NAME¶
cvanal - Converts a soundfile into a single Fourier transform frame. .
DESCRIPTION¶
Impulse Response Fourier Analysis for convolve operator
SYNTAX¶
csound -U cvanal [flags] infilename outfilename
cvanal [flags] infilename outfilename
INITIALIZATION¶
cvanal -- converts a soundfile into a single Fourier transform frame. The
output file can be used by the
convolve 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.
-s rate -- 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.
-c channel -- channel number sought. If omitted, the default is to
process all channels. If a value is given, only the selected channel will be
processed.
-b begin -- beginning time (in seconds) of the audio segment to be
analyzed. The default is 0.0
-d duration -- duration (in seconds) of the audio segment to be analyzed.
The default of 0.0 means to the end of the file.
EXAMPLES¶
will analyze the soundfile "asound" to produce the file
"cvfile" for the use with convolve.
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.
Files¶
The output file has a special
convolve header, containing details of the
source audio file. The analysis data is stored as “float”, in
rectangular (real/imaginary) form.
Note
The analysis file is
not system independent! Ensure that the original
impulse recording/data is retained. If/when required, the analysis file can be
recreated.
CREDITS¶
Author: Greg Sullivan
Based on algorithm given in
Elements Of Computer Music, by F. Richard
Moore.
AUTHORS¶
Barry Vercoe
MIT Media Lab
Author.
Dan Ellis
MIT Media Lab,
Cambridge
Massachussetts
Author.
COPYRIGHT¶