GUI frontend for ffmpeg. This runs on sandbox. You can use safely and must compare online converter. This software convert video file to mp4 or WebM or mp3. It is possible to convert to a lossless occasionally. If you only change container, you may use cut video. It is lossless. This is PNaCL version. PNaCL is portable version of native client developed by Google. Native Client is program code that run on virtual PC created by browser. Important thing, this virtual PC is sandbox. And therefore, we can run program code which is downloaded in internet, safely.