Fast Mode Decision and Motion Estimation with Object Segmentation in H.264/AVC Encoding

Abstract

In this paper we present a new and complete scheme of mode decision and motion estimation compliant with H.264/AVC encoding and decoding systems based on a moving object segmentation. It is particularly suited for applications, like surveillance, where a moving object segmentation is available. The knowledge of the moving object areas and background areas allows to reduce the set of modes permitted by the standard. This sub-set is selected in order to obtain a more accurately motion estimation for active objects and less intensive for quasi-static background. The number of comparisons needed to find the best motion vectors is reduced, conforming an encoding process simple and fast, compliant with the real time requirements of a surveillance application. An improved prediction of the motion vector is computed based on the result of the object segmentation. This avoids erroneous predictions to be carried out. Results will show that the number of comparisons needed to perform inter prediction is reduced by 60%-70% depending on the sequence, keeping the same image quality and bit-rate obtained without using segmentation.