Convert video files to mp3

I need someone to create a service on the amazon web services that checks a database to see what videos need to be converted. Those that have not been converted yet will be converted to mp3 files. Most of the videos right now will just come from YouTube or Vimeo. Once the video is converted it will be stored on Amazon web services as well. Your script will then update the database with the url to where the video is stored on Amazon. Need to convert as many videos to mp3 as possible in parallel as there might be high loads at times. Thanks!