R: lpsSpectrum

lpsSpectrum {wrassp} | R Documentation

## lpsSpectrum

### Description

Calculate Linear Prediction smoothed spectrum using libassp

### Usage

    lpsSpectrum(listOfFiles = NULL, optLogFilePath = NULL, beginTime = 0,
      centerTime = FALSE, endTime = 0, resolution = 40, fftLength = 0,
      windowSize = 20, windowShift = 5, window = "BLACKMAN", order = 0,
      preemphasis = -0.95, deemphasize = TRUE, toFile = TRUE,
      explicitExt = NULL, outputDirectory = NULL,
      forceToLog = useWrasspLogger, verbose = TRUE)

### Arguments

`listOfFiles` | vector of file paths to be processed by function
`optLogFilePath` | path to option log file
`beginTime` | = <time>: set begin of analysis interval to <time> seconds (default: begin of data)
`centerTime` | = <time>: set single-frame analysis with the analysis window centred at <time> seconds; overrules beginTime, endTime and windowShift options
`endTime` | = <time>: set end of analysis interval to <time> seconds (default: end of data)
`resolution` | = <freq>: set FFT length to the smallest value which results in a freqequency resolution of <freq> Hz or better (default: 40.0)
`fftLength` | = <num>: set FFT length to <num> points (overrules default and 'resolution' option)
`windowSize` | = <dur>: set effective analysis window size to <dur> ms
`windowShift` | = <dur>: set analysis window shift to <dur> ms (default: 5.0)
`window` | = <type>: set analysis window function to <type> (default: BLACKMAN)
`order` | = <num>: set prediction order to <num> (default: sampling rate in kHz + 3)
`preemphasis` | = <val>: set pre-emphasis factor to <val> (default: -0.95)
`deemphasize` | (default: undo spectral tilt due to pre-emphasis used in LP analysis, i.e. TRUE)
`toFile` | write results to file (default extension depends on )
`explicitExt` | set if you wish to overwride the default extension
`outputDirectory` | directory in which output files are stored. Defaults to NULL, i.e. the directory of the input files
`forceToLog` | is set by the global package variable useWrasspLogger. This is set to FALSE by default and should be set to TRUE is logging is desired.
`verbose` | display infos & show progress bar

### Details

Short-term spectral analysis of the signal in <listOfFiles> using the Fast Fourier Transform and linear predictive smoothing. Analysis results will be written to a file with the base name of the input file and the spectrum type in lower case as extension (i.e. '.lps'). Default output is in SSFF format with the spectrum type in lower case as track name.

### Value

nrOfProcessedFiles or if only one file to process return AsspDataObj of that file

### Author(s)

Raphael Winkelmann

Lasse Bombien

### See Also

`dftSpectrum`, `cssSpectrum`, `cepstrum`; all derived from libassp's spectrum function.

### Examples

    # get path to audio file
    path2wav <- list.files(system.file("extdata", package = "wrassp"),
                           pattern = glob2rx("*.wav"),
                           full.names = TRUE)[1]

    # calculate lps spectrum
    res <- lpsSpectrum(path2wav, toFile=FALSE)

    # plot spectral values at midpoint of signal
    plot(res$lps[dim(res$lps)[1]/2,],
         type='l',
         xlab='spectral value index',
         ylab='spectral value')

[Package wrassp version 0.1.4 Index]