Method, video encoder, and integrated circuit for detecting non-rigid body motion

A method for detecting a non-rigid-body in video coding and an integrated circuited for the same are disclosed. The integrated circuit capable of detecting non-rigid-body comprises a best matched block, a correlation unit, and a non-rigid-body detection unit. The best matched block unit receives a current block in a current video frame and block searching a reference video frame to determine an initial motion vector for a best matched block in the reference video frame. The correlation unit, coupled to the best matched block unit, receives the best matched block, and computes a correlation between a corresponding block and the best matched block. The non-rigid-body detection unit, coupled to the correlation unit, determines whether the current block contains non-rigid-body according to the correlation.