У вашего броузера проблема в совместимости с HTML5
Fastest way importing .MTS (AVCHD) files into your Apple Mac Computer especially if you own a Sony Mirrorless Camera. MP4 is easy to work with, but MTS (AVCHD) is better quality. Once you imported the files you could use iMovie, Final Cut Pro, Adobe Premiere, Adobe Media Encoder or other software to convert them to other formats of your choice.