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<refentry id="pvstanal">
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<indexterm id="IndexPvstanal"><primary>pvstanal</primary></indexterm>
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<refentryinfo><title>Spectral processing: pvstanal</title></refentryinfo>
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<refentrytitle>pvstanal</refentrytitle>
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<refname>pvstanal</refname>
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Phase vocoder analysis processing with onset detection/processing.
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<title>Description</title>
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<emphasis>pvstanal</emphasis> implements phase vocoder analysis by reading function tables
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containing sampled-sound sources, with <link linkend="GEN01"><citetitle>GEN01</citetitle></link>, and
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<emphasis>pvstanal</emphasis> will accept deferred allocation tables.
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This opcode allows for time and frequency-independent scaling. Time is advanced internally, but controlled by a tempo scaling parameter; when an onset is detected, timescaling is momentarily stopped to avoid smearing of attacks. The quality of the effect is generally improved with phase locking switched on.
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<emphasis>pvstanal</emphasis> will also scale pitch, independently of frequency, using a transposition factor (k-rate).
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<synopsis>asig <command>pvstanal</command> ktimescal,kamp,kpitch,ktab,[kdetect, kwrap, ioffset,ifftsize, ihop, ithresh]
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<title>Initialization</title>
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<emphasis>ifftsize</emphasis> -- FFT size (power-of-two), defaults to 2048.
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<emphasis>ihop</emphasis> -- hopsize, defaults to 512
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<emphasis>ioffset</emphasis> -- startup read offset into table, in secs.
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<emphasis>idbthresh</emphasis> -- threshold based on dB power spectrum ratio between two successive windows. A detected ratio above it will cancel timescaling momentarily, to avoid smearing (defaults to 1)
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<title>Performance</title>
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<emphasis>ktimescal</emphasis> -- timescaling ratio, < 1 stretch, > 1 contract.
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<emphasis>kamp</emphasis> -- amplitude scaling
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<emphasis>kpitch</emphasis> -- grain pitch scaling (1=normal pitch, < 1 lower, > 1 higher; negative, backwards)
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<emphasis>kdetect</emphasis> -- 0 or 1, to switch onset detection/processing
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<emphasis>ktab</emphasis> -- source signal function table. Deferred-allocation tables (see
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<link linkend="GEN01"><citetitle>GEN01</citetitle></link>) are accepted, but the opcode
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expects a mono source. Tables can be switched at k-rate.
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<emphasis>kwrap</emphasis> -- 0 or 1, to switch on/off table wrap-around read (default to 1)
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<title>Examples</title>
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<title>Example</title>
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ktime linseg 0.3, p3/2, 0.8, p3/2, 0.3
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fs1 pvstanal ktime,iamp,ipitch,itab
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<title>Credits</title>
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<member>Author: &namevictor;</member>
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<member>February 2010</member>
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<para>New plugin in version 5.13</para>
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<para>February 2005.</para>