Efficient block-size selection algorithm for inter-frame coding in H.264/MPEG-4 AVC

One of the new features introduced in the emerging video coding standard, H.264/ MPEG-4 AVC (advanced video coding), is the utilization of flexible block sizes ranging from 4×4 to 16×16 in inter-frame coding. The aim is to reduce the error due to fixed block size prediction within a macroblock. However, this feature results in extremely large encoding times, especially when the brute force full-search algorithm is employed. We propose a fast block-size selection algorithm for inter-frame coding. The proposed algorithm relies mainly on two robust and reliable predictive factors - the intrinsic complexity of the macroblock and mode knowledge from the previous frame. Extensive simulations verify that the proposed method provides significant improvement in computational requirement, without sacrificing picture quality and compression ratio.