'\" t
.\"     Title: cvanal
.\"    Author: 
.\" Generator: DocBook XSL Stylesheets v1.75.2 <http://docbook.sf.net/>
.\"      Date: 08/01/2011
.\"    Manual: The Canonical Csound Reference Manual
.\"    Source: 5.10
.\"  Language: English
.\"
.TH "CVANAL" "1" "08/01/2011" "5.10" "The Canonical Csound Reference"
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.SH "NAME"
cvanal \- Converts a soundfile into a single Fourier transform frame\&. .\" cvanal
.SH "DESCRIPTION"
.PP
Impulse Response Fourier Analysis for
convolve
operator
.SH "SYNTAX"
.sp
.if n \{\
.RS 4
.\}
.nf
\fBcsound \-U cvanal\fR [flags] infilename outfilename
.fi
.if n \{\
.RE
.\}
.sp
.if n \{\
.RS 4
.\}
.nf
\fBcvanal\fR [flags] infilename outfilename
.fi
.if n \{\
.RE
.\}
.SH "INITIALIZATION"
.PP

\fIcvanal\fR
\-\- converts a soundfile into a single Fourier transform frame\&. The output file can be used by the
\fIconvolve\fR
operator to perform Fast Convolution between an input signal and the original impulse response\&. Analysis is conditioned by the flags below\&. A space is optional between the flag and its argument\&.
.PP

\fI\-s rate\fR
\-\- sampling rate of the audio input file\&. This will over\-ride the srate of the soundfile header, which otherwise applies\&. If neither is present, the default is 10000\&.
.PP

\fI\-c channel\fR
\-\- channel number sought\&. If omitted, the default is to process all channels\&. If a value is given, only the selected channel will be processed\&.
.PP

\fI\-b begin\fR
\-\- beginning time (in seconds) of the audio segment to be analyzed\&. The default is 0\&.0
.PP

\fI\-d duration\fR
\-\- duration (in seconds) of the audio segment to be analyzed\&. The default of 0\&.0 means to the end of the file\&.
.SH "EXAMPLES"
.PP


.sp
.if n \{\
.RS 4
.\}
.nf
\fIcvanal\fR asound cvfile
.fi
.if n \{\
.RE
.\}
.sp

will analyze the soundfile "asound" to produce the file "cvfile" for the use with
convolve\&.
.PP
To use data that is not already contained in a soundfile, a soundfile converter that accepts text files may be used to create a standard audio file, e\&.g\&., the \&.DAT format for SOX\&. This is useful for implementing FIR filters\&.
.SS "Files"
.PP
The output file has a special
\fIconvolve\fR
header, containing details of the source audio file\&. The analysis data is stored as
\(lqfloat\(rq, in rectangular (real/imaginary) form\&.
.if n \{\
.sp
.\}
.RS 4
.it 1 an-trap
.nr an-no-space-flag 1
.nr an-break-flag 1
.br
.ps +1
\fBNote\fR
.ps -1
.br
.PP
The analysis file is
\fInot\fR
system independent! Ensure that the original impulse recording/data is retained\&. If/when required, the analysis file can be recreated\&.
.sp .5v
.RE
.SH "CREDITS"
.PP
Author: Greg Sullivan
.PP
Based on algorithm given in
\fIElements Of Computer Music\fR, by F\&. Richard Moore\&.
.SH "AUTHORS"
.PP
\fBBarry Vercoe\fR
.br
MIT Media Lab
          
.RS 4
Author.
.RE
.PP
\fBDan Ellis\fR
.br
MIT Media Lab, 
          Cambridge
          Massachussetts
        
.RS 4
Author.
.RE
.SH "COPYRIGHT"
.br