To build and use libavif (with avifenc/avifdec) in an Ubuntu Docker container with all dependencies, change into this directory and run:
docker-compose run libavif
This should install all necessary dependencies, including manually building and installing all supported codecs as shared libraries, and finally building and installing
avifdec. It will then drop you a shell running in the container.
If you just want to force a (re)build and skip the interactive shell, run:
docker-compose up --build --force-recreate libavif
Note: This build process will take a while (15-30m or more depending on your machine).