteration to compare the first video block to the candidate video blocks in the first search space; and reloading a subset of the columns to define a second search space, the second search space defining a second plurality of columns of candidate video blocks to be compared to a second video block to be encoded during a second iteration of the motion estimation routine.