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
cvanal asound cvfile
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