Nixos-Decklink-Ffmpeg

Minimal example of ffmpeg + decklink usage on NixOS

Setup

• Setup fresh NixOS on your machine

• Create new folder ./machines/<selected-host-name>

• Copy hardware-configuration.nix from /etc/nixos/ to ./machines/<selected-host-name>

• Change parts to match ./machines/decklink-machine/hardware-configuration.nix

• Copy ./machines/decklink-machine/configuration.nix to ./machines/<selected-host-name>/configuration.nix

• Change hostname to match new machine in ./machines/<selected-host-name>/configuration.nix

• Copy these files to /etc/nixos and run sudo nixos-rebuild switch

Useful ffmpeg commands

• List decklink devices ffmpeg -sources decklink
• List device available formats ffmpeg -f decklink -list_formats 1 -i "<name of device>"
• Record sample from card

ffmpeg -f decklink -i "DeckLink Mini Recorder 4K" -format_code "Hp59" -video_size 1920x1080 -rtbufsize 2100M -c:v libx264 -preset:v ultrafast -pix_fmt yuv422p -an -crf 18 output.mp4