Configurable VLSI Architecture for Deblocking Filter in H.264/AVC

In this paper, we study and analyze the computational complexity of the deblocking filter in H.264/AVC baseline decoder based on SimpleScalar/ARM simulator. The simulation result shows that the memory reference, content activity check operations, and filter operations are known to be very time consuming in the decoder of this new video coding standard. In order to improve overall system performance, we propose a configurable, extensible, and synthesizable window-based processing architecture which simultaneously processes the horizontal filtering of vertical edge and vertical filtering of horizontal edge. As a result, the memory performance of the proposed architecture is improved by four times when compared to previous designs. Moreover, the system performance of our window-based architecture significantly outperforms the previous designs from 7 times to 20 times.

I. Introduction

Video compression is the critical technology in today's multimedia systems. The limited transmission bandwidth or storage capacity for applications such as HDTV, video conferencing, 3G for mobile device, and Internet video streaming emphasizes the demand for higher video compression rates. To achieve this demand, the new video coding standard Recommendation H.264 of ITU-T [1], also known as International Standard 14496-10 or MPEG-4 Part 10 Advanced Video Coding (AVC) of ISO/IEC, has been developed. It significantly outperforms the previous ones (i.e., H.261 [2], MPEG-1 Video [3], MPEG-2 Video [4], H.263 [5], and MPEG-4 Visual or part 2 [6]) in bit-rate reduction. The functional blocks of H.264/AVC, as well as their features, are shown in Fig. 1. Comparing the H.264/AVC video coding tools (e.g., adaptive deblocking filter [7], integer DCT-like transform [8] instead of the DCT [9], multiple reference frame [10], new frame types (SP-frames and SI-frames) [11], further predictions using B-slices [12], quarter per motion compensation [13], or CABAC [14]) to the tools of previous video coding standard, H.264/AVC provides the most improved algorithm in the evolution of video coding as well as error robustness and network friendliness [15]–[20]. At the same time, preliminary studies [21] using software based on this new standard suggest that H.264 offers up to 50% better compression than MPEG-2 and up to 30% better than H.263+ and MPEG-4 advanced simple profile. Fig. 1.

Block diagram of H.264/AVC.