<title>Rate control strategy based on human visual sensitivity for MPEG video coder</title>

Abstract

The Moving Picture Experts Group (MPEG) has standardized the bit-stream syntax for the coded representation of video. This means that MPEG specifies only a decoding method and allows much flexibility in encoding methods. Therefore the picture quality of the reconstructed video sequences is considerably dependent on the rate control strategy in the encoding method. We propose a new rate control strategy conforming to the MPEG syntax that improves the reconstructed picture quality. The new rate control strategy allocates the target number of bits and assigns quantization step sizes adaptively based on the human visual sensitivity and the complexity of the picture to be coded. The proposed rate control strategy consists of the following steps. First, a 16 X 16 macroblock is classified into one of 8 macroblock classes based on human visual sensitivity for luminance and color components in the macroblock and then an 8 X 8 block is classified into one of block classes by its variance. Next, the target number of bits is allocated to a block and the quantization step size is assigned to a macroblock. The result of subjective tests showed the proposed rate control strategy improved the picture quality of the reconstructed video sequences considerably over the conventional strategy. Especially in the proposed strategy, the subjective picture quality between frames was more constant and hence was less degraded than conventional rate control strategies.© (1994) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.