Install FFMPEG on OS X with HomeBrew to convert Mp4 to WebM

ffmpeg-install.sh

# Installation
brew install ffmpeg --with-vpx --with-vorbis --with-libvorbis --with-vpx --with-vorbis --with-theora --with-libogg --with-libvorbis --with-gpl --with-version3 --with-nonfree --with-postproc --with-libaacplus --with-libass --with-libcelt --with-libfaac --with-libfdk-aac --with-libfreetype --with-libmp3lame --with-libopencore-amrnb --with-libopencore-amrwb --with-libopenjpeg --with-openssl --with-libopus --with-libschroedinger --with-libspeex --with-libtheora --with-libvo-aacenc --with-libvorbis --with-libvpx --with-libx264 --with-libxvid

# Easy Peasy
ffmpeg -i video.mp4 video.webm

# Encode to aac with mp4 container
ffmpeg -i taha.mp3 -c:a libfdk_aac -b:a 128k taha.m4a

# Encode to vorbis
ffmpeg -i taha.mp3 -c:a libvorbis -q:a 4 taha.ogg