FFmpeg with decklink support based on a Dockerfile from ffmpeg/docker-images/5.1/ubuntu2004/ It's just a Dockerfile to build your own FFmpeg with decklink support. You have to download a BMD driver and SDK then unpack it directly to the Dockerfile directory. The folders names should be Blackmagic_Desktop_Video_Linux_12.4 and Blackmagic_DeckLink_SDK_12.4 as is set in the Dockerfile. I have to turn off the libvmaf to compilation success.
The BMD driver 12.4 have to be installed at the host. Copy the Dockerfile and unpack it to the same directory as the downloaded Blackmagic_Desktop_Video_Linux_12.4 and Blackmagic_DeckLink_SDK_12.4 then type e.g
docker build -t ffmpeg-decklink:5.1-ubuntu2004 .
To run the container and go inside you can type e.g:
docker run -it --entrypoint='bash' --device=/dev/blackmagic ffmpeg-decklink:5.1-ubuntu2004