https://wccftech.com/av1-vdpau-hardware-acceleration-in-ffmpeg-now-supported-by-nvidias-ampere-gpus/

NVIDIA has added support to the open-source FFmpeg multimedia library to allow for the advantages of accelerated AV1 video encoding for compatible GPUs through the VDPAU API while utilizing the current-generational NVIDIA RTX 30 graphics cards that use the Ampere architecture.

The VDPAU API, also known as the Video Decode and Presentation API for UNIX, provides an interface to video decode acceleration and presentation hardware currently in contemporary graphics cards.