Translations:NVIDIA/nvidia-drivers/306/en
From Gentoo Wiki
Most NVIDIA GPUs are capable of donig hardware encoding/decoding, the support matrix can be found here. GeForce 8 series and later GPUs do come with VDPAU support which superseded legacy XvMCNVIDIA support. Some ebuilds, like media-video/ffmpeg and media-video/obs-studio, have USE flags vdpau and nvenc to enable support for NVIDIA hardware encoding/decoding.