uvg266: Open-Source VVC Intra Encoder

Versatile Video Coding (VVC/H.266) standard is the emerging successor to the widespread High Efficiency Video Coding (HEVC/H.265). This work introduces the latest version of our academic open-source VVC intra encoder called uvg266. It has been developed from our well-known Kvazaar HEVC encoder by introducing new VVC coding tools into carefully optimized and parallelized coding flow of Kvazaar. This paper outlines the design methodology and implementation aspects of all intra (AI) configuration of uvg266. The experimental results show that single-threaded uvg266 is more than twice as fast as the state-of-the-art VVenC encoder in all our test cases. In speed-optimized coding, the coding overhead of uvg266 is 21.7% but the gap narrows down to 2.6% in the rate distortion optimized coding case. uvg266 has almost linear speedup with core count up to 32 threads. The better scalability of uvg266 quadruples the speed over VVenC. Furthermore, single-threaded uvg266 is up to 380× as fast as VVC reference software VTM and the gap raises to over 11,000× with 32 threads. To the best of our knowledge, uvg266 is currently the fastest available open-source VVC intra software encoder.