<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8" />
<title>pvsbufread</title>
<link rel="stylesheet" type="text/css" href="csound.css" />
<meta name="generator" content="DocBook XSL Stylesheets V1.76.1" />
<link rel="home" href="index.html" title="The Canonical Csound Reference Manual" />
<link rel="up" href="OpcodesTop.html" title="Orchestra Opcodes and Operators" />
<link rel="prev" href="pvsbuffer.html" title="pvsbuffer" />
<link rel="next" href="pvsbufread2.html" title="pvsbufread2" />
</head>
<body>
<div class="navheader">
<table width="100%" summary="Navigation header">
<tr>
<th colspan="3" align="center">pvsbufread</th>
</tr>
<tr>
<td width="20%" align="left"><a accesskey="p" href="pvsbuffer.html">Prev</a> </td>
<th width="60%" align="center">Orchestra Opcodes and Operators</th>
<td width="20%" align="right"> <a accesskey="n" href="pvsbufread2.html">Next</a></td>
</tr>
</table>
<hr />
</div>
<div class="refentry" title="pvsbufread">
<a id="pvsbufread"></a>
<div class="titlepage"></div>
<a id="Indexpvsbufread" class="indexterm"></a>
<div class="refnamediv">
<h2>
<span class="refentrytitle">pvsbufread</span>
</h2>
<p>pvsbufread —
This opcode reads a circular buffer of f-signals (streaming PV signals).
</p>
</div>
<div class="refsect1" title="Description">
<a id="idp38333736"></a>
<h2>Description</h2>
<p>
This opcode reads from a circular buffer of length ilen (secs),
taking a handle for the buffer and a time pointer, which holds the
current read position (also in seconds). It is used in conjunction with a
<span class="emphasis"><em>pvsbuffer</em></span> opocde.
Reading is circular, wrapping around at the end of the buffer.
</p>
</div>
<div class="refsect1" title="Syntax">
<a id="idp38373128"></a>
<h2>Syntax</h2>
<pre class="synopsis">fsig <span class="command"><strong>pvsbufread</strong></span> ktime, khandle[, ilo, ihi, iclear] </pre>
</div>
<div class="refsect1" title="Initialisation">
<a id="idp38374232"></a>
<h2>Initialisation</h2>
<p>
<span class="emphasis"><em>ilo, ihi</em></span> -- set the lowest and highest freqs to be read from the buffer (defaults to 0, Nyquist).
</p>
<p>
<span class="emphasis"><em>iclear</em></span> -- set to 1 to clear output fsig before every write (default 1), 0 tells the opcode not to clear
the output fsig. This is relevant when writing to subsets of an fsig frame using <span class="emphasis"><em>ilo</em></span>, <span class="emphasis"><em>ihi</em></span>.
</p>
</div>
<div class="refsect1" title="Performance">
<a id="idp38376136"></a>
<h2>Performance</h2>
<p>
<span class="emphasis"><em>fsig</em></span> -- output pv stream
</p>
<p>
<span class="emphasis"><em>ktime</em></span> -- time position of reading pointer (in secs).
</p>
<p>
<span class="emphasis"><em>khandle</em></span> -- handle identifying the buffer to be read. When using k-rate
handles, it is important to initialise the k-rate variable to a given existing handle. When changing
buffers, fsig buffers need to be compatible (same fsig format).
</p>
<p>
With this opcode and <a class="link" href="pvsbuffer.html" title="pvsbuffer"><em class="citetitle">pvsbuffer</em></a>, it is possible to, among other things:
</p>
<div class="itemizedlist">
<ul class="itemizedlist" type="disc">
<li class="listitem">time-stretch/compress a fsig stream, by reading it at
different rates</li>
<li class="listitem">delay a fsig or portions of it.</li>
<li class="listitem">'brassage' two or more fsigs by switching buffers, since
the reading handles are k-rate. Note that, when using k-rate
handles, it is important to initialise the k-rate variable to a
given handle (so that the fsig initialisation can take place)
and it is only possible to switch handles between compatible
fsig buffers (with the same fftsize and overlap).</li>
</ul>
</div>
<p>
</p>
<div class="note" title="Note" style="margin-left: 0.5in; margin-right: 0.5in;">
<table border="0" summary="Note">
<tr>
<td rowspan="2" align="center" valign="top" width="25">
<img alt="[Note]" src="images/note.png" />
</td>
<th align="left">Note</th>
</tr>
<tr>
<td align="left" valign="top">
<p>It is important that the handle value passed to <span class="emphasis"><em>pvsbufread</em></span> is valid and was created by <a class="link" href="pvsbuffer.html" title="pvsbuffer"><em class="citetitle">pvsbuffer</em></a>. Csound will crash with invalid handles.
</p>
</td>
</tr>
</table>
</div>
</div>
<div class="refsect1" title="Examples">
<a id="idp38381536"></a>
<h2>Examples</h2>
<p>
Here is an example of the pvsbufread opcode. It does 'brassage' by switching between two buffers.
</p>
<div class="example">
<a id="idp38382120"></a>
<p class="title">
<strong>Example 642. Example of the pvsbufread opcode</strong>
</p>
<div class="example-contents">
<p>See the sections <a class="link" href="UsingRealTime.html" title="Real-Time Audio"><em class="citetitle">Real-time Audio</em></a> and <a class="link" href="CommandFlags.html" title="Csound command line"><em class="citetitle">Command Line Flags</em></a> for more information on using command line flags.</p>
<pre class="programlisting">
fsig1 <span class="opc">pvsanal</span> asig1, 1024, 256, 1024, 1
fsig2 <span class="opc">pvsanal</span> asig2, 1024, 256, 1024, 1
ibuf1, kt1 <span class="opc">pvsbuffer</span> fsig1, 10 <span class="comment">; 10-sec buf with fsig1</span>
ibuf2, kt2 <span class="opc">pvsbuffer</span> fsig2, 7 <span class="comment">; 7-sec buf with fsig2</span>
khan <span class="opc">init</span> ibuf1 <span class="comment">; initialise handle to buf1</span>
<span class="opc">if</span> ktrig <span class="op">></span> 0 <span class="opc">then</span> <span class="comment">; switch buffers according to trigger</span>
khan <span class="op">=</span> ibuf2
<span class="opc">else</span>
khan <span class="op">=</span> ibuf1
<span class="opc">endif</span>
fsb <span class="opc">pvsbufread</span> kt1, khan <span class="comment">; read buffer</span></pre>
</div>
</div>
<p><br class="example-break" />
</p>
<p>
Here is an example of the pvsbufread opcode. It uses the file <a class="ulink" href="examples/pvsbufread.csd" target="_top"><em class="citetitle">pvsbufread.csd</em></a>.
</p>
<div class="example">
<a id="idp38391256"></a>
<p class="title">
<strong>Example 643. Example of the pvsbufread opcode.</strong>
</p>
<div class="example-contents">
<p>See the sections <a class="link" href="UsingRealTime.html" title="Real-Time Audio"><em class="citetitle">Real-time Audio</em></a> and <a class="link" href="CommandFlags.html" title="Csound command line"><em class="citetitle">Command Line Flags</em></a> for more information on using command line flags.</p>
<pre class="programlisting">
<span class="csdtag"><CsoundSynthesizer></span>
<span class="csdtag"><CsOptions></span>
<span class="comment">; Select audio/midi flags here according to platform</span>
<span class="comment">; Audio out Audio in</span>
-odac <span class="comment">;;;RT audio I/O</span>
<span class="comment">; For Non-realtime ouput leave only the line below:</span>
<span class="comment">; -o pvsbufread.wav -W ;;; for file output any platform</span>
<span class="csdtag"></CsOptions></span>
<span class="csdtag"><CsInstruments></span>
<span class="ohdr">sr</span> <span class="op">=</span> 44100
<span class="ohdr">ksmps</span> <span class="op">=</span> 16
<span class="ohdr">nchnls</span> <span class="op">=</span> 1
<span class="ohdr">0dbfs</span> <span class="op">=</span> 1
<span class="comment">;; example written by joachim heintz 2009</span>
<span class="oblock">opcode</span> FileToPvsBuf, iik, Siiii
<span class="comment">;;writes an audio file at the first k-cycle to a fft-buffer (via pvsbuffer)</span>
Sfile, ifftsize, ioverlap, iwinsize, iwinshape <span class="opc">xin</span>
ktimek <span class="opc">timeinstk</span>
<span class="octrl">if</span> ktimek <span class="op">==</span> 1 then
ilen <span class="opc">filelen</span> Sfile
kcycles <span class="op">=</span> ilen <span class="op">*</span> <span class="ohdr">kr</span><span class="comment">; number of k-cycles to write the fft-buffer</span>
kcount <span class="opc">init</span> 0
<span class="olabel">loop</span><span class="op">:</span>
ain <span class="opc">soundin</span> Sfile
fftin <span class="opc">pvsanal</span> ain, ifftsize, ioverlap, iwinsize, iwinshape
ibuf, ktim <span class="opc">pvsbuffer</span> fftin, ilen <span class="op">+</span> (ifftsize <span class="op">/</span> sr)
<span class="octrl">loop_lt</span> kcount, 1, kcycles, <span class="olabel">loop</span>
<span class="opc">xout</span> ibuf, ilen, ktim
<span class="octrl">endif</span>
<span class="oblock">endop</span>
<span class="oblock">instr</span> 1
ifftsize <span class="op">=</span> 1024
ioverlap <span class="op">=</span> ifftsize <span class="op">/</span> 4
iwinsize <span class="op">=</span> ifftsize
iwinshape <span class="op">=</span> 1<span class="comment">; von-Hann window</span>
ibuffer, ilen, k0 FileToPvsBuf "fox.wav", ifftsize, ioverlap, iwinsize, iwinshape
ktmpnt <span class="opc">linseg</span> ilen, p3, 0<span class="comment">; reads the buffer backwards in p3 seconds</span>
fread <span class="opc">pvsbufread</span> ktmpnt, ibuffer
aout <span class="opc">pvsynth</span> fread
<span class="opc">out</span> aout
<span class="oblock">endin</span>
<span class="csdtag"></CsInstruments></span>
<span class="csdtag"><CsScore></span>
<span class="stamnt">i</span> 1 0 5
<span class="stamnt">e</span>
<span class="csdtag"></CsScore></span>
<span class="csdtag"></CsoundSynthesizer></span>
</pre>
</div>
</div>
<p><br class="example-break" />
</p>
</div>
<div class="refsect1" title="See Also">
<a id="idp38393536"></a>
<h2>See Also</h2>
<p>
<a class="link" href="pvsanal.html" title="pvsanal"><em class="citetitle">pvsanal</em></a>,
<a class="link" href="pvsynth.html" title="pvsynth"><em class="citetitle">pvsynth</em></a>,
<a class="link" href="pvsbuffer.html" title="pvsbuffer"><em class="citetitle">pvsbuffer</em></a>,
<a class="link" href="pvsadsyn.html" title="pvsadsyn"><em class="citetitle">pvsadsyn</em></a>
</p>
</div>
<div class="refsect1" title="Credits">
<a id="idp38395992"></a>
<h2>Credits</h2>
<p>
</p>
<table border="0" summary="Simple list" class="simplelist">
<tr>
<td>Author: Victor Lazzarini</td>
</tr>
<tr>
<td>July 2007</td>
</tr>
</table>
<p>
</p>
</div>
</div>
<div class="navfooter">
<hr />
<table width="100%" summary="Navigation footer">
<tr>
<td width="40%" align="left"><a accesskey="p" href="pvsbuffer.html">Prev</a> </td>
<td width="20%" align="center">
<a accesskey="u" href="OpcodesTop.html">Up</a>
</td>
<td width="40%" align="right"> <a accesskey="n" href="pvsbufread2.html">Next</a></td>
</tr>
<tr>
<td width="40%" align="left" valign="top">pvsbuffer </td>
<td width="20%" align="center">
<a accesskey="h" href="index.html">Home</a>
</td>
<td width="40%" align="right" valign="top"> pvsbufread2</td>
</tr>
</table>
</div>
</body>
</html>
distrib
>
Mageia
>
5
>
x86_64
>
media
>
core-release
>
by-pkgid
>
b707d9a4ee443103660a75ccb6e51334
>
files
>
2421
