title: Can anyone recommend a decent DSP/speech library in C++?
body: <p>Google returns too much results, although <a href="http://spuc.sourceforge.net/" rel="nofollow noreferrer">SPUC</a> caught my attention.
  Is there a standard recommended library like OpenCV for vision?
  The necessary features would be:</p>
  
  <ul>
  <li>Free Open Source</li>
  <li>filter design (Butterworth, Chebyshev, etc)</li>
  <li>FFT</li>
  <li>if possible, some speech processing features, like MFCC computation, although that's secondary, as I could use SPTK (sp-tk.sourceforge.net) for that part.</li>
  </ul>