Homebrew formulas for building FFmpeg with --enable-decklink option.
brew install https://github.com/dche/ffmpeg-decklink/raw/master/Library/Formula/decklink.rb
brew install https://github.com/dche/ffmpeg-decklink/raw/master/Library/Formula/ffmpeg.rb --with-decklink