<!-- Converted to DocBook/SGML by Kevin Conder -->
<refentry id="specdiff">
  <refmeta>
    <refentrytitle>specdiff</refentrytitle>
  </refmeta>
 
  <refnamediv>
    <refname>specdiff</refname>
    <refpurpose>
      Finds the positive difference values between consecutive spectral frames.
      <indexterm id="IndexSpecdiff"><primary>specdiff</primary></indexterm>
    </refpurpose>
  </refnamediv>
 
  <refsect1>
    <title>Description</title>
    <para>
      Finds the positive difference values between consecutive spectral frames.
    </para>
  </refsect1>
 
  <refsect1>
    <title>Syntax</title>
    <synopsis>wsig <command>specdiff</command> wsigin</synopsis>
  </refsect1>
 
  <refsect1>
    <title>Performance</title>
    <para>
      <emphasis>wsig</emphasis> -- the output spectrum.
    </para>

    <para>
      <emphasis>wsigin</emphasis> -- the input spectra.
    </para>

    <para>
      Finds the positive difference values between consecutive spectral frames. At each new frame of <emphasis>wsigin</emphasis>, each magnitude value is compared with its predecessor, and the positive changes written to the output spectrum. This unit is useful as an energy onset detector.
    </para>
  </refsect1>
 
  <refsect1>
    <title>Examples</title>
    <para>
      <informalexample>
        <programlisting>
  wsig2    <emphasis>specdiff</emphasis>         wsig1               ; sense onsets 
  wsig3    <emphasis>specfilt</emphasis>         wsig2, 2            ; absorb slowly 
           <emphasis>specdisp</emphasis>         wsig2, .1           ; &amp; display both spectra 
           <emphasis>specdisp</emphasis>         wsig3, .1
        </programlisting>
      </informalexample>
    </para>
  </refsect1>

  <refsect1>
    <title>See Also</title>
    <para>
      <link linkend="specaddm"><citetitle>specaddm</citetitle></link>,
      <link linkend="specfilt"><citetitle>specfilt</citetitle></link>,
      <link linkend="spechist"><citetitle>spechist</citetitle></link>,
      <link linkend="specscal"><citetitle>specscal</citetitle></link>
    </para>
  </refsect1>
</refentry>
