nginx.conf

rtmp {
    server {
        listen 1935;
        application encoder {
            live on;
            exec ffmpeg -i rtmp://localhost:1935/encoder/$name
              -c:v libx264 -b:v 750k -f flv -s 640x360 rtmp://localhost:1935/hls/$name_high
              -c:v libx264 -b:v 400k -f flv -s 426x240 rtmp://localhost:1935/hls/$name_mid
              -c:v libx264 -b:v 200k -f flv -s 426x240 rtmp://localhost:1935/hls/$name_low;
        }

        application hls {
            live on;
            hls on;

            hls_variant _high BANDWIDTH=878000,RESOLUTION=640x360;
            hls_variant _mid BANDWIDTH=528000,RESOLUTION=426x240;
            hls_variant _low BANDWIDTH=264000,RESOLUTION=426x240;
        }
    }
}