https://blog.faceutil.com/2017/04/15/mpeg-4-%ec%bd%94%eb%8d%b1-%eb%8b%a4%ec%9a%b4%eb%a1%9c%eb%93%9c-mpeg-4-video-%eb%8f%99%ec%98%81%ec%83%81-%ec%a7%80%ec%9b%90-%e3%88%8b/