FFMultiConverter for Linux Mint 17 and Ubuntu 14.04 based distros.

sudo add-apt-repository ppa:mc3man/trusty-media
sudo add-apt-repository ppa:ffmulticonverter/stable
sudo apt-get update
sudo apt-get install ffmulticonverter ffmpeg

ffmulticonverter
Comment:
After installing ffmpeg is good not to use mc3man PPA if not wanting to upgrade other packages like VLC, Audacious, etc.