Audacity is an easy-to-use audio editor and recorder. You can use it to:
Record live audio.
Convert tapes and records into digital recordings or CDs.
Edit Ogg Vorbis, MP3, and WAV sound files.
Cut, copy, splice, and mix sounds together.
Change the speed or pitch of a recording.
And more! See the complete list of features.
Source code:https://github.com/Audacity/