https://blog.faceutil.com/2017/03/22/%eb%8f%99%ec%98%81%ec%83%81-%ed%8c%8c%ec%9d%bc-mts-%ed%99%95%ec%9e%a5%ec%9e%90%eb%a5%bc-avi-mp4%eb%a1%9c-%eb%b3%80%ed%99%98%ed%95%98%ea%b8%b0-%eb%a3%a8%eb%af%b9%ec%8a%a4-dmc-gf2-%e3%81%97/