tuneR (version 0.2-6)

tuneR: tuneR

Description

tuneR, a collection of examples

Functions in tuneR

tuneR consists of several functions to work with and to analyze Wave files. In the following examples, some of the functions to generate some data (such as sine), to read and write Wave files (readWave, writeWave), to represent or construct Wave files (Wave), to transform Wave objects (bind, channel, downsample, extractWave, mono, stereo), and to play Wave objects are used. Other functions and classes are available to calculate several periodograms of a signal (periodogram, Wspec), to estimate the corresponding fundamental frequencies (FF, FFpure), to derive the corresponding notes (noteFromFF), and to apply a smoother. Now, the melody and corresponding energy values can be plotted using the function melodyplot. A next step is the quantization (quantize) and a corresponding plot (quantplot) showing the note values for binned data. Moreover, a function called lilyinput (and a data-preprocessing function quantMerge) can prepare a data frame to be presented as sheet music by postprocessing with the music typesetting software LilyPond. Of course, print (show), plot and summary methods are available for most classes.

concept

• Wave
• periodogram
• music

Examples

library(tuneR) # in a regular session, we are loading tuneR
  
# constructing a mono Wave object (2 sec.) containing sinus 
# sound with 440Hz and folled by 220Hz:
Wobj <- bind(sine(440, bit = 16), sine(220, bit = 16))
show(Wobj)
plot(Wobj) # it does not make sense to plot the whole stuff
plot(extractWave(Wobj, from = 1, to = 500))
play(Wobj) # listen to the sound

tmpfile <- file.path(tempdir(), "testfile.wav")
# write the Wave object into a Wave file (can be played with any player):
writeWave(Wobj, tmpfile)
# reading it in again:
Wobj2 <- readWave(tmpfile)

Wobjm <- mono(Wobj, "left") # extract the left channel
# and downsample to 11025 samples/sec.:
Wobjm11 <- downsample(Wobjm, 11025)
# extract a part of the signal interactively (click for left/right limits):
Wobjm11s <- extractWave(Wobjm11)
# or extract some values reproducibly 
Wobjm11s <- extractWave(Wobjm11, from=1000, to=17000)

# calculating periodograms of sections each consisting of 1024 observations,
# overlapping by 512 observations:
WspecObject <- periodogram(Wobjm11s, normalize = TRUE, width = 1024, overlap = 512)
# Let's look at the first periodogram:
plot(WspecObject, xlim = c(0, 2000), which = 1)
# or a spectrogram
image(WspecObject, ylim = c(0, 1000))
# calculate the fundamental frequency:
ff <- FF(WspecObject)
print(ff)
# derive note from FF given diapason a'=440
notes <- noteFromFF(ff, 440)
# smooth the notes:
snotes <- smoother(notes)
# outcome should be 0 for diapason "a'" and -12 (12 halftones lower) for "a"
print(snotes) 
# plot melody and energy of the sound:
melodyplot(WspecObject, snotes)

# apply some quantization (into 8 parts): 
qnotes <- quantize(snotes, WspecObject@energy, parts = 8) 
# an plot it, 4 parts a bar (including expected values):
quantplot(qnotes, expected = rep(c(0, -12), each = 4), bars = 2)
# now prepare for LilyPond
qlily <- quantMerge(snotes, 4, 4, 2)
qlily