As of upload date HandBrake does not have NVENC AV1 encoding yet but after a little searching I found that using their nightly build it has support for AV1 NVENC using RTX 40 series cards. We will have to wait for the official release for more functionality but at least we can transcode AV1 now. I was excited to see and test this feature as I got a 4060 Ti 8GB just for transcoding my media vault. I have to do more testing to see what the more optimal settings are to reduce file size without losing to much quality are but it looks promising if you are like my and are tired of constantly buying more storage devices.
HandBrake Snapshots
https://github.com/HandBrake/HandBrak...