Towards Fast and Efficient VVC Encoding

Versatile Video Coding (VVC) is a new international video coding standard to be finalized in July 2020. It is designed to provide around 50% bit-rate saving at the same subjective visual quality over its predecessor, High Efficiency Video Coding (H.265/HEVC). During the standard development, objective bit-rate savings of around 40% have been reported for the VVC reference software (VTM) compared to the HEVC reference software (HM). The unoptimized VTM encoder is around 9x, and the decoder around 2x, slower than HM. This paper discusses the VVC encoder complexity in terms of software runtime. The modular design of the standard allows a VVC encoder to trade off bit-rate savings and encoder runtime. Based on a detailed tradeoff analysis, results for different operating points are reported. Additionally, initial work on software and algorithm optimization is presented. With the optimized software algorithms, an operating point with an over 22x faster single-threaded encoder runtime than VTM can be achieved, i.e. around 2.5x faster than HM, while still providing more than 30% bit-rate savings over HM. Finally, our experiments demonstrate the flexibility of VVC and its potential for optimized software encoder implementations.