If you have a bunch of audio files that you want to convert to MP3, you can make use of the popular SoundConverter to convert audio files in Ubuntu.
While VLC is the most popular video player around, it is able to double as an audio converter as well. Here is how you can convert audio files in VLC.
If you’re looking for a built-in tool to convert files in Google Drive, then try DriveConverter, a web app and Chrome extension specially built for Google Drive. It offers more flexible conversion features for documents, images and music files.