title: MATLAB - Pitch Shifting an Audio Signal
body: <p>My group is developing a simple MATLAB Graphical User Interface (GUI) that is supposed to record audio from a microphone - plugged in or built in to the computer - and play back the signal.  So far we have that completed. Our GUI also can load a sample (a .wav file, etc..) and play it back using the same "Play" pushbutton on the GUI.  We have a Play, Record, Load, and Save push button. Now for the pitch-shifting of loaded or recorded samples... We know we need a peak-picking algorithm to find the fundamental frequencies of the signals.  We were then thinking that we could multiply each of those values by a constant to shift the pitch of all those frequencies.  What we aim to do it use this algorithm and assign the separate shifts to different Pushbuttons or radiobuttons, in which we can load our sample, press the button and manipulate the pitch by doing so, then play it back.  Will using a peak-picking algorithm sufficiently shift the pitch of our signals, or will the signal be screwed up during playback?</p>
  
  <p>(THIS IS NOT REAL-TIME PROCESSING)</p>