High-efficiency video coding encoders provide great improvements in coding efficiency and can also support higher resolution and multiple coding tools. The new coding structures such as coding unit (CU) and prediction unit (PU) have helped a lot, but the computational complexity is much higher than those of previous standards. This paper proposes a fast algorithm combining with CU and PU early termination decisions to reduce computational demand. Based on the analytic results, we can set up an adaptive threshold that can be obtained for early termination. Meanwhile, we also develop an adaptive search range determination according to the motion vector (MV). Compared with HM 12.0, our proposed method achieves an approximate 57% time saving, whereas the average Bjøntegaard-Delta Bit-rate (BDBR) increase is only 0.43%. In addition, our fast algorithm outperforms the previous works in both coding speed and coding performance. Index Terms-Coding unit (CU), high-efficiency video coding (HEVC) encoder, motion vector, prediction unit (PU), rate-distortion cost.
I. INTRODUCTIONH IGH-EFFICIENCY video coding (HEVC), also known as H.265, is the newest video compression standard finalized in 2013, and a potential successor of H.264/AVC, which is currently widely used. When compared to H.264, HEVC offers around double compression ratio at the same level of video quality, or substantially improved video quality at the same bitrate, and HEVC supports resolutions up to 8192 × 4320, which are