Currently to get the stream from ffmpeg into nginx you have to do the following: ffmpeg -re -i input_file -c copy -f flv rtmp://nginx_server_url:1935/app

It would be nice to have the ability to set up an app block that looked kind of like this

application source1 { exec fffmpeg -f decklink -i 'DeckLink Quad (1)@8' -f flv rtmp://localhost/app/$name }

ffmpeg is still pushing the stream to nginx, but nginx is in charge of starting that process.