ABSTRACT
There was a time when the only way to change the tempo of an audio recording was to alter the playback speed, or if you were an audio ninja, you could conform a performance with hours of editing magic. Altering the sample rate unfortunately changes the pitch of the audio and can degrade the quality of the playback. As an alternative to this, software companies have developed and implemented time-stretching/pitch-shifting algorithms into their software. This allows you to lengthen or shorten an audio file to fit the tempo of a song by altering the sample rate and pitch shifting it back to the correct pitch.
