affilter | R Documentation |
Filters the audio signal in listOfFiles
.
By specifying the high-pass and/or low-pass cut-off
frequency one of four filter characteristics may be
selected as shown in the table below. Per default a high-pass filter from 0 to 4000 Hz is applied.
The Kaiser-window design method is used to compute the
coefficients of a linear-phase FIR filter with unity gain
in the pass-band. The cut-off frequencies (-6 dB points)
affilter(
listOfFiles = NULL,
optLogFilePath = NULL,
highPass = 4000,
lowPass = 0,
stopBand = 96,
transition = 250,
useIIR = FALSE,
numIIRsections = 4,
toFile = TRUE,
explicitExt = NULL,
outputDirectory = NULL,
forceToLog = useWrasspLogger,
verbose = TRUE
)
listOfFiles |
vector of file paths to be processed by function |
optLogFilePath |
path to option log file |
highPass |
= |
lowPass |
= |
stopBand |
= |
transition |
= |
useIIR |
switch from the default FIR to IIR filter |
numIIRsections |
= |
toFile |
write results to file (for default extension see details section)) |
explicitExt |
set if you wish to override 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 |
of the filters are in the middle of the transition band. The filtered signal will be written to a file with the base name of the input file and an extension corresponding to the filter characteristic (see table). The format of the output file will be the same as that of the input file.
hp | lp | filter characteristic | extension |
'>0' | 0 | high-pass from hp | '.hpf' |
0 | > 0 | low-pass up to lp | '.lpf' |
'>0' | '>hp' | band-pass from hp to lp | '.bpf' |
'>lp' | '>0' | band-stop between lp and hp | '.bsf' |
nrOfProcessedFiles or if only one file to process return AsspDataObj of that file
Raphael Winkelmann
Lasse Bombien
# get path to audio file
path2wav <- list.files(system.file("extdata", package = "wrassp"),
pattern = glob2rx("*.wav"),
full.names = TRUE)[1]
# band-pass filter signal between 4000 and 5000 Hz
res <- affilter(path2wav, highPass=4000, lowPass=5000, toFile=FALSE)
# plot samples
# (only plot every 10th element to accelerate plotting)
plot(seq(0,numRecs.AsspDataObj(res) - 1, 10) / rate.AsspDataObj(res),
res$audio[c(TRUE, rep(FALSE,9))],
type='l',
xlab='time (s)',
ylab='Audio samples')
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