[Nginx] nginx에서 rtmp를 트랜스코딩 하는 방법 480p, 720p, 1080p

rtmp {
    server {
        listen 1935;
        chunk_size 4096;

        application transcode {
            live on;

            exec_static ffmpeg -i rtmp://localhost:1935/$app/$name
                -c:v libx264 -b:v 500k -s:v 640x480 -c:a aac -b:a 128k
                -f flv rtmp://localhost:1935/transcoded/480p/${name};

            exec_static ffmpeg -i rtmp://localhost:1935/$app/$name
                -c:v libx264 -b:v 1000k -s:v 1280x720 -c:a aac -b:a 128k
                -f flv rtmp://localhost:1935/transcoded/720p/${name};

            exec_static ffmpeg -i rtmp://localhost:1935/$app/$name
                -c:v libx264 -b:v 1500k -s:v 1920x1080 -c:a aac -b:a 128k
                -f flv rtmp://localhost:1935/transcoded/1080p/${name};
        }
    }
}