Efficient HW Design of Adaptive Loop Filter for 4k ASIC VVC Encoder

Abstract

Versatile Video Coding (VVC) is the next-generation video coding standard released in July 2020. VVC introduces new coding tools enhancing the coding efficiency compared to its predecessor, High Efficiency Video Coding (HEVC). These new tools significantly impact the VVC software and hardware implementations with a complexity estimated to two times and eight times the HEVC decoder and encoder complexity, respectively. In particular, the Adaptive Loop Filter (ALF), adopted in VVC as an in-loop filter, increases both the run time complexity and memory usage. These concerns need to be carefully addressed regarding the design of a VVC hardware encoder. In this paper, we present an efficient hardware implementation of the ALF tool with its decision process in the context of a professional VVC encoder. The proposed solution can reach a real-time encoding of 4K resolution videos with 4:2:2 chroma sub-sampling at 60 frames per second targeting ASIC platforms with 28-nm technology.