A Configurable Fixed-Complexity IME-FME Cost Ratio Based Inter ModeFiltering Method in HEVC Encoding

抄録

This paper presents a fixed-complexity inter mode filtering algorithm for High Efficiency Video Coding (HEVC).Motion estimation (ME) particularly the fractional motion estimation (FME) is the most computational challenge part because of the optimized Rate-Distortion (RD) evaluation for coding blocks with different sizes and prediction modes. Especially when HEVC introduces new tools like the coding tree unit and asymmetric motion partition (AMP), complexity of ME has increased furthermore. There are many approaches to reducing the ME complexity by removing the unlikely prediction modes. However, most mode filtering methods cannot guarantee the worst-case performance and limit overall speed in a pipelined video encoder.Thus, a fixed number of modes is required to ensure the worst-case performance and realize the pipeline design. By investigating the cost correlation of integer motion estimation (IME) and FME, we utilize the confidence interval (CI) of the cost ratio to remove fixed number of modes. Moreover, the dedicated configurable mode filtering makes the complexity of FME adaptive to different requirements of RD performance. According to experiment in HEVC reference software HM 16.0 with full FME, the proposed scheme achieves at almost 82.75% complexity reduction of the FME with an average of 1.63% BD rate loss.