Determining a sum of absolute differences using a circuit is described. Pairs of inputs, including a respective current value and a respective previous value, are obtained. The previous value is subtracted from the current value for each of the pairs of inputs to provide differences and associated carries. Inverted carries are applied to the differences to pass a first portion of the differences associated with positive absolute differences and to invert and then pass a second portion of the differences associated with negative absolute differences. The inverted carries are summed. The first portion and the second portion are provided to an adder tree to generate an interim sum of absolute differences. The sum of inverted carries obtained over a number of clock cycles is added to the interim sum of absolute differences obtained over the number of clock cycles to generate a sum of absolute difference result.