LPCAna

Source: /usr/local/share/SuperCollider/Extensions/SC3plugins/JoshUGens/classes/AnaUtils.sc

Inherits from: Object

Description

Adapted and expanded from R. Moore's LPC analysis code from Computer Music.

Class Methods

*new (path)

Arguments:

path	The path for a mono sound file to analyze.

Inherited class methods

Instance Methods

-ana (nPoles: 35, frameSize: 400, hop: 0.5, channel: 0, minFreq: 70, maxFreq: 200, check: 0, conditionSignal: 0, completion)

Arguments:

nPoles	the number of poles for the all-pole filter (default: 35, must be less the 200)
frameSize	the number of samples to use for each from of analysis (default: 400)
hop	a percentage of the frameSize to skip for the next window (default: 0.5)
channel	the channel to analyze if the file at 'path' is multi-channel (default: 0)
minFreq	a minFreq to search for in pitch tracking (defautl: 70)
maxFreq	a maxFreq to search for in pitch tracking (default: 200)
check	Attempts to check poles for stability. WARNING: Somewhere in this code, I've made a terrible mistake. It actually CAUSES instabilities rather then getting rid of them... but I can't, for the life of me, see where the error is. Don't use it. Moore's basic algorithm is pretty good, and the filters seems fairly stable. If you have problems, try increasing the number of poles (default: 0).
conditionSignal	Default: 0, 1 works well, choose 2 if you want exploding filters that might (?) be interesting. 0: does nothing, 1: applies a simple low pass filter to each window before doing the analysis (which helps avoid instabilities) 2: apply a DRASTIC low pass filter to the signal that I saw in some of CSounds LPC code. This REALLY smoothes out the signal, and usually causes some pretty crazy instabilities because the output of the filter is SO resonant.
completion	A function to evaluate when the analysis is finished. Handy for bulk analyzing files, and auto saving them.

-lperr (numTurns: 1)

low pass the error signal numTurns times

Arguments:

numTurns

-lprms (numTurns: 1)

low pass the overall rms signal numTurns times

Arguments:

numTurns

-lppch (numTurns: 1)

Low pass the pchcps signal numTurns times

Arguments:

numTurns

-saveToLPCFile (path)

save file to an LPC file usable by LPCFile, LPCSynth and LPCVals.

Arguments:

path

-saveToFiles (path)

Save file to an LPC file usable by LPCFile, LPCSynth and LPCVals, as well as a floating point .aif data file for use in NRT.

Arguments:

path

-calcLaguerre (a, m, x, eps, p)

Arguments:

a
m
x
eps
p

-checkRoots (theseCoefs, check)

Arguments:

theseCoefs
check

-findRoots (a)

Arguments:

-getpch

-clock

-clock =

-data

-resrms

-resrms = value

-sr

-hop

-channel

-initLPCAna

-analyzeWindow (check, conditionSignal)

Arguments:

check
conditionSignal

-path

-frames

-nPoles

-initAna (argNPoles, argFrameSize, argHop, argChannel, argMinFreq, argMaxFreq)

Arguments:

argNPoles
argFrameSize
argHop
argChannel
argMinFreq
argMaxFreq

-pchcps

-pchcps = value

-coefs

-anaBuf

-frameSize

-hopSamps

-origrms

-origrms = value

-inc

-tmpBuf

-err

-err = value

-sf

-calcOrigRMS

Inherited instance methods

Examples

a = LPCAna.new(Platform.resourceDir +/+ "sounds/a11wlk01.wav");
a.ana(50, 400, 0.5, 0, 70, 300);

// low pass an aspect of the analysis
a.err.plot
a.lperr;
a.err.plot;

a.pchcps.plot;
a.lppch;
a.pchcps.plot;

helpfile source: /usr/local/share/SuperCollider/Extensions/SC3plugins/JoshUGens/HelpSource/Classes/LPCAna.schelp
link::Classes/LPCAna::
sc version: 3.8dev