Scene level rate control algorithm for MPEG4 video coding Objectbased coding approaches, such as the MPEG4 standard approach, where a video scene is composed by several video objects, require that the rate control is performed by using two levels: the scene rate control and the object rate control. In this context, this paper presents a new scene level and object level rate control algorithm for low delay MPEG4 video encoding capable of performing bit allocation for the several VOs in the scene, encoded at different VOP rates, and aiming at obtaining a better tradeoff among spatial and temporal quality for the overall scene. The proposed approach combines ratedistortion modeling using model adaptation by least squares estimation and adaptive bit allocation to u0027shapeu0027 the encoded data in order that the overall subjective quality of the encoded scene is maximized.

A perceptualbased approach to bit allocation for H.264 encoder Since the ultimate receivers of encoded video are human eyes, the characteristics of human visual system should be taken into consideration in the design of bit allocation to improve the perceptual video quality. In this paper, we incorporate the structural similarity index as a distortion metric and propose a novel ratedistortion model to characterize the relationship between rate and the structural similarity index. Based on the model, we develop an optimum bit allocation and rate control scheme for H.264 encoders. Experimental results show that up to 25% bitrate reduction over the JM reference software can be achieved. Subjective evaluation further confirms that the proposed scheme preserves more structural information and improves the perceptual quality of the encoded video.