Adaptive Block-Size Transform Based on Extended Integer 8??8/4??4 Transforms for H.264/AVC

In this paper, a low-complexity adaptive block-size transform (ABT) scheme is proposed for the H.264/AVC. The integer 8x8/4x4 discrete cosine transforms with an extended relation are applied to the proposed ABT scheme for reducing the implementation complexities. In the proposed scheme, the 8x8/4x4 transforms can be merged together and share the same scale matrix. As a result, the transform units and storage resources can be effectively saved in both encoder and decoder. The 8x8 transform extended from the 4x4 transform of H.264/AVC can be easily implemented with several simple arithmetic operators, and its intermediate results can be strictly limited within 16-bit. The experimental results show that the proposed ABT scheme based on extended transforms achieves a similar coding performance to the original ABT scheme for H.264/AVC.