R: cepstrum

cepstrum {wrassp} | R Documentation

## cepstrum

### Description

calculate cepstral coeffisients using libassp

### Usage

    cepstrum(listOfFiles = NULL, optLogFilePath = NULL, beginTime = 0,
      centerTime = FALSE, endTime = 0, resolution = 40, fftLength = 0,
      windowShift = 5, window = "BLACKMAN", 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 frequency resolution of <freq> Hz or better (default: 40.0)
`fftLength` | = <num>: set FFT length to <num> points (overrules default and 'resolution' option)
`windowShift` | = <dur>: set analysis window shift to <dur> ms (default: 5.0)
`window` | = <type>: set analysis window function to <type> (default: BLACKMAN)
`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 cepstral analysis of the signal in <listOfFiles> using the Fast Fourier Transform. The number of coefficients per output record will also equal the FFT length / 2 + 1 (i.e. be non-mirrored). Analysis results will be written to a file with the base name of the input file and as extension '.cep'. Default output is in SSFF format with 'cep' 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`, `lpsSpectrum`; 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]

    # calulate cepstrum
    res <- cepstrum(path2wav, toFile=FALSE)

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

[Package wrassp version 0.1.4 Index]