Rate-Constrained Motion Estimation And Perceptual Coding

This paper proposes a video encoder with improved visual quality achieved through more accurate motion estimation and perceptual quantization. A quadtree-based variable size block motion estimation scheme jointly optimizes both motion vector coding and residual coding by minimizing the actual rate subject to a constraint on overall distortion. The residual coder includes perceptual quantization and direct block coding. Since the residual is encoded directly without any transform, the encoder achieves compariable speed with MPEG. The encoded video outperforms that of MPEG in terms of both PSNR and visual quality. 1. INTRODUCTION In variable block size motion estimation (VBME) [1, 2, 3, 4], the frame is segmented into variable size blocks according to local motion activities. Larger blocks are used in areas of stationary background or uniform motion while smaller blocks are used mostly around moving edges or textures. A `top-down' quad-tree approach is used in [2] where the block splitt..