Get disk space back from your Jellyfin, Plex or Emby library by re-encoding H.264 to HEVC. It predicts the saving before it encodes, and verifies each result before an original is ever replaced.

Install GitHub Latest release
Predicts firstThree 20 s samples in RAM. Files that won't shrink are skipped in seconds.
Verifies before replacingDuration, every stream, and a full decode pass, or the original stays.
Same name, same metadataWatched state and Sonarr/Radarr keep working.
Gentle on disksRead-capped encodes with pauses between files.

Install

Debian, Ubuntu and Proxmox (amd64, arm64, armhf). Every option below gives you updates through apt upgrade.

From the .deb recommended

Download it from the latest release. Installing it also adds this repository, so later versions arrive automatically.

sudo apt install ./nvenc-shrink_*_all.deb

With extrepo coming soon

Debian's tool for trusted third-party repositories. These commands will work once nvenc-shrink is listed there.

sudo apt install extrepo
sudo extrepo enable nvenc-shrink
sudo apt update && sudo apt install nvenc-shrink

Add the repository by hand

Save the signing key to /usr/share/keyrings/nvenc-shrink-archive-keyring.gpg, then create /etc/apt/sources.list.d/nvenc-shrink.sources:

Types: deb
URIs: https://jxadhd.github.io/nvenc-shrink/apt
Suites: stable
Components: main
Signed-By: /usr/share/keyrings/nvenc-shrink-archive-keyring.gpg
Key fingerprint 
DCD4 51D8 AC46 4AA0 C41E  0265 D883 4581 2C96 1A2F

Then

sudoedit /etc/nvenc-shrink.conf                  # list your library folders
nvenc-shrink                                     # dry run: what would change
nvenc-shrink --estimate --limit 10               # choose a quality setting
nvenc-shrink --apply --limit 5                   # convert a few, then watch them
sudo systemctl enable --now nvenc-shrink.timer   # nightly from then on

Full documentation is in the README and in man nvenc-shrink.