Analysis of Hierarchical B Pictures and MCTF

In this paper, an investigation of H.264/MPEG4-AVC conforming coding with hierarchical B pictures is presented. We analyze the coding delay and memory requirements, describe details of an improved encoder control, and compare the coding efficiency for different coding delays. Additionally, the coding efficiency of hierarchical B picture coding is compared to that of MCTF-based coding by using identical coding structures and a similar degree of encoder optimization. Our simulation results turned out that in comparison to the widely used IBBP...structure coding gains of more than 1 dB can be achieved at the expense of an increased coding delay. Further experiments have shown that the coding efficiency gains obtained by using the additional update steps in MCTF coding are generally smaller than the losses resulting from the required open-loop encoder control

1. Introduction

The increased flexibility of H.264/MPEG4-AVC [1] in comparison to prior video coding standards as MPEG-2 Visual, MPEG4 Visual or H.263 is one of the main reasons for its improved coding efficiency. However, this new flexibility on a picture/sequence level is still not a sufficiently well investigated topic. In contrast to previous video coding standards, the coding and display order of pictures in H.264/MPEG4-AVC is completely decoupled. Furthermore, any picture can be marked as reference picture and used for prediction of following pictures independent of the corresponding slice types. The set of pictures that is stored in the decoded picture buffer (DPB) and used for the prediction of following pictures can be adaptively controlled. These features allow the selection of arbitrary coding/prediction structures, which are not supported by previous standards.