LPANAL(1) The Canonical Csound Reference LPANAL(1)NAME
lpanal - Performs both linear predictive and pitch-tracking analysis on a soundfile. .
DESCRIPTION
Linear predictive analysis for the Csound Linear Predictive Coding (LPC) Resynthesis opcodes.
SYNTAX
csound -U lpanal [flags] infilename outfilename
lpanal [flags] infilename outfilename
INITIALIZATION
lpanal performs both lpc and pitch-tracking analysis on a soundfile to produce a time-ordered sequence of frames of control information
suitable for Csound resynthesis. Analysis is conditioned by the control flags below. A space is optional between the flag and its value.
-a -- [alternate storage] asks lpanal to write a file with filter poles values rather than the usual filter coefficient files. When lpread
/ lpreson are used with pole files, automatic stabilization is performed and the filter should not get wild. (This is the default in the
Windows GUI) - Changed by Marc Resibois.
-s srate -- 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. The default is 1.
-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.
-p npoles -- number of poles for analysis. The default is 34, the maximum 50.
-h hopsize -- hop size (in samples) between frames of analysis. This determines the number of frames per second (srate / hopsize) in the
output control file. The analysis framesize is hopsize * 2 samples. The default is 200, the maximum 500.
-C string -- text for the comments field of the lpfile header. The default is the null string.
-P mincps -- lowest frequency (in Hz) of pitch tracking. -P0 means no pitch tracking.
-Q maxcps -- highest frequency (in Hz) of pitch tracking. The narrower the pitch range, the more accurate the pitch estimate. The defaults
are -P70, -Q200.
-v verbosity -- level of terminal information during analysis.
o 0 = none
o 1 = verbose
o 2 = debug
The default is 0.
EXAMPLES
lpanal -a -p26 -d2.5 -P100 -Q400 audiofile.test lpfil22
will analyze the first 2.5 seconds of file "audiofile.test", producing srate/200 frames per second, each containing 26-pole filter
coefficients and a pitch estimate between 100 and 400 Hertz. Stabilized (-a) output will be placed in "lpfil22" in the current directory.
File Format
Output is a file comprised of an identifiable header plus a set of frames of floating point analysis data. Each frame contains four values
of pitch and gain information, followed by npoles filter coefficients. The file is readable by Csound's lpread.
lpanal is an extensive modification of Paul Lanksy's lpc analysis programs.
AUTHORS
Barry Vercoe
MIT Media Lab
Author.
Dan Ellis
MIT Media Lab,
Cambridge
Massachussetts
Author.
COPYRIGHT 5.07 06/23/2009 LPANAL(1)
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HETRO(1) The Canonical Csound Reference HETRO(1)NAME
hetro - Decomposes an input soundfile into component sinusoids. .
DESCRIPTION
Hetrodyne filter analysis for the Csound adsyn generator.
SYNTAX
csound -U hetro [flags] infilename outfilename
hetro [flags] infilename outfilename
INITIALIZATION
hetro takes an input soundfile, decomposes it into component sinusoids, and outputs a description of the components in the form of
breakpoint amplitude and frequency tracks. Analysis is conditioned by the control flags below. A space is optional between flag and value.
-s srate -- 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. Note that for adsyn synthesis the srate of the source file and the generating orchestra need not
be the same.
-c channel -- channel number sought. The default is 1.
-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. Maximum length
is 32.766 seconds.
-f begfreq -- estimated starting frequency of the fundamental, necessary to initialize the filter analysis. The default is 100 (cps).
-h partials -- number of harmonic partials sought in the audio file. Default is 10, maximum is a function of memory available.
-M maxamp -- maximum amplitude summed across all concurrent tracks. The default is 32767.
-m minamp -- amplitude threshold below which a single pair of amplitude/frequency tracks is considered dormant and will not contribute to
output summation. Typical values: 128 (48 db down from full scale), 64 (54 db down), 32 (60 db down), 0 (no thresholding). The default
threshold is 64 (54 db down).
-n brkpts -- initial number of analysis breakpoints in each amplitude and frequency track, prior to thresholding (-m) and linear breakpoint
consolidation. The initial points are spread evenly over the duration. The default is 256.
-l cutfreq -- substitute a 3rd order Butterworth low-pass filter with cutoff frequency cutfreq (in Hz), in place of the default averaging
comb filter. The default is 0 (don't use).
PERFORMANCE
As of Csound 4.08, hetro can write SDIF ouput files if the output file name ends with ".sdif" or ".SDIF". See the sdif2ad utility for more
information about the Csound's SDIF support.
EXAMPLES
hetro -s44100 -b.5 -d2.5 -h16 -M24000 audiofile.test adsynfile7
This will analyze 2.5 seconds of channel 1 of a file "audiofile.test", recorded at 44.1 kHz, beginning .5 seconds from the start, and place
the result in a file "adsynfile7". We request just the first 16 harmonics of the sound, with 256 initial breakpoint values per amplitude or
frequency track, and a peak summation amplitude of 24000. The fundamental is estimated to begin at 100 Hz. Amplitude thresholding is at 54
db down.
The Butterworth LPF is not enabled.
File Format
The output file contains time-sequenced amplitude and frequency values for each partial of an additive complex audio source. The
information is in the form of breakpoints (time, value, time, value, ....) using 16-bit integers in the range 0 - 32767. Time is given in
milliseconds, and frequency in Hertz (cps). The breakpoint data is exclusively non-negative, and the values -1 and -2 uniquely signify the
start of new amplitude and frequency tracks. A track is terminated by the value 32767. Before being written out, each track is data-reduced
by amplitude thresholding and linear breakpoint consolidation.
A component partial is defined by two breakpoint sets: an amplitude set, and a frequency set. Within a composite file these sets may appear
in any order (amplitude, frequency, amplitude ....; or amplitude, amplitude..., then frequency, frequency,...). During adsyn resynthesis
the sets are automatically paired (amplitude, frequency) from the order in which they were found. There should be an equal number of each.
A legal adsyn control file could have following format:
CREDITS
Author: Tom Sullivan
1992
Author: John ffitch
1994
Author: Richard Dobson
2000
October 2002. Thanks to Rasmus Ekman, added a note about the SDIF format.
AUTHORS
Barry Vercoe
MIT Media Lab
Author.
Dan Ellis
MIT Media Lab,
Cambridge
Massachussetts
Author.
COPYRIGHT 5.07 06/23/2009 HETRO(1)